Xa/oocU Hole, hWs .

)Ih h\eVnot»\( op
IPrtseitta IBraf slmltWgoMet^

1874-195^

W(Pe op TKowt^srHa*Hsoh Montgfomettj
SVudent ^ frt eh\bNjolo<|(j1897, tuYd coupes 1 90S
In summed ctox*ses, 19 H IVoucjK 1915

Assfstav* Ubrarfan, 1919-1924
UbNMrtah, 1925^-1947

The^ebooksfWeVe purchased b^j Vneans

ofafutid CohtHbidTed b\| fHends

(H appfecTatton of. her vifel paH

^^^

o

□
b- 1

□
CD

Ln

ru

;x

Vol.2.

Pvn

H,i I'UitlS

,1 1

Published hy J VauVc 3 65.

»

BRITISH CONCHOLOGY,

OR AN ACCOUNT OF

THE MOLLUSCA

WHICH NOW INHABIT THE BRITISH ISLES AND THE

SURROUNDING SEAS.

VOLUME II.

MARINE SHELLS,

COMPRISING THE BRACHIOPODA,
AND CONCHIFERA EROM THE FAMILY OF ANOMIIDJE

TO THAT OF MACTKID^E.

By JOHN GWYN JEFFREYS, F.R.S., F.G.S., &c.

LONDON:

JOHN VAN VOORST, PATERNOSTER ROW r .

MDCCCLXIII.

[The right of Translation if reserved.}

PRINTED IJY TAYLOR AND FRANCIS,
RED LION COURT, FLEET STREET.

■ ■ ,

1 *< ^

INTRODUCTION,

Since the publication of the first volume of this work
I have made two more dredging-excursions to the
Shetland Isles, a district which is by far the most
interesting that I know of for the further investigation
of the British Mollusca. In the interval I revisited the
South of France, and also went to the Hanse towns,
Denmark, Sweden, and Norway, for the express purpose
of examining public and private collections of Euro-
pean shells, and especially the types of species described
by O. F. Muller and subsequent writers on Scandinavian
conchology. Every naturalist will appreciate the ad-
vantage of such an undertaking, being aware that our
own fauna or flora cannot be properly studied apart
from that of the rest of Europe. These preliminary
remarks are offered to explain the cause of delay in
the appearance of the present volume, and likewise to
express my grateful acknowledgments for the kind
welcome and aid which I received from all the leading
zoologists in the countries above mentioned. Nor ought
I to omit a renewal of my thanks to many of my own
countrymen, who have again most liberally placed their
collections at my disposal and favoured me with valu-
able communications. I will now endeavour to profit
by the opportunities I have thus enjoyed, in extending
the list of our native Testacea, as well as in revising the

75033

IV INTRODUCTION.

synonymy and defining the range of previously known
species.

And here let me say a few words about the adoption
of names,, whether of genera or species. I would pre-
mise by stating that I am averse to unnecessary inno-
vation. All names which have been generally used,
and which may therefore be said to be established or
familiar, ought never to be changed, except for the
strongest reasons. To substitute new names for these
would be manifestly inexpedient and lead to much con-
fusion. Even the ground of priority is in most cases no
excuse for altering and unsettling the accepted nomen-
clature; and the attempt to revive old, obscure, and
long-forgotten names cannot be too strongly deprecated.
It is forbidden to disturb the ashes of the dead. But
no task is more difficult to the naturalist, or more open
to criticism, than the selection of names, where more
than one are still used by different authors for the same
genus or species. He has to perform the functions of
both judge and jury, and not only to weigh carefully
the evidence for and against the retention of any name
thus put upon its trial, but also to administer strict and
impartial justice, according to the laws of scientific ter-
minology. Besides, it must not be forgotten that the
nomenclature used by scientific men in other countries,
where many branches of natural history are cultivated
not less assiduously or successfully than in Great Britain,
does not altogether agree with ours. The utmost pains
ought to be taken to reconcile or lessen the difference
between us and them in this respect, so as to ensure as
much uniformity as possible. Naturalists of all coun-
tries are members of the great commonwealth of science,
and their technical language is the same. Our patriotic
feelings, although commendable in other matters, ought

INTRODUCTION. V

to give place to the higher object of serving the general
cause, while investigating the works of the Creator.

The favourable reception given to the preceding
volume has encouraged me to persevere in the attempt
to make this work readable by all, and at the same time
useful to my brother conchologists. The advice of our
old friend, Horace, should not be neglected by any

writer :

Onine tulit punctum, qui miscuit utile dulci
Lectoreni delectando pariterque monendo.

All that relates to Nature is in itself so delightful,
and the pursuit of it elicits so many of our best and
truest feelings, that every undertaking of this kind
ought to be imbued with the sentiment inculcated by
the above maxim, instead of repelling students by too
much technicality. The author and his readers have a
joint property in the subject-matter, and they are held
together by the same tie of sympathy.

" Pleasure is spread through the earth

In stray gifts to be claimed by whoever shall find."

Our communion with GrOD, through His works, affords
one of the purest and most unalloyed of pleasures that
is permitted to us in this transitory state. Even the
mere contemplation of them, in any of their various
aspects, if it is made in a fitting mood, assures us, much
more forcibly than human teaching can, that our minds
— our spirits — our souls partake of His eternity and are
imperishable. This idea has pervaded all men and in
every age. It is innate and ineradicable.

At the same time it cannot be denied that novels,
magazines, and newspapers constitute now-a-days the
literature which chiefly occupies the small reading-time
of the public, and that scientific books generally are

VI INTRODUCTION.

overlooked, unless they advance some startling proposi-
tion as to the origin or remote antiquity of our own
race. There can be no use, however, in blaming the
popular taste ; nor would it be reasonable to expect that
every one should follow a scientific path, if his inclina-
tions do not lead him that way. The love of Nature
is not confined to any one period, and its votaries must
not feel disappointed, should their peculiar studies not
be shared by all their contemporaries.

Before entering into the details of our marine Mol-
lusca, I would make a few more remarks as to their
distribution and structure. This I was prevented from
doing in the introductory part of the former volume by
an anxiety not to impose too long an exordium on the
patience of my readers.

The sea-bed may be said, in the technical language of
lawyers, to be u land covered with water." Its outline,
if it could be viewed through an aquatic telescope, would
be seen to be irregular, and nearly as much diversified
as the surface of the earth. Mountains, hills, rocks,
gorges, valleys, and plains would be successively exhi-
bited in the submarine panorama, having often the same
bold and abrupt contour that gives so picturesque an
aspect to land scenery. Oceanic and tidal currents
represent rivers, corresponding with them in volume and
rapidity, and equally scooping out channels of various
degrees of width and depth. But we have good reason
to believe that lifeless deserts, like the great Sahara, are
wanting below the broad watery girdle which encircles
the globe and covers at least three-fourths of its extent.
It is true that, in certain inlets or arms of the sea, rivers
flowing into them may have sufficient strength and
velocity to sweep the middle of the channel, and thus
prevent the deposit of mud or other sediment which

INTRODUCTION. Vll

would afford the necessary shelter or food to certain
animals. Indeed the continual motion of the stream
and the destructive property of fresh water might pre-
clude the possibility of any marine animals existing
within the prohibited area ; and in that case the central
bed of the channel would be partially covered with clear
sand, devoid of organic remains. An instance of this
kind has been given by Dr. Wallich in his account of
Hamilton's Inlet, Labrador "*. Such cases, however, are
exceptional ; and the limits of these areas are very cir-
cumscribed. Manv kinds of Invertebrata are known to
flourish in the most rapid tideways, and even in whirl-
pools; and the water of the ocean everywhere teems
with life. The dredge has never failed to bring up
some organisms from every part of the sea-bed which
has been hitherto explored. However unpromising it
may at first sight appear, the cleanest-looking sand
taken from any depth of water, and carefully examined
by the aid of a lens or microscope, will be found to con-
tain structural forms. Having these facts and a certain
degree of experience to guide us in the inquiry, it would
be a hasty assumption that any geological strata of
comparatively recent formation, which do not contain
fossils, are of marine origin. Whether the absence of
fossils from particular strata may be attributable to
chemical absorption or decomposition is a question
which must be decided on other grounds. Let Mr.
Sorby be the exponent. Until more is known of this
difficult and interesting subject, we may suspend our
judgment as to any formation being either azoic or pro-
tozoic. The presence of scarcely more distinct traces of
life than a few worm-casts in our lowest Silurian rocks
does not prove the improbability, much less the impos-
* ' The North-Atlantic Sea-bed,' p. 49.

Vlll INTRODUCTION.

sibility, of many other and more perfect structures
having been formed elsewhere at the same early period
of the world's history. The maxim " de non apparen-
tibus et non existentibns eadem est ratio - " is scarcely
applicable to geological cases of this nature.

The conditions which exist in one part of the sea-bed
are often quite different in another part. The late Pro-
fessor Forbes, in his valuable Report to the British
Association in 1843 on the Invertebrata of the iEgean,
stated his belief that the zero of animal life was pro-
bably about 300 fathoms, because his dredgings in that
sea at a depth of 230 fathoms yielded but very few
species. But in other tracts of the ocean living animals
of various kinds have been repeatedly obtained from far
greater depths. Our knowledge of abyssal life is only
checked by the difficulty of such explorations and by
the imperfect nature of our means of discovery. It is
a high and worthy object of the naturalist's ambition,
and by no means devoid of general interest.

" There is a magnet-like attraction in
These waters to the imaginative power
That links the viewless with the visible,
And pictures tilings unseen."

Speculations of this kind were not unknown to the
ancients. In the f Halieutica \ of Oppian, written nearly
seventeen centuries ago, it is stated that no one had
found the bottom of the sea ; and that the greatest depth
ascertained by man was 300 fathoms, where Amphi-
trite had been seen. But this grand discovery does
not seem to have satisfied the poetical philosopher, and
he enters into a long disquisition as to the many other
wonderful things that may be concealed in the recesses
of the boundless ocean — adding, however,

" . . i . . oXtyos $e voos fiepoireGOL tcai okici}.

i. "

INTRODUCTION. IX

Torell and W allien, fortunately for science, were re-
gardless of the consequences which, according to M.
Michelet (in his charming rhapsody of "La Mer"),
would ensue on their " curiositd sacrilege;" and, with
anxious gaze " eyeing the sea's blue depths," they have
dared to cross its mysterious threshold. To one of
these enterprising philosophers is perhaps reserved the
privilege of announcing, in the words of the poet,

. . . . " Lo ! the polar seas
Unbosom their last mysteries."

The glimpses which they succeeded in obtaining were

few and transient ; but we now know that the great

ocean-depths are inhabited by a variety as well as an

abundance of living animals, some of which are of no

mean rank in the scale of classification. Wordsworth

Was not wrong in his divination when he also said,

" Her procreant vigils Nature keeps
Amid the unfathomable deeps."

I have lately had, through the kindness of Dr. Wal-
lich, an opportunity of examining some of the material
brought up in his North- Atlantic soundings. One of
these yielded several dead shells of Mollusca, as well as
Globigerin(B and other Foraminifera, from the extra-
ordinary depth of 1622 fathoms, or nearly two miles !
This sounding was taken in lat. 55° 36' N., long. 54°
33' W., and about 100 miles N.W. of Hamilton's Inlet.
Crenella faba, one of the species of Mollusca thus ob-
tained, was dredged by Dr. Wallich on the adjacent
coast, at a depth of from 18 to 40 fathoms only; and it
is not uncommon on the shores of the Polar and Arctic
seas. The other species of Mollusca inhabit deep water ;
and one is undescribed. It may be conjectured that
these shells were dropped from the bottom of a melting
iceberg on its passage to the south ; but as icebergs take

X INTRODUCTION.

up only stones and earth from the land, like the moraine
of a glacier, such a conjecture does not seem to be en-
titled to much weight. An iceberg might certainly be
stranded, and thus pick up shells ; but it would in all
probability be dissolved on the spot in the course of time.
Its bulk and weight are too great to admit of its floating
off again under such circumstances as I have supposed.
It is, indeed, within the bounds of possibility that the
shells might have been collected on the shore by coast-
ice, and carried off to sea ; but Dr. Wallich informs me
that this kind of ice has never been known to travel so far
southward as the locality above mentioned. There is
much greater probability that the mollusca in question
lived and died on the sea-bottom where their remains
were found. Every one who considers the importance of
these researches ought to read and study Wallich's trea-
tise on the North- Atlantic Sea-bed, and especially the
chapter on the bathymetrical limits of animal life in the
ocean. He will find the subject treated in a philosophical
and masterly style ; and the account of living starfishes
having been discovered at a depth of 1260 fathoms in
the open sea, and also the geological application of that
discovery, especially deserve attention. Until of late
years the use of the dredge, as an instrument of zoolo-
gical research, was nearly unknown. All that natu-
ralists did in former times was to examine the refuse of
trawl nets, which seldom reached a depth of 20 fa-
thoms ; or now and then fishing-lines of more than twice
that length brought to the surface a few shells and
corals which were accidentally detached from the bottom
of the sea. These specimens (as Professor Forbes said)
" only served to whet our curiosity, without affording
the information we thirsted for." Now-a-days, how-
ever, the dredge is a scientific necessity ; and scarcely

INTRODUCTION. XI

any part of the ocean, from one pole to another, has
been exempt from its operations.

The level of the earth everywhere is continually
changing. That of the sea is, on the contrary, fixed;
and although we are accustomed to speak of its ad-
vancing and retiring, the only motion it has of this
kind is occasioned by the tides, and is never permanent.
Sea and earth may be compared to two sisters, the elder
one staid and sedate, the younger giddy and fickle.
The solidity of the earth and capriciousness of the sea
are poetical terms, but incorrect in a geological point of
view. Poetry and Geology have seldom much in com-
mon. It is a striking fact, that every part of the earth's
surface which is now habitable or dry, has at more
periods than one formed the bed of the sea :

" Each changing place with that which goes before,
In sequent toil all forwards do contend."

There is not an individual particle of this crust but what
has been often shifted and transformed ; and the phases
of a kaleidoscope are not more varied than the configu-
rations which have resulted from such changes since
time commenced its task of revolution. The inevitable
recurrence of similar fluctuations will assuredly make
our rich and favoured isle again the seat of watery
wealth — although it may not be laid waste by a deluge
such as Horace describes,

" Omne quum Proteus pecus egit altos

Visere montes,
Piscium et summa genus luesit ulmo,
N ota quae sedes fuerat columbis,
Et superjecto pavidre natarunt

iEquore damae."

Not long afterwards Manilius (who was a better geo-
logist than Horace) showed the reverse of the medal : —

Xll INTRODUCTION.

" Emersere fretis montes, orbisque per uudas
Exiliit, vasto clausus tamen undique ponto."

Such theories appear to have been first propounded by
Straton, the successor of Theophrastus in his school ;
and they were improved by Herodotus, and still more by
Strabo, who gave numerous instances of the changes of
sea and land. But it is not a mere theory, that what
has been will be ; and our own Shakespeare has pro-
phetically illustrated this idea in one of his exquisite
sonnets : —

" When I have seen the hungry ocean gain
Advantage on the kingdom of the shore,
And the firm soil win of the wat'ry main,
Increasing store with loss, and loss with store ;
When I have seen such interchange of state.
Or state itself confounded to decay ;
Ruin hath taught me thus to ruminate —
That time will come " —

Sea and land are in some respects convertible terms ;
and the epithet of " earth-embracing," given to the
former, conveys only an indistinct notion of their close
and inseparable union. One cannot exist without the
other. They contain many of the same iugredients. But
the sea is the main depository of all soluble matter;
and the greater number and bulk* of marine testacea,
compared with those which inhabit the land, may be
thus accounted for. The quantity of calcareous matter
from which the continual and immense construction of
shells is derived, appears to be infinitesimally small.
Liebig has calculated that sea-water contains only x 2 ^ -
of its weight of carbonate of lime, this being the princi-
pal ingredient of molluscous shells. How little do we
appreciate the action and effect of elements which are

* I have seen a specimen of Tridacna gig as, from Amboyna, said to
weigh 3 cwt. 3 qrs.

INTRODUCTION. Xlli

insignificant in themselves but inconceivably important
in their consequences ! — a consideration which is not less
applicable to moral than to physical nature. Paley in
his ( Natural Theology ' quaintly remarks, with regard
to the proportion of space occupied by the sea and land,
" I know not why the sea may not have as good a right
to its place as the land." No more do I. Each un-
consciously fulfils the peculiar function assigned to it
from the commencement by an allwise Providence. No
one can reflect on the innumerable and various trans-
formations which both have since undergone, without
being convinced that their creation and inherent forces
must be due to an extraneous cause. Palev's watch
is out of fashion ; but those of my readers who admire
— and who does not? — the still more antiquated but
equally devout writings of the " Father of English
Poets" will, I feel sure, not object to be reminded of
his sentiments on the same topic. They are in the Pro-
logue to his ' Testament of Love/ and as follows : —

"Nowe principally the mene to brynge in know-
leging and lovynge his creatour, is the consideracyon of
thynges made by the creatour, wher through by thylke
thinges that ben made, understandynge here to our
wyttes, arne the unsene pryvities of God made to us
syghtfull and knowinge, in our contemplacion and
under stondinge. These thinges than forsoth moche
bringen us to the ful knowleginge sothe, and to the

parfyte love of the maker of hevenly thynges

it is a grete likynge in love of knowinge ther cretoure :
and also in knowinge of causes in kindelye thynges,
considrid forsothe the formes of kindelye thinges and
the shap, a gret kyndely love we shulde have to the
werkman that 'hem made. The crafte of a werkman is
shewed in the werk."

b

XIV INTRODUCTION.

Who that breathes, and is endued with the powers

that so widely separate man from the brute, can for one

instant withhold his acknowledgment of an omnipresent

Being, which is sensibly spread

" o'er all that glides

Beneath the wave, yea, in the wave itself,
And mighty depth of waters " ?

I will now resume the special purpose of this work,
commencing with the Brachiopoda, as having the lowest
organization, and advancing upwards to the higher or
more perfect Mollusca. The descriptions of the ani-
mals or soft parts will, I regret to say, be sometimes
scanty and occasionally wanting. They are principally
taken from the observations of the late Mr. Clark and
Professor Forbes, Mr. Alder, and myself. My deficien-
cies in this respect will, I trust, stimulate other natu-
ralists to supply the desired information ; and I would
especially invite the assistance of those who have an
aquarium, and opportunities of keeping it supplied from
the various parts of our extensive seaboard. Every fact,
however trivial, is worth recording, because (even if it
is not new) it may be useful for the sake of confirming
the accounts given by other naturalists. Most of the
illustrations of molluscous animals in this volume have
been copied from the plates in Forbes and Hanley's
work, or engraved from original drawings by Mr. Alder.
For the figures of Crania, Crenella, and Cyamium I
am indebted to Dr. Saxby, and for that of Pinna to
Mr. Spence Bate.

The 1st Class, or Conchifera, has been described in
the first volume, so far as it relates to the freshwater
Mollusca ; and the only other division of the Acephala
is the Brachiopoda, which will now be noticed.

Class BRACHIOPODA*.

Body compressed, of an oval or occasionally a circular form,
contained within the two valves of a shell, which are in most
cases connected behind by a hinge, but never by a ligament or
cartilage. The shell is inequivalve, and furnished inside with
a complicated skeleton for supporting the arms, which will
be presently noticed. The mantle is divided into two lobes,
and its outer edge is fringed with a row of extensile tentacles,
every one of which has at its root or base a coloured spot,
which may be a rudimentary eye. Each lobe contains a folded
or spirally coiled arm, which is furnished with one or more
rows of flexible cirri or filaments. The animal is destitute of
a head or foot ; but it has a slit-shaped mouth behind the
arms, an excretory tube, a stomach, several vesicles which
serve the purpose of a heart, nerves, muscles, liver, and repro-
ductive organs. The circulatory system is supplied by the
mantle and arms, there being no gills. It is supposed by some
writers that both sexes are united in the same individual ; but
this is doubtful. In the majority of cases (e. g. Terebratididce)
the animal is attached to extraneous bodies by a fibrous stalk
or peduncle, which is placed at the back, and penetrates the
upper or convex valve ; while in others (e. g. Craniidce) it is
usually affixed by the outer surface of the lower valve, which
is flat.

This remarkable and peculiar Class is nearly equal in
value to the Conchifera (see vol. i.) as regards the im-
portance of its structural characters ; and, although it
does not contain so many species, they are quite as
abounding in individuals. In point of antiquity it is far
superior,

" of ancestrv

Mysteriously remote and high;"

and not even a Welshman, who would place Adam in
the middle of his genealogical tree, can boast such a

* From an erroneous notion that their feet take the shape of arms.

2 BRACHIOPODA. *

lineage. The Lingula-hed of the upper Cambrian system
is well known ; and other palaeozoic strata contain
equally rich mines of similar wealth. But although
the number and variety of recent Brachiopoda are not
equal to those of former days, the difference does not
appear to be so great as has been usually represented.
Mr. Davidson, who is perhaps the greatest authority on
the subject, says that there are 20 Silurian, 25 Devo-
nian, 19 Carboniferous, 12 Permian, 12 Triassic, 14 Ju-
rassic, 12 Cretaceous, 10 Tertiary, and 14 recent genera
and subgenera; so that we seem to have improved
in this respect on the middle ages, and future genera-
tions may exhibit a further advance, and even rival the
primeval era. The comparative rarity of Brachiopoda
in modern times may be easily accounted for. They
mostly inhabit rocky and stony parts of the sea-bed,
which cannot be reached by the dredge without great
risk of its being lost or injured, although they are gre-
garious and occur in vast numbers under favourable
circumstances. My late friend, Dr. Lukis, found more
than 200 specimens of Argiope cistellula on a single
stone brought up from a depth of 20 fathoms off Guern-
sey; and I have myself repeatedly taken Terebratula
caput -serpentis and Crania anomala in such profusion
on the western coasts of Scotland, as to be compelled
by a sheer embarras des richesses to throw many
hundreds overboard in the course of a day's dredging.
Even the comparatively rare T. cranium is no exception.
I have counted seventy specimens, although broken and
imperfect, which came up in a single haul off the Shet-
lands. Terebratella Spitzbergensis, which was at first
accounted extremely scarce, now appears, from Dr. Otto
Toreirs researches, to be by no means uncommon in its
native haunts ; and I lately picked up two or three fossil

BRACHIOPODA. 6

specimens of it at Uddevalla, in the course of a short
exploration of the raised sea-bed in that remarkably in-
teresting place. T. septata (or septigera), as regards the
frequency of its occurrence, may be placed in the same
category. The examination of fossiliferous strata is
attended with no risk, and the specimens are procured
without much difficulty; but I much doubt if we should
not find in a modern sea-bed, of the same extent and
having similar conditions, a collection of Brachiopoda
fully equal in number and variety to those contained in
any one Palseozoic, Mesozoic, or Cainozoic formation.
So many recent species have been made out of solitary
or a very few specimens, that it is evident much remains
to be known of this curious group as it at present exists.
Being individually numerous, and comparatively low in
the scale of organization, the tendency to variation is
of course great. An examination of nearly all the types
of recent species induces me to suggest the necessity of
a complete revision of these so-called species.

This group has been for more than half a century a
favourite study of naturalists. Pallas, Cuvier, De Blain-
ville, Owen, Quenstedt, Deshayes, Yogt, Forbes, Hux-
ley, M. J. Muller, Schmidt, Deslongchamps, Carpenter,
Barrett, Woodward, Gratiolet, Hancock, F. Muller,
Macdonald, Lacaze-Duthiers,and Shaler have at different
periods contributed a vast store of information as to the
structure of recent Brachiopoda; while De Koninck,
D'Orbigny, M'Coy, King, Davidson, Suess, and other
able palaeontologists have made us acquainted with the
fossil forms. Mr. Reeve has also rendered some good
service in respect of the synonymy and geographical dis-
tribution of existing species. Mr. Hancock's valuable
paper " on the Organization of the Brachiopoda " will
be found in the c Philosophical Transactions' for 1858.

b 2

4 BRACHIOPODA.

It deservedly gained him the Royal medal, and is the
more praiseworthy because he never, I believe, had the
good fortune to see a living specimen. This oppor-
tunity, however, has frequently occurred to me ; and I
will endeavour, with the aid of Mr. Hancock's and other
treatises, to present a few remarks on the structure and
habits of this extraordinarv class.

It has been usual to consider the valves of the shell
in Terebratula as covering the front and back of the
animal, the perforate valve being ventral, and the imper-
forate valve dorsal. When the Terebratula is attached
by its peduncle the perforate valve is uppermost. But
the analogy between the Brachiopoda and the Verte-
brata is very slight. The back of a Terebratula is really
that part which lies behind the arms and mouth, and is
close to the apex or point of attachment. Instead,
therefore, of calling the valves " ventral" and " dorsal,"
it would seem more correct to describe them as "upper"
and " lower " — the larger and deeper valve being perfo-
rate and uppermost, and the smaller and shallower valve
being imperforate and lowermost. In the Brachiopoda
the valves are articulated across the back ; in the Con-
chifera the valves are united by a ligament or cartilage
along the back. The arms occupy two-thirds of the
shell. They resemble the mainspring of a watch, and
are not capable of being protruded or unrolled. I have
never observed the cirri, with which they are clothed,
to project much beyond the edges of the shell in the
living animal. The great extent of these brachial organs
is very remarkable. In Rhynchonella psittacea the arms,
when forcibly stretched out, are said to be more than
four times the length of the shell, and to support about
3000 cirri. In Terebratula caput-serpentis the cirri
open and fold together somewhat like a butterfly-net.

BRACHIOPODA. O

Mr. Hancock is of opinion that "the brachial organs
subserve the function of gills, as well as that of respira-
tion." As far as I could judge from the examination of
living specimens of T. caput-serpentis, the inner folds of
the mantle appeared to have the same action as that of
the gills in many Lamellibranch Mollusca. The name
of Palliobranchiata was given to the class now under con-
sideration in consequence of a belief that their respiratory
system was dependent on the mantle. Mr. Macdonald
has shown, in the l Linnean Transactions ' (xxiii. p. 375),
that the pallial sinuses serve as organs of circulation.
Some of this class have calcareous spicula or plates in
the mantle, as well as in the arms and cirri. In Tere~
bratula caput -serpentis these spicula are very numerous,
large, and often branched like the antlers of a deer ; and
they form an extensive though incomplete network.
Their use is doubtless the same as that of the spicula in
sponges, viz. to strengthen and support the tissues of
the animal, and especially to protect the delicate canals
of the mantle from the pressure of the external fluid.
Under a microscope with polarized light these spicula
are remarkably beautiful objects. The pallial tentacles
resemble those of Anomia. When the animal is dead and
dried up, they are stiff from contraction, and of a horny
texture, for which reason they have been called sette or
bristles. The muscular system is well developed, and
admirably adapted to the complicated machinery by which
the animal opens, closes, and moves the valves of its shell.
Dr. Carpenter was the first to point out and explain a
very singular apparatus of canals or cylindrical holes
observable in the shells of Terebratula and other allied
genera, which are occupied by tubular appendages of
the mantle and closed on the outside. These processes
penetrate every part of the shell, but their function has

6 BRACHIOPODA.

not been satisfactorily made out. Mr. Hancock sup-
poses that they maintain the vitality of the 'shell, and
that perhaps by their means any injury to it may be re-
paired. Some provision of this sort appears to be neces-
sary, because the Brachiopods do not, to any great ex-
tent, thicken their shells by successive internal layers,
like bivalve Mollusca. The shells of the Brachiopocla
are never provided with an epidermis ; and this may also
account for their perforated structure. Many bivalve
shells, such as those of Astarte, from which the epider-
mis has been accidentally removed, peel off, or become
eroded near the beaks to such an extent that, if new
layers were not continually being secreted from within,
the animals would be laid bare and exposed to untold
dangers. Sponges, Balani, Serpulce, and other extra-
neous organisms are often seen covering or attached to
the shells of Terebratulce. The hinge in the articulated
kinds is so firmly interlocked, that it is impossible to
separate the valves without using a slight degree of force.
They appear to be in some measure sensible of light.
Lacaze-Duthiers gives an instance of Thecidia collapsing
suddenly when his shadow passed between them and the
sun. He succeeded in keeping these curious Brachio-
pods, in a lively and active state, for six weeks by merely
changing the water every day. The sexual nature of the
Brachiopoda is not quite determined. Dr. Gratiolet sug-
gests that the same individuals may become successively
male or female at different periods. Mr. Hancock con-
siders Lingula, at least, to be androgynous or monoecious ;
and he infers from analogy that both sexes are combined
also in the articulated Brachiopods. But Lacaze-Duthiers
has investigated this part of the subject more recently
and under circumstances more favourable than seem to
have fallen to the lot of any other writer. His elabo-

BRACHIOPODA. 7

rate essay on the Thecidium Mediterraneum will be
found in the ' Annales des Sciences Naturelles' for 1861,
and is the first of a series of monographs on the organi-
zation of the living Brachiopoda. He asserts most con-
fidently that the Thecidia are of different sexes, and
that the male and female can be distinguished even bv
their shells. According to his observations the embryo
of Tliecidium is divided into four distinct lobes, and it
has sometimes two, and at other times four eye-spots.
"When separated from the peduncle by which it is
attached, it swims or whirls head foremost by means of
vibratory cilia which cover the body. Fritz Miiller had
previously described in Wiegmann's Archiv (xxvii. p. 53)
the fry of a Brazilian Brachiopod. He says it was enclosed
in a bivalve shell like the adult, and that its structure
was the same, except in having two eyes and in wanting
the reproductive and circulatory organs. The arms were
covered with a complete coat of cilia, by the action of
which the little creature swam. It could also creep ;
and this was effected by a semirotatory movement
alternately to the right and left, and by pushing itself
along: bv means of the bristles or setae which fringe the
edges of the mantle, and upon the strongest of which it
would occasionally support itself while resting. The
Brachiopoda are extremely prolific, and their countless
eggs are of a spherical shape. After quitting the em-
bryonic state, they become invariably and permanently
fixed to other substances, being incapable of any other
motion than making a half-turn round the peduncle or
pivot. Their food consists of Infusoria or other minute
organisms. Milton has, with his usual felicity, de-
scribed the present animals as those which,

" in their pearl}- shells at ease, attend

Moist nutriment."

8 BRACHIOPODA. *

Some Terebralula: which I watched for a long time
seemed, however, to be more active than passive in
feeding. They were incessantly opening and folding
their cirrons arms, and drawing or sncking in, by means
of the whirlpool thus caused, every animalcule within its
influence. The action reminded me of that of a Bar-
nacle, the only difference being in the position of the
arms, which in Balanus are placed in front, and in
Terebratula on the sides of the animal. Possiblv Cuvier's
notion that the Brachiopods do not differ much from
the Cirripeds was correct, although the relationship be-
tween them may be one of analogy rather than of
affinity. Very lately Dr. Gratiolet has expressed an
opinion that the Brachiopods are allied to the Crus-
tacea in respect of their vascular system, and not to the
Mollusca, or least of all to the Tunicata. Milne-Ed-
wards has included them with the Tunicata and Poly-
zoa, in his Class " Molluscoida." Lacaze-Duthiers sepa-
rates them from the Acephala mainly on embryogenic
grounds, remarking that the difference in this respect
between the Brachiopoda and Acephala is as great as
between the latter and the Gasteropoda. In this contro-
verted and unsatisfactory state of our knowledge, it
would seem best to retain them for the present in the
great kingdom of the Mollusca, as a class of coordinate
value with the Conchifera, — the Pteropoda and Gastero-
poda forming another and equally poised group. The
Brachiopoda have certainly some features in common
with the Tunicata, as well as with the Conchifera ; but
they differ essentially from both in having cirrous arms,
in which latter respect they resemble the Cirripedia.
The perforated structure of their shells agrees with that
of the Balanidce, and also of the Polyzoa. They are con-
fessedly anomalous, and to a certain extent sui generis.

BRACHIOPODA. 9

The Brachiopods inhabit all the zones of vertical
depth. The Rev. M. J. Berkeley found a living speci-
men of Terebratula caput-serpentis attached to a rock
at low- water mark, on a part of the Scotch coast where
the tide falls only a few feet ; I have taken the same
species by dredging at various depths from 3 to 90
fathoms; M f Andrew and Barrett obtained T. cranium
alive at 160 fathoms; and Dr. Wallich has shown me
a shell of the last-named species which was brought
up by sounding off the east coast of Greenland in 228
fathoms. The nature of the sea-bottom, more than the
depth of water, determines the limit of their habitability.

This class has two great and distinct types of form,
viz. the jointed and hingeless, although a fossil genus
(Davidsonia) is considered by M. Bouchard- Chantereaux
to form a connecting link between them. The above
distinction was first noticed and proposed by M. Des-
hayes, and it is founded on malacological as well as
conchological characters. By far the greater part of
the Brachiopoda (including the Terebratulidce) belong
to the former section, while the other comprises only
Crania, Lingula, and a few more genera. Both of
these types or sections are represented in the British
fauna.

5"

i

B O

10 TEREBRATULIDjE.

* Jointed.

Family I. TEREBRATU'LID.E, Gray.

Body oval : arms folded back, and supported either by shelly
processes issuing from the hinge of the lower valve, or by lon-
gitudinal septa or partywalls in that valve : attachment formed
by a peduncle, which passes through a hole in the upper valve.

Shell longitudinally or transversely oval, more or less con-
vex : skeleton or apophysary system consisting of riband-shaped
plates, which are frequently looped or united : hinge formed of
two side-teeth in the upper valve, which lock into sockets in
the lower valve : muscular scars slight and seldom visible.

This family is very numerous and diversified in cha-
racter, and it is also widely dispersed both in space and
time. Some of its members occur in every sea, from
the arctic to the antarctic pole ; and its geological
range appears to include all the known strata, from the
Silurian to those which are now in course of forma-
tion. Colonna in 1616 was the first to use the name
Anomia, and applied it to species of Terebratula j and
Linne and other naturalists of the old school also placed
them in the former genus, because they are attached to
extraneous substances by a fibrous tendon passing
through one of the valves of the shell. But although
the analogy holds good to a certain extent, it is not
complete. In this section of the Brachiopoda the upper
valve, and in Anomia the lower valve is thus perforated,
to say nothing of the very different organization of the
animal and internal structure of the shell. Systematists
are not yet agreed as to the number of genera into
which this large family ought to be divided, nor whether
any or how many subgenera are allowable. Either mode
of distinction, however, is clearly artificial, and used
merely for the sake of convenient classification. As

TEREBRATULA. 11

our indigenous species are very few and reducible to
two types, I do not wish to burden the nomenclature
more than can be helped, and I therefore propose to
adopt the genera Terebratula and Argiope only. These
appear to have sufficiently definite characters by which
one may be distinguished from the other.

Genus I. TEREBRA'TULA*, Lhwyd. PI. I. f. 1.

Body convex : mantle free at its outer edges.

Shell acutely triangular: beak prominent: foramen, or
byssal perforation, small : hinge-line curved : skeleton consist-
ing of horizontally projecting blades, which are often looped.

There are only two British species, and for these as
many genera have been proposed by some authors. I
will arrange them in sections.

A. Shell smooth : skeleton consisting of two long blades, which
are not looped or connected. (Waldheimia and Macaa-
drevia, King.)

1. Terebratula cra'nium^ Miiller.

T. cranium, Mull. Zool. Dan. Prodr. p. 249, no. 3006 ; Forbes & Hanley.
vol. ii. p. 357, pi. lvii. f. 11.

Body cream- colour, with a brownish tinge : mantle thin ;
tentacles rather short, with small brown tubercles at their
base : arms dark brown ; cirri rather short : peduncle short
and compact.

Shell oval, with sometimes a squarish outline, convex,
rather thin, slightly lustrous : sculpture, smooth to the naked
eye, but very closely tubercled when examined with a mag-
nifying-power : colour white: margins compressed, often trun-
cate and sometimes flexuous in 'front : beak rather prominent,
but short, worn by rubbing against the stone or other hard
substance to which the shell is attached : foramen oval, in-

* From the hole in the shell.

t From a fancied resemblance of the shell to a human skull.

12

TEREBRATULID.E.

complete at the lower end : deltidium (or triangular space be-
low the beak) slight, and divided by the point of the lower
valve: lunge-plate of both valves exceedingly thick, forming
strong supports for the teeth and lamellar processes ; from
these processes extend into the interior two diverging ridges
or septa in the upper valve, and three or more in the lower
valve : teeth of upper valve very strong and projecting towards
each other : sockets in lower valve deep : skeleton consisting
of two thin and elastic blades, which reach within about one-
fourth of the front margin ; they are furnished with upright
spurs at a short distance from the hinge-plate, and have sharp
points. L. 1. B. 0-8.

Yar. oblonga. Shell much narrower and deeper than usual,
and having the front margin nearly straight.

Habitat : Rocky and stony ground, from 50 to 90
fathoms, on the north and east coasts of Shetland, but
exceedingly rare in a living state. More than fifty years
ago, when the late Professor Fleming was Minister of
Bressav Island, a stone was brousrht to him by one of
his parishioners, a long-line fisherman, to which three
specimens of this curious shell were attached. One of
them was sent to Col. Montagu, who described it in the
eleventh volume of the f Linnean Transactions/ My
late friend Mr. Barlee, as well as myself with Mr. Wal-
ler and Mr. Norman, have lately dredged specimens of
various sizes and ages in the same part of our seas, at
distances from land ranging from one to thirty-five miles.
The locality ("Dublin Bay"), recorded by Dr. Turton
in his ( Conchological Dictionary/ appears to be more
than questionable, especially as he omitted it in his sub-
sequent work on the British bivalves. This species
does not appear to have been found in any of our upper
tertiaries ; but, in all probability, the T. euthyra of Phi-
lippi, a fossil from a corresponding formation in Sicily,
is the same species. T. cranium is rather common on
the Scandinavian coasts; and Dr. Wallich obtained dead

TEREBRATULA. 13

specimens off the east coast of Greenland at the several
depths of 108 and 228 fathoms.

According to Mr. Barrett, this is more lively than
T. caput -serpentis, moving often on its pedicle, but it is
more easily alarmed. The excellent Montagu must have
indulged in an unusual nap when he imagined that the
animal protruded its tube through the aperture of the
beak, so as to serve the triple purpose of mouth, foot,
and sucker, and that it was capable of a certain degree
of locomotion ! But his notion that, bv means of the
hinge, the valves are similarlv and as firmlv articulated
as the claw of a crab, is much more correct, and shows
his admirable power of observation. The internal skele-
ton is very different from that of T. {Waldheimia) au-
stralis. Having carefully cleaned the inside of a speci-
men of T. cranium, containing the dried remains of the
animal, with a weak solution of potash, and examined
several other perfect shells of different ages, I could not
perceive the least appearance of a loop, which is so
evident in T. australis. The lamellar processes in the
lower valve of T. cranium are equal in length, and end
in sharp points. They may be compared to the chariot-
blades used by the ancient Scythians, and they some-
what resemble the falciform apophyses of Teredo and
Pholas. In the young of T. cranium these processes are
extremely short. Their arrangement and shape are so
dissimilar in species closely allied in other respects, that
I should be inclined to consider their importance, as
characters of generic distinction, somewhat doubtful.

T. cranium was at first mistaken by Professors Fleming
and Sars for T. vitrea, which is a native of the Mediter-
ranean, and has a different foramen and skeleton. Dr.
Leach gave the present species the name of T. glabra,
and its habitat " the coasts of Devon." The young have

14 TEREBRATULID.E.

slight ears, or triangular expansions, at the upper angles
of the lower valve, as in T. caput -serpentis ; and they
are furnished with a very distinct and prominent crest
or ridge, placed inside and nearly in the middle of this
valve, resembling, except in position, the marginal plate
of Argiope cistellula. This last-mentioned character
likewise occurs in T. septata, Philippi, a Sicilian fossil
(T. septigera, Loven) , and is remarkably developed in that
species ; but the foramen is incomplete in T. cranium,
and entire in T. septata. Some specimens of T. cranium
have the front margin more or less truncate, and others
have slight and blunt ridges or angularities extending
lengthwise to the front margin.

B. Shell longitudinally striate : skeleton composed of two short
ribs, which are looped and form a kind of ring. (Tere-
bratidina, D'Orbigny.)

2. T. caput-serpen'tis *, Linne.

Anomia caput-serpentis, Linn. Syst. Nat. ed. 12, p. 1153. T. caput-ser-
pentis, F. & H. ii. p. 353, pi. lvi. f. 1-4.

Body light orange-yellow : mantle thickened by calcareous
spicula ; tentacles extensile and pencilled, with a crimson
tubercle at the base of each : arms bright orange, inclining to
a crimson hue ; muscular stem thick ; cirri long, ciliated all
over, and arranged in a single row : peduncle rather short,
composed of numerous loose tubular fibres.

Shell lyre-shaped, very variable in respect of length and
breadth, sometimes nearly round and at other times oblong,
convex in the middle but compressed towards the front and
sides, rather solid, of a dull aspect : sculpture, scored by nu-
merous longitudinal striae or fine ribs, which radiate from the
beak to the outer margins, becoming occasionally tuberculate
where they are crossed by the hues of growth ; some of these
striae are forked, or divaricate, being simple and stronger near
the beak ; the surface is closely studded with microscopical
points, each resembling the bottom of a homoeopathic bottle,

* From its resemblance to a snake's head.

TEREBRATULA. 15

being the termination of the tubular perforations characteristic
of this family: colour yellowish -white: margins usually truncate
or square in front, and sometimes indistinctly notched or in-
dented in the middle ; the sides are rounded : heal' prominent
but blunt, worn down obliquely by continual rubbing : fora-
men nearly round and incomplete below : deltidium very slight,
being interrupted by the point or umbo of the lower valve :
lunge-plate solid: teeth of upper valve as in T. cranium, but
thicker and provided with a sort of bolt at the upper end :
sockets in lower valve broad : skeleton consisting of two small
but stout ribs, which are thicker at the shaft near the outer
angle of the socket-joint, but afterwards become thinner and
broader or flattened out, forming a double loop or bow, the
upper one being nearly round, and the lower one of a trans-
versely quadrangular shape with a curve above and below ;
this complicated process extends about three-eighths of the
distance from the beak to the front margin ; within the lower
valve, beneath the umbo, is also a small tooth or tubercle ;
the inner margins are crenulated or slightly notched, with the
points projecting outwardly, and furrowed in the middle : inside
pearly and glistening. L. 0*85. B. 0-65.

Tar. septentrional is. Shell thinner, with finer ribs, and of
a white colour. T. septentrioncdis, (Couthouy) Stimpson, Test.
Moll. Xew Engl. p. 75.

Habitat : 0-90 fathoms, on every part of the Scotch
and Shetland coasts, and on the north-east, west, and
south of Ireland, attached to stones, old shells, and occa-
sionallv to small sea- weeds and other substances. The
variety occurs in Loch Duich, Inverness-shire, and off
the east coast of Shetland. This now common shell
was discovered in our seas by Professor Fleming, be-
tween fortv and fiftv years ago, in Loch Broom, on a
stone which was brought up by the anchor of a vessel
belonging to the Commissioners of Northern Light-
houses, while on their annual visit of inspection. As a
tertiary fossil it occurs in the glacial deposits of Ayrshire
(Geikie), and in the Coralline Crag (Searles Wood).
M. Drouet has noticed it as fossil in the Azores. Its

16 TEREBRATULID.E.

hydrographical range extends from Spitzbergen to Sicily;
and the variety is not uncommon on the coasts of Nor-
way and North America. Mr. Arthur Adams has lately
dredged the typical form in the seas of Japan, at the
depths of 26, 55, and 63 fathoms. He considers T. Ja-
ponica to be a distinct species. I have a monstrosity
which is deeply cleft in the middle, so as to form two
lobes of unequal size and height ; and other specimens
also are slightly distorted in the same way.

The brachial cirri are set on the muscular stem like
the teeth of a comb, and when in action they bend for-
ward in a most graceful manner. The pallial tentacles
are also continually moving, and sometimes curl at the
point like a crosier. When the shell is closed during
the lifetime of the animal, these tentacles are still visi-
ble outside the edge of the shell, presenting the same
appearance as in Anomia. Sometimes the upper valve
is laden with a mass of barnacles and Serpulce. The
shells of young specimens are, of course, more strongly
ribbed or striate than those of the adult ; and the lower
valve is eared. The fry, however, are perfectly smooth,
and much longer in proportion than the adult ; and
they have a spoon-shaped, entire, and prominent beak.
Owing to the shell being so thin and nearly transparent,
the tiny arms are distinctly perceptible on the outside.
In the early stages of growth the skeleton is not com-
plete or annular, and it then somewhat resembles the
scythe-shaped processes of T. cranium.

The Anomia retusa of Linne and A. aurita of Gual-
tieri, as well as the T. nucleus and T. pubescens of O. F.
Muller, are synonyms of this species. The last-men-
tioned name originated in a coat of downy sponge, which
not unfrequently covers the shell, and was suspected
by the Danish zoologist to be merely a parasitic growth.

ARGIOPE. 17

Risso called the present species T. emarginata ; Mr.
Lowe described the young as T. cost at a ; Schlotheim
appears to have given the name of T. chrysalis to the
young of the variety septentrio?ialis ; and Dr. Leach,
with his unfortunate propensity to substitute new for
old and well-known names, rechristened the species
T. striata, adding that it inhabits the " western coasts
of Devonshire " !

Genus II. ARGI'OPE * Deslongchamps. PL I. f. 2.

Body compressed : mantle closely adherent to the shell
throughout : arms short ; tentacles so minute as to be almost
imperceptible.

Shell obtusely triangular : beak more or less produced :
foramen large : hinge-line wide and often straight : skeleton
composed of transverse ribs, which are united to longitudinal
ridges or septa.

The members of this genus are much inferior in size
to those of Terebratula. Some are ribbed, and others
smooth. Deslongchamps founded the genus in 1842;
but D'Orbigny, apparently being unaware of that cir-
cumstance, proposed, five years afterwards, another name
(Megathyris), deriving the characters from the same
type. The chief difference between this genus and Te-
rebratula consists in the latter having the mantle free
at the outer edges, while in the former it adheres
throughout to the shell, as well as in the large and wide
rostral opening in Argiope, and its marginal and inter-
rupted skeleton.

* From the appearance of white holes in the outer surface of the shell.

18 TEREBRATULID.E.

A. Shell ribbed.
1. Argiope decolla'ta*, Chemnitz.

Anomia decollate,, Chemn. Conch. Cab. viii. p.96, pi. 78. i.lOba-d. Argiope
decollate,, Jeffr. in Ann. Nat. Hist. 3rd ser. ii. p. 124, pi. v. f. 3 a-e.

Body reddish-brown : mantle forming a thin film : arms
nearly circular, divided into lobes, which correspond in number
with the septa in the shell ; cirri few and thick : 'peduncle very
short.

Shell of an irregular shape, varying from round to trans-
versely oval, sometimes resembling that of a horse's hoof,
compressed, much higher near the beak, and sloping abruptly
in a wedge-like fashion towards the front and sides, solid, of
a dull aspect : sculpture, 15-20 slight ribs which radiate from
the beak but scarcely reach the margins ; lines of growth
rather strong or conspicuous ; tubercles large and numerous,
the interstices having a frosted appearance arising from a
minute granular structure : colour light-brown : margins
rounded at the front and sides, so as to form a semicircle, and
obtusely angled behind : bealc rather prominent and worn by
continual friction ; the under side shows distinctly the layers
of increase : foramen exceedingly large, transversely and irre-
gularly oval, in consequence of its having been made partly
out of the umbo of the lower valve : deltidium scarcely trace-
able : hinge-plate remarkably thick and broad : teeth short and
triangular: sockets broad and deep: skeleton composed of a series
of narrow riband-like plates, which are curved and fit into the
hollows between the septa, lying at no great distance from the
front margin, and almost touching the shell ; within the upper
valve also are five septa, placed at equal distances, the middle
and longest of which springs from under the beak ; none of
them reach the margin, which is wedge-shaped ; in the lower
valve are three strong equidistant ridges, which are placed in
the central space ; these are notched in front, crested at the
top, and obliquely striate at the sides, where may be occa-
sionally observed a few small bead-like tubercles. L. 0*3.
B. 0-285.

Habitat : 18 fathoms, in gravelly shell-sand, two miles
east of Guernsey ; rare. This is the most northern limit

* Truncate.

ARGIOPE. 19

that has hitherto been discovered for the present spe-
cies j nor has it been noticed as inhabiting the northern
or western coasts of France. Its southern range extends
from the Mediterranean to the iEgean, as well as to
Madeira and the Canaries, at depths varying from 20 to
60 fathoms.

The upper valve of this curious shell is like a horse's
hoof. The plates or ribs of the skeleton are not con-
tinuous, but separately attached to the sides of the
septa.

Gmelin changed the original name to detruncata,
without assigning any reason, and he even recognized
the priority of Chemnitz by a correct reference to his
work. According to Philippi, it is the Terebratula
aperta of Blainville, and perhaps the T. urna antiqua and
T. cardita of RAsso. I should be inclined to consider
also the T. Soldaniana of the last-named author as the
young of the present species.

B. Shell smooth.
2. A. cistel'lttla*, SearlesWood.

Terebratula cistrfhda, S. Wood in Ann. N. H. vi. p. 253. Megathyris
(afterwards changed to Argiope) cistellula, F. &H. ii. p. 361, pi. Mi. f.9.

Body yellowish-brown : mantle so extremely thin as to be
scarcely visible : arms heart-shaped ; cirri few and thick :
peduncle rather long.

Shell oval, heart-shaped, or oblong, and often wedge-hke,
compressed but rising gradually towards the beak, rather solid,
occasionally somewhat glossy, but more frequently of a dull
aspect, sometimes bilobed or cleft in the middle : sculpture,
lines of growth numerous and exceedingly minute ; tubercles
close -set, and not very small : colour brown, with usually a
yellowish tint : margins rounded at the sides and also slightly
in front, forming behind angles of different degrees : beak

* A little chest.

20 TEREBRATULID.E.

mostly blunt and often worn by attrition, never much pro-
duced : foramen triangular, occupying nearly the whole of the
dorsal area : deltidium exceedingly slight : hinge-plate thick
and broad: teeth strong and triangular : sockets broad but not
deep : skeleton consisting of two very slight and narrow riband-
like plates or ribs, placed as in A. decollata, but having only
their front edges free, the remaining portion being united with
the shell; within the upper valve is a septum, extending from
the centre of the hinge to nearly the front margin, besides a
few parallel but indistinct striae ; the lower valve has a strong
blunt central ridge, which is higher in front and occupies about
half of the interior ; the front margin is minutely crenulated
inside. L. 0-06. B. 0-075.

Habitat : East Shetland, Skye, and co. Antrim ;
Moray Firth (Dawson) ; Dublin Bay (Waller) ; Exniouth
(Barlee and Clark) ; Guernsey (Lnkis & J. G. J.). Fos-
sil in the Coralline Crag. Sars has found it at Chris-
tiansund, Bergen, and Manger in Norway ; I have taken
it on the Normandy coast ; and among some small shells
which I received through M. Verany from Sardinia was
a single valve of this species.

The animal closely resembles that of A. decollata.
The anterior occlusor or retractor muscles are of enor-
mous size, and their impressions on old shells are very
conspicuous and deep, somewhat resembling those of
Crania. Very young shells have scarcely any of the
tubular perforations ; and their beaks remind one of
the bill of a Platypus. These delicate processes become
afterwards hardened and blunted by contact with the
external world, like the exquisitely sensitive feelings of a
child. The fry may be occasionally seen attached to the
outer folds of the mantle. They appear to be kidney-
shaped, and are of different sizes, or degrees of deve-
lopment.

This species was named, but not described, by Mr.
S. Wood in 1840 as a tertiary fossil ; and I was fortu-

ARGIOPE. 21

nately enabled to discover it seven years afterwards in a
living state. It may be easily distinguished from A.
decollata by its minute size and smooth surface, as well
as by its internal structure. It differs from A. Neapo-
litana in being only half the size and more convex, in
the foramen being much larger, and in the inside margin
of the upper valve being slightly and closely crenulated,
instead of having rather strong and distant tooth-like
notches, which is the case in A. Neapolitana.

3. A. cap'sula"* JefFrevs.

Terebratula capsida, Jeffr. in Ann. N. H. ser. 3, ii. p. 125, pi. v. f. 4, and

iii. pi. ii. f. 7, 8.

Body yellowish : peduncle rather long and slender.

Shell nearly equivalve, oval or pouch-shaped, compressed
but rather higher towards the beak, glossy : sculpture, lines of
growth slight and remote ; tubercles as in the last species :
colour yellowish- brown : margins rounded at the sides and in
front, almost straight behind, giving that part the appearance
of being auricled : beak slightly prominent, its point separated
by the hinge-area : foramen triangular, but not disproportion-
ately large, occupying about two-thirds of the dorsal space :
deltidium imperceptible : hinge-plate, teeth, and sockets as in the
last species: skeleton undeveloped, and septa wantiug. L. 0*03.
B. 0-02.

Habitat: 18-25 fathoms, Plymouth (Norman, from
Webster) ; Guernsey (Lukis) j Dublin Bay, and off Port-
rush (Waller); and Lame, co. Antrim (Hyndman &
J. G. J). It occurs with A. cistelhda, nestling in the
hollows of old shells of Pectunculus glycymeris and
other bivalves, frequently among clusters of Lepralice,
I have found it also at Etretat in Normandv on stones
which had been taken up in trawl-nets at a distance of
about four leagues from land.

* A little box.

22 TEREBRATULID^.

The beak resembles that of Lingida. Very young
shells are not tuberculated. This species cannot be mis-
taken in any stage of growth for the fry of Terebratula
caput-serpentis , which are of quite a different shape,
and more inequivalve than the adult. I have specimens
of the fry of that species only half the size of A. cap-
sula. The fry of T. cranium, which I have taken of
even a smaller size, have a longer and more slender
shell, and the valves are decidedly unequal. From the
young of A. cistellula the present species may be distin-
guished by being of a regularly oval shape and more
convex in every part, but especially by the contracted
hinge-line and comparatively small aperture.

Professor King proposed to make this species the type
of a new genus, which he named Givynia, out of com-
pliment to me ; but although I duly appreciate the
intended honour, I cannot conscientiously accept it.
Although the species is unquestionably distinct from
any of the foregoing, it may be the young of A. Neapo-
litana (probably T. cordata of Bisso) ; and I feel pretty
confident that the last-named species will be found on
our own as well as the Mediterranean coasts.

Terebratella (or Megerlea) truncata has but a very
slender claim to be admitted into our fauna. Dr.
Tur ton's cabinet contained a specimen bearing, in his
handwriting, the name of " Terebratula caput serpentis,"
and the locality " Tor quay ." It is not uncommon in
the seas of southern Europe ; and according to Collard
des Cherres it has been found on Caryophyllice at Quim-
per. In a footnote to the ' British Mollusca' (vol. ii.
p. 362) this species has been accidentally mistaken for
Argiope decollata, with reference to Turton's shell.

I am by no means satisfied that Khynchonella psit-
tacea still inhabits the British seas, although there is

ARGIOPE. 23

abundant evidence of its having been formerly a native.
Dr.Turton described it in his ' Conchological Dictionary '
as having been thrown up, after a severe gale, on the
shore near Teignmouth — a most unlikely place. Pro-
fessor King is said to have obtained two dead specimens
and a single valve off the Northumberland coast, at-
tached to the byssus of a Mytilus modiolus. Mr. Mac-
laren recorded the species as having been procured also
from a fisherman on the Berwickshire coast; and Capt.
Laskey is reported to have taken it by dredging in the
Firth of Forth. Capt. Thomas appears to have likewise
dredged valves off Berwick, and Mr. Dawson off Aber-
deen. In deep-sea dredging off the Shetland Isles, I
have more than once found single valves, and this year
a nearly perfect pair. Dr. Turton's specimen has a
very ancient aspect ; Professor King's and some of my
own are remarkably fresh -looking, and they may pos-
sibly be recent ; but I am rather disposed to think they
are some of the relics of the glacial epoch. The shell
being of a horny texture, would not be liable to undergo
much, if any, change while it remained under water. A
live specimen has never been taken, so far as I am
aware, anywhere south of Drontheim, where it seems to
dwindle in size. It is a gregarious species, and there-
fore common wherever it occurs. The arctic seas of
both hemispheres constitute its proper habitat. As a
tertiary fossil it is found in the Norwich or Mamma-
liferous Crag and later deposits.

24 CRANIID.E.

** Hingeless.

Family II. CRANI'EME, (Cramadce) King.

Body circular : arms spiralty coiled, and not supported by
any shelly process or septum : attachment formed by the ad-
hesion of the lower valve, or part of it, to other substances.

Shell circular or subquadrangular : upper valve conical or
cap-shaped: lower valve flat: muscular scars remarkably
■strong and conspicuous.

Our seas contain at present one only of this hingeless
group of Brachiopoda, which is distinguishable from all
the preceding kinds by the upper valve being conical
and the lower valve flat and attached, as well as in
neither valve being perforated. The shell is opened by
the action of the adjustor or protractor muscles; and
this takes place only to a very limited extent. Throu r ^
the Discinida? there appears to be a passage to Anomia,
both of which have a byssal peduncle issuing out of a
hole or slit in the lower valve for attachment to other
substances.

Genus I. CRANIA* Retz. PL I. f. 3.

As the family contains but this single genus, it is un-
necessary to recapitulate the characters.

1. Crania ano'malaI-, Miiller.

Patella anomala
F.&H

mala, Mull. Zool. Dan. Prodr. p. 237, no. 2870. C. anomala,
ii. p. 366, pi. lvi. f. 7, 8 ; (animal) pi. U. f. 2, as C. Norvegica.

Body of a milk-white colour, tinged with yellow or brown :
mantle very thin : arms thick and fleshy ; cirri rather nume-
rous, stiff, and rather long.

* From a fancied resemblance of the inside of the lower valve to the
front of a human skull,
f Irregular.

CRANIA. 25

Shell nearly round, -with a square outline : upper valve
umbrella-shaped above, more or less compressed, rather solid,
of a dull aspect : sculpture, wrinkled by the circular marks of
growth, sometimes microscopically but irregularly striate lon-
gitudinally: colour reddish-brown or yellowish, with blotches
or faint streaks of the first-mentioned hue : margins thin and
sharp : beak very small, nipple-shaped, placed nearer the dorsal
end : tower valve of various degrees of solidity, according to the
age and quickness of growth, but the inside margin is always
broad, thickened, and raised, so as to form a ridge or rampart
round the enclosed space ; it is reticulated or closely pit-
marked within: muscular scars in both valves deeply marked.
L. 0-55. B. 0*5.

Habitat : 18-90 fathoms, on almost every part of the
Scotch and Irish coasts, as well as in the seas of Shet-
land and the Orkneys \ Isle of Man (Forbes) . Abroad
it is distributed from Greenland to Vis:o : and I have
jqgbx unable to detect any difference between this species
and the C. ring ens of Honinghaus, which is not un-
common in the Mediterranean and iEgean Seas. Spe-
cimens from ail the above localities vary much in shape,
and in the dei h of the circular wrinkles or furrows, and
not less in the position and size of the muscular scars.

Even the sagacious M tiller was deceived by the strange
aspect of this shell. He placed it in the genus Patella,
having observed the upper valve only ; although he ad-
mitted that the animal (which he styled " vermis sin-
gularissimus ") differed toto ccelo from a limpet, and
that the shell, on closer inspection, was not quite the
same. It is most singular that he overlooked the lower
valve. His comparison of the branching arrangement
of the arms to the dusky horns of a wild goat is not in-
appropriate. Sometimes the shell is ribbed across or
obliquely, having taken the impression of an Astarte or
Pecten, on which it has been moulded. Being often
affixed to rugged stones or small pebbles, its shape is

c

26 craniidjE.

adapted to the angles and extent of the basal surface.
When it has bare standing-room only, it increases in
height and becomes regularly conical. The under valve
of specimens attached to the smooth shell of a Pinna is
usually a mere film. The brachial fringe can be pro-
truded slightly beyond the margin of the shell at each
side, but never in front or at the back. It may be
likened to the spokes of two wheels, each placed on its
nave within a circle ; and as the spokes are nearly equal
in length, it is evident that at the point where the wheels
approach each other, the inside spokes project into the
space between the wheels, and not outwardly. There
are no cirri at the back. The lower or flat valve con-
tains only the base of the adductor muscle, upon which
as a pivot; the upper valve turns by a semirotatory
but very confined motion. The arms and rest of the
body are enclosed in the upper or convex valve. The
animal is by no means timid. When a camePs-hair
brush is thrust between the gaping valves, they imme-
diately close, but in a few seconds after open again;
and this teasing experiment can be repeated many times,
without alarming the Crania, or making it sulky. The
cirri are not retractile, and do not withdraw or shrink
when touched. Each arm has about sixty of them.
The fry are quite white and semitransparent, and they
have only a few tubular perforations. They adhere in
the same way as their parents. Their appearance is not
unlike that of the very young of Anomia ephippium. The
largest specimen in my cabinet measures over four-fifths
of an inch in diameter.

Montagu called this species Patella distorta ; and it
has borne many other names, both generic and specific,
the latest being that of Criopus Orcadensis, given to it
by Dr. Leach.

CONCHIFERA. 27

Class CONCHIFERA.

Order LAMELLIBRANCHIATA.

The principal characters of this Order have been al-
ready given in the former volume. A few of the mem-
bers (e. g. certain species of Lucina, Tellina, and Thra-
cia) are said to have only one branchial leaflet or gill on
each side of the body ; but in all probability this leaflet
is double, although united and apparently single. The
Order is divisible into two unequal groups, which may
be distinguished from each other by the number of ad-
ductor muscles. The first and smaller group (Moxo-
myaria) has but one muscle, which is placed nearly in
the middle, or rather towards the back. The other and
far larger group (Dimyaria) has two separate muscles,
which are placed on the right and left sides of the
bodv. The scars or impressions made bv these muscles
on the inside of the shell serve to instruct the geologist
to which group every bivalve belongs. The British
Monomyaria comprise the families Anomiida , Ostreidce,
and Pectinida. All the remaining families are Di-
mvarian. The late Mr. Clark savs that the onlv true
Monomvarian Mollusca are Pholas and Teredo ; but his
observations in this respect do not agree with those of
other concholo gists. I do not attach much importance
to the form, or even the presence of the paliial scar,
being the mark left on the inner margin of the shell by
that part of the mantle which adheres to it and keeps
the rest of the body in its proper place ; although this
character may serve to recognize certain genera. In
some families the mantle is open on all sides but the

c 2

28 CONCHIFERA.

back, for the admission of food and water, as well as for
the ejection of faecal matter ; while in others it is more
or less closed in front, or open only in that part for the
passage of the foot. In the latter case the mantle on
one or either side is folded, so as to form a single or
double tube. This usually takes place on the posterior
side, where the shell is broadest ; but in a few instances
(as in the Kelliidce) the incurrent or alimentary tube is
placed on the anterior side, and the excurrent or anal
tube on the posterior side. The tubes are of various
lengths, and when they do not project beyond the edges
of the shell they are termed " sessile." The excretory
opening is always situate on the upper part of the pos-
terior side. That by which the animal takes in its
nourishment, and which supplies the gills with aerated
water, is usually on the same side, but below the other
opening. The excretory opening or tube is the smaller
of the two. With respect to the reproductive system of
the Lamellibranchiata, it is by no means settled whether
any, or which of them, have separate sexes. Loven is
positive that such is the case in Modiolaria, the em-
bryogeny of which he has investigated with his usual
care; and Sars assures us that Aximis is unquestionably
also dioecious. I have not myself examined the question ;
but I would refer my readers to what I have already said
in page xxv of the Introduction to the first volume.

ANOMIA. 29

* Mantle open and without tubes.

Family I. ANOMI'IDiE, (Anomiadce) Gray.

Body roundish : mantle having very thin edges, which are
furnished with fine and extensile tentacular filaments : gills
circular and double : foot small : muscle divided into two or
three parts, the largest of which passes through a hole in the
hinder part of the lower valve, serving for attachment to extra-
neous bodies, and forming on them a fibrous or horny plug.

Shell generally circular and flat, more or less inequivalve :
orifice pear-shaped, being interrupted behind by a narrow slit :
cartilage internal, short, placed somewhat obliquely below the
beak.

This family is connected with the Ostreida by the
genus Pododesmus of Philippi. Dr. Leach proposed to
raise it to the rank of an Order, which he called
Trimya.

Genus ANO'MIA* Linne. PI. I. f. 4.

Body compressed.

Shell inequilateral, of an irregular shape, dependent on
that of the substances to which it is attached : upper valve
rather convex and thick: lower valve flat and thin: hinge
toothless.

As I have before observed, Fabius Colonna, the origi-
nator of this name, applied it to species of Terebratula.
About a centurv and a half afterwards Linne used it in
the same sense, for he described the animal as having
two arms, and the shell as furnished with two bonv
processes or radii, the deeper valve being often per-
forated at the base. But he included in the genus
many species which we now recognize as belonging to
Anomia thus restricted, and long custom has sanc-

* Irregularity.

30 ANOMIID.E.

tioned the modern use of the word. Poli proposed the
name of Echion for the animal of the present genus.
According to Dr. Carpenter the outer layer of the shell
has a prismatic cellular structure ; and in this respect
it appears to resemble the shell of Argiope. There is
no visible trace of an epidermis. The plug of attach-
ment is secreted by that part of the adductor muscle
which passes through the lower valve. It is not shelly.
The fry are fixed in the same way as the adult, soon
after their exclusion from the ovary ; although it would
appear that they enjoy in the mean time a short period
of liberty, like their relative the oyster. The Anomiat
are popularly designated in this country " silver- shells."
In the State of New York they are called " Jingle-
shells." Dr. Otto Torell informs me that no species
has been found north of Iceland; but fossil shells are
not uncommon at Uddevalla in the same bed which
contains Terebratella Spitzbergensis, Piliscus commodiis,
and other forms of an extremely arctic kind.

1. Anomia ephip'pium % Linne.

A. Ephippium, Linn. Syst. Nat. p. 1150 ; F. & H. ii. p. 325, pi. It. f. 2, 3,
5, 7, and (animal) pi. T. f. 2.

Body somewhat depressed, red, yellow, brown, or of all in-
termediate shades of those colours : mantle circular : cirri or
tentacular filaments arranged in two or three rows, ciliated or
feathered, yellowish -white : mouth large, with a pair of long-
delicate lips on each side : foot short, cylindrical, and white,
sometimes curved and protruded from a slit in the shell above
the orifice, for the purpose of spinning a byssus and affording
an additional means of attachment.

Shell round, oval, oblong, cylindrical, angular, or even
amorphous, compressed, and sometimes flattened, of different
degrees of thickness according to age, outside of a dull ap-
pearance, although the inner layers are remarkably glossy and

* A horse-cloth.

ANOMIA. 31

iridescent: sculpture, scaly and sometimes prickly, minutely
striate in a longitudinal direction, and marked by irregular
lines of growth : colour white, with often a yellowish, pink,
rose-red, or brown tint : margins thin, rounded or wavy unless
contracted by position, nearly forming an obtuse angle behind :
beak straight and very small, not projecting beyond the dorsal
margin : cartilage short but strong, broad, semilunar, and
fixed in a cavity underneath the beak : hinge-line slightly
curved : hinge-plate thick and broad : orifice oval ; outer edge
reflected ; inside silvery and iridescent, sometimes having a
green tint, furnished in the lower valve at the hinge-end with
a thickened ledge to receive and support the cartilage : muscular
scar large, showing in the upper valve the impressions of three
inner portions of the muscle, which are nearly circular and
disposed in a descending but irregular line from the hinge, and
in the lower valve only one similar impression, which is placed
on the right hand of the observer : plug cylindrical, thick, and
longitudinally striate. L. 2-3. B. 2-5.

Habitat: From low- water mark to 80 fathoms on every
part of our coasts, attached to shells, stones, sea- weeds,
and other substances. In a fossil state it occurs in our
newer tertiaries, as well as in the Coralline Crag, and
in the Italian pliocene deposits. It is likewise found
in the post-glacial beds of Bohuslan, Sweden, associated
with arctic shells. It is widely distributed in the Euro-
pean seas, from Iceland to the iEgean Archipelago ; and
its range also comprises Algeria, Madeira, North Ame-
rica, Russia, Lapland, and the Black Sea. Danielssen
has recorded it as having been dredged in the Scandi-
navian seas at a depth of 180 fathoms.

In consequence of the lower valve being moulded on
the extraneous bodies to which it is attached bv the
plug, the upper valve partakes of a corresponding im-
pression, and the result is that the shell puts on a
Protean variety of shape. Bouchard-Chantereaux says
that out of two hundred specimens it is almost impos-
sible to find two exactly alike. When a specimen is
affixed to a Pecteii, Astarte, or other ribbed shell, it is

32 ANOMIIDvE.

similarly sculptured. No less than thirty-four species
have been made out of the one now described ; and
naturalists of every country have had a hand in this
wholesale manufacture. Eighteen of these species have
been enumerated as synonyms by Forbes and Hanley.
The variability of the shell, however, is now such an
established fact, that a conchologist who would attempt
to restore any of these so-called species must have
greater ingenuity than even the learned knight, of
whom it was said

" He could distinguish and divide
A hair, 'twixt south and south-west side."

The variety " squamula " is flatter and smoother than
usual ; " aculeata " has the imbricated scales pinched
up into vaulted or hollow spines ; and the narrow form
of " cylindrica " arises from the young Anomia selecting
for its resting-place a small stem of sea-weed, which
obliges it to assume a saddle- shape, not having any
room for lateral development. Occasionally specimens
are found exhibiting the characters of more than one
variety, being half "squamula" and half " aculeata."
The animal is said to be poisonous ; and Mr. M c Andrew
informs me that the captain and some of the crew of his
yacht were suddenly taken ill at Vigo, after having eaten
some fine Ano?nide, which looked to them so temptingly
like oysters. The muscle of attachment appears to
have an excavating or eroding power, like the foot of a
limpet or other boring mollusk. When an Anomia is
fixed to the shell of an oyster, the lower part of the plug
is sunk below the level of the surface, and is separated
from it by a kind of sloping ditch. This gives a stronger
hold ; and the base of the plug is often spread out, so as
to increase the fulcrum. The structure of the plug is
very remarkable. It is composed of perpendicular

ANOMIA.

33

plates, which are alternately high and low; and the stri-
ated appearance of the top or outer covering is pro-
duced by the edges of the higher plates. This appendage
is capable of receiving a high degree of polish, and m
that state it resembles ivory and is equally close-grained.
In the fry the orifice is larger in proportion to that of
the adult, and is placed on one side. The beak of
young specimens is sometimes much produced, and at
other times slightly incurved. When the shell is thin,
the long muscular scar seen through the upper valve
resembles a white line. The varied and nacreous hues
of the shell rival in lustre those of an opal. A group
of these specimens from Lulworth Cove, on a valve of
Pecten opercularis, now before me, are of different
colours, white, yellow, and pink, and reflect their pearly
gleams in every direction. In substance the shell bears
some affinity to talc. Specimens from Bantry Bay,
Lough Strangford, and Exmouth roads are larger than
usual. One from the first-named localitv measures four
inches in diameter. Now and then, but rarely, the
upper valve is flat, and the lower or perforated valve is
convex ; and in one case the front half of the shell is
divided into two distinct lobes, owing to the continual
obstruction and irritation caused by a small branch of
Sertularia abietina, which had insinuated itself and
grown up in front of the Anomia. But a more curious
instance of an adaptation to circumstances is presented
by specimens which I found many years ago on a mus-
sel-bed in Swansea Bay, laid bare by an unusually low
tide. The orifice in every specimen was completely
closed by a series of thin vaulted plates of the same
material as the shell. All the specimens were living,
and attached to the mussels by the byssal threads of the
latter. It appeared to me that, having been acciden-

c o

34 ANOMIID^. '

tally detached from oysters in an adjoining bed, to which
they were originally affixed, and being thus deprived of
their plugs, as w T ell as of the power to make new ones,
they filled up the openings w r ith a shelly substitute, for
the sake of protection against starfishes and other ene-
mies. Having lost their own plugs, they were well
satisfied by being securely moored to the bed by the
strong cables of their friendly neighbours, the mussels.
I dredged a specimen of the variety " squamula" off
Croulin Island, Skye, which was free, but had the orifice
completely closed in the same way as the Welsh exam-
ples. The A. tubularis of Turton is a young specimen
of the same variety, in which the orifice had only been
partially closed. Old Martin Lister w r as well acquainted
with the typical form, and gave an excellent figure of
it in his ' Historia Conchvliorum.'

2. A. patellifor mis *, Linne.

A. patelliformis, Linn. Syst. Nat. p. 1151 ; F. &IL ii. p. 334, pi. lvi. f. 5,6.

Body resembling that of A. ephippium, but the colour is
deeper : mantle thinner : cirri of unequal length and size, and
capable of considerable extension, some of them being a quarter
of an inch long ; they are minutely and closely ringed, and a
dusky line runs down the middle of each. No other part of
the animal is visible outside.

Shell round or sometimes longitudinally oval, usually flat-
tened, thin, rather glossy towards the beak, but elsewhere of
a dull appearance : sculpture, fine and close-set imbricated
scales, and 20-30 blunt ribs which radiate from the beak in
every direction towards the margins in a wavy manner ; lines
of growth irregular : colour yellowish-white, with frequently
reddish-brown but not continuous streaks or spots : margins
thin, scalloped or notched by the ribs, nearly straight behind :
bealc small, rather prominent, very seldom reaching to the
hind margin, and never overlapping it : cartilage short and

* Shaped like a Patella, or limpet.

ANOMIA. 35

narrow, fixed in a cavity beneath the hinge : lunge-line
slightly curved : hinge-plate thick but narrow : orifice rather
large, much broader below than above ; outer edge not re-
flected : inside bluish-green, highly iridescent, furnished in the
lower valve with a ledge to receive the cartilage: muscular
scar large, showing in the upper valve the impression of two
inner portions of the muscle of a roundish-oval shape and
often confluent, the larger one of which is placed in the middle,
and the smaller one a little below it on the left-hand side ; in
the lower valve there is only one impression, placed as in the
last species: plug pear-shaped, thin, and coarsely striate
lengthwise. L. 1*3. B. 1*45.

Var. striata. Shell sometimes nearly convex, covered with
numerous and fine longitudinal striae, which often rise into
minute scales, becoming prickly and occasionally decussated by
the transverse lines of growth; coloured rays more distinct
and somewhat wavv. A. striata, Loven, Ind. Moll. Scand.
p. 29. F. & H. ii. p. 336, pi. lv. f. 1, 6, and pi. liii. f. 6.

Habitat : 10-86 fathoms, on hard ground and shell-
banks everywhere, usually concealed in the hollows of
old bivalves. It is, however, not so common as the last
species, although equally diffused; and they are found
together. The variety occurs in Shetland and on the
west coast of Scotland. A. patelliformis is a tertiary
fossil of the Clyde beds, and of the Red and Coralline
Crag, as well as of the newer deposits of Italy and Sicily,
and also of theUddevalia shell-bed. Abroad this species
ranges from Scandinavia to the Mediterranean. Ac-
cording to Chierighini it inhabits the Adriatic ; \Vein-
kanff has included it in his list of Algerian shells under
the name of A.pectinifoiT/iis, Philippi; the variety, as
well as the ordinary form, have been taken by M. Martin
in the Gulf of Lyons; Middendorff has recorded it
from Sitka Sound, and Dr. Philip Carpenter from the
Xorth-west coast of America.

It differs from A. ephippium in its more regular out-
line, thinner texture, coloured streaks, peculiar sculp-

36 AXOMIIDJE.

ture, the number and position of its muscular scars, and
fiat (instead of raised) plug. It is also not so susceptible
of outward impressions as that species. An A. patelli-
f or mis attached to a scallop, although it sometimes par-
takes of its companion's ribs, has also its own natural
ribs, which run their independent course from the beak
to the margins. The orifice in young specimens is
nearly round. The prominent beak somewhat resem-
bles the apex of a limpet. The plug lies in a hollow,
which is apparently made in the same way as I have
suggested with regard to the other species. Owing pro-
bably to the green colour of the liver, the rostral area
or nucleus of the shell always appears to have a similar
tinge.

It is not without considerable hesitation that I have
ventured to unite with this species the A. striata of
Loven ; but, after examining his types at Stockholm,
and a long and careful comparison of a great many
specimens of this beautiful variety, I cannot make out
any definite specific character. The only difference
consists in the more delicate sculpture of LoveVs shell;
and specimens may be observed in which the ribs and
striae blend so insensibly into each other, that it is im-
possible to say whether they belong to the typical spe-
cies or the variety. Judging from Linnets description
of A. patelliformis, this variety appears to correspond
with it better than the typical form. I consider it ana-
logous to the variety " aculeata " of the last species.

A. patelliformis has not received so many names as
A. ephippium, and I can only find fourteen of them.
The Ostreum striatum of Da Costa (but not that of
Lister) appears to be this species. It has been placed
by some conchologists in the genus Placunanomia of
Broderip ; but the distinctive character of that genus

OSTREA. 37

lies in having two cardinal teeth, as in Placuna and Pla-
centa, and is not applicable to the present species.

Family II. OSTRE'ID.E, Broderip.

Body round : mantle having rather thick edges in front :
cirri short : gills simple. There is no foot, or muscle for ex-
ternal attachment. The animal is fixed in the earlier stage of
its growth, and sometimes in its adult state, by the lower or
more convex valve of its shell.

Shell circular, longitudinally oval or oblong, or of an irre-
gular shape, and inclined to be wedge-like, inequivalve : hinge
toothless, but having its margins sometimes notched: cartilage
internal, short and curved, placed horizontally on the hinge-
line.

Some genera are exotic, and others are extinct or
known only as fossil. We have but the typical genus.
The Oyster family differs from that of Anomia in the
gills being simple, in having no foot or plug of attach-
ment, and in the shells being either free or adhering to
other substances by the lower valve, which is invariably
larger and deeper than the other.

Genus OS'TREA *, Linne. PI. I. f. 5.

Body compressed.

Shell composed of numerous imbricated or tile-like plates,
which overlap one another in succession : beaks disunited :
cartilage strengthened by a ligament on each side of it.

The so-called species of Ostrea are exceedingly nume-
rous, and many of them are only distinguishable by very
slight characters. Almost every sea appears to have
several species or varieties. Their general form is very
inconstant and often irregular. It is more than pro-
bable that when a sufficiently extensive series from each

* Oyster.

38 ostreid^e.

place, and especially in the earlier states of growth, have
been carefully examined and compared, many recent
species may become " extinct " in consequence of a re-
duction in number, and with great advantage to science.
Poli gave the animal the name of Peloris. But that was
not an oyster.

Murice Baiano melior Lucrina peloris,
Ostrea Circeiis, Miseno oriuntur echini,
Pectinibus patulis jactat se niolle Tarentum.

Ostrea edu'lis *, Linne.

0. edulis, Linn. Svst. Nat. p. 1148 ; F. & H. ii. p. 307, pi. liv., and (ani-
mal) pi. T. f. 1.

Body much compressed, although rather thick, of a pale
drab colour more or less tinged with brown : mantle nearly
circular : cirri arranged in two rows, the outer one of which is
double but irregular, and the inner one single : mouth furnished
with a pair of large and nearly triangular lips on each side.

Shell round in its young state, and afterwards spreading
out in front or at the sides, with frequently a more or less
curved outline, usually compressed, rather thick, of a dull
appearance outside : sculpture, foliated or scaly ; lower valve
sometimes strongly ribbed lengthwise ; the entire surface of
the shell when young is microscopically shagreened ; lines of
growth well marked: colour yellowish -brown : margins thin
and closely appressed or squeezed together, usually semicir-
cular in front and more or less rounded at the sides : beaks
small, divided by the cartilage, which is thick and very strong,
light-brown or horncolour, and supported on each side by a
short ligament of a dark olive-green : hinge-line narrow and
nearly straight : hinge-plate thick : inside white and pearly ;
lateral edges (especially of the flat valve) finely crenulated or
notched on the upper part : muscular scar obliquely transverse,
pear-shaped or slightly incurved above. L. 3. B. 3*5.

Yar. 1. parasitica. Shell much smaller, flatter, and more
glossy ; colour purplish or greenish-brown, with streaks of a
darker hue radiating from the beaks. 0. parasitica, Turt.
Conch. Diet. p. 134, f. 8.

* Eatable.

OSTREA. 39

Yar. 2. luppopus. Shell large and extremely thick. 0.
Mppopus, Lam. An. sans Yert. vii. p. 219.

Yar. 3. deformis. Shell small, distorted, and often nearly
cylindrical. 0. deformis, Lam. 1. c. p. 229.

Yar. 4. Rutwpina. Shell small, transversely oval and of a
regular shape.

Yar. 5. tincta. Shell flattened and attached in every stage
of growth ; inside of a rich purplish-brown or olive-green ;
hinge-margins strongly crenulated.

Habitat : 0-45 fathoms, on every part of our coast
from Shetland to the Channel Isles, usually gregarious
and forming beds of various extent. Var. 1 . On shells,
crabs, and other substances, having rather a more south-
ern distribution. When this variety is affixed to a ribbed
scallop, it adopts the markings of that shell, but it re-
tains its own colour. It appears to be the 0. depressa
of Philippi. Var. 2. In deep water and solitary. Var. 3.
Occupying the crevices of rocks in the littoral and
laminarian zones, and called the " rock-ovster." Some
specimens resemble a Gryphcea in shape. Var. 4. Coasts
of Essex and north Kent, in a semicultivated state, and
well known in this country as "natives." Var. 5. West
of Scotland and Burra Isles, Shetland. Mr. Grainger
has noticed this ubiquitous species as "imbedded in
considerable myriads M in a raised pliocene deposit at
Belfast; and, according to Mr. James Smith and Mr.
Geikie, it occurs in the Clyde beds and other glacial
deposits in Scotland. Red and Coralline Crag (S .Wood) .
The shells may also be seen mixed with those of pecu-
liarly arctic species in the raised sea-beds near Udde-
valla. It is very difficult to ascertain its foreign distri-
bution, with any tolerable degree of correctness, in con-
sequence of its specific identity being enveloped in such
a cloud of different names. Depending, however, on

40

OSTREID.E.

those authorities which appear to be most accurate, I
consider that its range extends from Iceland (Mohr) to
Naples (Scacchi) and the Adriatic (Chierighini). I can
answer for the common form, as well as the variety
parasitica, being found at Cannes. Muller, Loven,
Lilljeborg, Asbjornsen, and Malm have recorded it as
inhabiting different parts of the Scandinavian sea, from
Christiansund southwards ; and Mr. M c Andrew has
found it in Vigo Bay and off Gibraltar. Philippi says
that in Sicily it occurs in a fossil state only. According
to Gould, it is undistinguishable from the oyster of New
York. It has not been observed by Dr. Otto Torell or
any arctic explorer on the coasts of Greenland ; but it is
common in some of the postglacial beds near Udde-
valla and in the diocese of Christiania, associated with
high-northern shells.

Although we are now favoured with only one species
of what Gmelin termed the " vermis sapidissimus," and
the supply is never equal to the demand, the case was
very different in days long since past. E. Forbes says,
" During ancient epochs, as we learn from the fossils of
both tertiary and secondary strata, many more kinds of
oyster lived within our area, and multiplied so as to
rival the contents of any modern oyster-beds. The dis-
coveries of geologists open scenes of regret to the en-
thusiastic oyster-eater, who can hardly gaze upon the
abundantly entombed remains of the apparently well-fed
and elegantly-shaped oysters of our Eocene formation,
without chasing ' a pearly tear away/ whilst he calls to
mind how all these delicate beings came into the world,
and vanished, to so little purpose." However, there is
some consolation in the idea that the breed of ovsters
may have since improved by " natural selection," and
that, if any of our prehistoric ancestors existed in those

OSTREA. 41

bygone epochs, they were not so well off as we are for
the quality of this gastronomic luxury. Oysters seem
to have been as much sought for and enjoyed in the
" stone " age as they are at present, judging from the
vast heaps of large empty shells which are found in the
Danish kjokkenmoddings, as well as in the northern
parts of the British isles.

Lister was the first to describe the anatomy of the
oyster, from particulars which were communicated to
him by Dr. Willis. This description is tolerably accu-
rate; and if the authority could be wholly relied on,
these mollusks ought not to suffer the discredit of being
so stupid as is proverbially alleged in Norway and
Brittanv. Willis states that when the tide comes iu
they lie with their hollow shells downwards, and when
it goes out they turn on the other side; and he adds
that they do not remove from their places, unless in
cold weather to cover themselves with the ooze ! Lister
appears to have trusted too much to his friend, and not
to have learnt for himself the fact that ovsters have

at

not the slightest power of locomotion, except in their
embryonic state. Bishop Sprat's account of our oyster-
fisheries, which has been so often quoted in works on
natural history, was chiefly compiled from this com-
munication of Dr. Willis. The " spat/' said to be like
a drop of candle- grease, is a pure fiction. From April
to July the ova are continuallv excluded from the ovary
and discharged into the gills, where they are hatched.
Every batch of fry in succession is then committed to
the sea ; and the young commence life as free animals,
like other bivalves, swimming or rather flitting about
with considerable rapidity by means of numerous cilia
which fringe their circumference. Each is enclosed in
an extremely thin and prismatic semiglobular bivalve

42 ostreidjE.

case. In the Report of the British Association for
1856 Mr. Eyton has given some farther information as
to the appearance and habits of the oyster-fry. He
says, " The animal was semitransparent, with two
reddish elongated dots placed on each side behind the
cilia, which were in constant and rapid motion. They
were exceedingly tenacious of life, the cilia moving until
the water was dried up upon the glass. Some that I
placed in a little salt and water were alive the next
day." After a short enjoyment of freedom they attach
themselves to a stone or some other object ; the mantle
soon afterwards begins its work of secretion, and converts
the case into a shell ; the latter becomes agglutinated
to some extraneous body ; the cilia and eye-like spots
disappear, and the permanent organs are developed.
This metamorphosis has its parallel in the Cirripedia
and other classes of invertebrate animals. The parent
oyster is slow in recovering from its long-continued par-
turition ; and it is not fit to eat until about the middle
of August. Indeed, it is not considered to be in full
flavour until September. The period of its longevity is
not known. It is said to be in prime condition from
the fourth to the seventh year, and rarely to live beyond
its fifteenth year. If the numerous laminse or plates of
which the shell is composed denote the marks of annual
growth, some individuals must attain a very venerable
age; but these plates are formed inwardly, instead of
outwardly as is the case with the trunks of coniferous
trees, and the analogy therefore fails. A severe winter
causes great mortality among those which are laid in
park sor shore-beds, in consequence of the valves being
closed by ice during the recess of the tide. In all pro-
bability the stock of sea- water, which had been taken
in before the oyster was laid bare, requires occasional

OSTREA. 43

aeration from the atmosphere. The green colour, so
much prized by the Parisians, is owing to the oyster
feeding on the Navicula, a kind of Diatom or vegetable
organism which abounds in comparatively still and
brackish waters. According to physiologists the in-
testine passes the heart without coming into contact
with it, being an exception to the general rule with
respect to the relative position of these organs in the
Acephala. The oyster, therefore, cannot in fairness be
twitted with the proverb that the way to the heart is
through the stomach. Nor is the idea of its being
( f crossed in love }> less fallacious, seeing that each in-
dividual is of both sexes and can only be enamoured of
itself. Clark, as well as Gr. B. Sower by, asserts that the
animal has two adductor muscles, and that the corre-
sponding impressions may be seen in each valve, the
posterior one being very small and placed close to the
hinge. I have not been able, however, to detect more
than one impression, which lies nearly in the middle.
I would therefore invite the attention of naturalists to
the elucidation of this simple point. On it depends the
Lamarckian division of the Lamellibranchiata into
Monomyaria and Dimyaria, the oyster being the type of
the former group. Dr. Fischer says that the adductor
muscle in Pecten (which is allied to the oyster and
belongs to the same group) is divided, so as to form an-
terior and posterior bundles placed at different angles'
He is of opinion that the group of Monomyaria exists
only in appearance and not in reality. The cartilage
and ligament advance with the growth of the animal, in
consequence of which the old layers become useless and
are external. The oldest or first-formed portions of the
shell cease in time to be occupied by the animal, so that
the beaks become disunited and in adult specimens are

44 0STREID.E. ,

separated by a wide chasm. The shell is remarkably
calcareous, and consists for the most part of layers
termed by Dr. Carpenter " sub-nacreous " and having
comparatively little adhesion one to another. These layers
are internal. The outer layers are composed of pris-
matic cellular structure, and have no natural cohesion.
The weight of the animal in a full-grown example is
very disproportionate to that of the shell. The late Mr.
Thompson of Belfast ascertained that a large oyster
from that bay weighed altogether two pounds, but that
the weight of the animal taken out of the shell was only
an ounce and a half. Large-sized specimens from the
British seas seldom exceed six inches in length ; but on
the North- American coast this species (if it be the same
as ours) is said to attain occasionally twice that size.
Young shells are sometimes marked with radiating
purple streaks ; and now and then one is found attached
to the operculum of a living Buccinum undatum, the sur-
face of which it completely covers and takes its form.

Before adverting to the economical point of view, I
may mention some of the minor uses to which oysters
are put. These are few : they serve to keep an aqua-
rium free from the spores of sea-weeds ; their shells are
burnt as a substitute for lime ; and formerly certain
medicines were prepared from their calcined material.
Also pearls of inferior lustre, often small and of an
irregular shape, are obtained from them. Antiquaries
tell us that the shells have been discovered in Saxon
tombs, and that in still older places of sepulture in the
Orkneys they are found drilled in such a manner as to
show that they probably formed articles of personal
ornament. They must have made a clumsy necklace.
But their chief value results from the fisheries, which
for more than eighteen centuries have rendered Great

OSTREA. 45

Britain famous as an oyster-store, and continue to give
employment to thousands and a delicate and wholesome
food to millions. Although Catullus calls the Helles-
pont "caeteris ostreosior oris/' his countrymen always
gave the preference to our natives. Some interesting
statistics of the trade will be found in the ' British
Mollusca.' In a later account of this important branch
of our commerce it is stated that in London alone about
700 millions of oysters are annually consumed, and that
in the provinces there is equal voracity and constant
crying out for more. The consumption in Paris in 1861
reached 132 millions, according to a statistical report
of the archostreologer, M. Coste. The preservation of
oyster-fisheries has been frequently the subject of legis-
lative enactments in this and other countries. A dispute,
which threatened at one time to be serious, arose not
many years ago between the French and ourselves as to
the limits of such fisheries in the English Channel. It
shows the weight that these humble mollusks, insulted
in proverbs, but sought after with such eagerness, have
in the scale of nations. The same jealousy prevailed
lately on the other side of the Atlantic. The Governor
of Virginia in 1857 was said to have been in a per-
petual stew on this account, and to have sent an urgent
" message " or appeal to the Legislature for protection,
believing that the idea of an oysterless State was much too
gloomy for contemplation ! Our Transatlantic cousins
boast that their oysters are far superior in flavour to
any in the Old World. In the ' Natural History of
New York/ published in 1843, it is stated that there
were two principal varieties in the then United States —
viz. northern and southern — and that connoisseurs pre-
tended to distinguish these varieties by the smell alone.
The oyster may have played, although unconsciously, a

46 OSTREID^E.

part in the sad tragedy which has been performed in
that unfortunate country, by indicating (like the herald
in a Greek play) the approaching separation of the
States, with reference to the distinction in its own case
into "northern" and "southern." The art of "huitre-
culture," which has been practised in France with so
much success, is simple as well as useful. It consists
of fixing, in sheltered and suitable spots, wooden stakes
interlaced with branches of trees, arranged like fascines,
on which a few breeding- oysters are laid. At the end
of three or four years the stakes are pulled up ; the
mature oysters are selected for market, the small ones
being left to grow and breed; and the stakes and
branches are replaced. A similar harvest is gathered in
each succeeding year. The preserve or " park V is paved,
to prevent an excessive accumulation of mud, which
would destroy the fry. Its enclosed and raised position
prevents the access of fish and other injurious animals.
The German Ocean has been so long the fishing-pond
of Europe, that its supplies are beginning to fail us;
and we cannot feel too grateful to M. Coste for his
ingenious method of replenishing the nearly exhausted
stock of oysters. Besides man, the oyster has many
enemies ; and were it not for its wonderful fecundity, it
must long ere this have been extirpated. Starfishes,
whelks, and annelids attack and devour the adult ; and
countless shoals of small fish, bivalve mollusks, and
other animals swallow the fry while they are disporting
themselves in the brief period of their free and active
state.

The oyster is a classical character; and its praises
have been said or sung by innumerable writers, from
Aristotle to " Professor " Blezard. It furnished Shake-
speare with many a playful allusion ; and the philoso-

OSTREA. 47

phical question which he makes the fool ask of Lear, as
to the mode of constructing its shell, would be difficult
for the best conchologist to answer satisfactorily. It
has even been celebrated in pastoral verse. Sannaza-
rius, an eccentric Italian writer of the last century,
changed the scene in this kind of poetry from woods
and lawns to the barren beach and boundless ocean,
introducing sea-calves in the room of kids and lambs,
seamews for the lark and the linnet, and presenting his
mistress with oysters instead of fruits and flowers. There
is no lack of gossip on the subject. The recent publi-
cation of three books attests its popularity. One con-
tains the " Life of an Oyster"; another gives directions
" where, how, and when to find, breed, cook, and eat
it"; and the third explains its medicinal and nutritious
qualities. All these brochures are very amusing. The
second teaches no less than fifteen different ways of
dressing this delicacy ; and it would especially interest
those who are not true lovers of it in its natural state,
and therefore approve of Gay's sentiment —

" The man had sure a palate covered o'er
With brass or steel, that on the rocky shore
First broke the oozy oyster's pearly coat,
And risq'd the living morsel down his throat."

But there is death even in the pot; and the 'Comptes
Rendus' for March last mentions some fatal cases of
poisoning by green oysters imported into Rochefort from
Falmouth. The Editor of the ( Journal de Conchylio-
logie/ in commenting on this accident, remarks that
English copper, in a metallic state, is a product " tres-
estimable," but less valuable as an article of food. Old
Fuller, in his ' Worthies/ says that oysters are the only
meat which men eat alive and yet account it no cruelty.
Probably, in his time German ladies did not crunch

48 PECTINID^.

ants between their teeth for the sake of the formic acid,
nor Russian ladies swallow little fishes alive in order to
tickle their throats. I am told that at St. Petersburg
fresh oysters are not reckoned eatable, but that they
are kept till they become ' ' high " and have a gamy
flavour ! One of the many good qualities of the oyster
is perhaps not generally known, and it has not been
noticed by any popular writer. It is reticence. Colman,
in his c Broad Grins/ says that the tiny page of Lady
Erpingham

" Slipp'd the Dame's note into the Friar's hand,
As he was walking in the cloister ;
And, then, slipp'd off — as silent as an oyster."

Family III. PECTI'NID^E, Lamarck.

Body oval or oblong, compressed : mantle having thick
edges : cini long and extensile : gills reflected : foot deve-
loped.

Shell spade-shaped, usually inequivalve and inequilateral :
beaks small, straight, and pointed, with lateral triangular pro-
cesses like ears or wings : hinge toothless : cartilage internal,
placed in a cavity beneath the beaks and strengthened by a
narrow ligament on each side.

The animal has a distinct foot, which is capable of
spinning a byssus, or bundle of horny threads, for attach-
ment to other bodies. It is also endued with a peculiar
power of locomotion. By a muscular action, analogous
to that which is known as systole and diastole, and by
repeatedly taking in and expelling a quantity of water,
it flits or jerks itself along for a considerable distance
although not in a straight line, flapping the valves of
its shell inwards like the wings of a bird in full flight.
The ventral margins are in front, the beaks are behind,

PECTEN. 49

and the less convex valve uppermost. But as the " beak"
of a shell is posterior, and that of a bird is anterior,
their relative position is reversed, although the motion
of each is nearly the same. Even Pecten pusio in its
younger state, and before it is permanently fixed, is free
and can swim about like its congeners. In other respects
also this family differs from the Ostreidce. The shell
is of a more regular and symmetrical shape, and its
hind margin is expanded on each side into the ears or
winglike processes above noticed. Its structure is
less compact — its composition, according to Mr. Sorby,
being " arragonite/' while that of the oyster is " calcite."
The impression of the great adductor muscle is placed
more on one side than in the ovster, where it is
almost central. The muscle by which the front edge
of the mantle is attached to the shell leaves a conspi-
cuous scar on the inside of each valve. The cartilage
and ligament advance with the growth of the animal, in
the same way as in the oyster, but more slowly. All
the British Pectinidce are ribbed or striate lengthwise.
Pecten similis, which is commonly smooth, is hardly an
exception, for it sometimes has distinct ridges diverging
from the beak to the margin of the shell.

•b J

Genus I. PECTEN *, Plinv. PI. II. f. 1.

Body oval : mantle fringed with ocelli or eye-like tubercles.

Shell more or less in eqiri valve: ligament internal : muscu-
lar scar nearly central.

The name of this genus is nearly as ancient as that
of Ostrea. It is very expressive, the shell usually
having ribs which are arranged like the teeth of a
lady's comb. Sometimes it resembles the expanded

* A comb.

D

50 PECTINID^E.

frame of a fan. Scallops are especial favourites of shell-
collectors and amateurs, on account of their elegant
shape and their brilliant and varied hues. The curious
organs called ' ' ocelli v or eyelets are supposed by some
physiologists to be rather highly organized, and even
superior to the so-called eyes of most Gasteropodous
Mollusca. More than one hundred of them have been
counted in a single individual of some species oiPecten.
For this reason Poli called the animal Argus. These
little eyes have a prismatic lustre, and gleam like pre-
cious stones which are set round the inside of a casket
lined with mother-of-pearl. Their structure has been
lately and independently investigated by Grube, Krohn,
and Will. Very young shells of all the species are
destitute of ribs ; and they are nearly rhomboiclal, owing
to their breadth and the size of their ears being propor-
tionally greater at that stage of growth than afterwards
is the case. In consequence of the Scallops being gene-
rally attached or sedentary, the upper valve is more
deeply and brightly coloured than the lower one.

Although all the essential characters of the present
genus are uniform and do not vary much in the several
species, it has been divided by authors into no less
than twenty-eight, most of which will be found enu-
merated in the useful Index of Herrmannsen. In nearly
all the British species the upper or left valve is the
larger, and is also distinguished from the other by its
brighter or deeper hue. In Pecten maximus, however,
and occasionally in P. septemradiatus, the lower or right
valve is the larger, and almost or quite colourless. The
intensity of colour is supposed to depend on the action
of solar light, although it is not wanting in animals
living in the abysses of the ocean, which the most atte-
nuated sunbeam has never directly penetrated.

PECTEN. 51

A. Upper valve more or less convex : hinge-line ribbed across.
1. Pecten pu'sio"*, Linne.

Ostrea pusio, Linn. Syst. Nat. p. 1146. T.^usio, F. & H. ii. p. 278, pi. L.
f. 4, 5, and li. f. 7.

Body vermilion or yellowish -white with a brown tint, or
particoloured : cirri numerous, short, and blunt, arranged in
from 5 to 7 rows : ocelli large and few in number.

Shell varying in shape according to age, being when young
considerably longer than broad, and regular, but in its adult
state broader in proportion, and distorted or twisted in con-
sequence of its fitting the cavities and sinuosities of the bodies
to which it is fixed ; in the earlier stage of growth it is almost
equivalve, but afterwards the upper valve becomes usually the
larger and more convex of the two ; sides nearly equal ; it is
rather solid, and not glossy : sculpture, about 70 narrow and
sharp ribs which are alternately large and small, crossed by
numerous transverse plates, which by their intersection form
scales or prickles on the crests of the ribs ; the whole surface
is exquisitely marked by microscopical longitudinal striae which
diverge from each successive layer of growth ; in the fry these
stria3 only are visible, the ribs not then existing : colour red-
dish, yellowish, brown, or white, or of intermediate shades,
variegated by straight or diverging streaks or blotches of some
of those tints : margins rounded in front and at both sides, and
notched or indented by the impression of the ribs ; in the
young the upper edge of the angle on the right-hand side,
which lies under the large ear, has a row of curved spines,
which are arranged like the teeth of a saw : beaks prominent :
ears of unequal size, especially in the young, that on the left-
hand side of .the upper valve and -on the right of the lower
valve being the largest ; all of them are sculptured like the
rest of the shell, the ribs diverging from each side of the beak
outwards ; the right-hand ear of the lower valve is notched at
the base, and it is smaller than the opposite one on the left
hand of the upper valve, in order to make an opening and
passage for the byssus : hinge-line straight : cartilage short but
strong : ligament long and slender : hinge-plate strengthened
by a thick and knob-like rib on each side of the beak, to form
the sides of the cartilage-pit: inside pearly, microscopically

* A youngster.

D 2

52 PECTINID/E.

pitted, and sometimes very finely and closely striate length-
wise : muscular scars slight. L. 1*65. B. 1-45.

Habitat : Every rocky coast from Shetland to Corn-
wall, often on oyster-beds, and attached, in the adult
state by the whole or last-formed part of its lower valve
to the inside of old bivalve shells, or to rocks, Eschara
foliacea, and other substances. The depth of water in
which it lives varies from 5 to 85 fathoms, and the
young are occasionally found at low-water mark on
some shores where the tide retires for two or three
fathoms. In a fossil state P. pusio occurs in the Clyde
beds, as well as in the Red and Coralline Crag. Its
extra-British range is considerable, extending from Nor-
way to the Azores on the one side and to the iEgean on
the other.

In more northern seas this species soon fixes itself
permanently to various bodies by means of an aggluti-
nating secretion ; but in the Mediterranean and more
southern latitudes it usually remains free, or attached
by a byssus only, from which it has the power of
withdrawing or disengaging itself at pleasure. In the
former or fixed state it belongs to the genus Hinnites
of Defrance. It has been clearly shown, however, by
the late Mr. G. B. Sowerby thirty-five years ago, on con-
chological grounds, and by Dr. Fischer in 1862, physio-
logically, that this species is a true Pecten, and that the
genus Hinnites is not maintainable. The peculiar mode
of attachment by the shell in this case is the reverse of
that adopted by the oyster, the former having the
smaller valve and the latter the larger valve uppermost.
The prickly scales are sometimes produced also on the
lower valve, and become leaf-like or foliated as in the
oyster. In fixed specimens the byssal sinus is more
or less closed; but I have some of a large size and

PECTEN. 53

much distorted, which were attached by a strong byssus
as well as adhering by the shell. According to Fischer
the foot does not become atrophied or proportionally
smaller in the fixed adult, although it is then quite use-
less for the purpose of locomotion. This fact is opposed
to the general idea that the size of organs is modified
or affected by a change in the habits of an animal. The
present species was first described by Lister with his
wonted accuracy. Wallace, in his ' History of the
Orkneys/ has an ingenious way of accounting for the
shells being so distorted. He calls them the ' ' twisted
Pectines of Stroma," and says, " I cannot think the odd
strange tumbling the tides make there can contribute
anything to that frame ; yet after all I never see them
in any other place."

It is the Ostrea sinuosa of Gmelin and the P. distortus
of Da Costa. In its younger state it is the P. multi-
striatus of Poli, and the P. Isabella of Macgillivray but
not of Lamarck.

2. P. va'rius*, Linne.

Ostrea varia, Linn. Syst. Nat. p. 1146. P. varius, F. & H. ii p 27.3
pi. L. f. 1.

Body pale red, pink, brown, or yellow, sometimes mottled
with white or streaked with purplish -brown : mantle broad-
edged : cirri numerous, of unequal length but mostly long
and slender, arranged in four rows : ocelli about 30, black, and
smaller than in the last species : foot rather large, thick, and
white.

Shell transversely oval, much broader in front than be-
hind, nearly equilateral, rather solid and slightly glossy : sculp-
ture, 25-30 smooth and rounded ribs, which are equal-sized •
the whole surface is also covered transversely with fine plates
which often form vaulted spines on the crests of the ribs j the
interstices of the ribs are marked with minute bifurcatino-

* Variegated.

51 PECTINID.E.

striae : colour red, pink, yellow, purple, brown, and rarely
milk-white, with streaks or blotches variously disposed :
margins rounded in front and at the sides, and notched or
indented by the ribs, sloping abruptly to the beak on each side
from a little above the middle ; upper side of the slope on the
right hand of the lower valve toothed or serrate as in the
last species : beaks prominent : ears unequal and formed as in
P. pusio ; the right-hand one of the lower valve projects
beyond and slightly overlaps the opposite ear of the upper
valve ; their markings and the byssal notch are the same as in
the last species, as well as the cartilage, ligament, and internal
structure ; but the muscular scars are more distinct. L. 1*85.
B. 1-65.

Yar. 1. purpurea. Shell larger, broader, and natter : colour
purplish-brown marbled with yellow.

Yar. 2. nivea. Shell of the same shape as the last variety,
and having about 45 ribs : colour snow-white, sometimes tinged
with purple, or more rarely orange, yellowish, purple, or brown
of different shades. P. niveus, Macgillivray, Edinb. Xat. & Phil.
Journ. xiii. p. 166, pi. 3. f. 1 ; F. & H. ii. p. 276, pi. L. f. 2,
and (animal) pi. S. f. 3.

Habitat : Equally common with the last species,, and
in similar situations; but it does not appear to have been
found on these coasts north of the Orkneys, whence
a white variety has been procured by the Rev. Dr. Smith
of Old Aberdeen. The range of depth varies from low-
water-mark at spring-tides to 40 fathoms. Yar. 1. Fal-
mouth harbour and off Portsmouth (J. G. J.) ; Cork
harbour (Humphreys); Bantry Bay (Barlee). Yar. 2.
Western coasts of Scotland, in 3-25 fathoms, on Lami-
naria saccharina and occasionally attached to stones ;
Glengariff, Bantry Bay (Barlee). As a fossil or subfossil
this species is found, in the upper tertiaries of the Bel-
fast, Clyde, and Sussex beds. Abroad it is distributed
in every sea from Bergen (Sars) to theiEgean (Forbes);
and according to Weinkauff it is not uncommon on the
Algerian coast.

PECTEN. 00

In the north of France it is called " Petite- Vanne";
and Collard des Cherres says that it is eaten in Brittany,
as well as other kinds of scallops. The pallial ten-
tacles or cirri of the variety nivea are extremely inter-
esting and beautiful objects. They are of different
colours in the same individual — white, yellow, and brown
— and are sometimes edged with black or purple. Some
of them are much longer than others, and each has a
white line or streak down the middle. The longest have
a few milk-white specks, and their tips are curled like a
crosier. A few of these tentacles are three-quarters of
an inch long. All are contractile and extremely sensi-
tive. The outermost row folds back over the margins
of the shell. The edges of the mantle are studded with
papillae. The ocelli do not correspond in number or
position with the ribs of the shell, there being two eye-
lets for every three ribs. All the specimens (about
twenty in number) examined by me on the 1st of Sep-
tember 1862, at Oban, shed from time to time a milky
fluid which I found was entirely composed of sper-
matozoa. These moved actively about in every direc-
tion and spread in the water like a thick mist. The
quantity emitted by each individual was very great, and
after every discharge the water became more turbid.
All these specimens had ovaries of a pale-yellow or
cream colour. This seemed to me a sufficient proof
of the monoecious character of the Scallop; and it
showed that the mode of its fecundation is the same
as takes place in many plants — only substituting sper-
matozoa for pollen-dust, and the waves for the wind
or winged insects. A quarter of a century ago, when
this pretty variety was not easily procurable and
therefore exceedingly rare, a specimen fetched £2.
Fifty or more may now be had for the same price. I

56 PECTINID^.

have the fry attached to a rib of Rissoa parva, showing
that they remove from place to place, at least in the
earlier stages of growth. The hooded crow is very fond
of these scallops. It takes one from the tangle at low
water and carries it to the shore or a bank, on which it
drops its prey, watching with cunning patience until the
scallop opens its shell. It then quickly thrusts its
pointed and strong beak into the gaping valves, forces
them asunder, and devours the dainty morsel. Dead
and bleached shells are thus often found in places at
some distance from the sea, where crows had been feast-
ing. Without this explanation they might have been
mistaken for fossils. Specimens of the variety pur-
purea attain a considerable size. One of mine is 3^%
inches long and 3 inches broad. This species differs
from the younger state of P.pusio in being larger, and
in the ribs being much less numerous, and equal in size
instead of alternately large and small. Being free and
Of a regular shape at all ages, it is readily distinguish-
able from the adherent and distorted adult of the other
species.

I fear that some of my conchological friends will be
terribly shocked at my innovation in uniting P. niveus
with P. varius ; but I feel constrained to take this bold
step, even at the risk of not being soon forgiven. I had
for a long time great misgivings on the subject; but it
was not until I had most carefully examined and com-
pared a multitude of specimens of both these so-called
species, collected from various and distant places, that I
was able to arrive at a satisfactory conclusion. The
only points of difference between P. varius and P. niveus
consist in the latter having a broader and flatter shell
with more numerous and delicate ribs, and in the colour
being white. All these characters are combined or

PECTEX. 57

blended in specimens of P. varius and what I consider
to be its two principal varieties. Some are broader and
flatter than others : the number of ribs varies from 27
to 45 , and consequently in their comparative fineness ;
and the white of P. niveus is sometimes beautifully
tinted with purple, and passes into different shades of
other colours. I have taken P. niveus only in every
part of the Hebrides, and I have never seen a single
specimen of P. varius from that district. In Loch Fyne
and at Jura an intermediate variety occurs. A speci-
men from the former locality has 36 ribs, and one from
the latter 32 ribs. I noticed in the collection of M.
Martin, at Martigues, a white variety having also 32
ribs. A still more puzzling form was sent to me in
1852 by Mr. Barlee from GlengarifF in Bantry Bay,
which clearly connects the two species; and the variety
purpurea forms another link in the chain of specific
identity. I believe this varietal difference arises from
habitat. The strong and few-ribbed P. varius lives on
oyster-banks and rough ground on an exposed coast;
while the delicate and many-ribbed P. niveus is only
found in sheltered lochs and arms of the sea, moored by
its strong byssus to the upper surface of the broad and
smooth fronds of Laminari<B. The very circumstance of
the latter being confined to a limited district is suspi-
cious as regards its specific distinction. Dr. Gray, in com-
menting on the species in question (Ann. Phil. no. 59.
p. 387), says, " Mr. Macgillivray only compares it with
P. varius, perhaps not aware that Pecten Islandicus,
Lam., of which this shell appears to be only a variety, has
long been known as a British species." The last-named
species, however, has never been found in Great Britain
except as an upper tertiary fossil ; and it has only a
generic resemblance to Macgillivray's shell.

d 5

58 PECTINID.E.

P. Islandicus, Miiller, once lived within the area which
now constitutes the more northern part of the British
seas and nearly the whole of Scotland. It is, however,
no longer an inhabitant of our coasts. Dead shells in a
semifossil state, but occasionally retaining their beau-
tiful pink colour, are not unfrequently dredged upon
both sides of Scotland and off the coasts of Shetland,
close to land and also at various distances from it, at
depths of from 30 to 80 fathoms. It is not uncommon
in pleistocene beds on the west of Scotland and in the
Moray Firth. The best explanation I can offer for its
never having been found alive in any part of our seas is
by suggesting that the ancient sea-bed which it in-
habited during some part, if not the whole, of the glacial
epoch was afterwards upheaved above the level of the
sea, so as to cause the extinction of this and other arctic
species, and that at a subsequent period a great part of
this district was slowly submerged and is now again
covered by the sea. We know that this process of eleva-
tion in some and depression in other parts of the Atlantic
sea-bed is still going on. Sweden and Greenland are
instances of the former phenomenon ; and to the latter
may be referred the discovery by Dr. Wallich of star-
fishes belonging to a species which usually inhabits
shallow water, living at a depth of 1260 fathoms, as
well as the occurrence of Nassa incrassata and other
littoral kinds of Mollusca in nearly 80 fathoms off the
coast of Shetland. P. Islandicus survives and is abun-
dant in every part of the Arctic Ocean at depths varying
from 15 to 150 fathoms. It has not been recorded as
living south of Drontheim ; and Malm says that it does
not now exist anywhere on the Swedish coast, although
it is common there in a fossil state. This species is not
unlike the variety nivea of P. varius in shape and the

PECTEX. 59

number of ribs; but the shell is more solid, the ribs
sharper, and the surface resembles shagreen.

3. P. opercula'ris*, Linne.

Ostrea opercularis, Linn. Syst. ISat. p. 1147. -P. opercularis, F. & H. ii.
p. 299, pi. L. f. 3 ; li. f. o, 6 ; liii. f. 7.

Body thick, variegated with pink, cream- colour, fawn, orange,
or brown, and mottled with flake-white meandering lines, spots,
and blotches : mantle thin, except at the fleshy margins : cirri
conical, white, of unequal length and irregularly disposed in
two or three rows, the outer one of which has the longest fila-
ments : ocelli 35-40, nearly globose, having pearl- coloured
pupils within black circles : foot small, subcylindrical, deeply
cloven or furrowed, and scoop-shaped at its extremity, of a
yellowish-white colour.

Shell circular and equilateral, except at the back (where the
periphery is interrupted by the beak and ears), rather thin,
scarcely glossy: sculpture, about 20 rounded ribs, which are of
equal size and somewhat broader than the interstices ; the
surface is more or less covered with extremely fine and wave-
like transverse plates, which often form numerous rows of short
prickles, especially along the ribs and on their crests, making
the shell feel rough as shagreen : colour red, pink, orange,
yellow, purple, brown, or of intermediate shades, often streaked
or marked with blotches or spots, and sometimes (but rarely)
milk-white : margins rounded in front and at the sides, notched
or indented by the ribs, sloping gradually to the beak on each
side from about three-fourths of the distance from the front
margin ; slope below the byssal sinus strongly toothed or ser-
rate : heaJcs prominent : ears nearly equal, sculptured by ribs
which radiate from the beak; the ears of the lower valve
slightly project beyond and overlap those of the upper valve ;
byssal notch deep : hinge-line straight : cartilage rather large :
ligament narrow and slight: hinge-plate somewhat broad,
minutely striate across ; transverse rib strong and raised on
each side of the cartilage-pit : inside fluted or grooved, so as
to correspond with the folds of the outside ribs ; each shoulder
under the ears is furnished with a thick ledge, which rests on
that in the opposite valve, thus giving additional support to the

* Like a cover or pot-lid.

60 PECTINID.E.

hinge and preventing its being too closely pressed : muscular
scars distinct. L. 2*35. B. 2-5.

Tar. 1. lineata. Shell white, with a brown line running
down the crest of each rib. P. liaeatus, Da Costa, Brit. Conch,
p. 147, pi. x. f. 8.

Yar. 2. tumida. Shell more swollen and deeper.

Yar. 3. elongata. Shell smaller, and longer than broad.

Habitat : Common on all sandy coasts, and grega-
rious, in 6-90 fathoms. Yar. 1. Not nnfrequently found
with specimens of the usual colour, and sometimes having
a mixed hue. Var. 2. Plymouth (J. G. J.) ; Exmouth
(Clark); Cork (Humphreys). Var. 3. Loch Torridon,
Ross-shire (J. G. J.); BirterbuyBay, co. Galway (Barlee) :
rare. This species is a common fossil in the Scotch
glacial deposits, and in the Norwich, Red, and Coralline
Crag. Steenstrup informs me that he has found it in
Iceland; Mohr has recorded it from the Faroe Isles,
Weinkauff from Algeria, Forbes from the iEgean, and
M c Andrew from Madeira; and it is widely distributed
throughout the intervening seas.

This pretty and well-known species was first described
by Lister. Mr. Norman says that quantities are dredged
in the Firth of Clyde, where they are called " clams,"
for bait in the long-line fishery. When cooked they
have a rich and agreeable, but peculiar, flavour : they
are not much eaten in this country. According to
Montagu they are called " frills " or " queens " on the
South Devon coast. The fishermen on the Dorset coast
call them " squinns." In the north of France this kind
bears the name of " vanneau " or " olivette. 1 " The
shells make pretty pincushion- cases; and in the North-
American States another species (P. concentricus) is
used for the same purpose.

PECTEN. 61

The 'Rev. Dr. Landsborough has given the following
interesting account of their habits in an earlier stage of
growth : — " We observed on a sunny September day in
a pool of sea- water left on Stevenston strand (Ayrshire)
by the ebbing tide, what we at first thought some of the
scaly brood at play. On close investigation, however,
we found that it was the fry of Pecten opercularis
skipping quite nimbly through the pool. Their motion
was rapid and zigzag, very like that of ducks in a sunny
blink rejoicing in the prospect of rain. They seemed,
by the sudden opening and closing of their valves, to
have the power of darting like an arrow through the
water. One jerk carried them some yards, and then
by another sudden jerk they were off in a moment on a
different tack. We doubt not that, when full-grown,
they engage in similar amusements, though, as Pectens
of greater gravity, they choose to romp unseen and play
their gambols in the deep." The animal of the adult
scallop, when at rest, is a study for a painter, with its
large and bright pink ovary, and its mantle studded on
each side with a row of brilliant eyelets, like dewdrops
glittering in the sun of a May morning. The trans-
verse plates form hollow or vaulted scales in young
shells ; and their surface is minutely and closely tuber-
cled, like the cells of Polyzoa. In the fry the upper
valve is much larger than the lower one and overlaps
it. The ribs are not then formed, but the byssal sinus
is well developed. Specimens from the Firth of Forth
and Shetland are much larger than usual, although
slightly differing from each other in their relative pro-
portions. I have one from the latter district measuring
Sjjj inches long and 3^ broad, and another from Porto-
bello 3^- long and nearly 4 broad. Occasional distor-
tions or monstrosities occur.

62 pectinid^:.

P. opercularis may be readily known from either of
the two foregoing species by its circular form, greater
size, and nearly equal ears. The P. Audouinii of Pay-
raudeau can hardly be considered a variety. Its sculpture
is that of the P. lineatus of Da Costa, and only differs
from that of ordinary specimens in the scales being
more regular and continued across the ribs. The P.
subrufus of Turton is merely the young state, with a
straighter outline. Many other specific names have
been invented by authors for still more trifling varieties.

4. P. septemradia'tus*, Miiller.

P. septemradiatus, Mull. Zool. Dan. Prodr. p. 248, no. 2992. P. Danicus,
F. & H. ii. p. 288, pi. Hi. f. 1-2, 7-10.

Shell nearly circular and equilateral, except as in the last
species, thin, somewhat glossy : sculpture, mostly 7 rounded
but compressed ribs (the middle one being the largest), which
are much narrower than the interstices ; the surface is covered
with minute and close-set longitudinal strise, which are crossed
by equally fine but more remote transverse plates, so as occa-
sionally to form prickles at the points of intersection ; the sides
are marked with short and stronger strise, placed at right
angles to the longitudinal striae: colour reddish-brown, mot-
tled or streaked with white : margins as in P. opercularis ;
slope below the byssal sinus seldom, and never distinctly, ser-
rate : beaks prominent : ears nearly equal in the upper valve,
but not so in the lower valve, in which the right ear is the
larger ; all of them are sculptured by ribs radiating from the
beak, as well as by fine and numerous striaa, which run from
the sides or shoulders and diverge outwards ; there are also
some wavy striaa in the line of growth, crossing the auricular
ribs ; the ears of the lower valve project beyond and overlap
those of the upper valve, but much less than in any of the pre-
ceding species ; byssal notch slight : hinge-line straight : car-
tilage small : ligament very thin : hinge-plate rather broad,
microscopically striate across ; transverse rib slight and raised
a little on each side of the cartilage -pit : inside fluted or

* Seven-rayed.

PECTEN. 63

grooved as in other ribbed species : muscular scars rather
distinct. L. 1-625. B. 1*475.

Var. 1. alba. Shell of a milk-white colour.

Var. 2. Dumasii. Shell smaller and more solid, longer in
proportion to its breadth ; upper valve less convex than the
lower one and sometimes quite flat or even slightly concave :
sculpture coarse, with 3-10 sharp ribs : ears often unequal,
those on the byssal side smaller than the opposite pair. P.
Dumasii, Payr. Cat. Moll. Corse, p. 75, pi. ii. f. 6, 7.

Habitat : Rather plentiful in Loch Fyne, and gene-
rally distributed over our northern seas, and southward
as far as the Northumberland coast, in 20-90 fathoms,
rough ground. Var. 1. Loch Fyne and Shetland (Bar-
lee). Var. 2. Hebrides and Shetland. This species is
fossil in the Clyde basin, and in other glacial deposits in
Scotland as well as Norway. It ranges from Finmark
to the iEgean, but it appears not to be so common in
the south as in the north. The variety Dumasii occurs
in the upper miocene strata near Antibes.

P. septemradiatus was added to the British fauna by
the late Capt. Brown in 1835. It is remarkable that
such a handsome and by no means small shell should
have previously escaped the notice of Laskey, Fleming,
Macgillivray, and others of our northern conchologists.
This can scarcely be accounted for by the dredge not
having been used in those days, because specimens are
usually procured from fishermen. They are frequently
caught in the herring-nets, when disturbed on their
feeding- grounds and swimming or flitting about. I
am not aware that the animal has ever been described ;
and I have unfortunately missed the opportunity of
observing it. Asbjornsen mentions his having taken
specimens in the beginning of May, which were full of a
milky fluid. The shell is extremely variable in respect
of shape and the number of ribs, as well as of the pro-

64 PECUNIAE.

portionate size of the ears. A single valve which I
dredged off Skye in 1847 somewhat resembles Philippics
var. 77. of P. polymorphus ; the front of each valve is
folded inwards and grooved, with the inside margin
finely notched or crenulated. In young shells the sur-
face is regularly cancellated. The fry is glossy and has
very prominent beaks ; its sculpture consists of nume-
rous microscopical longitudinal strise on the upper
valve, and equally minute transverse strise on both
valves.

A dozen names have been given by different concho-
logists to this species. If the authority of O. F. Miiller,
the original discoverer, were at all questionable, Gme-
lin's name of hybridus would have the priority over that
of Danicus, which was proposed by Chemnitz nineteen
years after the publication of the Prodromus to the
1 Zoologia Danica/

P. glaber of Pennant and Montagu is a well-known
Mediterranean species ; and there does not seem to be
any reason for supposing that it ever inhabited the
Welsh or Scotch coasts, as stated by those authors.

I have a single valve of P. sulcatus, Miiller, which was
dredged off the east coast of Shetland by Mr. Barlee ;
but as it is an imperfect specimen, I do not at present
describe this species as British, but merely offer a short
notice of it. It has thirty-two ribs, besides small inter-
mediate ones ; they are rounded and cord-like, with
thin transverse plates in the interstices. The colour of
my specimen is orange-yellow. The ears are propor-
tionally larger than in P. septemradiatus. The inside
is marked by furrows, which correspond with the ribs
as in P. glaber. The species now noticed inhabits the
Scandinavian seas. A small single valve, in a semi-
fossil state, was taken by Capt. Hoskyns at a depth of

PECTEN. 65

340 fathoms, in his recent soundings off the west coast
of Ireland. In consequence of the specific name (sul-
catus) having been preoccupied by Born for a very dif-
ferent kind of scallop from Malabar, the name proposed
bv Miiller is inadmissible : and Gmelin made a better
hit than usual in changing the name of the northern
shell to aratus. Lamarck carelessly applied the same
name of sulcatus to another species of Pecten which is
common in the Mediterranean. It is possible that the
P. 20-sulcatus of Miiller may be a variety of his P. sul-
catus ) and in that case the first of these names ought
to be adopted in preference to that given by Gmelin.

5. P. tigri'nus*, Miiller.

P. tigerinv.s, Mull. Zool. Dan. Prodr. p. 248, no. 2993. P. tigrinus, F. & H.
ii. p. 285, pl.li. f. 8-11.

Body bright red or occasionally creamy-white : mantle
edged with white and mottled with dusky or brown rays :
cirri short : ocelli 10, brown with a golden centre : foot white
and very flexible : byssus transparent.

Shell of the same shape as the last two species, bnt rather
narrower at the back, moderately solid, and somewhat glossy :
sculpture, extremely fine and numerous impressed striae, which
radiate from the beak and gradually diverge to the front and
side margins ; these striae are not visible to the naked eye, and
under a strong magnifier they appear regularly but slightly
punctured in consequence of the intersection of equally minute
and close-set transverse striae, which follow the fine of growth ;
the longitudinal striae are sometimes irregularly waved or
interrupted, and are often forked : colour yellow, brown, or
purple, and now and then white, with variously disposed
bands, streaks, blotches, spots and other markings of those
hues : margins rounded in front, so as to form a semicircle,
and sloping from near the middle to the beaks at an angle of
about 45 degrees ; the front margin is sometimes folded in-
wards and strongly notched ; the upper part of the slope below

* Barred like a tiger.

66 PECTINID^.

the byssal sinus is finely toothed : beaJcs very prominent and
considerably raised : ears unequal ; those on the left hand of
the upper valve and right hand of the lower valve are at least
four times the size of the others; all of them have a few
strong ribs which radiate from the beaks, and they are also
marked with coarse and numerous striae which cross the ribs
obliquely ; the ears of the lower valve project very little be-
yond those of the upper valve ; byssal notch deep : hinge-line
straight : cartilage small : ligament very thin : hinge-plate
narrow, microscopically striate across ; transverse rib strong
and considerably raised on each side of the cartilage-pit : in-
side nacreous, finely and closely striate lengthwise and notched
on the front margin ; within the larger ears are strong grooves
which correspond with the outside ribs : muscular scars dis-
tinct, especially in aged specimens. L. 0-9. B. 0-885.

Yar. costata. Shell stronger than usual, and having either
five ribs and intermediate small ones, or else several riblets
of equal size : inside grooved and striate accordingly.

Habitat : Not uncommon from Shetland to the
Channel Isles in 7-82 fathoms, on a sandy bottom mixed
with gravel ; and the variety is equally diffused. This
species occurs as an upper tertiary fossil in the Scotch
glacial deposits, and also in the Red and Coralline Crag.
It is a native of the Icelandic and Scandinavian coasts ;
and Mr. M'Andrew has taken it in Vigo Bay at a depth
of only 8 fathoms.

The shell varies greatly in size and proportions, as
well as in colour and the number of ribs. My largest
specimens are one inch and two-tenths long, and nearly
the same in breadth. Sometimes the breadth slightly
exceeds the length. Young shells are proportionally
longer than old ones. In the former the so-called "eyes"
are perceptible through the semitransparent shell many
years after the animal has ceased to exist. The fry are
not sculptured, but perfectly smooth; and the lower
valve is nearly flat and smaller than the other. Miiller
noticed the way in which he presumed this scallop pro-

PECTEX. 67

cures its food, viz. by rapidly opening the valves of its
shell and clapping them together with an audible noise
ten or twelve times in succession. It then kept them
wide open and for a much longer time than suited the
patience of the great zoologist. By this violent agita-
tion of the water a fresh supply of animalcula may be
brought to its insatiable maw. He adds that it can
squirt the water out of a vessel half an ell high ; but I
have never seen it perform such an extraordinary feat.
The jet of water would be at least fifty times the length
of the animal.

A slight and pardonable liberty has been taken in
changing the original spelling of the specific name from
tiger inus to tigrinus. This shell was called P. parvus
by Da Costa, P. domesticus (used of course in the sense
of native) by Chemnitz, and P. obsoletus by Pennant.

6. P. Test^:*, Bivona.

P.. Testes. (Bivona) Philippi, Moll. Sic. i. p. 81, t. v. f. 17. P. furtivus,
Lot. Ind. Moll. Scand. p. 31.

Shell somewhat resembling P. tigrinus in shape, but
rounder and much more depressed, rather thin and glossy :
sculpture, minute longitudinal and transverse striae, which are
arranged as in the last species, but they are more regular and
never forked ; they are deeply punctured at the points of
intersection ; sometimes there are also from 30 to 35 delicate
ribs, which become scaly or prickly where they are crossed by
the transverse striae: colour yellow, orange, brown, purple,
pink, or occasionally white, usually diversified by streaks, rays,
blotches, spots, diagonal lines, and other markings of the above
hues : margins rounded in front, and forming an arc of two-
thirds of a circle in consequence of the lateral slopes towards
the beaks commencing higher up than in P. tigrinus ; byssal
slope finely toothed : beaks prominent but not much raised :
ears unequal, those on the byssal side being about twice as
large as the other pah ; all of them have several fine ribs,

• * Named in honour of S r . Testa, a conchologist at Panorino in Sicily.

68 PECTINID^.

which radiate from the beaks and are crossed by coarse flexuous
strise ; the edges of the ears on the lower valve project very
slightly ; byssal sinus deep : hinge-line straight, finely notched
or serrate at its edge : cartilage rather large : ligament ex-
tremely slight : hinge-plate very narrow, microscopically striate
across ; transverse rib slight, and not much raised on each
side of the cartilage-pit, which is proportionally more open
than in any of the foregoing species : inside slightly nacreous,
finely and closely striate lengthwise, or furrowed when the
outside is ribbed ; margin sometimes notched or crennlated :
muscular scars indistinct except in aged specimens. L. 0*575.
B. 0-55.

Var. suborbicularis. Shell larger, with the slope much
higher than usual, and considerably narrower behind: ears
smaller. L. 0-7. B. 0-7.

Habitat: Shetland, Skye, Larne (co. Antrim), Birter-
buy Bay (co. Galway), Guernsey (J. G. J.) ; Exmouth
(Clark) ; in gravelly sand, 18-80 fathoms. It is a rare
species. The variety is remarkable. I obtained only a
single valve by dredging off the north coast of Shetland in
86 fathoms. Although of much smaller size, this variety
resembles in shape and other respects the P. Gerardii
of Nyst, one of our Coralline Crag fossils. The foreign
range of P. Testa extends from Norway to Algeria and
the iEgean. Asbjornsen gives the depth at which it is
found in Christiania fiord as 10-20 fathoms.

This beautiful species differs from P. tigrinus, with
which it is sometimes found, in the following particu-
lars. The shell is broader, flatter, and thinner; the
ribs, when they occur, are scaly or prickly ; the punc-
tures are very strongly marked and arranged in squares;
the beaks are much less prominent and raised ; the ears
are not so unequal ; and the inside margin is seldom
crenulated. Forbes and Hanley considered it to be a
variety of P. striatus-, but Malm has satisfactorily
shown some of the points of difference between these

PECTEN. 69

two species. I have never seen an intermediate form,
although I have examined many hundred specimens of
P. striatus and about fifty of P. Testce with a view to the
comparison. The present species has some of the sculp-
ture of P. tigrinus and the shape of P. striatus. The
colouring of P. Testce is more bright and vivid than that
of the other two. Some specimens are perfect gems.
Mediterranean examples are usually much smaller than
those from the North Atlantic, although I have seen
several of a tolerable size which were collected by S r .
Costa at Naples. Mr. Claries specimen from Exmouth,
in my collection, was mixed with P. tigrinus ; and I am
rather surprised that his habit of close observation did
not enable him to separate them.

It is probably the P. incomparabilis and P. vitreus
of Risso; but his love of species-making seems to
have been so inveterate, and his collection is in such
a deplorable state of confusion, that it is almost hopeless
to attempt any identification of his names. The P.
vitreus of Chemnitz is quite a different species, as Phi-
lippi has w r ell observed.

7. P. stria'tus*, Muller.

P. striatus, Mull. Zool. Dan. Prodr. p. 248, no. 2994 ; P. & H. ii. p. 281,
pi. Ii. f. 1-4, and (animal) pi. S. f. 2.

Body whitish, irregularly streaked lengthwise with opaque
white lines : mantle edged with white and having an outer
fringe of extensile white cirri : ocelli 25 in number, blue-
black with crimson centres ; behind them is an inner fringe of
short white cirri : gills also furnished with 20 reddish -brown
ocelli, each of which surmounts the crest of a leaflet.

Shell resembling that of P. Testce in shape; but it is rather
larger, thinner, and more fragile, and the sculpture (especially
of the upper valve) is very different. In the present species it

* Striate.

70 pectinidjE.

consists of numerous fine ribs, which radiate from the beaks to
the front and side margins, and have their crests thickly set
with short vaulted spines or prickles ; besides these riblets, the
surface is closely covered with extremely minute and irregular
longitudinal striae, which are raised and divaricate or become
forked, but they are never reticulated or punctured as in
P. Tested. The .colour is of a more sombre hue. The left ear
of the upper valve hangs down much lower, and is nearly
entire instead of being deeply notched as in that species ; and
the byssal sinus is consequently larger. L. 0-725. B. 0*7.

Habitat : Seas of Shetland, Scotland, north-eastern
coasts of England, north, east, south, and west of Ire-
land, Isle of Man, and Scilly, in 12-90 fathoms, hard
ground. Morch has procured it from the Faroe Isles,
and Danielssen from West Finmark. It also inhabits
other parts of the Scandinavian coast. M f Andrew has
dredged it in Vigo Bay at a depth of 15 fathoms, and
Philippi describes it as a Calabrian fossil under the
name of P. rhnulosus.

The shell is sometimes distorted. The pallial ocelli or
eyelets are of unequal size and irregularly placed ; they
gleam with an opaline lustre. Living specimens which
I dredged in 85 fathoms had the shells highly coloured
and streaked. Mr. Norman has noticed, in his list of
Clyde Mollusca, that the shells of this species lose the
azure-blue colour after being kept in a closed cabinet.
This is remarkable, because certain colours of shells and
other animals {e.g. pink and reddish- brown) fade, and
even vanish, unless the light is excluded. In the British
Museum it has been found necessary to replace, every
two or three years, fresh specimens of many delicate-
tinted butterflies exposed in the show-cases; and in
the museum at Amsterdam the shells are always kept
covered to prevent loss of colour. P. striatus attains a
greater size than P. Testes. My largest specimen is about

PECTEX. 71

an inch long, and a trifle more than nine-tenths of an
inch in breadth. The stride in the present species are
raised and irregular ; and they are never punctured or
reticulate. In the other species the striae are sunk or
impressed and regular, aud they are strongly punctured
or reticulate. The different substance of the shell, the
style and intensity of coloration, and the comparative
size of the left ear of the upper valve are also notable
marks of distinction. Even the fry of each species ex-
hibits its own peculiar characters.

It is the P. fuci of Gmeliu, P. reticulatus of Chem-
nitz, P. Landsburgi of Forbes, and P. aculeatus of my-
self.

8. P. si'milis *, Laskey.

P. similis, Lask. Mem. Wern. Soc. i. p. 387, t. viii. f. 8 ; F. & H. ii. p. 293,
pi. lii. f. 6, and (animal) pi. S. f. 1.

Body very variable in colour, often pale yellow or whitish
with brown streaks and blotches : mantle fawn-coloured with
patches and lines of orange and black : cirri short ; some are
white and others brown, a few being thicker and longer than
the rest and mottled with milk-white : ocelli 6-8 in front and
nearly twice as many in a second row behind ; the former are
comparatively larger, pearly, and ringed with jet : foot of a
brilliant orange-colonr or white.

Shell nearly circular but expanding towards each side,
where it forms an obtuse angle, and rhomboidal behind in
consequence of the projection of the ears, equilateral, de-
pressed, extremely thin and rather glossy ; lower valve con-
siderably smaller than the other, and to some extent enclosed
within it : sculpture, fine and close-set concentric lines only:
colour yellowish or milk-white mottled with reddish-brown
or flake-white spots or streaks, and often marked by longi-
tudinal white rays or transverse zigzag lines of a Vandyke
pattern : margins very thin, semicircular in front and sloping
about halfway on each side at an angle of 45 degrees to the
beaks ; byssal slope not toothed or serrate : heals small but

* Like the fry of P. maxmius.

72 PECTINIBvE.

prominent : ears long and drooping, nearly square-set, those
on the byssal side being the smallest, rounded at the corner ;
byssal notch slight: hinge-line straight, two-fifths of the
breadth of the shell : cartilage small : ligament so thin as to
be almost imperceptible : hinge-plate broad and smooth; trans-
verse rib slight and scarcely raised : inside pearly, minutely
striate lengthwise : muscular scars distinct. L. 0*285. B. 0*3.

Habitat : Sparingly occurring, although gregarious,
on all our coasts, in muddy sand at 2-82 fathoms.
Glacial deposits, Fifeshire (Fleming) ; Coralline Crag
(S. Wood). Its distribution extends from Finmark to
the iEgean ; and both in northern and southern locali-
ties it appears to have a considerable range of depth,
viz. 15-200 fathoms, Upper Norway, according to
M f Andrew and Barrett, and 27-185 fathoms in the
iEgean, according to Forbes. Norwegian specimens
collected by Professor Sars are of an extraordinarily
large size.

The animal, as well as the shell, of this tiniest of
scallops is very lovely. If, when fresh caught, put
into a glass of sea- water, it flits about like a bat for a
long time, and then fastens itself to the side of the vessel
by a fine and almost transparent byssus. After a while
it slips its cable and resumes its voyage of discovery,
until it becomes apparently exhausted by the fruitless
search and lies down on one side. My largest specimen
measures only 0'35 by 0375. The breadth invariably
exceeds the length.

For the discovery of this species science is indebted
to the late Capt. Laskey, although he described and
figured it from a right valve only, not having at that
time obtained a perfect specimen. It is the Ostrea
tumida of Turton, P.pygmaus of Von Minister, P. mini-
mus of Sars, P. Actoni of Von Martens, and P. Foresti
of Martin. The P. Grcenlandicus of Sowerby (P. vitreus

PECTEN. id

of Dr. Gray but not of Chemnitz) resembles the present
species in nearly every respect but that of size. It
may be an arctic variety of P, similis or (more probably)
a direct and ( pur-sang ' descendant from the original
stock.

B. Upper valve nearly flat and concave towards the beak :
hinge-line ribbed obliquely.

9. P. max'imtjs *, Linne.

Ostrea maxima, Linn. Syst. Nat. p. 1144. P. maximus, F. & H. ii. p. 296,
pi. xlix.

Body pinkish-white above and bright red or pink in front :
mantle variously marbled with brown, black, and white : cirri
on the inner margin of the mantle short, white, and arranged
in a single row ; those on the fixed or exterior margin are of
different lengths and arranged in three irregular rows : ocelli
of a greenish- blue or purplish hue, forming two rows, and
numbering from 30 to 35 ; those in the front row are con-
siderably larger than the rest, and correspond with the ribs of
the shell : foot snow-white, short, grooved, with a spatulate
extremity.

Shell nearly circular, except behind, where the projecting
ears give a square outline, equilateral above and nearly so
beneath; upper valve slightly raised in the middle, and
smaller than the lower valve, which is very convex ; it is thick
and solid, glossy in the umbonal region but elsewhere of a
dull hue : sculpture, 15 or 16 ribs in each valve, which radiate
from the beaks, and are strong, and nearly as broad as the in-
terstices between them ; the ribs and interstices are scored bv
a few parallel striaB, which are more numerous on the lower
than the upper valve ; the whole surface is covered with
minute and close-set thin concentric plates, which are im-
bricated or overlap one another like roof -tiles : colour reddish-
brown on the upper valve, with a yellow tint on the lower
valve ; both valves are sometimes beautifully mottled or marked
with bands, zigzag streaks, and spots of burnt umber, or bright
yellow suffused with a delicate pink hue ; occasionally, but

* Largest.

E

74 PECTINID.E.

rarely, the colour is white, with an orange tint at the beaks :
margins semicircular in front and sloping at the distance of
about one-fourth from the hinge-line at an angle of 30 degrees
to the beaks ; byssal slope not notched or serrate : beaks small
and not prominent in full-grown specimens : ears exactly equal
on the upper valve and nearly so on the other valve, furnished
with a few ribs or striae which radiate from the beaks ; byssal
notch closed in the adult state: hinge-line straight, rather
more than half the breadth of the shell : cartilage large, thick,
and strong: ligament narrow and rather slight: hinge-plate
broad, closely and microscopically striate across ; transverse
rib strong and raised on each side of the broad cartilage-pit ;
in the lower or deeper valve are two or three short oblique
ribs, which diverge from above the cartilage-pit towards the
sides in wave-like lines : inside glossy, tinged more or less
deeply with reddish-brown, fluted as in P. opercularis, and
having similar shoulders or ledges on the posterior slopes to pre-
vent contact at the hinge -area : muscular scars well marked,
especially on the upper valve. L. 4*5. B. 5.

Habitat : Nearly everywhere, and often gregarious
on banks, in 7-78 fathoms. It is also not uncommon
in all our upper tertiaries, both new and old. Its foreign
range comprises all the sea-bed lying between Norway
and the Canaries ; and, according to Sars, it occurs with
arctic shells in the "postglacial " beds of Christiania.

If the oyster is the king of mollusks, this has a just
claim to the rank and title of prince. In Lister's time
they were held in nearly the same esteem; and the
great scallop is even preferred by some, although from
its luscious quality it is not so provocative of appetite.
I have not heard of its being eaten raw in this country.
In the fish-markets of the north of France it is called
" grand'-pelerine," l ' gofiche," or " palourde." In the
south of England it shares with P. opercularis the name
of " frill/' and in the north that of " clam." According
to Afhenreus, this or an allied species (P. Jacobceus) was
used by the ancients for medicinal purposes, as well as

PECTEN. /O

for food. Old fishermen have a notion that it is taken
in greater quantities after a fall of snow ; but, if true,
this is difficult of explanation, because a scallop never
burrows or lives anywhere but on the surface of the
sea-bed. They used to be plentiful in Lulworth Bay on
the Dorset coast ; but now they are rarely found alive.
I was told that the breed had been exterminated there
by an epicurean officer of the coast-guard. The late
Major Martin would allow any conchologist to dredge
as much as he pleased in the bays of the Connemara
coast, provided he only took useless shells, such as
Tellina balaustina ; but all the big clams (P. maximus)
were reserved for the table at Ballynahinch Castle.
This kind of preserve would be much less expensive to
keep than a good pheasant-cover or a well-stocked moor,
and it would not be so liable to be poached. Nor were
the shells less prized in the days when Ossian sung.
The flat valves were the plates, the hollow ones the
drinking-cups of Fingal and his heroes, and "the joy of
the shell went round/'' The animal of P. maximus has
long attracted the attention of naturalists. As Mr.
Clark observed, " When the valves are opened, and the
mottled surfaces of the double margins of each valve are
in conjunction, and the various circles of filaments and
cirri fullv exserted in a shallow basin of sea- water, it is
scarcely possible to conceive a more beautiful and in-
teresting appearance/' The animal is small compared
with the size of the shell. This is also the case with
other kinds of Pecten ; and it may be owing to the
expansibility of the organs, which require much space
for their action. Donovan mentions a strange idea,
which was entertained by "modern as well as ancient
authors," that the way in which scallops leap or raise
themselves up is by forcing the under valve against

e2

76 PECTINID.E.

whatever they lie upon ! Shells sometimes attain an
enormous size. Dr. Landsborough says he measured
one which was 8 inches long. I have another specimen
that is barely -g^th of an inch in length. The young are
attached by a byssus. They are quite smooth ; and in
the place of ribs a few fine white lines radiate from the
beaks, as is not unfrequently seen in P. similis. This
might be considered by the advocates of a theory, which
was once put forward in the ' Vestiges of Creation/ a
case of arrested development as regards P. similis ; but
they ought to be aware of the fact that both these species
of every age inhabit the same spots and yet retain their
own distinctive characters. One species never grows or
merges into the other. The young of P. maximus may
be known from P. similis of the same size by the upper
valve in the former being flat, and in the other convex,
as well as by the inequality of the ears in the first-named
species. It bears a considerable resemblance to a young
Avicula, and shows the affinity which exists between
that genus and the Pectinida. The adult seem not to
have the power of spinning a byssus, nor to have any
occasion for it. Their solid shells can withstand a good
deal of buffeting by the tide ; if they were slighter, they
would require the cable of a Pinna to hold them on their
anchorage-ground. The substance of the shells is very
durable. I have had some of the deep valves in frequent
use during the last eighteen years for scalloping oysters ;
and although they must have been baked in an oven at
least five hundred times, they are as perfect and ser-
viceable as ever. The prettiest specimens come from
Dublin, Cork, and the Channel Isles.

This species belongs to the genus Vola of Klein. The
young is the P. Icevis of Pennant and the older British
conchologists.

LIMA. 77

P. Jacobceus (the famous " pilgrim " scallop) was at
one time erroneously supposed to be a native of these
seas. It is common in the Mediterranean, and M.
Mace has lately included it in a list of shells which he
has found at Cherbourg. It is distinguishable from the
present species by the ribs of the lower valve being
angular instead of rounded.

Genus II. LIMA* Bruguiere. PI. II. f. 2.

Body oblong : mantle not furnished with ocelli.

Shell equivalve : cartilage external : muscular scar placed
on one side.

Lima and Pecten have nearly the same characters ; but
the value or importance of generic, as well as of spe-
cific differences is comparative and varies in each case.
In the present genus the animal has a bright uniform
colour, while the shell is always white. Both animal
and shell in the other genus are more highly favoured
in this respect and exhibit various hues. The former
has its mantle studded with numerous eyes like the tail
of a peacock, and looks down upon its cousin as a poor
blind creature. The Lima moves or rather darts through
the water like a scallop, but in a contrary posture. The
hinder instead of the ventral end is in front, so that the
mode of its progression may be compared to that of a
fish swimming tail foremost. Some species construct
dwelling-places called " nests " out of fragments of
shells, nullipores, gravel, and other material, which
they ingeniously fasten together by their byssal threads
and attach to the roots of large seaweeds. Several
young ones often occupy the same nest or case ; but
when they become adult each individual has a house of

* A file.

78 PECTINID^E.

its own. This remarkable construction is funnel-shaped
with the larger end contracted, and sufficiently wide to
admit of the Lima moving freely up and down, but not
turning round in it. Here it lives, secure from prowl-
ing fish and crabs. The case is lined inside with a
closely-woven net of byssal threads, plastered over with
slime or excrement. This smooth and soft lining con-
tains a quantity of Diatom- cells, and yields a rich
harvest to those who collect these exquisite organisms
for microscopical examination. Such remains of per-
petual feasts remind one of the similar exuviae which are
found at the bottom of a spider's web. No species of
Lima is noticed in Dr. Gould's ' Invertebrata of Massa-
chusetts/ or in any other work on the conchology of
the United States ; nor has Dr. Philip Carpenter, in his
elaborate list of the Mollusca inhabiting the north-west
coast of America, enumerated any as belonging to the
northern fauna of that extensive district.

The very ancient genus Plagiostomus of Lhwyd (Pla-
giostoma of Sowerby's ' Mineral Conchology ') is con-
sidered by some palaeontologists to be identical with the
present genus. It may be connected with it through
the genus Limea of Bronn, and form a passage to Spon-
dylus. Poli used the name Glaucus for the animal of
the present genus.

A. Shell equilateral, with a straight outline.
1. Lima Sar'sii*, Loven.

Limea Sarsii, Lov. Ind. Moll. Scand. p. 32.

Body milk-white : mantle set with large, thick, and ringed,
but not numerous cirri or tentacles.

Shell roundish -oval, slightly oblique, convex, rather solid
* Named in honour of Professor Sars, an eminent Norwegian zoologist.

LIMA. 79

but semitransparent, glossy : sculpture, 25-30 raised concentric
plates or laminae, which are imbricate and partly overlap one
another in succession, the distance between them increasing
in proportion to the period of formation, so that the earliest
ones lie close together; these plates are crossed by about
the same number of slight ribs, which give the surface an
imperfectly cancellated appearance : colour white : margins
rounded, except at the hinge : beaks small, straight and
blunt, projecting beyond the dorsal margin: ears very small
and indistinct : cartilage small, placed in a shallow tri-
angular pit, which is perpendicular instead of horizontal as
in the last genus : hinge-line short and straight : hinge-plate
narrow, bluntly but distinctly crenulated across : inside pearly,
grooved by the reflection of the ribs and strongly crenate or
notched within the front margin : muscular scars slight.
L. 0-125. B. 0-1.

Habitat : Shetland, in 85 fathoms, with Limopsis aurita
and other rare mollusks. This remote cluster of our sea-
girt isles, which with their craggy fastnesses guard

" The unadorned bosom of the deep,"

has yielded more novelties of the highest interest to
marine zoologists than any other part of the British
coasts. My friend Mr. Waller detected two fresh valves
in some gravelly sand which I dredged in 1862 and sent
to him for examination ; and I found another specimen
this year on the same ground. The species was first
discovered by Professor Sars at Bergen, and described
by Professor Loven. Danielssen found it at Vadso, in
40-80 fathoms, and Lilljeborg at Christiansund. It is
rare.

In consequence of the hinge-plate in certain fossil
species of Lima being partly toothed or crenulated, the
late Professor Bronn proposed in 1831 to make of them
a new genus, which he called Limea ; and in the fol-
lowing year Miinster described the same genus under
the name of Limoarca. Bronn remarks that, but for
its having only one muscular impression, this genus

80 PECTINID^.

could scarcely be distinguished from Limopsis. The
species which he noticed were five in number, viz. two
from the lias and lower oolite, and three from tertiary-
strata. But in giving the Ostrea strigilata of Brocchi
as the type of his genus Limea, he seems to have mis-
understood the Italian geologist, who nowhere mentions
the hinge of his shell being toothed. The words used
by him are, " II margine delle valve comparisce cre-
nellato tutto all* intorno ; il cardine non e obbliquo come
nella precedente [Ostrea tuberculata, Olivi) ma sibbene
retto, e nel? area del legamento si scorge una fossetta
trasversalmente bislunga." Brocchi^s species belongs
to the section which comprises our L. Loscombii. Loven
adopted Bronn's genus for L. Sarsiij considering it to be
a passage towards Limopsis, and says that the mantle of
the animal has no cirri ; but Sars, in his account of the
Arctic Mollusca on the coast of Upper Norway, has
since observed that the mantle of this species is like
that of the rest, and set with proportionally large ten-
tacles or cirri which are thick and ringed, although not
particularly numerous. According to Searles Wood,
some of his specimens of L. subauriculata from the Crag
have the hinge-plate minutely crenulated. The same
character is seen in many species of Pecten. These
crenulations probably serve for the firmer attachment
of the cartilage to the hinge-plate, and not for a separate
fastening as in the interlocking teeth of Area. They
are too slight for the last-mentioned purpose. Norwe-
gian specimens of L. Sarsii are much larger than ours.
This and the next two species form a distinct section,
which Klein more than a century ago called Ctenoides,
and for which Searles Wood has proposed the subgenus
Limatula.

LIMA. 81

2. L. ellip'tica*, Jeffreys.

L. subauriculata, F. & H. ii. p. 2G3 (partly), pi. liii. f. 4, 5.

Body pale orange : Untacula pale pink : foot pale orange.
(F. & H.)

Shell oval or elliptical, convex, slightly and almost equally
expanding towards the sides, thin and glossy, semitranspa-
rent: sculpture, 30-40 fine longitudinal ribs, which become
very faint and indistinct as they approach the sides ; one. of
these ribs, near the middle but more towards the posterior
side, is rather larger than the rest, and a corresponding furrow
is formed inside each valve, appearing outside like an oblique
white line; the ribs are crossed by extremely delicate and
numerous concentric striae, making the crests beautifully
serrate ; the substance of the shell also exhibits a few diagonal
white streaks or lines, which diverge from the centre to each
side : colour pearl-white : margins broadly rounded in front,
and sloping with a gentle but somewhat flexuous curve up-
wards to the ears, much compressed at the sides : beaks ex-
tremely prominent and gibbous, projecting considerably be-
yond the hinge : ears triangular, small, erect : cartilage dia-
mond-shaped, occupying about one-third of the hinge, and
minutely striate across; there is also a very slight and in-
distinct ligament on each side of the cartilage : hhuje-line
straight except in the middle, where it is incurved to receive
the cartilage : hinge-plate blunt : cartilage-pit forming an ob-
tuse triangle, smooth ; under each ear is a shelving triangular
space confined below by a narrow rib : inside highly nacreous,
and marked by a furrow which runs obliquely down the
middle, and is the reverse or under side of the larger rib on
the outer surface ; it is also indistinctly grooved by the im-
pression of the ribs ; the front margin is slightly notched by
the edges of those ribs : muscular scar irregularly circular and
distinct. L. 0--55. B. 0*35.

Var. leviuscula. Shell nearly smooth, the ribs being want-

Habitat : Sandy mud, in 15-85 fathoms, off the
Shetland Isles and west coast of Scotland. It is not
uncommon in the latter district. The variety is from

* Elliptical.

E O

82 PECTIXID.E.

Skye ; but although evidently immature, it differs from
the young of the typical form in being destitute of ribs.
Sars, Lilljeborg, and Malm have taken this species on
different parts of the Scandinavian coasts from Bergen
southwards, and supposed it to be the Pecten subauri-
culata of Montagu.

It does not appear that this or either of the other
species in the present section is a nest-builder. I have
often dredged living specimens in every stage of growth,
but always found them free. The shell of L. elliptica is
sometimes covered with Foraminifera and Polyzoa : but
this does not prove that they are never enclosed in cases,
because shells of L. hians, taken alive from their nests,
are often thus encrusted.

After much consideration I am satisfied that Mon-
tagu's name of subauriculata ought to be assigned to
the following species and not to the present. His de-
scription and figure evidently apply to the other species,
which occurs in the same locality that he mentions, viz.
the coast of Devon. L. elliptica has not, I believe, been
found south of the Hebrides. Both live together in the
northern part of our seas, as well as on the Scandina-
vian coast. Their distinctive characters will be pointed
out after describing the next species. Forbes and
Hanley united the synonyms and localities for the two
species ; but their description appears to have been taken
from a specimen of L. elliptica.

3. L. subauricula'ta * } Montagu.

Pecten suhav.riculata, Mont. Test. Brit. Suppl. p. 03, t. 29. f. 2.

Body milk-white : mantle clothed with about a dozen tubu-
lar clear- white tentacles of different lengths, which are closely
ringed and ciliated : foot white and cylindrical.

* Slightly eared.

LIMA. 83

Shell oblong, extremely convex, rather thin and glossy,
semitransparent : sculpture, 24 slight but sharp ribs, which
radiate from the beaks and do not extend to the sides ; the
middle rib is the largest, and runs straight down to the front
margin ; the ribs are crossed by extremely fine and numerous
concentric stria?, making the crests appear somewhat jagged :
colour milk-white: margins rounded in front, and sloping with
a gentle curve upwards to the ears: beaks extremely promi-
nent and gibbous, projecting considerably beyond the hinge :
ears triangular, very small, hanging a little downwards : carti-
lage diamond-shaped, occupying nearly one-third of the hinge :
ligament narrow and slight : hinge-line straight except in the
middle, where it is incurved : hinge-plate sharp : cartilage-pit
forming an acute triangle, faintly striate across ; under each
ear is a shelving triangular space as in L. ellipjtica, but pro-
portionally narrower : inside highly nacreous, and marked by
a furrow which runs down the middle, and is the reverse or
under side of the central rib ; it is also indistinctly grooved
by the impression of the outside ribs ; front margin slightly
notched by the edges of those ribs: muscular scar faint.
L. 0-275. B. 0-15.

Habitat : Sandy and gravelly ground in almost every
part of the British seas, from 18 to 90 fathoms. It is
also a Coralline Crag fossil. Its distribution in other
parts of the northern hemisphere is very extensive, em-
bracing Greenland, Iceland, Scandinavia, the Adriatic,
both shores of the Mediterranean, the iEgean, and the
Canary Isles. Nor is its bathymetrical range in widely
separated seas less worthy of remark. Wallich obtained
it by means of his deep-sea soundings in the North
Atlantic from 227 fathoms ; and M' Andrew has recorded
the depths at which he dredged living specimens on the
coast of upper Norway as 15-150 fathoms, and Forbes
in the iEgean as 15-140 fathoms.

The animal is shy. It uses its foot for crawling. The
alimentarv and branchial current enters in at the middle
of the front margin ; and the excretory current passes
out below the ear on the posterior side. In a single

84 PECTINID-E.

valve now before me, one of the ears is twice the size of
the other. The fry, — th of an inch long, are roundish-
oval and distinctly ribbed.

L. subauriculata differs from L. elliptica in the shell
being more arched or equally convex throughout, as
well as much smaller and longer ; the sculpture is coarser
and the ribs fewer; the ears are smaller and droop a
little; and the furrow is straight and placed in the
middle. In the other species the shell is considerably
broader and more expanded ; the sculpture is finer and
the ribs more numerous ; the ears are larger and more
erect; and the furrow runs obliquely, and is placed
somewhat nearer to the posterior margin. The young
of each species have corresponding characters. That
of L. elliptica resembles L. Sarsii in shape, but differs
toto ccelo in the sculpture and in having a conspicuous
furrow.

The present species is the L. sulcata (" Leach ") of
M oiler, L. elongata of Forbes, L. subauricula of Phi-
lippi, L. sulculus (" Leach ") of Loven, andL. unicostata
of Leach's posthumous work on the Mollusca of Great
Britain. I at one time thought it might also be the
Ostrea nivea of Renier, which has been well described
and figured by Brocchi. But although our shell is found
in the Adriatic, and may therefore have been the species
intended by Renier, I do not believe it occurs in the
Subapennine tertiaries, so as to have fallen under
Brocchi's observation ; and neither of these authors has
noticed the central groove or furrow, which is so charac-
teristic of this species and L. elliptica. The Ostrea
subauriculata of Turton's ' Conchological Dictionary '
appears to have been the young of L. Loscombii, judging
from his description and specimens.

LIMA. 85

B. Shell inequilateral, with an oblique outline.
4, L. Loscom'bii *, G. B. Sowerby.

L. Losco?nbii, Sow, G-en. Sh. (Lima) f. 4 ; F. & H. ii. p. 265, pi. liii. f. 1-3.

Bod y bright orange-colour : mantle haying its edges over-
lapping one another in front : tentacles of different lengths,
ringed or verticillate as in some Nudibranchs, and arranged
in several irregular rows ; the front row is folded back over
the outer edge of the shell : foot cylindrical and extensile,
reddish-orange.

Shell rhomboidal, twisted to one side, extremely convex,
thin, rather glossy : sculpture, 50-60 very fine and sharp ribs
or fluted striae, which radiate from the beaks to the front and
sides, but become faint or absent on the sides and near the
hinge ; the ribs are slightly flexuous and of unequal size,
often alternately large and small, or two or three small ribs
between some of the larger ones; there are also the same
microscopical transverse lines as in L. subauriculata and other
species, producing a similar serrature or corrugation of the
ribs : colour snow-white : margins thin, oblique, bluntly
rounded in front, ventral edge compressed and nearly straight,
posterior edge rounded and sloping from the front and hinge-
line to an obtuse angle about one-third down; the valves
when closed gape a little on the upper part of the dorsal side :
beaks extremely prominent and gibbous, projecting consider-
ably beyond the hinge : ears triangular and veiy small, wrin-
kled in the line of growth : cartilage large and yellow : liga-
ment thin, olive-green: hinge-line nearly straight, slightly
curved outwards : hinge-plate narrow and sharp : cartilage-
area broad ; triangular space on each side of the beaks and
within the ears small, but supported by a stout and somewhat
incurved ledge : inside pearly, slightly granular, showing (al-
though faintly) the impression of the outside ribs ; front mar-
gin crenulated in young, but thickened in adult specimens :
muscular and pallial scars distinct. L. 0*8. B. 0*55.

Habitat : With the last species, and equally distri-
buted, but usually not so common nor at such great

* Named in honour of Mr. C. W. Loscombe, who discovered this and
other shells at Exmouth.

86 PECTINIDJE.

depths. Capt. Beechey, however, dredged a living spe-
cimen off the Mull of Galloway in 1^5 fathoms. It
occurs fossil in our Red and Coralline Crag. Abroad it
ranges from the coast of East Finmark to the iEgean
and the North African coast of the Mediterranean.
Asbjornsen gives the depth at which he found this spe-
cies living in Christiania fiord as 5-20 fathoms.

It seldom makes a "nest"; but I have one enclosed
in this way, which I dredged on the north coast of Ire-
land. The case lies within a valve of Mytilus modiolus,
and is composed of large fragments of shells, crabs, and
barnacles. Sars obtained a similar specimen on the
Norwegian coast. In all probability this habit depends
on the nature of the sea-bottom. When the latter is
soft mud the Lima can partly bury itself, and does not
require to be otherwise protected from its voracious
enemies. The haddock seems fond of it, the shells being
often found in its stomach. The animal of L. Loscombii
differs but little from that of L. hians. The pallial ten-
tacles are somewhat thicker, and the foot is shorter and
of a paler hue. Mr. Clark has seen it " repeatedly fix
itself by fine byssal filaments, then detach itself and
move with the greatest rapidity, crossing a dish of six
inches diameter whilst one could be counted." When
it crawls it uses its foot in the same way as Modiolaria
discors, by extending and attaching the flexible point to
the surface of the body it is traversing, and then draw-
ing or warping itself up. This mode of locomotion is
much slower than the usual one of swimming by a repe-
tition of jerks. The fry are ribbed like the adult, but
the lines of division between the strise in the former arc
more remote.

It is the Pecten fragilis of Montagu but not of Chem-
nitz, the L. bull at a of Turton but not the Ostrea bullata

LIMA. 87

of Born, and the L. reticulata of Leach. The L. Los-
combea of the last-named author, from Torbay, is in all
probability the young of the present species ; but his
diagnosis is very obscure. Philippi considers Turton's
L. bullata to be the L. strigilata of Scacchi but not the
Ostrea striyilata of Brocchi. The latter is a common
miocene fossil, and constitutes the type of Bronn's
genus Limea.

5. L. hi'ans*, Gmelin.

Ostrea kians, Gmelin, Linn. Syst. Is at. ed.xiii. p. 3332. L. Mans, F. & H.
ii. p. 268, pi. lii. f. 3-5, and (animal) pi. E, as L. tcnera.

Body of different shades of colour between pale crimson and
intense vermilion : mantle of an orange tint : tentacles very
numerous, arranged in rows as in the last species : foot also
similar.

Shell rhomboidal, considerably twisted to the ventral or
anterior side, compressed, rather solid, of a dull aspect : sculp-
ture nearly the same as that of L. LoseomLii ; but the ribs are
stronger, and often become coarse and rough towards the
margins : colour snow-white in the young, but dirty-brown in
old specimens, which are frequently covered with fragments
of byssal hairs, as well as with zoophytes and Foraminifera :
margins thick, oblique, bluntly rounded in front, the ventral
or anterior edge compressed and nearly straight, and the pos-
terior edge truncate and sloping outwards at the same angle
with the lower margin of that side as in the last species ; the
valves when closed gape very widely on both sides : heals
prominent and gibbous, not projecting much beyond the hinge :
ears triangular, strong, and unequal, that on the anterior side
being longer and wider than the other, which is sharp-pointed;
both are coarsely wrinkled in the line of growth : cartilage
and ligament large, horncolour : hinge-line formed like an arch,
and increasing with age in the degree of curvature ; its length
is not equal to one-third of the entire breadth of the shell :
hinge-plate thick, incurved in the middle to receive the carti-
lage : cartilage-area very large, causing the beaks to be widely
separated when the valves are closed ; triangular space on the
anterior side indistinct, but that on the other side is deeply

* Gaping.

88 PECTINID.E.

perforated in the centre and strengthened by a thick rib : in-
side pearly, closely granular, slightly impressed by the ribs ;
front margin scalloped or fluted in the young and very thick
in the adult: muscular and pallial scars indistinct, especially
the former. L. 1*6. B. 1.

Var. tenera. Shell smaller, narrower, and more depressed,
with fewer ribs. L. tenera, Turton in Zool. Journ. ii. p. 362,
t. xiii. f. 2. L. 1. B. 0-6.

Habitat : Hard ground, in 12-40 fathoms, very com-
mon in the West of Scotland; Orkneys (Thomas);
Aberdeen (Macgillivray) ; north-east coast of Ireland
(Portlock, Hyndman, and Waller) ; Anglesea (M f An-
drew and Forbes) ; Isle of Man (Forbes) . A specimen
from the last- mentioned locality, which I received from
the late Professor Forbes, is intermediate between the
typical form and the variety, as well as a specimen
which Mr. W.W.Walpole sent me from Killiney Bay,
near Dublin. As an upper tertiary fossil it has been
noticed by the late Mr. W. Thompson and Mr. Grainger
in a bed of blue clay at Belfast, and by Mr. Searles
Wood in the Coralline Crag at Ramsholt. The variety
is found on the southern coast of Cornwall and in the
Channel Isles. It is not uncommon at Herm, under
large stones, at low- water mark. The range of this
variety southward is very extensive, having been re-
corded by numerous authors in different parts of the
Mediterranean, iEgean, and North Atlantic seas, as
far as the Canary Isles, Madeira, and the Azores, at
depths of 0-50 fathoms. The typical or northern form
inhabits the coasts of Norway and Sweden, in 4-30
fathoms. Malm found a specimen in the stomach of a
cod-fish.

In Mr. Norman's interesting notices of the Clyde
Mollusca (published in the c Zoologist' for 1858) is the
following : — " Nothing can be more lovely than the ani-

LIMA. 89

mal of L. hians, with its thousand delicate and beauti-
fully ringed vermilion tentacula, each maintaining, as it
were, a life independent of its neighbours, turning and
twisting in every direction ; the rich crimson foot and
snow-white shell form an object which, to my eyes, is
unsurpassed among the British Mollusca." He, however,
adds : — " There is but one thing I have to say against
this interesting molluscan ; and that is, the animal has
a peculiar, tenacious, and to me sickening odour : after
having handled a number of them it is no easy matter to
remove the smell from the hands with soap and water ;
and so strong a hold has the nauseous -smell sometimes
taken on my olfactory nerves that a whole night has
scarcely sufficed to remove the impression." Perhaps
the nasty smell may be accounted for by presuming that
its apartment is never cleaned. When the Lima is first
taken out of its case and put into a basin of sea- water,
it is exceedingly active and restless, either violently
darting round the sides of the vessel, or else gracefully
careering about, with its long and thick fringe of fila-
ments trailing behind it. In the course of a few minutes
it seems to get tired, or reconciled to its prison ; and it
then lies on its back, the valves of the shell expanded,
and reposes on its own soft luxurious cushion. The
filaments at first curl and entwine round one another,
a perfect nest of snakes, but afterwards they are with-
drawn and become contracted ; a circular inner row,
like a coronet, surrounds the slowly-flapping gills ; and
the outer rows fold over on each side and form a sort of
chevaux de frise. Dr. Landsborough supposed that these
filaments were useful to the Lima in catching its prey.
He observed that they are veiy easily broken off, and
that they seem to live for many hours after being de-
tached from the body, wriggling about like so many

90 PECTINID^.

worms. The fry are of the same shape as the adult, and
have slight but distinct ribs.

The habit of making a case or " nest " appears to be
common everywhere % nor is it restricted to full-grown
individuals. The Rev. It. N. Dennis informs me that he
found at Herm certainly more than one hundred speci-
mens of the variety thus enclosed, and that they were
of all ages, but mostly young. He adds, " The nests
were generally fixed under good-sized stones at low-
water mark, and were broken in turning over the
stones, when the Limas swam off in all directions. The
largest number I found in one nest was, I think, seven ;
the largest and oldest-looking specimens were alone in
the nest. I did not find a single specimen out of a nest.
The Herm people call them ' Angels' -wings. ; '■' The nest
of L. Mans measures from two to ten inches in length,
according to the age and size of the occupier and the
supply of materials. It somewhat resembles the case
made by certain species of Mytilus (or Modiola), and
has no analogy to the nest of birds and some fishes,
being permanently inhabited by the Lima itself, or a
colony of them. The fry are always left to provide for
themselves, and do not require any parental care. This
kind of u nest-hunting/' therefore, is not a cruel, though
an unusual sport. In a review of my first volume in
f Blackwood's Magazine/ the writer referred the pursuit
of natural history to a Nimrod instinct. Perhaps, after
all, he touched the right chord j for although we dignify
hunting for shells, insects, and flowers by the imposing
names of Conchology, Entomology, and Botany, such
researches may partake as much of an innate love of
sport as of the spirit of scientific inquiry. Dredging
for Lima's nests is at any rate an amusement more
suitable to grave naturalists, than looking after the eggs

LIMA. 91

of our feathered songsters in woods and hedges, like
schoolboys. A very intelligent naturalist, Mr. David
Robertson of Glasgow, has favoured me with more in-
formation respecting the habits of L. Mans in Scotch
waters. He says, " In confinement they build freely ;
and so far as my observations go, they live longer in
that state when they are supplied with the requisite
materials, but failing such supply they frequently make
nests of their own byssus. They also spin their byssal
threads to assist them in ascending perpendicular or
steep places; and, like the common mussel, the Lima
often suspends itself by one or more fibres. Its attach-
ment, however, is only slight; for the least irritation
or alarm causes it to detach itself from the cable and
bound off. It does not seem to be particular as to the
kind of building-material which it uses. At Lochronsa
in Arran I found their nests among the muddy roots of
Phyllophora rubens, without the addition of any harder
substance. At Rothesay the nests are made of small
gravel ; and at Cumbrae they soon fill the dredge, being
formed of thick and matted clusters of nullipore. On
this bank I never find them free ; they are all encased,
at all seasons of the year, young and old, from the size
of a pea to the full-grown state, each having its own
separate nest. A remarkable peculiarity of Lima con-
sists in the tenacious grasp of its tentacles. Some-
times when my finger touched the animal, it was rapidly
seized by the tentacles, as by those of an Actinia, and
so firmly that I have thus dragged the Lima round the
tank. It seldom let go its hold till the tentacles were
torn away, or (as I believe) voluntarily thrown off by
the animal. The tentacles so detached still adhere
closely to the object they have grasped, their free ends
twisting about as if in conscious life, and they are with

92 PECTINIDJ2.

difficulty taken off. Notwithstanding this property, I
frequently find a small crab (Porcellana longicornis) in
their nests, and not unfrequently an annelid (Polynoe),
but almost invariably a greenish gelatinous annelid.
This last kind I have noticed lying across the tentacles
of a large Lima, which seemed to be quite at its ease
and by no means incommoded by its neighbour. I
have frequently kept L. hians in captivity for many
months. I have now (January 1863) one which I took
in May last, and it looks in good health. It com-
menced building in a day or two after it was put into
the tank, and has ever since lived under its own roof,
adding from time to time to the size of its oblong nest.
This word (' nest ') is, in a wide sense, not inappro-
priate as applied to the mode of architecture ; but it
must not lead to the idea of incubation, with which the
structure seems in no way connected." I am indebted
also to Mr. Robertson for another important observa-
tion, viz. that he has seen some individuals of L. hians
shedding blood-red ova, and others spermatozoa at the
same time, and that the flow of ova continued for about
fifteen minutes, and to all appearance in two streams.
This observation is of great value as regards the genera-
tive system of the Lamellibranch Mollusca; but we
must not overlook the possibility that each individual
may be of both sexes, although the period may vary for
the development of its organs — i. e. that it may be male
at one time and female at another, as is said to be the
case with Valvata and Ancylus among the freshwater
univalves. Or it may be analogous to what takes place
in certain flowering plants. Lobelia is hermaphrodite,
but usually sheds its pollen before the anther is pre-
pared to receive it, so that self-fertilization is seldom
effected, and the pollen of a neighbouring plant with the

AVICULID^E. 93

aid of winds or insects is almost always necessary to
ensure propagation. It is to be hoped that some expe-
rienced physiologist will investigate the subject in all
its bearings and set at rest this long-agitated question.

L. Mans differs from L. Loscombii in its much larger
size, being more depressed, and widely gaping at both
sides instead of at the dorsal side only. It is the L.
j rag His of Fleming, L. vitrina of Brown, L. aperta of
Sowerby, L. inflata of Forbes, and L. tenuis of Leach.
The original describer of the species was Schroter ; but
the name he gave it, being in his own language, is not
admissible according to scientific rules. The Ostrea
tenera of Chemnitz is a West Indian species of Lima and
very different from the southern variety of L. Mans.

I found a very small and imperfect single valve of
L. inflata (Philippi) in trawl-refuse from the Plymouth
coast. It is rather common in the Mediterranean. The
shell is tumid and very strong for its size ; the surface
is coarsely decussated or reticulate by strong longi-
tudinal ribs and transverse plates ; the ears are remark-
ably small ; and the hinge is furnished with a horizontal
cartilage-pit as in Pecten. Lamarck's species of the
same name is distinct from this ; and according to him
it inhabits " POcean americain."

** Mantle open in front, and forming at the posterior side
(rarely at both sides) one or two tubes, which are mostly
sessile.

Family IV. AVICU'LID^E, Swamson.

Body obliquely oval or oblong, compressed : mantle open,
and free at its edges, which are fringed with cirri : foot small
and cylindrical, furnished with a byssal groove.

94 AVICULID.E.

Shell shaped like the animal, inequilateral, scaly outside
and nacreous within: beaks straight: ligament long and
narrow, mostly internal and contained in a groove.

In this distinct family we have only two genera, each
containing but a single species, which widely differs
from the other. The intermediate links are wanting at
our northern end of the chain. Elsewhere both genera
and species abound in great variety; and, in remote
periods of the earth's history, what are now called the
British seas had also their full share. In studying the
particular fauna of any district we are too apt to regard
it in an isolated point of view, instead of associating it
with the faunae of other and distant regions. No mem-
ber of this large family has been noticed as inhabiting
the north-east coast or the northern part of the western
coast of America, nor is any one enumerated in the
lists of Arctic or Scandinavian Mollusca. The shell is
composed of outer and inner layers. The outer layers
are of a fibrous texture, and consist of extremely minute
and closely-packed tubes or cells, which exhibit on
their surface irregularly hexagonal prisms ; they are
separated from each other by a deposit of unusually
thick animal matter ; and, upon being steeped for some
time in caustic potash, they easily become disintegrated
and fall asunder, resembling in that state extremely
short threads of spun glass. The inner layers are more
compact and highly iridescent. The surface of the
shell, both in Avicula and Pinna, appears under the
microscope to be finely punctured, as in some species of
Lepton. The anterior adductor muscle is small, showing
a transition from the Monomyaria to the Dimyaria.
Leach included this family in the first-mentioned di-
vision.

AVICULA. 95

Genus I. AVI'CULA*, Klein. PL II. f. 3.

Body oval : palps or labial appendages large : byssus fibrous,
coarse, and thin.

Shell square or elliptical, often winged or lobed, inequi-
valve : upper margin of the lower or left valve notched for
the passage of the byssus : beaks placed nearer the anterior or
narrower end, but never terminal: hinge furnished with
teeth.

This genus is distinguished by the nacreous and
iridescent lining of its shell, which in one species pro-
duces the oriental pearl, and in another is extensively
used for inlaying and button-making.

1. Avicula hirun'do f, Linne.

Mytili's hirundo, Linn. Syst. Nat. p. 1159. A. Tarentina, F. & H. ii.
p. 251, pi. slii. f. 1-3, and (animal) pi. S. f. 4.

Body suboval, yellowish-white mottled with brown : cirri
arranged in two rows, numerous and close-set, those in the
front or outer row being longer than those in the inner row :
foot white.

Shell elliptical, resembling that of a Pinna, with the
addition of an unequal wing-like appendage on each side of
the beak, very inequivalve in the young, but less so in the
adult state, the upper or right valve being larger than the
other, much compressed towards the margins, rather fragile,
more or less glossy : sculpture, thin concentric plates or scales,
which irregularly imbricate the surface and are sometimes
spinous towards the anterior margin, besides superficial micro-
scopic and close-set punctures : colour yellowish-brown, with
purplish streaks which radiate from the beaks and are fre-
quently interrupted or zigzag : margins very thin, rounded in
front, more or less deeply incurved on the upper part of eaeh
side in consequence of the projection of the wings, straight or
nearly so behind : beaks small, sharp, and slightly projecting
over the hinge : wings triangular and bluntly pointed ; they
are of unequal size, those on the anterior side being small,

* A little bird. t Swallow.

96 aviculid^:.

and the opposite ones from six to ten times as long in full-
grown specimens : hinge-line very long : ligament broad, sepa-
rating the beaks, so as to form a rather wide area : hinge-plate
thick, strong, and ronnded : teeth consisting of a blunt tubercle
in the upper valve, placed a little in front of and below the
hinge, and a double tooth in the other valve, into which the
tubercular tooth locks: inside highly and beautifully irides-
cent, marked with faint and irregular grooves which diverge
from the beaks : muscular scars distinct, especially that of the
posterior adductor. L. 3. B. 1*65.

Habitat : Plymouth offing, procured by the trawlers
in 20-25 fathoms, sometimes attached to species of
Gorgonia and Sertularia. It is said also to have been
found in Dublin and Bantry Bays ; but this wants con-
firmation. Dr. Turton's specimen from the first of
these localities looks too highly coloured to be British,
and is more probably of foreign extraction. The collec-
tion of Irish shells made bv the late Mr. T. W. Warren,
and now in the museum of the Boyal Dublin Society,
contains a single valve of A. hirundo, which, according
to Mr. Warren's Catalogue, was found by him at Port-
marnock. This specimen has been kindly sent to me
by Dr. Carte, the Superintendent of the museum, for
my inspection. Together with it, and on the same
tablet, is a young shell of a tropical species of Avicula
(or Meleagrina) , which is not unfrequently met with on
the bottoms of vessels from South America. The pre-
sent species, being in our seas an inhabitant of deep
water and always attached, is not likely to be thrown up
on a sandy shore. I have never heard of a Pinna being
picked up as a similar waif of the ocean. Dr. Carte in-
forms me that wrecks too frequently occur in Dublin
Bay, which is completely exposed to eastern gales and
situate in very nearly the same parallel of latitude as
Liverpool, to which port the unfortunate merchant

AVICULA. 97

vessels are bound. Miss Hutchings, who (according to
the late Mr. James Sowerby) discovered this species in
Bantry Bay, was infinitely better acquainted with sea-
weeds than with shells. I have some of the latter which
Mr. Dillwyn received from that lady, as collected by her
in Bantry Bay, and which are unquestionably Mediter-
ranean and not Irish. One of them is Area barbata.
Such mistakes often happen in spite of the best inten-
tions. I do not say, however, that A. hirundo has never
been found in Ireland, or that it may not hereafter be
rediscovered there. It occurs, but very rarely, in the
Coralline Crag. Its exotic distribution is wide, and
comprises both sides of the Mediterranean, as well as
the Adriatic and iEgean Seas, the Canary Isles, Madeira,
and the Azores. Mr. M 'Andrew has taken it on the
shore near Gibraltar, and in the Canaries as deep as 50
fathoms.

The shell has a very remarkable shape, not unlike
that of a swallow on the wing. Two of Lamarck's
species of Avicula (Atlantica and Tarentind) appear to
be the same as the present species, representing the
younger and mature states of growth. The former he
describes as having the valves unequal in size, and the
latter as being equal- valved. If one of these specific
names had to be selected, the description of "Atlan-
tica " would therefore be more appropriate than that of
" Tarentina M to our shell. Linne's diagnosis of Mytilus
hirundo is equally applicable ; and it would be a pity to
reject that time-honoured name in favour of any other
given by subsequent writers. Turton was mistaken
when he described, in his f Conchological Dictionary/ a
second species {A. morio) as British, on the authority of
Dr. Leach. The latter distinctly stated that species to
be exotic; but in his account of the genus Avicida

F

98 AVICULIDiE.

(contained in the ' Zoological Miscellany' for 1814) lie
mentioned that " one indigenous species " had been dis-
covered at Plymouth by Mr. Prideaux. In his ' Synopsis
of the British Mollusca' he gave the last-mentioned
species the name of Britannica.

Pema alata (Crenatula Travisii of Turton) is a native
of tropical seas, but was accidentally imported into this
country on the bottom of a ship which came into Scar-
borough. Many foreign mollusca have been introduced
in the same way. They continue to live for some time
after entering our colder seas, but they never become
acclimatized.

Genus II. PINNA *, Lister.
Frontispiece and PL III. f. 1.

Body oblong and attenuated : palps small : byssus silky and
copious.

Shell forming an elongated triangle, equivalve, widely
gaping in front, and slightly on the anterior side for the passage
of the byssus : margins entire : beaks terminal and pointed :
hinge toothless.

We now approach the Mussels, to which the shells
composing the present genus bear a considerable resem-
blance. The principal distinction is that the former
have the valves entirely closed, while in the latter they
gape widely at the larger end, as well as that the beaks
in Mytilus and its allies are not placed at one end of the
shell as in Pinna. According to Da Costa the shell of
Pinna is called in France "jambon" and "jambon-
neau" ; and it looks exceedingly like a small ham. In
another point of view it is a wingless Avicula. Pliny's
account of the little pea-crab, which is so often found in
this mollusk (as well as in Mytilus modiolus and Cyprina

* From the irivva of Aristotle, who first mentioned tins mollusk.

PINNA. 99

Islandica), and of its playing the part of jackal to the
lion, has been so often repeated, that I will not inflict it
again on my readers. Cicero was fully persuaded of the
truth of this pretty fable, and he used it as an illustra-
tion in his treatise ' De Natura Deorum/ Swan, in his
' Speculum Mundi/ moralized upon it as follows : —
cc And thus day by day they get their living, like a com-
bined knot of cheaters, who have no other trade than
the cunning deceit of quaint cousenage ; hooking in the
simple sort with such subtill tricks, that be their purses
stuft with either more or lesse, they know a way to
sound the bottome, and send them lighter home : lighter
in purse, though heavier in heart." But Pierius, in his
( Hieroglyphica/ draws a different conclusion ; for, after
quoting Theophrastus (" vita fortasse conchis servari non
potest, nisi ope cancri "), he commends the example of
the Pinna and its companion to any one who cannot do
without the aid and counsel of another. Poli gave the
name Chimcera to the animal of this genus, and fully
treated its anatomical details, the illustration of which
occupies no less than four plates of his magnificent work.
But he denied it a foot (" pes nullus"), and stated that the
byssus issued from the base of an organ which he called
e ' ligula." Another Neapolitan writer (Giannettasi) ,
although not also a naturalist, celebrated the Pinna at
great length in the eighth book of his ' Halieuticon/

1. Pinna ru'dis*, Linne.

P. rudis, Linn. Syst. Nat. p. 1159. P. pectinata, F. & H. ii. p. 255, pi, xliii.
f. 1, 2, and pi. liii. f. 8.

Body large, reddish -brown or yellowish : cirri arranged in
two rows on the posterior margin of the mantle, and in one
only on the anterior margin : foot conically subcylindrical, and
having a byssal groove at the posterior bend.

* Bough.

f2

100 AVICULID.E.

Shell tapering to a point at one end and expanding at the
other to an obtusely rounded or slightly truncate edge, convex,
with a gradual slope towards the sides, rather thin for its size,
more or less glossy : sculpture, 8-12 long delicate ribs on the
dorsal portion, radiating from the beaks, and sometimes nume-
rous shorter ribs on the anterior portion of the shell, extend-
ing to that margin ; these ribs often rise at irregular intervals
into vaulted prickles in consequence of an exfoliation of the
outer layers ; the whole surface is also covered with the mi-
croscopical punctures peculiar to this family : colour yellow-
ish-brown : margins very thin in front and on the anterior
side, but thickened on the dorsal side, which is straight or
occasionally a little incurved, and sloping gradually on the
other side (with the exception of a slight indentation for the
byssus) to a blunt angle, where it meets the front margin :
beaks strong and exceedingly prominent, much worn and
broken in adult specimens, and furnished inside with a series
of concentric plates, in consequence of the successive shift-
ings and advance of the anterior adductor muscle : hinge-
line extremely produced, occupying two-thirds of the entire
length : ligament horny, narrow, very strong and elastic :
hinge-plate folded over the ligament, so as to contain it in a
kind of sheath or groove, closed or firmly soldered for a short
distance beyond the posterior termination of the ligament :
inside highly nacreous and iridescent, of a darker colour on
the upper half than below: muscular scars very distinct.
L. 10-5. B. 6.

Habitat : Sparingly and locally distributed on all the
British coasts, but gregarious., from low- water mark to
80 fathoms, in muddy or sandy gravel. Fragments have
been found in the Coralline Crag. Its foreign range
extends south to both sides of the Mediterranean, and
also to the Canary Isles. It has not been noticed as
occurring anywhere north of Shetland.

The " fan-mussel " is by far our largest shell, mea-
suring sometimes fifteen inches in length and eight in
breadth. It varies greatly in proportions and sculpture.
Specimens in some situations have a tendency to ex-
pand, and become distorted in consequence of their con-
fined position. The fry have spoon-shaped and some-

PINNA. 101

what incurved beaks, and in that state no ribs or strise are
formed. Dr. Walker savs that the Gaelic name of the
shell is " feaskand." Very little appears to be known in
this country as to the animal. Pennant gravely called it
" a slug." Montagu, and recently Mr. Couch, imagined
that it could close the larger end for the same purpose
as that stated by the ancients, viz. to catch little fish !
Many writers have supposed that it can weigh anchor
when it pleases, and remove to a better feeding-ground ;
but it would not seem to be fond (if capable) of changing
its place of abode, unless when very young, and before
it has settled down for life. The worn state of the
beaks and the not unfrequently distorted contour of the
shell show that it lies partly buried in the ground and
continues for a long time in the same place. If it is
forcibly torn or driven from its anchorage, it can un-
doubtedly spin a new byssus and reattach itself. The
fibre of this curious appendage or " beard V is tubular
like hair. When dried it is stiff and wiry j but if used
fresh it is sufficiently flexible to be woven into gloves
and stockings. Tarento is a noted place of manufac-
ture for such articles ; and at our last International
Exhibition a Cornish muff made of this material might
have been seen by those who were disposed to venture
into an obscure gallery in search of the few objects of
natural history for which any space was allotted. Ac-
cording to Verany the byssus is a successful remedy for
the ear-ache : but he does not sav in what manner it is
applied. However, this production is evidently of more
use to the Pinna than it can be to man. Most other
bivalves are provided with the same apparatus. Reau-
mur justly remarked that the sea has her spinners in
the mussels, as the earth has in her caterpillars and
spiders. The animal is said to be good to eat; but it

102 MYTILID^E.

requires five or six hours' stewing, and then is not so
tender as a scallop. The fibrous particles which com-
pose the shell are crystalline, and very beautiful objects
for the microscope. Mr. Spence Bate informs me that
the trawlers at Plymouth call these shells "eaper-
longers," and that they avoid the Pinna-ground for fear
of their nets being torn. The shells are described as
standing upright on their narrow end, and as bearing
some resemblance to trees in a thick forest. The word
"caperlonger " appears to be a corruption of Cappa lunga,
by which name the Pinna is known in the Mediter-
ranean. So many of our men-of-war have been at
Naples, that the familiarity of Plymouth seamen with
such Italian words is easily explained.

Owing to the variableness of its sculpture and solidity,
this species has received many names from British con-
chologists, viz. borealis, pectinata, fragilis, muricata,
ingenSy l<evis, papyracea, rotundata, and elegans. It
may, however, be observed that the P. muricata of
Linne has never been found in this country, and that
" India" is stated to be the habitat of his P. pectinata.

Family V. MYTI'LID^E, Fleming.

Body thick and rather convex : mantle more or less open in
front, and usually folded on the posterior side into a wide ex-
current tube or slit : foot shaped like a strap or worm, and
having a byssal groove.

Shell obliquely oblong, oval, or rhomboidal, equivalve, in-
equilateral, and covered with an epidermis : beaks incurved :
ligament long and narrow, mostly internal, and contained in a
groove.

The Mussel family differs from the last in the mantle
not being open throughout, but having its edges united

MYTILUS. 103

behind, so as to form a separate opening for excretal
purposes, as well as in the shell increasing excentrically,
and not being scaly but provided with an epidermis,
and in its beaks being incurved instead of straight.
Although all mussels spin a byssus, and are commonly
attached by this mode, some of them have a consider-
able power of locomotion, dropping their anchors and
casting new ones at will. The composition of their
shells, according to Mr. Sorby, is calcite, and ought
therefore to be durable; but I have generally found
them to be much decomposed in the newer tertiaries.
The anterior adductor muscle is very small and placed
immediately within the beaks of the shell.

*

Genus I. MY'TILUS * Linne\ PL III. f. 2.

Body subcorneal : mantle widely open in front : foot strap-
shaped.

Shell oblong or oval : hinge often furnished with small
tubercular teeth.

The Linnean characters of Mytilus were very various,
and comprised freshwater as well as marine shells.
Bruguiere was the first to restrict and define the genus
as it is now recognized. Lamarck separated from it
certain species to form his genus Modiola ; but I believe
the opinion that they ought to be reunited is held by
most authors who have bestowed much attention on the
classification of the Mollusca. The only indications
which Lamarck has given to distinguish Modiola from
Mytilus are that the beaks of the shell in the first of
these genera are not quite terminal, and that the ani-
mal is seldom fixed by a byssus. But on neither ground
can the genera be separated. Any one who has exa-

* From [xvtLXos, a name given by the Greeks to this sort of shell-fish.

104 MYTILIM.

mined the beaks in a common mussel must see that
they are not placed at the end. Their comparative
distance from this point is in every case, whether of
Mytilus or Modiola, a mere question of degree. The
so-called Modiola are invariably fixed by a byssus ; and
the typical species (M. modiolus) are attached to the beds
on which they congregate precisely in the same way as
Mytilus edulis. The only appreciable difference in a
generic point of view that I can detect between M. mo-
diolus and M. edulis is that in the latter the front
edges of the mantle are fringed, while in the former they
are plain, and also that the small tubercles of the hinge
in M. edulis only occur in the very young of M. modiolus,
and not in a subsequent stage of growth. In M. pha~
seolinus, however (which has always been regarded as a
Modiola), these tubercles are represented by minute
but distinct crenulations. The shells of all the British
species of Mytilus are smooth. The byssus proceeds
from a gristly shaft, which appears to support the bundle
of filaments like the handle of a broom. Mytilus is a
very ancient name, and was also spelt by classic authors
Mytulus, Mitulus, and Mutulus. The animal is the Cal-
litriche of Poli.

1. Mytilus edulis"^, Linne.

M. edulis, Linn. Syst. Nat. p. 1157 ; F. & H. ii. p. 170, pi. xlviii. f. 1-4,
and (animal) pi. Q. f. 5.

Body varying in colour from white to orange-yellow, with
a tint of reddish-brown or purple : mantle having two mar-
gins ; outer one plain ; the inner one pinnated, or fringed on
the ventral and anterior sides with 15-25 tentacular cirri, and
serrated on the branchial portion : foot dark brown, occasion-
ally streaked with w r hite down the middle.

Shell irregularly triangular, expanding from the smaller

* Eatable.

MYTILUS.

105

end to an obtusely rounded edge, gibbous with a gradual slope
towards the front and sides, rather thin and glossy : sculpture,
concentric and indistinct lines of increase: colour bluish or
purple : epidermis dark brown or olive, occasionally yellowish
or having a reddish tint, rarely black, microscopically striated
lengthwise and shagreened, sometimes puckered in particular
spots : margins rather thick, nearly straight on the ventral
side and arched behind, obliquely rounded in front : beaks
blunt, more or less divergent, placed a little below the termi-
nation or point of the shell, which is formed by the dorsal
edge of the first-formed part or nucleus ; beneath the beaks
is an imperfect lunule or heart-shaped impression, which
often appears to be repeated, showing the marks of successive
growth: hinge-line nearly straight, occupying almost the
upper half of the dorsal margin: ligament very thick and
strong : hinge-plate partly folded over the ligament, the middle
of which is consequently exposed : hinge furnished with 3-10
small tubercular teeth in each valve : inside chalky- white,
slightly nacreous at the edges, and pitted (as in Unio margari-
tifer) by the impressions of the mantle : muscular scars very
distinct. L. 2-3. B. 1-2.

Yar. 1. ungulata. Shell larger, more pointed at the nar-
rower end, and sometimes angular at the other, with the
ventral margin incurved : beaks more widely separated than
usual. M. ungidatus, Linn. Syst. Nat. p. 1157.

Yar. 2. incurvata. Shell stunted and bent, often marked
by longitudinal ravs of purple. M. incurvatus, Pennant, Brit.
Zool. iv. p. Ill, pi. 64. f. 74.

Yar. 3. Galloprovincialis. Shell broader and natter, with
the ventral margin somewhat prominent and the posterior
angle more acute than in the typical form : beaks incurved.
M. Galloprovincialis, Lamarck, An. sans Yert. vi. p. 126.

Yar. 4. pellucida. Shell thin, narrower, less gibbous, and
beautifully streaked by longitudinal rays of dark brown or
purple, which are irregularly disposed. M. pellacidus, Penn.
op. c. p. 112, pi. 63. f. 75.

Habitat : Abundant everywhere and gregarious, from
high-water mark to the depth of a few fathoms, on a
rocky, stony, or muddy bottom. Var. 1. Cornwall and
Channel Isles, at low spring tides. This variety is the

f5

106 MYTILIM.

M. hesperianus of Lamarck. It attains a considerable
size, and I have a specimen which measures nearly five
inches in length. I may here observe that Mr. Barlee's
shell, recorded in the f British Mollusca ' as belonging
to this species and eight inches and a half long, is M.
modiolus. Var. 2. On all rocky coasts, filling crevices
and crowded together, so as to prevent the free deve-
lopment of each individual. Var. 3. Solitary and there-
fore larger and more expanding. Var. 4. On floating
buoys and sunken wrecks, often at a considerable dis-
tance from land. Young shells of the ordinary kind
often resemble the last variety in substance and markings.
The common mussel is found in all our upper tertiaries ;
but only the sublittoral variety [M. hesperianus) occurs
in the Coralline Crag. It is distributed throughout the
northern hemisphere from the polar circle to the iEgean
Sea and the coast of Morocco, and it seems to thrive
equally on both sides of the Atlantic. The M. trossulus
of Gould, from Vancouver's Island, probably differs in
no other respect than being called a " representative "
species.

Although M. edulis here inhabits the coast-line only,
Dr. Walker is said to have dredged it in Baffin's Bay at
a depth of 140 fathoms. I once obtained a fresh single
valve in between 70 and 80 fathoms about forty miles
off the Shetlands ; but it had perhaps been voided by a
coal-fish (Gadus carbonarius) , which frequents the shore
in the spawning- season. The mussel is occasionally found
with the common periwinkle [Littorina litored), living
on the shore in a stream of perfectly fresh water during the
recess of the tide. The common cockle (Cardium edule)
and My a arenaria have the same habit; and I have
even seen the two latter species associated with fresh-
water mollusca. All of these can exist for many days

MYTILUS. 107

out of water. Young shells of M. edulis are coated with
short bristly hairs, and resemble in shape those of M.
modiolus. They grow very rapidly. According to Mr.
Clark, if the fishermen's lobster-pots are left for a week
or two in the autumn, they will be covered with mussels
more than half an inch long. M. Bouchard- Chan-
tereaux has often watched this mollusk in the act of
spinning its byssus. He says that when put into a
vessel of sea-water, it first creeps along the bottom by
means of its foot and tries to ascend the side. After a
while it deposits from the end of its foot a speck of white
transparent matter, which spreads out and immediately
hardens like china-cement. This plate serves as a base
of attachment ; and from the centre of it the mussel
secretes very slowly and by a backward movement a
gluey thread, repeating this process ten or twelve times
in a circular direction. The threads become horncolour
in from twenty-four to thirty hours after being spun.
It is said to have the power of contracting its byssus at
will ; but I should be inclined to doubt it. The mussel
is on the whole a respectable and stay-at-home cha-
racter, seldom leaving its place of abode unless it has
been dislodged by an unusually boisterous wave or by
the equally rude and violent hands of man. Charles
Lamb speaks of its t( dignified leisure," while traversing
the circuit of two inches square, within which it swings
by the aid of its elastic cables. When confined in a
prison called an aquarium, it appears to be more rest-
less than in its native haunts, perhaps trying to escape
from the unaccustomed quarters in which it finds itself,
and in vain awaiting the welcome refluence of the
tide. It may then be observed making occasional jour-
neys from one part to another, and leaving at every
stage or halting-place a bundle of filaments attached to

108 mytilid^e.

the glass. It is also curious to notice a young mussel
in a rock-pool, slowly and painfully warping itself along
by its extensile foot, the point of which is attached like
the sucker of a leech. The foot is stretched far beyond
the beak of the shell on the anterior side. For anato-
mical details of the animal I would refer my readers to
tlfce admirable treatise of Professor Loven on the deve-
lopment of the Lamellibranchiate Acephala. The fry
has two very distinct eyes, which soon disappear and
are quite absent in the adult. The cilia which clothe
the gills are extremely beautiful and interesting objects
of microscopical examination. If a small portion of
one of the gills is cut off and put into sea-water, it will
swim about for a considerable time by means of these
cilia, appearing like an independent animal. The shell
sometimes grows to a colossal size. In the ' Transac-
tions ' of the Imperial University of Moscow for 1863
is a notice by Dr. Nordmann of a gigantic form of the
present species found by Holmberg on Edgecombe Isle
in Russian North America. One specimen, which is
figured of the natural size, measures upAvards of 9
inches in length and 4^ in breadth, and is stated to
weigh 1 lb. 5 dr. 16 gr. The stunted variety (incurvata)
forms on some parts of our rocky coast a mass so closely
packed that the point of a knife could scarcely be thrust
between them. This was probably the " amazing bed
of small mussels " mentioned by Pennant in his ' Intro-
duction to Arctic Zoology/ and as to which he remarks,
11 1 think they were brought there by sea-fowl to eat at
leisure " ! Fabricius says it is viviparous, and that in
the spring he has found the fry lodged within the hinge
of their parent's shell ; but it seems more probable that
this was only a place of temporary shelter for them.
In the Shetland Isles the edible mussel is called "Crock-

MYTILUS. 109

ling," being evidently a corruption of the Icelandic
word " Kraeklingur," having the same signification. The
hinge-teeth are usually three or four only. The shell is
often distorted.

The mussel has been from time immemorial a fa-
vourite article of food in this and other maritime coun-
tries. Pennant, after a preface of " Ne fraudentur
gloria sua littora," especially praises those from Lan-
cashire. Large quantities are regularly brought to
Billingsgate from the Dutch coast. A small kind,
called in Brittany " Cayeu," is chiefly in request there,
being esteemed more delicate and digestible. " Potage
aux moules " is by no means to be despised at the table
d'hote of the Hotel de PEpee at Quimper. Herr
Adolphe Meyer informs me that boughs of elm and
other trees are laid down in the Bay of Kiel, and taken
up at the end of three, four, or five years, between
December and March, being then covered with fine
mussels. These laden boughs are sold by weight, and
the shell-harvest is sent into the interior of Germany,
where it is in great request. He adds that the mussel
is not reckoned wholesome in summer. Many cases of
serious illness, and even of death, have resulted from its
occasionally deleterious qualities. "The faculty" seem
to be completely at fault as to the nature of this poison.
By some it is attributed to the mussels living among
putrescent matters, as in docks and near the outlet of
public sewers ; by others to their feeding on the spawn
of starfish, which are well known to be poisonous ; by
others to their being too freely eaten and causing a sur-
feit, or to a morbid state of the system in the persons
eating them ; by a few to their imbibing into their
tissues a solution of copper; and Delle Chiaje showed
that in many instances it was owing to these mollusks

110 MYTILIDjE.

being at the time in spawn and therefore out of season.
A strange notion once prevailed that the poor little pea-
crab was the author of all this mischief; and it was con-
sequently stigmatized as " malignant. "

Nor is it only as an article of food that these shell-fish
are of use to man. In Lister's time live mussels were
gathered and spread over the fields in Lancashire for
manure. Fabricius mentions that the fish eaten raw is
an excellent remedy for sore eyes, and that the shell
serves as a razor to shave with. I should not like to
try the latter experiment on a frosty morning, or when
late for breakfast. Mohr says that mussels are not
eaten in Iceland, but that lime is made from their cal-
cined shells, and is much more binding and becomes
harder than mortar made from limestone. They are
also used extensively for bait in our long-line fisheries ;
and Asbjornsen has given, in his ' Christianiafjordens
Litoralfauna/ some interesting particulars of the mus-
sel-fishings on that part of the Norwegian coast, and
especially with regard to an epidemic that in the summer
of 1852 destroyed millions of them and caused great
distress to the poor fishermen. In Drummond's * Letters
to a Young Naturalist' it is stated that mussels are
used at Bideford to fix by means of their byssus the
stones of a bridge, which is difficult to keep in repair
owing to the rapidity of the tide. The interstices of the
bridge are filled with them, and it is said that only their
strong threads support the fabric and prevent its being
carried away. It is one of the instances of contrivance
enumerated by Paley in illustration of his chapter on
compensation, and to show that the works of the Deity
are known by expedients. He saj^s, " A muscle, which
might seem, by its helplessness, to lie at the mercy of
every wave that went over it, has the singular power of

MYTILUS. Ill

spinning strong tendinous threads, by which she moors
her shell to rocks and timbers." Pearls too are pro-
duced by them in considerable quantities, although of
an irregular shape and indifferent lustre. Formerly
they were applied medicinally as an absorbent. Great
numbers are still collected at the mouth of the River
Conway in North Wales, the fish being boiled and trodden
out by the naked feet of women. What is done with
these " seed-pearls " is a mystery. I have been told
that the Jews purchase them for the Birmingham mar-
ket; and a correspondent in Loudon's Magazine of
Natural History for 1830 mentions a surmise that they
are exported to India to be dissolved in the sherbet of
the nabobs !

This species in a recent and fossil state has received
twenty-eight different names. Its variability is coex-
tensive with its diffusion.

2. M. modi'olus *j Linne.

M. modiolus, Linn. Syst. Nat. p. 1158. Modiola modiolus, F. & H. ii.
p. 182, pi. xliv. f. 1,2.

Body dark orange, speckled with white and often tinted
with brown: mantle having both margins plain throughout,
but finely ciliated : foot red on the upper part, and whitish at
the base, where it is very thick and strongly wrinkled.

Shell oblong, bluntly rounded, nearly square at the smaller
end and expanding outwards to a semicircular edge in front,
convex, and gibbous towards the beaks, solid and glossy :
sculpture, fine concentric lines of increase : colour purplish-
yellow : epidermis thick, dark brown or dusky, almost black
in the adult, minutely striate lengthwise, foliated in the
young and produced into long thorn-like filaments, which are
plain at their edges and arranged in concentric rows on the
posterior side and in front : 'margins thick, straight or but
slightly incurved on the ventral side, obtusely rounded be-
hind and semicircular in front : beaks blunt, divergent and in-

* The box of a pump.

112 MYTILID.E.

curved, placed a little below the point of the shell and at a
short distance from the anterior margin: hinge-line gently
curved, occupying nearly the upper half of the dorsal margin :
ligament extremely strong, partly exposed : hinge-plate solid :
hinge toothless, reflected: inside nacreous and often studded
with incipient pearls : muscular and jjallial scars very distinct.
L. 5. B. 2-5.

Var. 1. ovata. Shell smaller, narrower at the smaller end
and broader at the other. L. 3. B. 2.

Var. 2. umbilieata. Shell narrower ; anterior margin in-
flected and forming a deep sinuosity. M. umbilicatus, Penn.
Brit. Zool. iv. p. 112, pi. 65. f. 76.

Habitat : Coasts of England, Wales, Ireland, and
Scotland, from low- water mark to 80 fathoms, and at a
distance of more than forty miles from land, in muddy
gravel. It is not common in the first two localities,
but abundant and gregarious in the north and west of
Scotland and Shetland, at depths varying from 2 to
20 fathoms. Var. 1. Lismore (Bedford) ; Portmarnock
and county Antrim (J. Gr. J.). Var. 2. Cork Harbour
(Humphreys). The species occurs in all our upper ter-
tiaries, and especially in the glacial beds. It ranges
from Behring's Straits (Wosness), New England (Stimp-
son), and Iceland (Steenstrup) to the Danish coasts of
the Baltic ; but I am not aware that it has been noticed
further south. In Calabria, however, it is fossil, and was
described by Philippi under the name of Mocliola grandis.
This is another proof of arctic conditions having for-
merly pervaded the South of Europe.

Pennant must have considered this to be a fish, when
he says it " often seizes the bait of the ground-lines."
It is now and then caught by the beard and hooked up
in this way. In some parts of Shetland and the north
of Ireland it is eaten by the poorer class ; and every-
where it is reckoned an excellent bait for fish. The epi-

MYTILUS. 113

dermis of immature shells is yellowish-brown, and has
an agglutinating property, being frequently coated with
gravel and bits of shell. In this state the dorsal angle
is more acute. Rude nests or cases are occasionally
made by the young for their protection. The spots
where pearls are in course of formation exactly corre-
spond with the holes drilled by species of the curious
sponge called Cliona from the outside of the shell. A
transverse section admirably displays the mode of growth
and secretion of colour. The outside layers are purple ;
while the inner layers, which are three times as thick
and numerous as the others in full-grown shells, are
white. The "horse-mussel/' as it is called, attains an
enormous size under favourable circumstances. One of
my specimens, which Professor King got on the Nor-
thumberland coast, is about nine inches and a quarter
long and of a proportionate breadth and capacity. It
would have made a dainty drinking-cup for Mimer, or a
pretty toy for one of the other giants, of whom Ohlen-
slager sung in his ' Nordische Guder/

"And all round the cavern might plainly be seen,
Where Giants had once been at play ;
For the ground was with heaps of huge muscle-shells strewn,
And strange fish were mark'd in the clay."

This is the Modiola papuana of Lamarck, but not the
Mytilus Papuanus of D'Argenville, which is a tropical
species. The former referred to his Modiola tulipa the
Mytilus modiolus of Linne. Mr. Hanley also states that,
from an examination of the typical specimens, the M.
modiolus of Linne is not our species but the Modiola
tulipa of Lamarck. This shows the discrepancy between
the Linnean collection of shells and the ' System a Na-
turae/ and how little reliance can now be placed on the
former for identifying some of the species. Linnets de-

114 mytilidjE.

scription agrees ad amussim with trie common shell which
is usually regarded as M. modiolus, the animal of which
he says is eaten in Norway. According to Lamarck, his
Modiola tulipa inhabits " les mers d'Amerique." Our
shell is the Modiola vulgaris of Fleming. The young is
the Mytilus curtus of Pennant and the Modiola barbata
of Macgillivray.

3. M. barba'tus #j Linne.

M. barbatv.s, Linn. Syst. Nat. p. 1156. Modiola barbata, F. & H. ii. p. 190,
pi. xliv. f. 4.

Body reddish-brown : mantle not folded : gills narrow,
coarsely pectinated ; lower pair more than twice the depth of
the upper ones.

Shell irregularly triangular, pointed at the smaller end and
expanding obliquely outward to a broad and obtusely rounded
edge in front, compressed, but gibbous towards the beaks, solid,
somewhat glossy on the upper part, but elsewhere of a dull
hue owing to the close investment of the bearded epidermis :
sculpture, numerous concentric membranaceous ridges : colour
yellowish-red, or scarlet: epidermis thick, yellowish-brown,
minutely but deeply striated lengthwise, thickly foliated, and
rising on the posterior side and in front into a fringe of thorn -
like projections, which are distinctly serrated or barbed on the
side facing the ventral portion ; the epidermis is reflected over
the front edge and forms a glistening band inside it : margins
thick, straight or incurved on the ventral side, angulated
behind, and obtusely rounded in front : byssal sinus large and
rather long : beaks small, close together, incurved, placed (as
in M. edulis) very near the point of the shell: hinge-liiie
straight, occupying about one-half of the dorsal margin : liga-
ment narrow, much sunk: hinge-plate thick, deeply grooved
for the reception of the ligament : hinge toothless, reflected :
inside highly nacreous and iridescent, sometimes beautifully
stained with purple on the posterior side and occasionally
studded with sessile pearls : muscidar scars indistinct : pallia!
scar well defined. L. 1*8. B. 1.

Yar. oblonga. Shell more elongated and tumid ; ventral

* Bearded.

MYTILUS. 115

f

side incurved, and dorsal side arched instead of being angu-
lated.

Monstr. Upper valve nearly flat and much smaller than the
other.

Habitat : Not uncommon on the southern and west-
ern coasts of England, Wales, and Ireland, and found
by Mr. Bean at Scarborough, on rocky and stony ground,
from low-water mark to 18 fathoms. Var. Portsmouth
(J. G. J.). Monstr. South Devon (Mus. Loscombe).
This species is a Red Crag fossil. It has not been re-
corded from any place north of England; but its south-
ern range extends to the iEgean and Algeria.

According to Mr. Clark the gills " entirely coast the
body, being brought close to the posterior extremity to
receive the water. This structure of the branchiae is
the substitute for the absence of tubes or any sort of
siphonal fold of the mantle." The shaggy beard of the
shell is very peculiar. Montagu says that it is partly
owing to the epidermis being broken and divided into
fibres; and he also observes that, while in a soft and
glutinous state, it arrests such extraneous matter as
comes in contact. Gould suspected that the epidermis
was a parasitic vegetable ; but he evidently had not then
had an opportunity of seeing it. The byssus resembles
a bundle of fine tow. M . barbatus differs from the young
of M. modiolus in the shell being narrower at the an-
terior and much broader in proportion at the posterior,
side, as well as in the angularity of the dorsal margin,
straight hinge-line, strong laminar ridges, reddish colour,
and the epidermis being serrated or barbed on one side
instead of being plain as in that species.

This species does not appear to inhabit the north of
Europe, unless it is the shell noticed by Muller in his
' Zoologia Danica • as smaller than M. modiolus, with a

116 MYTILID^.

black epidermis and quite of a purple colour inside to-
wards the broader end, and having the valves less raised
near the hinge and compressed in front. The M . bar-
batus of his ' Prodromus ' is probably the young of M.
modiolus. Linne also described the present species in
his ' Fauna Suecica/ but not with sufficient precision.
It is the Modiola Gibbsii of Leach's c Zoological Miscel-
lany/ and Mytilus Gibbsianus of his work on British
Mollusca edited by Dr. Gray.

4. M. Adria'ticus *, Lamarck.

Modiola adriatica, Lam. An. s. Yert. vi. p. 112. Modiola tulipa, F. &H.
ii. p. 187, pi. xlv. f. 7 ; pi. xlviii. f. 6 ; and (animal) pi. Q. 1". 6.

Body pale red with a yellowish tint : mantle forming two
incomplete very wide and short tubes, which are of equal length
and scarcely separated from each other ; the mouth of each
tube is fringed with about twenty close-set short cirri : gills
pale brown : foot long, flattish and slender, divided lengthwise
by a flake-white line, and having a byssal groove which in-
creases in depth from point to heel : byssus strong, yellowish.

Shell oval, inclining to rhomboidal, bluntly pointed or
rounded at the smaller end, and expanding outwards as in the
last species, convex, extremely gibbons towards the beaks, thin
and of a delicate texture, glossy : sculpture, fine but irregular
lines of growth: colour yellowish, with usually rose-red rays
on the posterior half, occasionally purple ; these rays or streaks
resemble those of a tulip, and are very beautiful ; they are
variously arranged, and sometimes broken or interrupted :
epidermis thin, yellowish, and like a coat of varnish, some-
times a little exfoliated on the dorsal side and in front, and
forming slight hairs, marked lengthwise by minute lines or
scratches : margins thin, straight on the ventral side, angn-
iated behind and rising into a shoulder or sharp keel towards
which the posterior sides are compressed, semicircular in front :
byssal sinus represented by a narrow slit : heals small, close
together, inflected, placed at comparatively a considerable dis-
tance from the anterior margin : hinge-line gently curved,
occupying about one-half of the dorsal margin : ligament nar-

* Inhabiting the Adriatic.

i

MYTILTJS. 117

row, much sunk : hinge-plate thin, with a deep ligamental
groove beneath it, which is supported by a strong rib : hinge
toothless, reflected : inside nacreous and iridescent, sometimes
red or tinged by the outside rays : scars rather distinct. L. 1*2.
B. 0-7.

Var. ovalis. Shell much larger and narrower, almost cylin-
drical, more solid ; ventral margin slightly incurved : colour
yellow, with dark-purple rays : epidermis horncolour or
brownish-yellow. L. 2. B. 0-85. Modiola ovalis, Sowerby,
111. Ind. Brit. Shells, pi. 7. f. 7.

Habitat : By no means rare, although not common,
in the South of England and the Channel Isles, as well
as on the coasts of North and South Wales and Ireland,
in 7-40 fathoms, muddy gravel or sand. I know of only
three localities for it in Scotland, viz. Firth of Forth
(Forbes) j off Foula, Zetland, in 45 fathoms (M f An-
drew) ; and Loch Carron, Ross-shire, in 28 fathoms
(J. G. J.). A specimen dredged by me in the last-men-
tioned place is of a uniform pale yellow and much larger
than those from the south, as might have been expected.
The variety is rather plentiful in one part of Falmouth
harbour ; and I have also taken it off Guernsey, but of
small size. The same variety occurred in excavating
a channel in Belfast harbour, and may be considered a
newer pliocene fossil. Lilljeborg has found this species
in Finmark, Malm on the coast of Sweden in 10-15
fathoms (in one case attached by the byssus to Corallina
officinalis), and Hsellebsek on the Baltic coast of Zea-
land. Its distribution southward extends to the iEgean
and the Gulf of Tunis, at depths varying from 2 to 50
fathoms.

This prettily painted mussel often makes in its young
state a case like that of M. modiolus. When the animal
is dead, the shell floats on the surface of water, by
reason of its lightness and being perhaps buoyed up by

118 MYTILID.E.

gas generated in the process of decay. The thin texture
of the shell, the coloured rays, and the greater distance
of the beaks from the anterior margin will readily serve
to distinguish this species from the young of M. modio-
lus. It differs from M. barbatus in its rhomboidal
shape, in being much more convex, and its paler colour,
as well as in the rays, position of the beaks, sculpture,
and epidermis.

M. Adriaticus appears to have been known to Mon-
tagu ; for in his account of M . barbatus he says, " A
variety is faintly radiated." The Modiola tulipa of
Lamarck (for which the British species has been mis-
taken) is described as a native of the American seas,
and a variety of it as coming from New Holland. The
tropical shell is of a different shape and substance from
ours, and they only agree in the style of colouring.
Lamarck pointed out the distinction between them.
The present species may be the Mytilus pictus of Gmelin
(from Bonanni), which is said to inhabit the coasts of
Spain ; but the diagnosis given by him is too slight for
the purpose of identification, and the Modiola picta of
Lamarck is another species and better known. In
Thorpe's f Marine Conchology ' our shell has the appro-
priate name of " radiata" which appears to have been
given to it by the late Captain Brown.

5. M. phaseoli'nus *, Philippi.

Modiola phaseolina, Phil. Moll. Sic. ii. p. 51, tab. xv. f. 14; F. & H.ii.
p. 186, pi. xliv. f. 3.

Body reddish-brown : foot long and cylindrical : byssm-
strong, light horncolour.

Shell conformable with its name, obliquely expanding from
* Shaped like a kidney-bean.

MYTILUS. 119

a blunt point to a rounded edge, remarkably convex and gib-
bous, rather solid and glossy: sculpture, fine but irregular
lines of growth : colour beneath the epidermis yellow tinged
with purple : epidermis thick, yellowish-brown and of a darker
hue on the sides, exfoliated in all parts except towards the
anterior margin, and rising into numerous stiff beard-like
points of different lengths, those on the lower part of the
ventral side being the finest : margins thick, incurved on the
ventral side, rounded behind, both these margins being nearly
parallel, semicircular in front : byssal sinus narrow but dis-
tinct : beaks small, blunt, and inflected, lying horizontally on
the point of the shell, slightly diverging from each other, and
placed at a very short distance from the anterior margin :
hinge-line slightly curved, occupying less than two-fifths of
the dorsal margin : ligament thick and strong, very little ex-
posed : hinge-plate solid, with a deep ligamental groove as in
the last species, and the rib is continued within the anterior
margin, so as to form a small vaulted chamber below the
hinge; inner edge of the dorsal margin finely crenulated
across : hinge thick and prominent, also finely crenulated or
toothed : inside nacreous and iridescent, purplish-yellow, and
stained with brown on the dorsal side and in front : scars in-
distinct. L. 0-65. B. 0-375.

Habitat : On all our coasts, from the extremity of
Shetland to the Land's End and Jersey, rather common
on rocky and hard ground from low- water mark to 86
fathoms. It appears to be a Coralline Crag fossil, as I
observed in Mr. Searles Wood's collection some speci-
mens mixed with the young of M. modiolus from that
deposit. Steenstrnp found it in Iceland; and it has
been enumerated by all writers on the Scandinavian
mollusca as occurring from Vadso (near the North
Cape) southwards at depths ranging from 30 to 160
fathoms. A living specimen has been taken at Cannes
by M. Mace. It was first described by Philippi from
the upper tertiary beds of Calabria and Sicily.

The animal is rather active when detached from its
byssus, using its extensile foot for creeping like its con-
geners, and moving with considerable agility. It often

120 MYTTLID^:.

invests itself in a case of gravelly and shelly fragments.
The fry are of a rhomboidal shape. The size of adult
specimens does not appear to exceed three-quarters of
an inch, those from the south being much smaller than
northern ones. The shell resembles that of Modiolaria
in the denticulation of the dorsal margin. It differs
from the young of M. modiolus in having this peculiar
character, as well as in being much thicker, more con-
vex, of a darker colour, and angulated behind.

Allied to M.phaseolinus in respect of the denticulated
hinge and dorsal margin is the M. crenatus of Lamarck,
which was imported in 1816 into. Portsmouth harbour
on the bottom of H. M. S. Wellesley from Bombay;
but it has not become naturalized. M . bidens of Linne
and M. Africanus of Chemnitz were subsequently intro-
duced in the same manner, and with a like result, into
Scarborough and Plymouth. The former is a West-
Indian, and the latter a West-African species. Modiola
agglutinans of Cantraine (M. vestita, Philippi) is said to
have been once found in Ardmore Bay, near Youghal,
and was described by Captain Brown under the name
of Modiola Ballii. It is a Mediterranean species. The
Mytilus (Lithodomus) aristatus of Dillwyn was found
many years ago in a piece of ballast limestone imported
into this country from the West Indies, and was for-
merly included among British shells.

Genus II. MODIOLA'RIA * Beck. PI. III. f. 3.

Body suboval : mantle folded in front into a wide incurrent
tube, and behind into a conical excurrent tube : foot strap-
shaped.

Shell rhomboidal, sculptured by two rows (one on each
side) of striae which radiate from the beaks, leaving the middle

* Allied to the genus Modiola of Lamarck.

MODIOLARIA. 121

portion smooth : berths incurved : hinge mostly toothless, but
sometimes crenulated : hinge-plate finely notched.

This genus differs from Mytilus in the mantle being
folded into a distinct tube for the supply of food and
aerated water, as well as in the remarkable sculpture of
the shell. The hinge-plate is crenulated as in Mytilus
phaseolinus . The foot is very flexible and extensile ; and
when fully stretched out, it is two or three times as long
as the shell, and becomes almost thread-shaped. The
animal can crawl rather fast along a level surface by
extending and fixing the point of its foot in front, using
it as a fulcrum, and then dragging itself forwards ; and
it occasionally floats on its back like Kellia suborbicu-
laris and other small bivalves. One species (M. mar-
morata) burrows into the tunic or outer coat of Asci-
dians, and others form nests or wrapping-cases with the
aid of their byssus. It would seem, however, that the
European habit of infesting Tunicata is not possessed by
any Transatlantic species.

Although Beck has the credit of founding the genus
Modiolaria, and it has been adopted by Loven, Mid-
dendorff, and other writers on the northern mollusca,
it has never been described or characterized by any of
them. The same remark applies to the genera La-
nistes of Humphreys and Lanistina of Gray, both of
which are synonyms of the present genus. Modiolaria
may be distinguished from Brown's genus Crenella by
the shell of the latter being covered all over with stride
or ribs, and by its having a strong and crenulated
tooth in the hinge of each valve. The animal also
differs in some important particulars, which will be pre-
sently noticed. Whether all these differences are gene-
ric or subgeneric, may be a moot question ; but as the
lines of demarcation between any one group of animals

G

122 MYTILIDiE.

and those on each side of it in the same family are
never capable of being precisely defined, it is obviously
undesirable to encumber our system of classification
with more divisions and names than are necessary to
separate and recognize the species contained in such
group.

1. Modiolaria marmora'ta*, Forbes.

Mytilus marmoratus, Forb. Mai. Mon. p. 44. Crenella mctrmorata, F. & H.
ii. p. 198, pi. xlv. f. 4.

Body thick, pale-yellow: incurrent tube large and bag-
shaped, formed of two pendulous puckered flaps of the mantle,
mottled with purplish- or reddish-brown and white flakes ;
margin plain : ecccurrent (or anal) tube small and conical, of
the same colour as the larger tube, farrowed at the base, and
having the mouth or opening fringed witb four or five minute
dark cirri : foot white, very long and almost cylindrical, with
a deep byssal groove : byssus semitransparent but strong.

Shell oval, very gibbous and obliquely angular, rather
thin, glossy, and somewhat iridescent : sculpture, 15-18 lon-
gitudinal ribs on the anterior side and 20-25 on the other
side ; these ribs or striae occupy the two sides only ; the inter-
mediate space is smooth, with the exception of very fine and
crowded transverse lines, which traverse the whole surface
and give the ribs an appearance of being minutely punctured :
colour yellowish, irregularly mottled with purplish- or red-
dish-brown spots or blotches, sometimes forming zigzag
streaks, occasionally of a uniform orange hue : epidermis light
green : margins rounded and obliquely truncate at the ante-
rior end, nearly straight and slightly gaping on the ventral
side, wedge-shaped or bluntly pointed at the posterior end,
whence they slope backwards with a gentle curve to the dorsal
angle or hinge-line : byssal sinus long and narrow : beaks
small, swollen, inflected (as in the genus Verticorclia), and
divergent, placed near the anterior margin: ligament thick
and strong, yellowish-brown, nearly concealed in the embrace
of the hinge-plate : hinge-line slightly curved, occupying the
whole of the dorsal margin : hinge-plate strengthened by an
internal rib and receiving the ligament in a shallow groove ; it

* Marbled.

MODIOLARIA. . 123

is obliquely and finely crenulated : hinge reflected and deeply
indented : inside nacreous and iridescent, notched all round
the edge, except on the ventral side : muscular scars slight and
scarcely perceptible. L. 075. B. 0*45.

Habitat : Imbedded in the skin or outer integu-
ment of Ascidia mentula and other simple Tunicata, or
attached by its byssus to old shells, in the Laminarian
and Coralline zones on all our coasts. It is by no
means rare ; and sometimes a score of specimens may
be extracted from a large Ascidia. In a fossil state it
occurs in the Red and Coralline Crag. The limits of its
foreign distribution comprise the sea- bed lying between
Finmark and the iEgean, and reach westward to the
Canaries. On the Norwegian coast Asbjornsen has
given 10, and Danielssen 150 fathoms as its bathy-
metrical range. It has not been quoted in any list of
Icelandic, or of North American shells.

On being dislodged from its usual place of abode,
M. marmorata puts out its foot and feels its way in
search of another retreat ; and when it has found one to
its liking, it immediately spins a byssus and securely
fastens itself, sometimes on or within the fold of a
seaweed, or in the crevice of a stone. I have seen it (as
if acting on a sudden impulse, or disliking to be watched)
detach itself from its mooring and set out again on its
travels to select a more sheltered or suitable spot. The
genesis or development of the animal has been fully and
most ably elucidated by Loven.

This species used to be called the Mytilus discors of
Linne; and it is not improbable that in his descrip-
tion he included it with the Mytilus discrepans of Mon-
tagu, which we now refer to Linnets species. But the
epithet " fusca "i in the ' Systema Naturse * is scarcely
applicable to the present species; and as one of the

g2

124 mytilidjE.

localities given by Linne, on the authority of his pupil
Zoega, is Iceland (where M. marmorata has not since
been found), it may be on the whole better to confine
the specific name of discors to the other species. Leach
was, I believe, the first to call in question the identity
of M. marmorata with the Mytilus discors of Linne.
In his monograph of the genus Modiola, published in
the 'Zoological Miscellany i (vol. ii. p. 56), he says, as
to the species in one section, " Montagu described two
species as natives of Great Britain : one he named M.
discors (but I am by no means satisfied that it is the
discors of Linne) ; the other, which is a very distinct
species, discrepans" The change of name afterwards
proposed by Forbes was not effected without much
opposition. Philippi called it Poliana, in the Supple-
plement to his work on the Sicilian Mollusca, in the
' Zeitschrift fiir Malakozoologie ' for June 1844 ; Hanley
substituted another name (tumida), in his Appendix to
Wood's ' Index Testaceologicus '; and D'Orbigny after-
wards added a fourth, viz. Europcea. Lamarck had
described it in 1819 as Modiola discrepans. If the
Linnean collection of shells had been preserved intact,
instead of being so often and so carelessly disarranged and
rearranged by Sir James Smith's pupils and various
other persons, it might have helped to explain some of
the short and doubtful descriptions contained in the
' Systema Naturse ' and other works of the great Cory-
phaeus of northern naturalists, and would have pre-
vented much of the confusion which has prevailed with
regard to the species above alluded to. Even the num-
bers marked on some of the specimens, with reference
to those works, cannot be identified with the handwriting
of Linne ; and it is extremely rare to find a case where
the name has been so inscribed.

MODIOLARIA. 125

2. M. costula'ta *, Risso.

Modiolus costidatus, Risso, Hist. nat. l'Eur. rnerid. iv. p. 324, f. 165.
Crenella costidata, F. & H. ii. p. 205, pi. xlv. f. 1.

Shell oblong, narrower at the anterior than at the opposite
end, convex, rather thin, and glossy : sculpture, about 10 ribs
on the anterior side and twice as many on the other side ;
middle area somewhat depressed, destitute of ribs, but the
whole surface of the shell is marked by very numerous and
wavy transverse striae, which gives it a silky appearance :
colour cream-white, beautifully mottled with rich purplish-
brown streaks often arranged in a zigzag pattern : epidermis
thin, light green : margins rounded at the anterior end, nearly
straight or slightly incurved on the ventral side, broad and
rounded at the posterior end, and forming a gentle curve on
the dorsal side : beaks small, inflected and divergent, not so
much swollen as in M. marmorata, nor placed so near the
anterior margin : byssal sinus, ligament, and hinge-line as in
that species : hinge-plate strengthened by an internal rib or
ledge and strongly toothed ; ligamental groove narrow : hinge
reflected and slightly indented or notched : inside highly na-
creous, and of a deep purplish-brown except at the edge,
which is finely crenulated on the anterior and posterior sides :
scars indistinct. L. 0*4. B. 0-2.

Habitat : Under stones and among small sea- weeds
in rock-pools at low spring-tides on the south coasts of
Devon and Cornwall ; Herm (Macculloch) ; Oxwich Bay,
near Swansea (J. G. J.) ; and Bundoran, co. Donegal
(Waller). It is rather local, but not uncommon. Searles
Wood has found it in the Red and Coralline Crag. It
appears to be a southern form, and to range from Brittany
(Mace) to Sicily (Philippi) and the Canaries (Webb and
Berthelot) .

This very pretty shell differs from M. marmorata in
being less gibbous or tumid, much narrower, and of a
brighter and more variegated colour; the posterior
margin is regularly curved instead of obliquely wedge-

* Slightly ribbed.

126 MYTILIDJE.

shaped ; the central area is depressed ; and the beaks
are placed at a greater distance from the anterior
margin. Mr. Dennis says that it is frequently imbedded
in a very snug little nest on sea- weeds, but never among
their roots, where M. discors takes up its abode and
occurs in great numbers. My largest specimen is half
an inch long; but I believe it is usually very much
smaller, and that in cubical contents it is not a tenth of
the last species.

3. M. dis'cors*, Linne.

Mytilus discors, Linn. Syst. Nat. p. 1159. Crenella discors, F. &H. ii.
p. 195, pi. xlv. f. 5, 6 ; and pi. xlviii. f. 5.

Body yellowish-white, with a few scattered minute specks
of flake-white : incurrent tube formed by a wide protube-
rant slit of the mantle in front for the admission of food and
water: excurrent tube conical, and projecting considerably
beyond the shell at the posterior or broader end : foot strap-
shaped, capable of being extended more than twice the
length of the shell, and used (like that of Mytilus edulis) for
crawling.

Shell oval, much broader than either of the other species
above described, somewhat compressed, rather thin, usually
not glossy : sculpture, 10-12 remote ribs on the anterior side,
and 30-40 close-set ribs on the other side ; middle area de-
pressed and smooth ; transverse stria? very minute and fine :
colour yellowish-brown : epidermis rather thick, light green :
margins rounded on all sides, except the ventral, which is
nearly straight : beaks small, rather prominent, incurved and
diverging, placed near the anterior margin : byssal sinus,
ligament, and hinge-line as in the other species : hinge-plate
strengthened by an internal rib, and obliquely and strongly
toothed ; ligamental groove narrow : hinge slightly reflected
and thickened, crenulated: inside highly nacreous, purplish-
yellow or liver- colour, with the anterior and posterior edges
finely notched : scars rather distinct. L. 0-5. B. 0-35.

Var. 1. angustior. Shell smaller, narrower, and more glossy.

* Disagreeing.

MODIOLARIA. 127

Yar. 2. semilcevis. Shell narrower, yellowish-horncolonr; ribs
on the posterior area slight and scarcely perceptible, L. 0*1 7-5.
B. 0-1.

Habitat : Gregarious at the roots of seaweeds (espe-
cially Corallina officinalis) between tide-marks, and in
the Laminarian zone everywhere from Shetland to the
the Channel Isles. Var. 1. Southampton (J. G. J.) ;
estuary of the Orwell, Suffolk (Clarke). Var. 2. Staffa
(Alder). Some specimens from Lismore near Oban
also have no trace of ribs on the upper part of the pos-
terior area. Having had an opportunity of carefully
examining and comparing an extensive series of speci-
mens of Modiola laevigata, Gray, and the variety sub-
striata, from different parts of the Arctic seas, I am con-
vinced that they are not distinct from the present spe-
cies. The gradual passage from any one of these forms
to another is very evident, if a sufficient number ol
examples of all ages and from many localities are sub-
mitted to the inspection of a tolerably practised ob-
server; and the deplorable fashion of species-making
might be in some measure restrained by adopting this
method in all cases, instead of selecting a few particu-
lar specimens and discarding young shells and those
which offer inconvenient proofs of transition. As an
upper tertiary fossil the variety laevigata has been found
at Elie in Fifeshire by the Rev. Thomas Brown, and the
typical form occurs in the mammalian bed at Chilles-
ford. It has a wide extra- British range, from North
Greenland and New England to the iEgean.

This little creature is a very industrious seamstress ;
for Mr. Alder says it " forms for itself a kind of nest or
case by stitching together the small seaweeds or coral-
lines with its byssal threads." Forbes and M 'Andrew
dredged it at a depth of 30 fathoms in the Irish Sea, off

128 mytilid^:.

Anglesea, in the line of strong currents, enveloped in
similar nests. Dr. Gray has observed that " it creeps
with the foot on the surface of the water, with the shell
down wards like a Cyclas, and it has the power, like that
genus, of crawling up the smooth surface of glass or
china."" The old northern writers called it " anatum
cibus," its littoral habitat rendering it a tempting prey
to wild- fowl. According to Fabricius it is eaten, al-
though seldom, by the Greenlanders.

The meaning of the specific name has reference to
the opposite direction in which the two sets of ribs or
stria? appear to diverge. It is to be regretted that this
discordance has extended to the synonymy. Montagu
called the present species Mytilus discrepans ; and more
than ten years afterwards Lamarck used the same name
for Modiolaria marmorata, as well as for M. impacta,
a tropical shell.

4. M. ni'gra*, Gray.

Modiola nigra, Gray, Supp. to App. to Parry's First Voyage to the North
Pole, p. ccxliv. Crenella nigra, F. & H. ii. p. 202, pi. xliv. f. 5, and
(animal) pi. Q. f. 7.

Body " of a transparent white hue, with the margin of the
cloak and siphon tinged with pink, and speckled with brown
and opaque white." (Alder.)

Shell oval, inclining to oblong, compressed, rather thin,
moderately glossy and slightly iridescent: sculpture, about a
dozen remote ribs on the anterior side, and 50-60 close-set
and thread-like ribs on the other side, which latter become
finer towards the middle of the shell ; ventral area not de-
pressed, but without ribs ; transverse striae numerous, coarse,
and flexuous, sometimes forming tubercles or a rough net-
work where they intersect the longitudinal ribs : colour
purplish-brown : epidermis rather thick, fawn-colour in the
young, olive-green at a subsequent stage of growth, and dark

* Black.

MODIOLARIA. 129

brown or even pitch-black in aged examples : margins rounded
on all sides except the ventral, which is nearely straight :
beaks small, prominent, incurved, and diverging, placed at
some distance from the anterior margin : byssal sinus, ligament,
and hinge-line as in the other species : hinge-plate strength-
ened by a rib to receive the ligament, and hnely notched;
ligamental groove narrow and deep : hinge crenulated : inside
highly nacreous, purplish-brown, finely notched on the ante-
rior and posterior edges, and showing the impressions of the
ribs as well as faint traces of similar but finer striae on the
middle area : scars distinct. L. 1*5. B. 0*65.

Habitat : Muddy gravel, at depths varying from 7
to 90 fathoms on the coasts of Yorkshire, Northumber-
land, and Durham, both sides of Scotland, and the Shet-
land Isles. Although not generally distributed, it is not
uncommon in some places, and in the Firth of Forth it is
called by the fishermen the " corduroy mussel." The
Dogger bank appears to be its southernmost limit in our
seas. The Rev. H. W. Crosskey found a single valve in a
postglacial bed in the Kyles of Bute. Meyer and Mobius
obtained specimens by dredging in the bay of Kiel, on
the German coast of the Baltic, whence the species
ranges northwards along the Scandinavian shores to
Nova Zembla on the east, and Iceland on the west. On
the other side of the Atlantic it inhabits the coasts of
Greenland, Newfoundland, New England, and Massa-
chusetts.

This fine species may be at once known from M.
discors by its sculpture. There are nearly twice as
many ribs on the posterior area, and the transverse stride
or wrinkles are so coarse as to give a granular appear-
ance to that part of the shell. Besides, the anterior
margin is more produced, and consequently the beaks
recede further from that extremity. The fry are quite
smooth and have a prismatic lustre. The largest speci-
mens I have seen were lately procured on the Durham

g 5

130 MYTILIM.

coast, one of them measuring nearly two inches and
a half in length.

Chemnitz and Fabricius considered it to be a variety
of M. discors ; and Montagu noticed it as a large form
of his Mytilus discrepans. Leach, in his ' Zoological
Miscellany/ excellently described it by the last-men-
tioned name; and he referred the Devonshire speci-
mens of M. discors to a small variety of the same species.
This was many years before Gray's publication; and
perhaps, in strict justice, the name of discrepans ought
to be restored and applied to the present species. But
I will mercifully abstain from increasing the perplexity
which has so long involved the nomenclature of the
Modiolarice.

Genus III. CftENE'LLA*, Brown. PI. III. f. 4.

Body roundish-oval : mantle open in front, and folded be-
hind into a sessile excurrent tube : foot worm-shaped, the
point being disk-like and issuing out of a sheath.

Shell oval or rhomboidal, cancellated by longitudinal ribs
and transverse plates : beaks straight : ligament small : hinge
of each valve furnished with an upright tooth, which is crenu-
lated as well as the hinge-plate.

The name of this genus was probably derived from
the circumstance of the hinge-plate being slightly
notched. The shell is entirely composed of nacre, and
has a silvery hue when deprived of the epidermis : in
this respect it resembles that of Nucula. The animal is
unlike that of Modiolaria. It has the mantle completely
open in front, instead of being folded into a special tube
for the entry of food and water ; the excretory tube is
exceedingly short, and sessile, instead of being produced

* A little notch.

CRENELLA. 131

and conical ; and the foot is a very extraordinary organ.
This is formed of two parts : one is the stalk, of a cylin-
drical form \ and from the npper end of it, as if from a
sheath, issues a tongue-shaped disk which serves for
crawling. The animal does not spin a thick byssus,
like Modiolaria, but secretes only a single slight thread
or filament as a point of attachment, and by means of
which it holds itself suspended in the water.

Herrmannsen supposed that the genus was synony-
mous with Limopsis and belonged to the Arcidce. Mac-
gillivray placed it with Lima and Anomia in his family
Pectinina.

1. Crenella rhom'bea"*, Berkeley.

Modiola rhombea, Berk, in Zool. Journ. iii. p. 229. C. rhombea, F. & H.
ii. p. 208, pi. xlv. f. 3.

Shell obliquely rhomboidal, gibbous, rather solid, somewhat
glossy and iridescent : sculpture, 60-70 fine longitudinal ribs,
crossed by 12-15 transverse plates ; the former radiate from
the direction of the beaks, and occasionally bifurcate or
branch off towards the margin; the latter form imbricated
ridges, and are stronger on the posterior slope : colour pearl-
white : epidermis extremely thin and easily rubbed off, pale
yellow : margins truncate or obtusely rounded on the anterior
side, slightly incurved in front, produced into a semicircular
lobe on the posterior side, and forming a wing or arched crest
behind: byssal sinus small: beaks globular and prominent,
placed close to the anterior margin, minutely striate in a
transverse direction, but not sculptured in any other way:
ligament narrow but thick, yellowish-brown, occupying about
two-thirds of the hinge-line : hinge-line straight : hinge-plate
rather broad and strong, finely crenulated: hinge furnished with
a rather large wedge-shaped serrated tooth in each valve, one of
which interlocks within the other : inside nacreous and glossy,
showing distinctly the impression of the ribs ; inner margins
notched all round : muscular scars very slight. L. 0*13. B. 0-2.

Habitat : Rocks and gravelly bottoms, from low-

* Rhomboidal.

132 MYTILID^l.

water mark to 20 fathoms, on the coasts of Cornwall,
Devon, Dorset, and the Channel Isles. The collection
of Mr. George Humphreys, the well-known dealer in
shells, made in the last century, contained a single
valve labelled lc Ireland ? ; but if the locality was cor-
rectly stated, this species has not been rediscovered
there. I am only aware of a few (ten) places where it has
been discovered in England, though it is tolerably com-
mon at Lulworth and Guernsey. Single valves are very
abundant in the Coralline Crag at Sutton. M. Martin
has found it in the Gulf of Lyons, and Mr. M 'Andrew in
the Gulf of Tunis and the Canary Isles.

Dr. Lukis informed me that some of his finest speci-
mens were taken alive in a rock-pool lying immediately
below half-tide mark on the western shore of Guernsey.
They occupied a chink in the rock a little under the
surface of the water. The transverse ridges perhaps
denote the annual growth of the shell. The fry are so
totallv dissimilar from the adult, that I was misled into
describing and figuring the former under the name of
Limopsis pellucida in the ' Annals and Magazine of
Natural History ' for January 1859. They are smooth
and oval, resembling a minute Ungulina in shape ; the
hinge is placed exactly in the middle of the dorsal
margin ; and the arrangement of the teeth or crenula-
tions on the hinge-line further indicates the affinity of
Crenella to Nucula.

Dr. Leach admirably described this lovely and re-
markable shell in his ' Zoological Miscellany ' (1814) as
" Modiola Prideaux." Unfortunately the termination
of the specific name is not in accordance with the rules
of zoological nomenclature, and it must therefore be re-
jected. It is true that Capt. Brown altered the name to
Prideauxiana in his ' Illustrations of British Concho-

CRENELLA. 133

logy/ published in 1827, being the same year as that in
which Mr. Berkeley's notice appeared in the f Zoological
Journal/ a circumstance that undoubtedly must have
some weight with a scientific jury ; but after consider-
ing the whole case, and taking into account the positive
disadvantage which would result from a change of any
name that has been generally recognized, I must give
my verdict in favour of Mr. Berkeley. This species is
the Modiola asperula of Searles Wood's Catalogue of
Crag fossils.

2. C. decussa'ta*, Montagu.

Mytilus decussaftis, Mont. Test. Brit. Suppl. p. 69. C. decussahis, F. & H.
ii. p. 210, pi. xlv. f. 2.

Body greyish-white : mantle quite open in front, and folded
at the posterior or broader end of the shell to form an excre-
tory tube ; edges fringed with very short and minute glistening
cilia, which correspond with the ribs of the shell : tube very
short and sessile, with a plain margin : foot worm-shaped, con-
sisting of a long stalk with a sheath at the end, from which
proceeds an oval creeping- disk.

Shell obliquely oval, with a slight approach to a rhomboidal
form when viewed sideways, rather solid, somewhat glossy and
prismatic : sculpture, 50-60 fine longitudinal ribs, crossed by
40-50 transverse striae ; the former resemble those of the last
species ; the latter are thread-like and form minute nodules or
beads on the ribs at the points of intersection : colour pearl-
white : epidermis rather thick and yellowish-brown : margins
rounded on all sides except at the back, where an obtuse
angle separates the hinge-line : beaks globular and prominent,
placed close to the anterior margin, over which they slightly
project; they are quite smooth, with the exception of some
delicate transverse striae : ligament thick, reddish-brown :
hinge-line nearly straight : hinge-plate rather broad, finely cre-
nulated : hinge toothed as in the last species : inside nacreous,
showing more or less distinctly the impression of the ribs ;
inner margin notched all round : scars more perceptible than

* Divided crosswise.

134 mytilidjs.

in C. rhombea, owing to the greater thickness of the inner coat
of nacre. L. 0-15. B. 0-12.

Habitat : Coasts of Yorkshire, Northumberland, An-
trim, and Scotland from the Clyde district and Firth of
Forth north to the Shetlands, in gravelly sand from 3
to 70 fathoms. It appears to be gregarious. Post-
glacial deposit at Elie, Fifeshire (Rev. T. Brown). It
inhabits the seas of Scandinavia, Iceland, Greenland,
and New England, occurring at various depths from
low-water to 150 fathoms.

This exquisite gem of a mollusk is hardy and active.
Not being able to examine living specimens at the time
they were taken, I picked out a few from a small heap
of dredged sand, which had been lying on a pathway for
two days, exposed to continual rain and partly trodden
underfoot. After keeping them eighteen hours in a
small glass vessel of sea-water, they revived and were
alive for many days, the water being occasionally re-
newed. While crawling about, they sometimes carried
the shell erect with the beaks in front, but more fre-
quently in a slanting position. They seemed fond of
getting to the surface of the water, when the Crenella
would spin with its foot a single pellucid thread, which
it fixed to the side of the vessel, and it would hang (like
a Sphcerium) for hours thus suspended, the beaks of the
shell being undermost. The shell being nearly trans-
parent during the lifetime of the animal, the green liver
is distinctly seen through it, occupying the umbonal
region. The foot-stalk or pedicle is semicylindrical,
and becomes twisted if the animal is placed on the wrong
side. The creeping-disk or lobe is very flexible and in
some degree extensile. It is half as broad again as the
stalk, and proportionally thicker. A dusky line runs
down the middle of the stalk, apparently showing the

CRENELLA. 135

muscle which connects the terminal lobe with the basal
attachment of the foot to the body. While the animal
is crawling a tremulous movement is seen to pervade
the lobe. The stalk and sheath are faintlv wrinkled
across. The foot is protruded from the ventral opening
in the mantle, and extends in a direction opposite to
that of the beaks.

Col. Montagu described and established this species
from a single valve, which was found by his friend
Capt. Laskey at Dunbar; but he erroneously supposed
it might be the Mytilus faba of Miiller. It is the
Modiola cicercula of Moller, but not the M. glandula of
Totten, which latter species (as Sars has remarked) is
more rhomboidal and broader, besides being three or
four times the size of our shell. C. glandula and C.
faba are more nearly allied. The Mytilus decussatus of
Lamarck is a large South American mussel.

Two specimens of C. faba were procured some years
ago by Professor King from the stomach of a wild duck
that was shot near Newcastle ; and one of them is in
my collection. This shell is common in the arctic zone
on both sides of the Atlantic. The bird may have picked
up the shells in upper Norway or Iceland ; and better
evidence is wanting before C. faba cau be admitted into
the British fauna.

Another species, however, of a much more novel and
interesting kind has been takemon our northern coasts
under similar circumstances. During the severe winter
of 1855 several birds of passage were killed near Scar-
borough. One of them came into the possession of
Mr. Alfred Roberts, an intelligent bird-stuffer, who
found a number of small shells in its crop. These he
gave to Mr. Bean, and they proved to be the young of
Mytilus edulis and Littorina litorea, and an unknown

136 MYTILID^.

bivalve. Mr. Bean kindly sent me a specimen of the
latter, and I described it in the f Annals and Magazine
of Natural History ' for January 1859 (p. 40) under the
name of Modiola cuprea. I subjoin the description : —

" Testa ovato-trapezoidea, gibbosa, solidula, nitida, epider-
mide prismatica, frdva (antice flava), pilosa vestita, subtus
albida, rugis concentricis raris irregulariter notata; angulo
trans versali ex apicibus ad latus posticum oblique decurrente ;
umbonibus obtusis ; lateribus, dorsali rectiusculo elevatiore
postice rotundato, antico abrupte truncato, ventrali convexo
subsinuato antice declivi, posteriore quadrato ; marginibus in-
tegris ; bysso ex filis perpaucis curtis crassulis composito ;
long. -1 lat. 4- unc."

On* ft

But this description is incomplete, inasmuch as
no mention is made of the internal structure of the
hinge. Having succeeded in opening the shell, after
steeping it for a long time in water, I am now enabled
to supply this deficiency; and the result has compen-
sated for the care and patience bestowed on the opera-
tion. Each valve has on the anterior side of the beak
four small but prominent tubercular teeth, and on the
posterior side the same number of angular teeth, which
are set obliquely and resemble in shape those of Nucula
or Leda. The hinge-line is microscopically but indis-
tinctly notched, as in Crenella and some species of Area.
I do not know if this peculiar arrangement of tuber-
cular teeth on one side and of lamellar teeth on the
other side of the hinge has any parallel in bivalve
shells, unless it be the genus Nuculocardia of D'Orbigny.
The little shell in question is evidently littoral, judging
from the habits of the other species which were found
with it in the bird's stomach. From what coast, or
from what part of the northern hemisphere, it was
brought to our shores, it is almost impossible to con-
jecture. The animal was preserved in my specimen,

arcidjE. 137

and does not seem to have undergone the least decom-
position; and the shell still retains its original colour
and gloss. The species has not been noticed by any
other writer, nor have I detected anything approaching
it in the extensive collections made by Dr. Torell on
the coasts of Iceland, North Greenland, and Spitzbergen.
There is some doubt as to the kind of bird from whose
crop the shells were extracted. Mr. Bean asserts that
that it was a Sanderling. Mr. Roberts is equally posi-
tive that it was a Brent-goose ; and he supports his state-
ment by the following domestic anecdote. Having
heard that a Brent-goose was excellent eating, he de-
pended on this bird for his Sunday dinner; but, to
his disgust, when his wife was preparing it for the spit,
it smelt so very " loud," that bread and cheese had to
be substituted. He attributed the smell to the decay-
ing Ulva on which the bird had fed, and among which
were the shells he had given Mr. Bean. Mr. Roberts
therefore had good reason for remembering what bird it
was that caused so much pleasure to Mr. Bean, but disap-
pointment to himself. Several specimens of this sin-
gular bivalve were taken on the above occasion. It
is figured in Sowerby's Illustrated Index to British
Shells, pi. 7.1 11.

Family VI. AR'CID^, Lowe.

Body thick, corresponding in shape with the shell : mantle
open in front, but in some genera forming a single fold or two
tubes at the posterior end : gills two on each side, arranged in
pairs : foot shaped like a disk, worm, axe, or tongue, capable
of burrowing, creeping, or spinning a byssus.

Shell triangular, oval, wedge-shaped, round, oblong, or
rhomboidal, equivalve, inequilateral : epidermis thick : liga-
ment external ; certain genera have an internal cartilage in

138 ARCID.E.

addition to, or subtitution of, the ligament : hinge-plate fur-
nished with a row of close-set teeth in each valve, which
mutually interlock : muscular scars lateral, deep or distinctly
marked.

The old and characteristic genus Area of Linne has
multiplied so fast since his time, that it now forms a
very numerous family. The quota which has been con-
tributed to it by palaeontology, or the record of extinct
races and generations, is nearly equal to that of recent
genera ; and in this sense the march of science may be
said to advance with almost the same rapidity in a re-
trograde as in a forward direction. Both zoologists
and palaeontologists are strenuous in the race ; but in-
stead of being hostile rivals, the only object of their
emulation is to assist each other and thus promote the
common cause.

The character which makes this group (whether we re-
gard it as a genus, a family, or a set of families) so distinct
and self-contained is the peculiar structure of the hinge.
Instead of having, like other bivalves, only one, two, three,
or, at the most, four tubercular teeth under the beak, and
occasionally a single or double laminar fold on each side,
all the Arcidce are furnished with a symmetrical row
of these processes, occupying the whole of the hinge in
each valve, and interlocking like the real teeth of many
kinds of fish. This apparatus, aided by stout retractor
muscles and an elastic ligament, and in some genera by
a strong internal cartilage, enables the mollusk to keep
its house closed against most of its predatory enemies ;
and it is only when the shell is drilled by some canalifer-
ous Gasteropod, or else swallowed whole by a voracious
fish or by a member of the Bulla family, that its days
are numbered. Those species of Area which habitually
shelter themselves in the crevices of rocks, and are

ARCID^. 139

attached by a solid byssus, may escape this doom for a
longer period. The thickness and apparent longevity of
specimens of A. tetragona and A. lactea may be thus
accounted for. Lamarck proposed the expressive name
of " Polyodontes " for the present family. According
to Dr. Carpenter, a microscopical examination of the
shell shows in many of the genera a tubular structure
intersecting the upper layer and spreading outwards, the
lower or inside layer being nacreous.

The Arcidce may be conveniently divided into two
sections, viz.

t Shell triangular or wedge-shaped : epidermis smooth and
glossy : beaks close together and recurved : hinge fur-
nished with a row of teeth set like those of a comb, on
each side of an oblique spoon-shaped process, which
contains a cartilage.

* Shell triangular.

1. Nucula.

** Shell wedge-shaped.

2. Leda.

ft Shell round, oblong, or rhomboidal: epidermis hairy or
fibrous : beaks separated by the ligamental area, and in-
curved : hinge furnished with a single continuous row
of plate-like teeth, destitute of an intermediate cartilage
or pit.

* Shell round.

3. Limopsis.

4. Pectukctjlus.

** Shell oblong, or rhomboidal.
o. Aeca.

140 ARCID.E.

Genus I. NU'CULA*, Lamarck. PL IV. f. 1.

Body roundish-oval, somewhat compressed : mantle open in
front and at both sides : gills unequal in size, one pair over-
lapping the other : lips or palpi long and pendulous : foot oval
and having its margin serrated or notched.

Shell triangular and compressed, highly nacreous : margin
of the posterior side rounded : lunule or area below the beaks
heart-shaped : ligament partly internal : cartilage internal and
contained in a spoon-shaped cavity : teeth sharp and recurved,
those on the anterior side being fewer than those on the other
side : pallial scar entire.

The Nuculce inhabit mud, sand, and gravel in all the
marine zones on our coast ; and they appear to be gre-
garious. They are found in every degree of longitude
and latitude throughout the globe. The umbonal area,
or that part of the shell which is terminated by the
beak, is often eroded and the nacreous layers exposed,
probably owing to the action of sulphuretted hydrogen,
which is evolved from animal matter in a state of de-
composition contained in the mud. Sometimes the
beak is encrusted with a ferruginous or mineral deposit.
The lunule in the present genus and Leda projects con-
siderably, so as to resemble a pair of pouting lips. Each
organ (in the mollusk as well as in Woman) encloses a
row of dazzling white teeth. But here the analogy ends.
Such comparisons of natural beauty constitute one of
the minor charms of science, and may be pardoned in
an enthusiastic naturalist.

I am not prepared to accept D'Orbigny's proposition,
which has been adopted by Gray and other concho-
logists, that this genus ought to form a distinct family.
The genus Nuculana of Searles Wood resembles Nucula
in shape, but has teeth like those of Pectunciihts, and no

* A small nut.

NUCULA. 141

cartilage ; while Limopsis has the form of Pectunculus,
with a cartilage and a cavity for its reception, as in the
so-called Nuculida, although placed differently, viz. out-
side the hinge, instead of in the middle of it. Stimpson
advocates the separation of Nucula from the Arcidce be-
cause of the want of a byssus ; but Pectunculus has none.
This appendage is only necessary when the habitation is
rocky or " hard/' In sandy and muddy, or " soft "
ground the foot is used for burrowing, instead of spin-
ning a byssus; and it is consequently larger in Nucula,
Leda, Limopsis, and Pectunculus, which live in such
situations, than in Area, which attaches itself to rocks
and old shells. Recluz suggested the removal of Leda
from the Arcidae and Nuculidce, and considered that all
of them belonged to different tribes ; but our progress in
classification has not yet advanced sufficiently to allow
of such extreme subdivision. Gray placed Nucididce
between the families represented by Solen and My a, and
in another order than that which contains Area, Pec-
tunculus and Limopsis. Leach's arrangement is rather
more eccentric or opposed to general views. His fami-
lies of Nuculadce and Pectunculidae lie between Mactra
and Venus, and his Arcadce [longo intervallo) between
Pinna and Avicula. The late Mr. G. B. Sower by was
the first to point out the separation of Leda and Nucula
from Area.

A. Inner margin notched.
1. Nucula sulcata*, Bronn.

N. sulcata, Bronn. Italiens Tertiargebilde, p. 109, no. 633. N. decussata,
F. & H. ii. p. 221, pi. xlvii. f. 1-3.

Shell obtusely triangular, rather convex, solid, of a dull
hue: sculpture, numerous transverse striae or ridges, which

* Furrowed.

142 ARCID.E.

are crossed by finer longitudinal striae or ribs, giving the sur-
face a cancellated appearance ; these markings are coarser and
more irregular at the sides, but they do not extend to the
lunule or space below the beaks : colour flake- white under the
epidermis, which is thickish, olive-green, and microscopically
striate like hair- cloth in a transverse direction : margins an-
gular and slightly truncate on the anterior side, curved in
front, and expanding on the posterior side to a wedge-shaped
but rounded angle : beaks rather prominent and blunt, slightly
recurved : lunule furrowed obliquely by strong and irregular
wrinkles (being a continuation of the transverse striae), and
indented or grooved in the direction of the beaks ; it is sepa-
rated from the rest of the shell by a ledge, and projects in the
middle so as to form a distinct keel : ligament narrow but
strong : cartilage small, pear-shaped, contained in a narrow
cavity underneath the beaks and projecting inwards : hinge-
line gently curved : hinge-plate broad and strong, occupying
the whole of the dorsal space and rather more than one -third
of the circumference of the shell : teeth sharply pointed, 10-12
on the anterior side and 20-24 on the posterior side of the
cartilage -pit, arranged in nearly straight rows, which diverge
outwards at almost a right angle ; they become larger as they
recede from the beak, in consequence of the progress of
growth: inside cream- colour and slightly iridescent, faintly
striated, or marked with lines which radiate from the beak and
terminate in distinct notches or crenulations on the anterior
angle and in front ; but these notches do not extend to the
posterior angle : muscular scars oval and conspicuous. L. 0'65.
B. 0-7.

Habitat : Sandy mud and clay on the west coast of
Scotland, at various depths, as well as in Dublin Bay
(Branscombe and Warren) ; Bantry Bay (Humphreys) ;
and south-west coast of Ireland (M f Andrew). Captain
Bedford has dredged it in a semifossil state at Lismore,
imbedded in a concrete of indurated clay. It is a local
species. Loven, Asbjornsen, and Malm have recorded
it from several parts of the Scandinavian coasts, the
second of these authors giving 15-20, and the last 14-35
fathoms. It also inhabits the coasts of Spain and both
sides of the Mediterranean, as well as the iEgean, where

NUCULA. 143

Forbes obtained it at depths varying from 45 to 145
fathoms. Bronn and Philippi have described it as a
fossil of the Subapennine tertiaries ; and I have found it
in upper miocene strata at Biot near Antibes.

This is the largest British species of Nucula. It can
hardly be the N. decussata of Sowerby's f Conchological
Illustrations/ because the description and figure do not
answer to our shell, and that species is stated to have
come from the Gulf of Guinea. It may be his N. rugu-
losa, which is said to be of the size of N. nitida, although
the locality is not mentioned. At all events Bronn's
name has the precedence of many years over those of
Sowerby. Philippi described, in the first volume of the
' Sicilian Testacea/ the present species under the name
of N. Polii. Bronn^s diagnosis exactly agrees with our
shell ; and he justly observes that it is larger and
broader than A 7 , nucleus. In the l Proceedings ' of the
Zoological Society for 1856, another species from New
Zealand has been called, by Mr. A. Adams, N. sulcata.

2. N. nu'cleus*, Linne.

Area nucleus, Linn. Syst. Nat. p. 1143. N. nucleus, F. & H. ii. p. 215,
pi. xlvii. f. 7, 8, and (animal) pi. P. f. 4.

Body suboval, cream-colour, mottled with flake-white: man-
tle having a plain margin : gills triangular and elongated,
finelv striated on the outer and inner surfaces, and of a brown
colour ; the upper lamina of each pair is by far the larger of
the two, and entirely covers the other : lips pendulous, and
transversely striated, each of them folded inwards or doubled :
foot oval, pale yellow, deeply serrated at the margin, and ex-
hibiting about fifty denticles.

Shell like that of the last species in shape, but much smaller,
shorter, and more tumid, as well as more triangular in con-
sequence of the posterior side being less produced : sculpture,

* A small nut.

144 ARCID^.

numerous fine striae which radiate from the beak, and a few
irregular lines of growth which form dark zones but do not
intersect the longitudinal striae ; these striae are wanting
on the lunule and dorsal area : colour greyish- white under
the epidermis, which is yellowish -green and very closely and
microscopically wrinkled in a transverse direction : margins
angular and somewhat truncate on the anterior side, curved
in front, and obtusely wedge-shaped and rounded on the
posterior side ; beaks prominent bat blunt, slightly recurved :
lunule marked obliquely by the lines of growth, and strongly
indented or grooved across below the beaks ; it is defined by
a slight furrow, and projects a little outwards, so as to form a
blunt and indistinct keel : ligament slight : cartilage oval, con-
tained in a short projecting cavity underneath the beaks :
hinge-line somewhat curved : Jiinge-plate as in the last species :
teeth sharply pointed and slightly recurved, about 15 on the
anterior, and 25 on the posterior side : inside nacreous and
highly iridescent, striated and notched as in N. sulcata, but in
the present species the crenulations extend to the posterior
angle : muscular scars oval and distinct. L. 0*475. B. 0*475.

Yar. 1. radiata. Shell larger, flatter, more decidedly tri-
angular and produced at the posterior side, and marked with
numerous purplish-brown streaks, which radiate from the
beaks outwards. L. 0*6. B. 0*6. N. radiata, F. & H. ii.
p. 220, pi. xlvii. f. 4, 5, and xlviii. f. 7.

Yar. 2. lumidida. Shell smaller, more triangular and con-
vex. N. tumidula, Malm, Proc. Scand. Soc. (1862), p. 621.

Habitat : Common in sand and gravel on all our
coasts from Shetland to the Channel Isles, at various
depths ranging from 3 to 85 fathoms. Capt. Beechey
dredged it off the Mull of Galloway in 145 fathoms.
Var. 1. More local, but widely distributed in the British
seas, as well as from the Swedish coast (Malm) to
Algeria and Sicily (M f Andrew). Var. 2. Off Unst, in
85 fathoms ; very rare. This variety is also Scandi-
navian, and was obtained by Dr. Torell in 80 fathoms.
The typical form and the first variety occur in all the
upper tertiaries, both in Great Britain and the south of
Europe. Beyond our shores the recent species inhabits

NUCULA. 145

every coast from the Faroe Isles to Sicily and the
iEgean, and also the North African side of the Medi-
terranean.

Mr. Clark says that the animal is timid, and therefore
difficult to observe. When in motion, its foot becomes
a flat and nearly circular disk; its progress is not
direct, but, turning round as on a pivot, its path de-
scribes an irregular ellipse. M. Gay of Toulon informs
me that he constantly finds empty but perfect shells,
with the epidermis entire, inside starfishes, which would
therefore seem to have the power of killing the animal
and sucking it out of the shell, after swallowing it.
Petiver called this pretty kind the " silver cockle ?'} and
it is a favourite prize of children when they gather their
sea-side harvest in the autumn,

" On the beached margent of the sea."
It may be

"The shell from the bright golden sands of the ocean.
Which the emerald waves at your feet gladly threw,"

alluded to bv Keats in his delightful sonnet to some
ladies. Specimens are now and then found more convex
than others, even from the same localitv. Occasionallv
the lines of growth are raised ; and where they cross the
longitudinal striae a decussated appearance is the result.
My first impression, that the N. radiata of Forbes
and Hanley was a distinct species, has yielded to a con-
trary conviction, in consequence of having compared
numerous specimens of all ages and sizes from various
places ; and I feel myself bound to reunite it with
N. nucleus. Typical, and even ordinary specimens of
each form cannot be confounded with each other ; but
I have some from Plymouth and Tenby, which may be
referred to either form. The grounds of supposed dif-
ference are the comparative size, shape, convexity, and

H

146 ARCIDM.

colouring. The first ground is evidently untenable,
because size is notoriously dependent on food, shelter,
and the proportionate quantity of carbonate of lime con-
tained in sea-water, according to its proximity to the
shore, or distance from it, and to the action of fresh-
water and marine currents. The second ground, or the
degree of those angles which affect the contour of
Nucula, is influenced by the growth of the shell in any
particular direction. All the Nuculce represent an iso-
sceles triangle, the beak or point of one angle always re-
maining the same, while the sides or points of the other
two angles extend pari passu by the addition of new
layers in either direction. If one of these sides is more
produced than the other while the angle of each is
greater or less than that of the beak, a scalene triangle
is the result. This is the case with N. radiata ; and if
it were a permanent or invariable character, I should
regard it as having considerable weight in deciding the
question. But were the most acute mathematician to
measure the angles in certain specimens of the two so-
called species, he would assuredly fail to detect any
sensible difference. As to convexity, it is true that spe-
cimens of N. radiata are usually more compressed than
those of N. nucleus. Other specimens, however, of both
species are equally convex. The coloured rays are
clearly a varietal, and not a specific character. They
are even more conspicuous in another species (N. nitida),
which has commonly a plain and sober hue. Instances
of a similar diversity in this respect occur in Astarte
triangularis and many other marine shells, as well as in
species of the freshwater genus Unio. The nature and
cause of colour in shells has not yet received that atten-
tion from philosophical chemists which the interest of
this curious subject demands. Probably the most in-

NUCULA. 147

structive and elaborate examination of this problem will
be found in the essay of Professor Lacaze-Duthiers,
entitled "Natural History of the Purple of the Ancients/'
to which I have referred in the Introduction to the first
volume (p. lxvii), and which I shall again have occasion
to notice. There seems to be no doubt that all colours
are of mineral origin, and that they are secreted, by the
Mollusca and other animals, from inorganic matter hj
special glands. But there is no necessary connexion
between the colour of the mollusk and that of its shell.
The plain variety of our native Cowry (Cypraa Europcea)
is a familiar illustration of this fact. While the shell
is of a uniform porcelain-white colour, its inhabitant
and fabricator exhibits most varied and brilliant tints of
vermilion, yellow, brown, green, and red. The coloured
markings of shells cannot be relied upon as a specific
test, especially when the same hue predominates; and
N. radiata is in this respect undistinguishable from
N. nucleus. Taking into consideration the question of
locality, with reference to the remarks which I made in
the Introduction to Vol. I. (pp. xix and xx), I believe it
will be found that the two forms do not live together.
I have never taken them in the same spot ; and Forbes
and M.' Andrew have observed that N. radiata occurs
at Milford Haven " always in separate parts of the bay
from nucleus" This circumstance would of itself in-
cline me to doubt the propriety of separating these forms
unless as varieties. Sufficient weight does not seem to
have been given to the remarkable occurrence in the
same locality of different species of marine animals
which are bisexual but require mutual impregnation *.

* Oppian speaks of this mode of generation with abhorrence : —
Eire irpbs dXXrjXcov, repas dypiov, eKcpvovrai,
Notri/u 7r69iov, Kai vbatyi fa\ui)v, na\ vbatyi tokoio.

H 2

148 ARCID.E.

The difficulty arising from the sterility of hybrids among
unisexual animals being thus removed, how does it
happen that so many distinct but allied species assem-
ble and live together without interbreeding or mingling
their respective races ? There is no fusion, there are
no intermediate forms or gradations from one to an-
other; each pursues its own course and mode of life,
and appears to have no communion w T ith its neighbour.
Surely this emboldens naturalists to maintain the in-
tegrity of species as at present existing, however much
they may have changed in the course of bygone ages.
We take Nature as it is and apparently has been — not as
it might have been ; and all speculations as to the origin
of species, although ingenious and interesting, are useless,
for want of sufficient data to guide us in the inquiry.

The variety tumidula resembles N. nitida in shape ;
but the surface is not glossy as in that species, and the
sculpture is the same as in N. nucleus.

The present species seems not to be liable to distor-
tion ; but a valve now before me from Guernsey has a
fold on the posterior slope, contracting the shell, and
somewhat resembling the sinuosity of Axinus fleocuosus.
Specimens from the Hebrides and the south-west of Ire-
land are larger than any I have seen from other parts,
whether British or foreign. Besides the characters above
noticed in the description of this species, it differs from
N. sulcata in sculpture, in the beaks being more promi-
nent, the hinge-line more curved, and the cartilage-pit
shorter and broader, in having more teeth on the ante-
rior side, and in the crenulations of the inside margin
extending further towards the posterior angle.

It is the Area margaritacea of Bruguiere, and Gly-
cijmeris argentea of Da Costa. The fry is the Nucula
argentea of Brown.

NUCULA. 149

3. N. ni'tida*, G. B. Sowerby.

X. nitida, Sow. Conch. 111. (Nucula) p. 5, f. 20 ; F. & H. ii. p. 218, pi. xlvii.
f. 9.

Body similar to that of N. nucleus ; but the gills are light
brown, smoother outside, and more strongly striated on the
inner surface : foot of a paler colour, and its disk less deeply
serrated at the margin.

Shell acutely triangular, convex towards the beaks, but
compressed in front, moderately solid, remarkably glossy :
sculpture nearly the same as in jV. nucleus ; but the longi-
tudinal striae are slighter, and the transverse striae are stronger,
especially at the sides, giving the surface a partly cancellated
or notched appearance at the points of intersection ; the lunule
is only marked by the lines of growth, and the dorsal area is
smooth: colour milk-white under the epidermis, which is
yellowish-brown, highly polished and lustrous, without any
trace of the microscopical lines or wrinkles observable in
the foregoing species; the latter is sometimes beautifully
tinted with yellow or purplish -brown longitudinal streaks,
which are arranged in irregular bundles, and resemble the
rays of the setting sun : margins truncate on the anterior
side, forming an obtuse angle where it joins the ventral range,
rounded in front, and slightly produced or wedge-shaped at
the posterior side : beaks prominent, apparently overhang-
ing the anterior margin owing to its truncature, and re-
curved : lunule as in the last species, but deeper immediately
below the beaks, and not so much raised, separated from the
rest of the shell by a blunt ridge in each valve : ligament very
slight: cartilage pear-shaped; cavity larger and projecting
more than in the last species : hinge-line slightly curved :
hinge-plate rather narrow : teeth long, sharp, and recurved,
about twelve on the anterior, and twenty on the posterior
side : inside highly nacreous and iridescent, conspicuously
striated lengthwise, strongly notched on the ventral and
anterior margins, but the crenulations do not extend to the
posterior angle : muscular scars oval, not very distinct. L. 0*4o.
B. 0-45.

Habitat : With the last, but neither so generally dif-
fused nor so plentiful. I have taken it at low spring-tides,

* Shining.

]50 arcidjE.

and at depths ranging between that mark and 86 fa-
thoms. Glacial deposit, Paisley (Crosskey). Morch
and Walker have recorded it from Greenland, Asbjorn-
sen from Norway, Loven and Malm from Sweden,
M 'Andrew from the Spanish coast and Algiers, and I
have fonnd it in the Gulf of Genoa. Gould says that
the N. proximo, of Say (from the Massachusetts coast)
is closely allied to the present species, if not identical
with it ; but that shell seems to be less glossy, and the
shape rather more obliquely transverse.

My note of the animal differs a little from Mr. Clark's
description, and is as follows : — ' ' Colour greyish-white.
Mantle finely fringed. Foot tongue-shaped, folded
up when at rest; when it is expanded, it assumes a
roundish-oval shape, and its margin is regularly den-
tate, or set with numerous point-like tentacles." The
shell is usually less solid than that of A r . nucleus ; the
anterior slope is more abruptly truncate, and the pos-
terior slope more produced ; the umbonal area is more
convex and prominent; the beaks are more terminal;
and the polished epidermis will always serve to distin-
guish it from its dull congener.

It is not the Area nitida of Brocchi, which is a species
of Leda. Weinkauff supposes that our shell may be the
young of N. sulcata ; but this idea is not correct, and I
fear that it may tend to throw some discredit on his list
of Algerian Mollusca, although it cannot be denied that
he has considerably extended our knowledge of this
branch of the North African fauna, and further results
may be expected from his zeal and opportunities. The
young of N. sulcata, instead of being smooth and glossy
like N. nitida, is remarkably rough, and of a dusky hue,
and it is a much broader and flatter shell.

NUCULA. 151

B. Inner margin plain.
4. N. te'nuis*, Montagu.

Area tenuis, Mont, Test. Brit. Suppl. p. 56, tab. 29. f. 1. N. tenuis, F. & H.
ii. p. 223, pi. xlvii. f. 6, and (animal) pi. P. f. 5.

Body white : mantle open in front and at the posterior side,
with a plain edge : foot white, rather longer and not so decidedly
pedunculated as in the other species, nor are the margins of its
disk so coarsely serrated, although the crenulations are more
numerous.

Shell obtusely and obliquely triangular, and inclining to a
circular form, compressed, thin, glossy : sculpture, only slight
and irregular transverse ridges : colour bluish- white under the
epidermis, which is yellowish, with a tinge of light brown,
highly polished and lustrous, and destitute of microscopical
or any other markings : margins truncate at the anterior side,
and obtusely angled at the point of junction with the ventral
range, rounded and broad in front, and slightly produced or
wedge-shaped on the posterior side : beaJcs blunt, and scarcely
prominent, not much recurved: lunule comparatively small
but raised, denned by a slight ridge ; ligament strong : carti-
lage pear-shaped, contained in a rather large and broad cavity :
hinge-line curved, occupying about one-third of the circum-
ference of the shell: hinge-plate forming an oblique groove
on each side of the beak : teeth long, sharp, and nearly straight,
about six on the anterior, and sixteen on the posterior side :
inside silvery-white and iridescent, faintly striated length-
wise, with the margin somewhat thickened : muscular scars
roundish-oval, rather distinct. L. 0-425. B. 0-45.

Var. inflata. Shell smaller, more triangular and tumid,
with the front or ventral margin less curved : beetles more pro-
minent. L. 0-3. B. 0-3. N. inflata, Hancock, in Ann. & Mag.
Nat. Hist, xviii. p. 333, pi. v. f. 13, 14.

Habitat : Sand and mud, in 25-100 fathoms, on the
north-east coast of England, every part of Scotland
from the Firth of Forth to Unst, Dublin Bay, and
(according to the late Mr. Thompson) the east of Ire-
land. It is, however, a local species. Dr. Goodall was

* Thin.

152 ARCID^S.

mistaken in giving Tenby as a locality. He collected
many shells there, but procured his specimens of N.
tenuis from the late Mr. G. B. Sowerby. It occurs in
all our upper tertiaries, and especially in deposits con-
taining shells of arctic species. The variety comes from
the deepest part of Loch Fyne and the Shetland sea. It
resembles N. nitida in shape, but is more convex. The
foreign distribution of this species and its variety extends
from Spitsbergen and Greenland to New England in the
Western hemisphere, and from Iceland along the whole
of the Scandinavian coast on our side of the Atlantic.
Danielssen has taken the variety at Vadso at from 30 to
160 fathoms. The typical form has been dredged by
Sars and M f Andrew in Finmark and Upper Norway,
by (Jrsted and Asbjornsen in Christianiafiord, and by
Malm on the coast of Bohuslan in Sweden, at various
depths from 55 to 100 fathoms. Philippi has recorded
it as a Calabrian fossil under the name of N. decipiens,
being probably one of the numerous relics of the glacial
epoch.

Tor ell regards the N. expansa of Reeve (Belcher's
Arctic Voyage, vol. ii. p. 397, pi. 33. f. 2 a, b) as iden-
tical with the N. inflata of Morch, and perhaps also
with Hancock's species ; and he suggests the possibility
of its being a high-northern or arctic variety of the pre-
sent species. Having examined a great number of spe-
cimens of all acres collected by Dr. Torell in the arctic
seas and Iceland, which he refers to Reeve's and Morch's
species, and having compared the types of Hancock's
species, I have been unable to detect anything beyond
a slight varietal difference between these shells and
British specimens of N. tenuis. The arctic specimens
are exactly of the same shape as the Shetland variety
above described, but considerably larger.

LEUA. 153

Genus II. LE'DA*, Schumacher. PL IV. f. 2.

Body transversely oval : mantle open in front, as well as on
the anterior side, and forming on the posterior side two cylin-
drical tubes of unequal length. Other characters as in Nucida .

Shell triangular- oval, or oblong : margin produced on the
posterior side, and in some species slightly gaping or open :
lwn.uk lance-shaped : ligament, cartilage, and teeth as in Nucula,
except that the number of teeth on the anterior side is nearly
equal to that on the posterior side : pallial scar interrupted by
the tubes.

This genus is closely allied to Nucula in its distribu-
tion and habits, as well as in most of the characters exhi-
bited bv the animal and shell : but the mantle in Leda
forms two distinct tubes, and the shape of the shell is
oval or oblong, instead of triangular as in Nucula. The
teeth, also, in the present genus are set more obliquely,
and the disparity of number is less between those in the
front and those in the back row. It corresponds with
the genus Lembulus of Leach, quoted by Risso; and
according to Morch (' Gronlands Bloddyr ') it is Link's
genus Nuculana, a name of prior date to that of
Schumacher.

Holler's genus Yoldia is said to differ from Leda in
the tubes being longer, and curved instead of straight, in
the foot being larger and thicker, in the posterior edges
of the mantle being ciliated instead of plain, and in the
shell gaping at both ends, whereas that of Leda is closed
at the anterior end and truncate at the other ; and the
posterior side has two or three blunt external ridges,
and an internal rib or epiphysis caused by the separation
of the tubes. But in L. minuta the posterior edges of
the mantle are ciliated, or fringed by short filaments,
and the shell of L.pygmaa, which is referred by northern

* A proper name in Greek mythology.

H 5

154 ARCID.E.

writers to the so-called genus Yoldia, is closed at both
ends. These (and probably L. pernula) being the only
species indigenous to our seas, I must hesitate before
admitting the proposed division of Leda into two genera,
so far as concerns the British Mollusca.

A. Shell triangularly oval, smooth and polished; posterior
extremity rounded and closed : lunide indistinct ; teeth set
like those of a comb.

1. Leda pygm^e'a*, Minister.

Niccula pygmcBa, (Minister) Goldfusa, Petref. p. 157, t. cxxv. f. 17. L.
pygm&a, F. & H. ii. p. 230, pi. xlvii. f. 10, and (animal) pi. P. f. 3.

Body pale fawn-white colour : tubes short, united, with plain
orihces : foot hatchet-shaped, and widely grooved at its poste-
rior edge, forming when expanded a crenated disk.

Shell nearly equilateral, sloping gradually from the beak to
each side, tumid, glossy, and iridescent : sculpture, only a few
irregular marks of growth : colour pearl-white under the epi-
dermis, which is yellowish -brown, highly polished and lustrous :
margins rounded at the anterior side, with an oblique slope to
the ventral range, which is also rounded, somewhat produced
and wedge-shaped at the posterior side, with a slight tendency
to curve upwards : beaks small and blunt, rather incurved than
recurved ; lunide lance-shaped, but scarcely visible, and faintly
denned by an obscure ridge, which runs from the beak to the
posterior angle in each valve : ligament exceedingly slight :
cartilage and the cavity containing it very small and short :
Jiinge-line slightly curved, occupying nearly the whole of the
dorsal area and considerably more than one-third of the cir-
cumference : hinge-plate deeply grooved, and becoming wider
as the distance from the cartilage-pit increases : teeth rather
long and sharp, placed on the inner margin of the hinge-
plate, slightly curved outwards or reflected ; there are 10-12
on the anterior side, and 12-14 on the other : inside glossy,
with the margin somewhat thickened and entire : pallia! and
muscular scars slight, except in aged or dead specimens.
L. 0-15. B. 0-2.

* Dwarf.

LEDA. 155

Habitat : Mud and sand, in 20-86 fathoms, on the
Antrim coast, Skye, Hebrides, and Shetland. It is
very local in a recent state, but widely diffused in
glacial beds, and occurs also in the Coralline Crag.
Many conchologists have noticed it as an arctic and
Scandinavian species ; Danielssen and Asbjornsen say
it is found on the Norwegian coast at depths varying
from 10 to 140 fathoms, and Malm on the coast of
Sweden in 30-53 fathoms. The only southern habitat
that I am aware of is Naples, where Scacchi is said
(according to Philippi) to have taken it. It is a tertiary
fossil in Siberia and Sicily.

Some specimens are shorter and more gibbous than
others. Owing to the semitransparency of the shell,
the teeth are distinctly visible outside the hinge-line.

Philippi named this species Nucula tenuis, before he
was aware that Goldfuss had described it, or that Mon-
tagu had already used that name for another species.
Mr. James Smith called this species Nucula gibbosa,
and Moller N. lenticula. The Yolclia abyssicola of Torell
and Sars is probably a variety of the present species.
The Y. lucida of Loven seems different.

B. Shell triangularly oblong, transversely ribbed, with two
ridges extending obliquely from the beak in each valve
to the posterior extremity, which is truncate and some-
what open : teeth set in a herring-bone fashion.

2. L. mintj'ta*, Miiller.

Area mimda. Mull. Prodr. Zool. Dan. p. 247, no. 2985. L. cav.data,
F. & H. ii. p. 226, pi. xlvii. f. 11-13, and (animal) pi. P. f. 2.

Body oblong and pear-shaped, greyish-white: mantle fringed
or denticulated at its posterior side by a row of five very short

* Small.

156 ARCIDiE.

filaments : tubes united for more than half their length,
considerably produced, slender and smooth ; the incurrent
(or branchial) tube is shorter than the excurrent (or anal)
tube, and the latter has a square orifice, with finely pointed
angles : foot oblong, compressed, white, deeply grooved, and
capable of being expanded into a creeping-disk with notched
margins.

Shell inequilateral, sloping from the beak with an oblique
curve to the posterior extremity, which somewhat resembles
a duck's bill, compressed, rather solid and opaque, scarcely
glossy : sculpture, about 30 transverse laminar ribs which
vary very much in strength and compactness, besides extremely
fine glittering and prismatic lines, which radiate from the
beaks, but do not usually extend to the front margin unless
in very young shells ; and there are also two ridges, which
diverge from the beak in each valve, and embrace the trun-
cated point at the posterior angle : colour pearl-white under
the epidermis, which is yellowish-brown and generally of a
dull hue : margins rounded at the anterior side, more or less
curved in front, and elongated at the posterior side to a blunt,
upturned, and truncate point, where the valves slightly gape :
beaks small, rounded, nearly straight, destitute of transverse
ribs, and glossy : lunule lance-shaped, ribless, depressed, with
slightly prominent edges or lips, and defined by the inner
ridge of the posterior slope : ligament slight : cartilage oval
and small, contained in an oblique pit : hinge-line curved on
the anterior side of the dorsal area, and inflected on the other
side, occupying about two-fifths of the circumference : hinge-
plate grooved, and increasing in width in proportion to the
growth of the shell: teeth vault-like or concave, slightly
curved outwards, higher in the centre of each row, and dimi-
nishing in size towards either end ; there are about 16 on the
anterior side, and about 20 on the posterior side : inside por-
cellanous and glossy, somewhat thickened near the margin,
which is smooth, with a distinct ridge running down the middle
of the beak -like extension of the posterior side : pallial and
muscular scars well marked. L. 0'3. B. 0-55.

Var. brevirostns. Shell smaller, longer in proportion to its
breadth, with the posterior extension much shorter, more con-
vex or tumid : ribs finer and more crowded.

Habitat : Everywhere on our northern coasts, in
muddy gravel and sand, from 20 to 90 fathoms. Captain

LEDA. 157

Beechey has dredged it alive in 145 fathoms off the
Mull of GaUoway. It occurs in all our upper tertiary
deposits, although in all probability an allied species
(L. pernula, Miiller) has been often mistaken for it in
compiling lists of fossil shells. The variety has a more
southern habitat, and is found on all the English, Welsh,
and Irish coasts, as well as at Oban and in the Hebrides.
Both the typical form and variety frequent the Arctic
and Scandinavian seas, at depths of from 10 to 160
fathoms. Gould has recorded this species from Massa-
chusetts, and observed that he could find no difference
between the American shell and a specimen of L. minuta
from Norway, which had been sent to him by Dr. Loven.

Specimens vary very much in convexity and the de-
gree of striation. Those obtained from deep water are
usually flatter, and more delicately grooved, while spe-
cimens from comparatively shallow water are more or
less tumid, and have stronger ribs. The flat and fine-
ribbed form has been taken by Dr. Torell at Spitz-
bergen. The fry have no ribs, but the cross lines are
very conspicuous.

Loven has not given any reason why he considers the
Area minuta of Montagu is not that of Fabricius, and
this eminent conchologist has strangely omitted the
authority of O. F. Miiller for that name. Three vears
after the publication of his * Prodromus ■ to the ' Zoo-
logia Danica/ Miiller described L. pernula ; so that he
was evidently aware of the difference between the two
species. Both are found living side by side in the north-
ern seas. L. pernula is the Nucula oblonga of Brown,
which is not uncommon in the Clyde beds ; and Stimp-
son has enumerated it among the pleistocene fossils lately
collected by Mri Drexler in Hudson's Bay. It may be
identical with the A r . cuspidata of Philippi, from the

158 ARCID.E.

Calabrian tertiaries. Miiller's description of Area mi-
nuta is in every respect applicable to our shell ; and I
do not see why the specific name given by him should
be superseded by that of caudata, which Donovan long
afterwards imposed on the same species. Fabricius
appears to have found his original specimens of A. mi-
nuta in the crop of an eider duck, which may have picked
up the shells on the coast of Norway before taking its
return flight to Greenland. I have examined the type
of Macgillivray's Nucula rostrata ; and it is merely the
compressed form of the present species, being probably
the L. intermedia of Orsted, and analogous to the L.
complanata of M oiler. M. Weinkauff gives Area minuta
of Fabricius as an Algerian shell ; but this appears to
be a mistake, because one of the synonyms cited in his
list is Nucula striata, Lamarck, a very different species,
and an inhabitant of the Mediterranean. A. minuta of
Brocchi (an Italian fossil) is another species, and Phi-
lippi has distinguished it, in the Supplement to his work
on the Sicilian Testacea, by the name of Nucula com-
mutata.

I dredged a young live specimen and a small single
valve of L. pernula, in 80 fathoms, off the Shetland
coast, in the same ground with the slender and long-
beaked form of L. minuta. It is much more smooth
and glossy than the last, proportionally longer from
the beak to the front margin ; and the posterior slope is
flatter, and has three instead of two ridges. Not having,
however, obtained a full-grown specimen, I must post-
pone a formal introduction of L. pernula into the cata-
logue of British shells.

The Area rostrata of Montagu is a tropical shell.
Nucula arctica of Gray (N. truncata of Brown, and N.
Portlandica of Hitchcock) is a fossil of the Scotch gla-

LIMOPSIS. 159

cial beck, but its habitation is now restricted to higher
latitudes. Both of these species belong to the genus
Leda.

Genus III. LIMOFSIS % Sassi. PL IV. f. 3.

Body longitudinally oval, or inclining to a circular shape :
mantle open on all sides except the back : foot long, slender,
and pointed at each end.

Shell shaped like the body, nearly equal-sided, porcel-
lanous : epidermis hairy or fibrous : beaks incurved and diverg-
ing from each other in the course of growth : cartilage thick,
contained in a shallow triangular cavity or depression, which
is placed directly under the beaks and outside the hinge-plate :
teeth tubercular, arranged in a continuous and curved line :
pallial scar entire.

This remarkable, and what some would call ' ' critical,"
genus is related intrinsically to Leda, and extrinsically
to Pectunculus. Like the former, it has a cartilage,
with a cavity for its reception ; but this process is not
placed, as in Leda, inside the shell, but on the hinge-
line and between the beaks and the hinge-plate. Pec-
tunculus has no cartilage ; and its shell is kept closed
behind by a ligament, which is wanting in Limopsis.
The teeth are arranged in a single continuous row, as in
Pectunculus, instead of in two separate rows in the same
line, as in Leda, The shape of the teeth in the present
genus is intermediate between that of Leda and Pectun-
culus, being erect but blunt. The contour of the shell
is much more like that of the last-mentioned genus, but
it is somewhat longer in proportion to its breadth.
Limopsis has scarcely any resemblance to Lima. Al-
though the back of the shell in both these genera is fur-
nished with a small wing or prolongation on the upper
part of each side, and the cartilage-pit is similar, Lima

* From its supposed resemblance to the genus Lima.

160 ARCIM.

lias a differently constructed hinge-apparatus, and only
one, nearly central, adductor muscle.

The first to point out the difference between Limopsis
and Pectunculus (although he retained both in the old
Linnean genus Area) was the celebrated Italian palaeon-
tologist Brocchi, who, in his 'Conchiologia fossile Suba-
pennina/ described the species which I now propose to
record as indigenous to the British seas. His descrip-
tion and remarks are (as usual) most excellent, and he
especially noticed the similarity of his Area aurita to
the Ostrea lima of Linne in respect of the triangular
cavity in the hinge. The history of the present genus
is involved in some obscurity, owing to the rarity of the
work in which it was originally published. This was
done by Sassi in the ' Giornale Ligustico di Scienze,
Lettere, ed Arti ' (fascicolo quinto) for September
1827. The British Museum library does not contain
the work ; and it is only through the kindness of
Prof. Lessona of Genoa that I have been enabled to
refer to it. Nyst, in his f Catalogue of the Tertiary Fos-
sils of Belgium ' (1843), professed to be ignorant of
Sassi's publication or its date, although Bronn, in his
f Lethsea Geognostica/ had given both these particulars
twelve years before this statement was made by Nyst.
The last-mentioned author, in conjunction with Gale-
otti, had in 1835 renamed this genus Trigonoccelius.
Nyst altered the name to Trigonocalia. The late Pro-
fessor D'Orbigny, equally disregarding the rule of pri-
ority in scientific nomenclature, gave, in the c Paleonto-
logie Francaise' (1844), another name, that of Pectun-
culina. This has been lately adopted by Dr. Chenu in
his very useful ' Manuel de Conchyliologie et de Pale-
ontologie conchy liologi que '; but he most unaccount-
ably makes Limopsis and Trigonoccelia subgenera of Pec-

LIMOPSIS. 161

tunculina. Gray added a fifth name (Limnopsis) in
1840 ; and Herrmannsen, being apparently misled by
Agassiz, considered Limopsis as a synonym of Brown's
genus Crenella. The last two errors may be attribut-
able, however, to lapsus calami, or to a too hasty attempt
at classification. Only a very few species were until
lately known in a recent state ; but Mr. A. Adams has
given, in the ' Proceedings ' of the Zoological Society
for November 1862, a description of no less than nine
additional species from different parts of the world.
Many species flourished in the tertiary, and others in
the cretaceous period.

1. Limopsis auri'ta**, Brocchi.

Area aurita, Brocchi, Conch, foss. Subap. ii. p. 485, tav. xi. f. 9.

Body cream- colour : mantle thin and plain-edged, open in
ft ont and at both sides : gills consisting of two pairs — the outer
pair being the larger, and overlapping the other which is folded
together, with the edges projecting outwards : foot narrow
and worm-shaped, when fully extended longer than the shell,
bluntly pointed at each end ; it is protruded from the anterior
side ; foot-stalk or pedicle short and broad : hyssus filmy.

Shell roundish- oval, with an oblique outline, compressed,
solid, opaque, rather glossy : sculpture, numerous and fine
longitudinal striae, which radiate from the beaks to the outer
margins, besides equally numerous but irregular concentric
ridges, some of which are larger than the rest, and all are
more or less beaded or notched by the intersection of the
striae ; at the posterior side, these markings are deeper and
stronger, and the surface is slightly granulated: colour porce-
lain-white : epidermis yellowish-brown, forming in front and
at the sides a long fringe, which projects beyond the edge
of the shell : margins rounded on all sides except at the back
or hinge-area, which is sometimes straight, giving that part
the appearance of having an ear-like appendage on each side :
beaks small, sharp, and prominent, regularly incurved : hinge-

* Eared.

162 ARCID^l.

area, or the cavity behind the beaks, narrow, striated trans-
versely : cartilage small, but thick and strong, yellowish, con-
tained in a shallow triangular pit or depression, which is
placed immediately under the beaks, and lies between them
and the hinge-plate : hinge-line nearly straight, interrupted
by the cartilage-pit : hinge-plate very broad, occupying scarcely
one-fourth of the circumference of the shell: teeth, about a
dozen, strong, somewhat curved, and set obliquely : inside
porcellanous and glossy, remotely and indistinctly striated
lengthwise, bevelled off towards the margin, so as to form a
broad and smooth edge : pallial and muscular scars very dis-
tinct. L. 0-385. B. 0-385.

Habitat : Off Unst, the most northerly of the Shet-
land Isles, in 85 fathoms, sandy gravel. Altogether
four living examples, a large and perfect dead one,
and several single valves of different sizes have been
found. Capt. Hoskyn obtained two small valves in a
subfossil state from a sounding at 340 fathoms off the
west coast of Ireland. It is not an uncommon shell in
the Coralline Crag at Gedgrave ; and Mr. Searles Wood
says his cabinet contains one specimen from the Red
Crag, but it is much waterworn. I have also found it
in upper miocene strata in the south of France ; and it
has been recorded from the same formation in other
parts of the Continent, as well as from the Subapen-
nine tertiaries, where Brocchi first discovered the spe-
cies. Michelotti must have been mistaken in citing
it as still living in the Mediterranean.

The animal is very shy, and perhaps feels uncomfort-
able at being disturbed and removed from its native bed.
No part of it was visible in the first specimen which I
captured (in 1862), although I watched it for a long time.
The shell is a lovely object when fresh and examined in
water. The long and delicate but stiff hairs of its epi-
dermis resembled a fringe of silken eyelashes surround-
ing the lids of a sleeping beauty ; and it was exceedingly

LIMOPSIS. 163

tantalizing not to see the enclosed treasure as a reward
for my patience. I was more fortunate, however, in
the specimens which I obtained the following year.
One of them came out during the night and displayed
itself. The foot was the only part visible outside. The
mantle appeared to have no tube, although I saw dis-
tinctly through its open folds the gills regularly napping.
The alimentary and branchial orifice was in front. The
excretal orifice was at the broader end, where faecal
pellets were occasionally ejected. The Limopsis ex-
tended the foot beyond the narrower end of the shell,
and after attaching the extremity to the side of the
glass vessel, and contracting the foot above, it drew
itself up to the further point, like warping a vessel to
the anchor when moored; it then again stretched out
the foot, using on each occasion the whole of the elon-
gated disk or sole, in the same manner as a Planaria.
Repeating this operation, it contrived by slow degrees
to crawl up the side, and travelled four inches in two
hours, being at the rate of a mile in little less than three
years and eight months. On reaching the top it spun
with its foot a very fine and almost transparent but tena-
cious thread, the end of which it fixed to the inside rim
of the vessel; and it remained for twelve hours thus
suspended, with the beaks of its shell downwards. When
I emptied the bottle, and put in fresh water, the byssal
thread still continued fixed, and the Limopsis kept its
former place. It only loosed its hold after having a slight
degree of force used. In this respect the strength and
duration of the attachment differed from that by which
Sphcerium lacustre orKellia suborbicularis suspends itself.
The process, however, is the same in all cases, whether
it be the occasional secretion by the last-mentioned bi-
valves of a slight gossamer filament or the production

164 ARCIDiE.

by a Pinna of the comparatively stout cords or cables
by which it is permanently anchored to the sea-bottom.
Most of the Conchifera appear to be byssiferous.

A species of Limopsis closely allied to the present
has been taken by Mr. M f Andrew on the coast of Upper
Norway, in from 70 to 100 fathoms, and was referred
by him to the Pectunculus pygmaus of Philippi. Sars
found the same species also on the Norwegian coast, but
considered it to be the P. minutus of Philippi. Both
species are fossil. The L. pygmaea of Searles Wood
from our Coralline Crag is certainly different from Mr.
M f Andrew's shell. In Adams's ' Genera of Recent Mol-
lusca' the Norwegian species is called " L. borealis,
Woodward." The inside margin of the shells found by
M f Andrew and Sars is notched or crenulated, but in
L. aurita it is plain or entire, and the contour of this
last shell is rather less oblique. Whether the crenu-
lated margin is a specific character in Limopsis may be
open to doubt. Of two species of Astarte {A. sulcata
and A. triangularis) usually having notched edges, a
variety of each is not uncommon which has smooth
edges ; and specimens are occasionally found possessing
both characters, or having the inner margin partly
notched.

Genus IV. PECTUN'CULUS % Lamarck.

PL IV. f. 4.

Body nearly circular, or suborbicular : mantle open in front,
as well as on the anterior side, and sometimes folded on the
posterior side into a very short excretal duct ; the other part
of the mantle on the posterior side has its margin furnished
with numerous ocelli or eye-like points : foot large and thick,

* A small scallop (Pliny).

PECTUNCULUS. 165

shaped when at rest like an axe, bnt capable when in motion
of being expanded into a discoidal form.

Shell suborbicular, convex, nearly equal-sided, porcel-
lanous : epidermis velvety : beaks slightly incurved, and be-
coming separated from each other in the course of growth.
ligament altogether external, very strong, occupying a vaulted
cavity at the back of the shell, composed of several bundles of
cylindrical fibres, which radiate from the beak to the hinge-
plate, to the outer edge of which they are united: teeth
laminar and continuous, arranged in a curved line but in two
distinct rows : pallial scar entire : muscular scars oval, sym-
metrical, and strongly marked.

The rounded form of Pectunculus prevents its being
mistaken for any other genus of the same family, except
Limopsis ; and the substitution of a compound ligament
for a simple cartilage, besides other specialties of the
hinge-structure, offer sufficient marks by which these
genera can be known one from the other. Moreover
Pectunculus has never been observed to produce a byssus :
but I do not consider this a distinguishing characteristic.
The nature of their habitation is the same.

The present genus has descended in an unbroken line
from the Silurian epoch to the present time. The
extent of its distribution in space is equally great. It
is prolific in species ; but only one of them has yet been
found as far north as the Loffoden Isles. This is the
kind that inhabits our seas.

Lister was the first naturalist, since Pliny, to use the
word Pectunculus; but he applied it to most bivalve
shells. His second division of Pectunculi had a fright-
fully long adjective — Polyleptoginglymi — and comprised
Area and Pectunculus. Eight years before Lamarck
published the present genus, Poli proposed the name
Axincea for the animal. This last name has been adopted
by Oken and Gray ; but as it was founded solely on
anatomical, and therefore insufficient characters, it does

166 arcidjE.

not seem expedient to substitute it for the long-esta-
blished name given by Lamarck.

1. Pectuncultjs glycy'meris *, Linne.

Area glycymeris, Linn. Syst. Nat. p. 1 143. P. glycimeris, F. & H. ii. p. 245,
pi. xlvi. f. 4-7, and (animal) pi. P. f. 6.

Body nearly round and compressed, yellowish-brown :
mantle thick, covered with minute specks of brown and flake-
white ; it is quite open on the anterior side, and but slightly
contracted on the other side : the edges on the posterior side
are studded with numerous, small, black, eye-like tubercles :
foot very large, axe-shaped, deeply cloven or folded length-
wise when not in action.

Shell slightly compressed, very thick and solid, of a dull
hue : sculpture, numerous fine longitudinal striae, and more
remote impressed lines, which are crossed by transverse or
concentric striae, varying in number and strength, the surface
being thus often reticulated : colour yellowish-white, irre-
gularly mottled with zigzag streaks or blotches of purplish
brown, or marked with spots or longitudinal lines of the same
colour, sometimes of a beautiful pink or lighter tint, and even
milk-white : epidermis brown and thick, forming rows of
short bristles on the impressed lines in young specimens : mar-
gins rounded on all sides except at the back, where they are
interrupted by the beak and hinge -line : beaks small and pro-
minent, incurved : ligament dark brown, consisting of eight or
nine bundles, which are placed in a large triangular and grooved
cavity below the beak ; these bundles are consequently longer
at each end, the shortest being in the middle : hinge-line semi-
circular : hinge-plate also curved, extremely broad and thick,
occupying two-sevenths of the circumference: teeth set ob-
liquely, six or seven in the adult (besides a few others of a
smaller size) on the anterior side, and nearly as many on the
posterior side, the intermediate space being smooth ; in younger
shells the number of primary teeth is the same, but the middle
area is furnished with four or five minute teeth : inside yel-
lowish, with a purple tinge in some parts, freckled or closely
pit-marked, bevelled towards the margin, which is broad and
strongly notched at the edge : muscular scars very conspi-
cuous. L. 2-25. B. 2-25.

* A name given by Pliny to a kind of shell-fish.

PECTUNCULITS. 167

Habitat : Sandy and shelly gravel and nullipore on
every part of our coast from the Shetland to the Channel
Isles, in 7-90 fathoms. It is gregarious, as well as gene-
rally diffused ; and it occurs in all our upper tertiaries.
Sars has recorded it from the Loffoden Isles, and Lillje-
borg from Christiansund ; and it ranges southward on the
east to the iEgean, and on the west to Madeira and the
Canaries. Brocchi and Philippi have enumerated it as
fossil in the Subapennine and Sicilian tertiaries.

This is the " Dog-cockle " of Da Costa. The animal
is sluggish and shy. I never saw it crawling. Mr.
Clark observes that " the animal does not execute a
direct progressive locomotion, but only turns the shell
round on its disk or from side to side." The great
thickness of its shell does not effectually protect this
succulent mollusk from all its enemies. I was in-
formed by Dr. Lukis that the dredge often brought up
large empty shells, with the valves united, but having
pieces broken off. This has been probably the work of
the cat-fish, whose enormously strong jaws and teeth
nothing but a solid stone can resist. Mr. Cleghorn
attributed the imperfect state of all boulder- clay shells
to this cause; but with respect to Cyprina Islandica,
which is the most common shell in such deposits, I will
in the proper place suggest another explanation. Spe-
cimens of P. glycymeris vary considerably in the degree
of convexity, as well as in the obliquity of their outline,
and in colouring. The typical or usual form is more
produced at the posterior side, especially in the adult
state ; the variety pilosa is more orbicular ; in the va-
riety decussata the longitudinal strise are deeper, but
less numerous ; and small, round coloured spots distin-
guish the pretty variety nummaria. The largest speci-
mens I possess are about three inches in diameter. The

168 ARCIDiE.

fry have a square shape, and are only sculptured by con-
centric strise. Their inside margin is quite plain, and
has no appearance of the crenulations which are deve-
loped in a subsequent stage of growth. The impressions
left by the ligament on the triangular space between the
beaks in full-grown shells are very distinct. I do not
find that the remarkable structure of the ligament,
which is evident from these impressions, has ever been
noticed. The hinge-process is liable to become abnormal
or monstrous. A curious instance of it was exhibited
in a specimen found by Mr. Bariee in the Shetlands.
The hinge-plate had none of the ordinary cardinal teeth ;
but, by way of substitute, each valve was provided with
a rather strong laminar and horizontal tooth on each
side, which locked into a corresponding groove in the
opposite valve. The teeth occasionally decay and be-
come carious in living specimens. Whether the animal
suffers from tooth-ache would be a novel subject for dis-
cussion by the Odontological Society. Aged individuals
are often almost toothless, in consequence of the liga-
ment pushing so far forward on the hinge-plate, as to
obliterate all the central teeth : it reminds one of the
hardened gums of an old man who has lost the greater
part of this extremely useful apparatus. The shells are
often seen in grotto-work; and Mr. M' Andrew says
that at Algarve on the coast of Spain they are used,
instead of lead, by the fishermen for sinking their lines.
The anterior side of the shell, while the animal is alive,
is frequently fringed with the tubes of a Hydroid polype
(one of the Tubulariidce) , which seems to take advantage
of the strong gyratory current produced by the mollusk
for its own food-seeking purpose. This may be an
analogous case to the supposed parasitic nature of Mon-
tacuta substriata, which is always found attached to the

ARCA. 169

ventral spines of certain Echinoderms. Living speci-
mens of P. glycymeris, which I have dredged in 85
fathoms, had their shells beautifully marked by varie-
gated streaks of a bright reddish-brown.

Mr. Searles Wood has taken a great deal of pains in
making out the synonymy of this variable species in a
recent and fossil state. He cites no less than eighteen
different names. Among the best-known of these are
Area pilosa (Linne), A. bimaculata (Poli), Pectuncidus
stellatus (Lamarck), P. undatus, decussatus, and num-
marius (Turton, but not Linnets species of Area bearing
these names), and P. lineatus (Philippi). The Area
minima of Turton' s ' Conchological Dictionary ' was ad-
mitted by him, in his ' Dithyra/ to be the fry of this
species, although Leach subsequently referred it to A.
Noes. Mr. Hanlev at first asserted that, from an exa-
mination of Linnets own specimens, his A. glycymeris
was the P." violas cens" (violas cescens) of Lamarck ; but
he afterwards corrected the mistake. The first localitv
given by Linne (on the authority of Lister) for A. gly-
cymeris was " Garnsey," where P. violascescens has never
been found. The last-named species appears to be his
A. nummaria, judging from the description in the ( Sys-
tema Naturae/

Genus V. ARCA*, Linne. PL IV. f. 5.

Body oblong and thick : mantle entirely open, except at the
back, in some species fringed with tentacular filaments, or
furnished (as in Pectuncidus) with ocelli : foot large and ex-
tensile : byssus composed of glutinous threads, which some-
times form a compact mass, or plug of attachment.

Shell oblong or rhomboidal, gibbous, inequilateral, and in
a few species slightly inequivalve : epidermis fibrous : ligament

* A chest ; or from the supposed resemblance of Noah's ark to this shell.

I

170 arcidjE.

as in the last genus ; but the bundles are not in all cases
placed diagonally, being in some species across the space be-
tween the beaks : hinge-line straight : teeth laminar, and set at
or a little more or less than a right angle to the hinge-line, con-
tinuous in most species, but divided into two distinct rows in
others : pallial scar entire : muscular scars oblong, symmetri-
cal and strongly marked.

Area rivals Pectunculus in its high descent, as well
as in its fertility; and it far excels it in the number
of species. It has, besides, a wider distribution, one
species (A. pectunculoides) being found both on the coast
of Greenland and in the iEgean. Its bathymetrical
range is considerable, extending from low- water mark
to between 300 and 400 fathoms. Unlike Pectunculus,
it spins a byssus, and is by this means attached to sub-
marine substances, from which it can disengage itself
at pleasure ; or it takes permanent shelter and makes its
abode in the cranny of a rock, the shell occasionally
becoming distorted by the narrow limits of its habi-
tation.

The generic name is encumbered by a load of no less
than thirty synonyms, which have been from time to
time imposed by the fanciful ambition of systematists,
or for the more laudable purpose of distinguishing parti-
cular groups of species. It will probably always remain
a question whether subgenera are advisable, the settle-
ment of it depending in a great measure on the defini-
tion of a genus. The characters of all genera cannot be
equivalent ; or perhaps we have not yet found the right
key to Nature's lock. All are agreed as to the existence
of varieties ; and they must be discriminated by certain
names, in the same way as species, genera, and higher
groups. One of Linnets botanical axioms may be cited
in support of this method of identification : — ' ' Nomina
si nescis, perit et cognitio rerum." Whether subgenera

ARCA. 171

stand in the same relation to genera as varieties to spe-
cies, is the point at issue. I am not in favour of this
intermediate sort of classification, and believe it would
lead to unnecessary confusion, and to a redundancy of
names for the same object.. "Area (subg. Cucullaza)
pectunculoides " is not easy to pronounce, or even to
remember, on account of the parenthetical epithet.
Such a mode of subgeneric nomenclature appears to me
quite opposed to the spirit and simplicity of the bino-
mial system ; and it may not be desirable to follow the
example of some modern painters in reviving a state of
things that has passed away and become obsolete, by
now having a pre-Linnean school. The animal of Area
constituted the genus Daphne of Poli.

A. Shell slightly inequivalve : teeth few in number, set either
obliquely or in the line of the hinge-plate, and arranged
in two rows, one at each end of the plate, besides nume-
rous crenulations in the middle across the plate.

1. Arca pectunculoi'des *, Scacchi.

A. pectunculoides, Scacchi, Ann. civ. d. due Sicil. vi. p. 82. A. raridera-
tata, F. & H. ii. p. 241, pi. xlv. f. 8.

Body reddish-brown : foot long and narrow, when in motion
resembling that of a Gasteropod : byssus rather long, horny,
and consisting of a single cylindrical thread.

Shell obliquely rhomboidal, describing in its contour a seg-
ment equal to nearly two-thirds of a circle, tumid, thin, rather
glossy ; the right valve (or that which has the anterior side to
the right hand of the observer) is unmistakeably smaller than
the left valve, the margin of which slightly projects and en-
closes the opposite valve : sculpture, numerous fine and sharp
longitudinal ribs, radiating from the beaks, and equally nume-
rous but less raised transverse or concentric ribs, which cross
the other striae and give the surface a regularly reticulated

* Like Pectunculus.

i2

172 arcid^:.

aspect : colour yellowish- white, faintly tinged with brown :
epidermis laminar, thicker towards the margins, and when
fresh forming a line of short hairs on each of the longitudinal
strise : margins rounded on all sides except the dorsal or
hinge-line ; anterior margin only half the depth of the pos-
terior one ; ventral margin slightly indented by the byssal
chink : beaks not widely separated, small but prominent and a
little recurved : ligament reddish-brown, slight and never per-
fect, composed of numerous line threads, which cross the de-
pressed and narrow area at the back, and leave their impress
in the shape of minute strise : liinge-line quite straight, and
forming almost a right angle at each end, occupying nearly the
whole breadth of the shell : hinge-plate narrow in the middle
and widening towards each end, so as to afford a broad angu-
lar space for the reception of the teeth on either side : teeth
3 or 4 on the anterior side, and 4 or 5 on the posterior side,
indistinctly and irregularly notched on their outer edges, set
more or less obliquely and sometimes nearly parallel with the
hinge-line ; besides these teeth, and on that part of the hinge-
plate which lies between the two rows, is a series of minute
crenulations (like the ordinary teeth in A. lactea and allied
species), which cross the hinge -plate and lie nearly at a right
angle with the side teeth : inside porcellanous and somewhat
nacreous, obscurely marked by remote longitudinal striae ; mar-
gin often indistinctly notched, especially at the sides : pallial
sear slightly nexuous : muscular scars very large and conspi-
cuous. L. 0-175. B. 0-2.

Habitat : The Hebrides and Shetland Isles, from 35
to 90 fathoms, in muddy and sandy gravel. Mr. M f An-
drew has dredged it off Cape Clear in 60 fathoms,
and Capt. Hoskyn off the west coast of Ireland in 100
fathoms. It is an abundant fossil in the Coralline Crag
at Sutton. According to Scacchi and Philippi it like-
wise occurs in the upper tertiaries of the south of Italy ;
and Nyst has recorded it from a similar formation in
Belgium. In the Arctic seas it attains a remarkably
large size. Dr. Wallich took, at a depth of 108 fathoms,
on the east coast of Greenland, a specimen whose di-
mensions nearly equal those of A. glacialis. Speci-

ARCA. 173

mens obtained by Sars and Mf Andrew on the coast of
Finmark at depths of from 20 to 160 fathoms are smaller
than the Greenland shells; bnt those from our own
seas and more southern latitudes dwindle into insigni-
ficant proportions compared with any of the above.
M f Andrew has also dredged this species alive off Gib-
raltar, in 45 fathoms, and Forbes in the iEgean, in
200 fathoms. Two specimens which I procured from
deep water off the north coast of Shetland were at-
tached bv the bvssus to tubes of Pomatoceros arietinus,
Muller [Ditrupa subulata, Berkeley) ; and I kept one of
them alive for more than a day. Soon after it was put
into a glass vessel and had a fresh supply of water, it left
its plug of attachment on the Annelid case, and crawled
away at a fair pace on its narrow foot, the valves of its
shell spread out with the beaks uppermost. The action
appeared to be similar to that of Galeomma Turtoni.

The shell has all the characteristics of Lamarck's
genus Cucullcsa, the side teeth being nearly parallel
with the hinge-line, and consequently at almost a right
angle to the central teeth or crenulations. But this
angle varies in different individuals and at successive
periods of growth, and the position of the side teeth is
more frequently oblique than horizontal. The central
teeth are often wanting. I therefore abstain from
removing this species from Area, as well as from offer-
ing any opinion as to the value of Lamarck's genus.
Mr. G. B. Sowerby was the first to notice the inequality
of the valves in Cucullcea.

Dr. Torell called my attention to the probability that
the present species might be identical with the A.
glacialis of Gray. Professor Sars had previously ex-
pressed the same opinion ; and in his Report on the so-
called glacial formation in the Diocese of Christiania.

174 ARCID&.

he referred to the latter species as " A. raridentata, var.
major" Having carefully inspected and compared a
great nmnber of specimens, recent and fossil, reputed
to belong to both species, and having had the advantage
of examining on the spot the grounds upon which Sars
formed his opinion, I am not satisfied that these species
ought to be united. At first sight, indeed, it might
seem as if A. glacialis were only a large form of A.
pectunculoides, and that the difference of size was ex-
plained by the former having a more northern habitat.
But since A. pectunculoides has been found in Green-
land, and A. glacialis is not uncommon in Iceland, while
each constantly exhibits its own distinctive features, and
attains nearly an equal size in the Arctic seas, we must
inquire whether there is any intermediate link or variety
connecting the two forms. I believe this question must
be answered in the negative, so far as our present know-
ledge extends. The shell of A. pectunculoides is round-
ish-oval or trapezoidal ; that of A. glacialis is obliquely
oblong. The former is more gibbous or convex than
the latter ; the length, or distance from the umbo to the
front margin, is proportionally greater ; the beaks are
more prominent and placed nearer the centre of the
hinge-line ; the posterior margin is rounded, instead of
wedge-shaped (as in A. glacialis) ; the sculpture is much
finer, and the strise more numerous, even in specimens
of a corresponding age and size ; and the teeth are fewer
and set less diagonally than in the other species. The
only description Which has been published of the ani-
mal of A. glacialis is contained in Dr. Gray's Supple-
ment to the Appendix to Parry's First Voyage, and is as
follows : — " Animal : mantle lobes separate ; foot flat,
compressed, subquadrate, front two cut with one or two
fibres from the lower edge ; trachea none." For want

ARCA. 175

of sufficient information on this point, it is at present
impossible to make a complete comparison between the
so-called species. All the fossil specimens which I have
seen from the Christiania and Uddevalla districts be-
long to A. glacialis, and they significantly indicate the
climatal conditions which prevailed during the period
immediately preceding the elevation of these sea-beds.

A. pectunculoides, being found in the Coralline Crag,
as well as in the upper tertiaries of Belgium and Sicily,
would appear to be the older of the two. Although I
am not aware of any intervening form having been dis-
covered, such may have existed ; and supposing that to
be the case, it would be fair to infer that A. pectuncu-
loides was the ancestor of A. glacialis. Naturalists
have been so much accustomed to regard species in an
objective point of view, and not as abstract ideas, that
it is difficult to bring their minds into the proper frame
of thought for discussing speculative theories upon con-
fessedly so difficult a question as the origin of species.

The present species is the A. raridentata of Searles
Wood, who has recognized, in his work on the Crag
Mollusca, the priority of Scacchr's publication, and
adopted the name which I have now given ; and it ap-
pears to be also the A. pusilla of Nyst.

B. Shell equivalve : teeth numerous and uniform, set across

the hinge -plate, and either divided into two rows or
arranged in a single and continuous row.

2. A. obli'qua*, Philippi.

A. obh'qua, Phil. Faun. Moll. Sic. ii. p. 43, t. xv. f. 2.

Shell obliquely oval, with a rhomboidal outline, much nar-
rower at the anterior side, and spreading out on the other side,

* Oblique.

176 ARCID.E.

compressed in the middle and indistinctly furrowed by a lon-
gitudinal groove, which runs from the beak to the front margin,
convex, rather solid, scarcely glossy : sculpture, numerous fine
and rounded ribs, radiating from the umbo, and equally nume-
rous but laminar transverse striae which are raised or imbricated
over the longitudinal ribs — a reticulated appearance resulting
from their crossing each other : colour milk-white : epidermis
thin and silky : margins rounded on all sides except behind,
with a slight inflection in front, sloping abruptly on the
anterior side, and wedge-shaped on the posterior side ; dorsal
angle well developed : leaks small, blunt, and glossy, placed
near the anterior margin and close to the hinge-line : ligament
yellowish, slight, and narrow : hinge-line nearly straight,
occupying three-fourths of the shell's breadth, gently curved :
teeth arranged in two rows, that on the anterior side consist-
ing of 4 or 5, and the other of 10 or 12, set nearly at a right
angle to the hinge-line, but slightly diverging as they ap-
proach each end ; the intermediate space is smooth : inside
porcellanous, marked with a few longitudinal striae, which
only extend to the pallial scar ; margin thickened and broad,
with the edges faintly crenulated : muscular sca?*s very large
and conspicuous. L. 0*15. B. 0*2.

Habitat: 80-85 fathoms, off Unst, in shell-sand.
Two valves only (right and left) have been found, one
by myself and the other by Mr. Waller ; both are fresh
and perfect. It is a Scandinavian species, and has been
taken by Danielssen in 60-80 fathoms at Vadso, by
Sars in West Finmark, and by Malm in 100 fathoms
on the Bohuslan coast. It was discovered by Philippi
in newer tertiary strata at Lamato in Calabria; and
Mr. M 'Andrew has shown me two recent valves which
he received from the late Professor Forbes, probably
iEgean.

This interesting addition to the British mollusca is
intermediate between A. pectunculoides and A. lactea.
From the former it differs in being shorter in proportion
to its breadth (the shape also being more oblique), and in
having the beaks placed much nearer to the anterior side,

ARC A. 177

and from the latter in its smaller size and coarser sculp-
ture, and in having only half the number of teeth. The
longitudinal furrow or indentation in the middle is also
a peculiar character of the present species. Norwegian
specimens are twice the size of ours, and these last are
larger than Forbes' s specimens.

It is the A. Korenii of Danielssen (' Beretning om en
Zoologisk Reise/ 1859) and A. lactea of Malm. The
A. obliqua of Reeve is a West- African shell, and a very
different species.

3. A. lac'tea *, Linne.

A. lactea, Linn. Syst, Nat. p. 1141 ; F. & H. ii. p. 238, pi. xlvi. f. 1-3.

Body white : mantle having its border finely notched, and
pale-red towards the middle of the dorsal area ; the under
surface of the ventral line is marked with irregular flake -
brown blotches on a pale-yellow ground, and the upper surface
is marked for some little depth with a sand-like rusty-brown
belt and a darker interrupted line nearer the margin : gills
symmetrical and equal in size, very thin and gradually taper-
ing, pale yellow : foot extensile, fleshy, and pure white : bi/ssus
short, horny, composed of several leaf- like threads.

Shell varying in shape from rhomboidal to triangular,
tumid, solid, of a dull hue : sculpture, numerous and fine lon-
gitudinal ribs, which become fewer and stronger at the sides,
besides slighter and rather more numerous transverse ribs,
which cross the other, making the front surface appear reticu-
lated, and forming rows of minute tubercles at the point of inter-
section ; sometimes a few smaller and intermediate longitudinal
ribs are perceptible in front: colour yellowish-white: epidermis
brown, laminar and downy, thicker and forming towards the
front and sides longer threads, which occasionally resemble
short bristles : margins rounded at the anterior side, straight
or nearly so in front, obtusely wedge-shaped and somewhat
truncate on the posterior side, with a blunt keel or ridge sepa-
rating that side from the rest of the shell, and which is very
distinct and sharp on the umbonal area: byssal sinus some-

* Milk-white.

i 5

178 akcidjE.

times distinctly visible in front: beaks small, not very pro-
minent, blunt and slightly recurved : ligament thin, and re-
sembling that of A. pectunculoides in every respect, except
that in the present species it is of a lozenge shape, corre-
sponding with that of the ligamental cavity, which is deep ;
the number of cords is between 40 and 50 : hinge-line quite
straight, and forming an obtuse angle at each end, occupying
about two-thirds of the entire breadth of the shell : hinge-
plate as in the last species : teeth about 35, small and straight
in the centre of the hinge, becoming larger and diverging
obliquely and gradually towards each side, so as to form a
gently curved row ; each tooth is finely striate on both sides :
inside porcellanous, marked lengthwise with remote striae to
within a short distance from the margin, which is usually
quite smooth and plain, although occasionally the left valve is
slightly crenulated, especially on the posterior side : pallia!
scar entire : muscular scars very large and well defined, of a
quadrangular shape. L. 0-45. B. 0*65.

Habitat : Gravel, from 15 to 25 fathoms, on the
English, Welsh, and Irish coasts, from Berwick Bay to
Jersey, and also at Oban (Bedford), where it becomes
rare. It is fossil in the Hed and Coralline Crag, as
well as in the Subapennine and Sicilian tertiaries.
M 'Andrew has taken it at low water in Algarve, and
Forbes at from 10 to 150 fathoms in the iEgean ; it is
common in the Mediterranean, and ranges to the Canary
Isles ; but it does not appear to have been found north
of the British Isles.

Lister first noticed this species as English ; and
Dr. Pulteney called it the ' ' hairy ark-shell." Mr. Clark
has remarked that the foot is very like that of Galeomma
Turtoni, showing the connexion between the latter and
the present genus, in respect both of the animal and
the shell. A. lactea is usually fixed by its byssus to the
inside of old bivalve shells, or (in the south of Devon)
wedged in crevices of loose fragments of New Red sand-
stone. The latter circumstance induced Turton at one

ARCA. 1 79

time to suppose that the animal excavated rocks ; and
he gave this shell the specific name of perforans, believ-
ing that it was not the A. lactea of Linne. The shell
varies considerably in the proportion of its different
parts, as well as in the comparative tenuity of sculpture.
It never grows to much greater dimensions than I have
stated in the description. My largest specimen, which
was evidently a veteran, and must have outlived most
of its generation, is not much more than three-quarters
of an inch in length.

I should have been inclined to consider the present
species the A. modiolus of Linne, if it were not for the
expression that it is exactly the shape of Mytilus mo-
diolus and the size of a large bean. The rest of his de-
scription agrees with it in every particular. He even
placed A. modiolus in one section as having a plain
margin, and A. lactea in another as having a notched
margin. He says both inhabit the Mediterranean, and
that A. lactea is " diaphana" which is certainly not
the case in our shell. In all probability his A. lactea is
the A. imbricata of Poli, a thinner shell and having
the inside margin strongly notched. Brocchi applied
Muller's name of nodulosa to the present species, be-
cause A, lactea was described by Linne as possessing
the last-mentioned character ; and for the same reason
Poli, Olivi, Chierighini, and Costa adopted the name of
A. modiolus. But I will not venture to expunge the
generally received name of lactea, and to substitute for
it another which is referred by many conchologists to a
common West-Indian shell — especially as so much ob-
scurity still involves several of the Linnean species,
notwithstanding the laborious research devoted to the
subject by Mr. Hanley. What we call A. lactea may
be the A. barbata of Muller's ' Prodromus/ although

180 ARCID/E.

certainly not that of Linne. Pennant made the same
mistake. It has had many other names, including
Mytilus Garnseice (Petiver), A. crinita (Pulteney), A,
Gaimardii and A. Quoyii (Payraudeau), A, striata
(Reeve), and A. Pennantiana (Leach).

I found a small single valve of A. nodulosa, Miiller,
in some dredged sand from Shetland. This species in-
habits the Swedish and Norwegian coasts, and occurs
at depths varying from 15 to 150 fathoms. The shell
is broader or more produced at each end, and thinner
than that of A. lactea ; the sculpture consists of several
longitudinal rows of vaulted or imbricated scales instead
of cross ribs ; and the teeth are not half so many as in
the other species, and they are placed more obliquely or
diagonally. It is closely allied to A. imbricata, but in
that species the inside margin is notched. A, aspera,
Philippi, from the Sicilian tertiaries, appears to be the
same as Midler's species.

4. A. tetrago'na *, Poli.

A. tetragona, Poli, Test. Sic. ii. p. 137, t.25. f. 12, 13; F.&H. ii. p. 234,
pi. xlv. f. 9, 10, and (animal) pi. P. f. 1.

Body white : mantle having its border plain, but the upper
half of it on the posterior side is fringed with about 40 close-
set and equidistant ocelli or dark dots, which vanish or are in-
distinct towards the anterior side ; the margin is also mottled,
both above and below, with flakes of «pale yellow : gills nearly
coequal in size, and striated, of a brown colour : lips ex-
panded, formed out of the extremities of the gills : foot white
and subconical, tapering to a blunt point, and furnished with
a deep byssal groove : byssus dark-green, composed of a few
leaf-like plates.

Shell forming an irregular parallelopipedon, and angular,
sometimes twisted on the posterior side, very tumid, solid, of
a dull hue : sculpture, the same as in the last species : colour

* Quadrangular.

ARCA. 181

yellowish, irregularly mottled with reddish-brown : epidermis
light brown, filamentous, and forming rows of short leaf-like
bristles in the interstices of the longitudinal ribs, becoming
thicker towards the front and at the sides : margins rounded
on the anterior side, which is very short, flexuous in front,
wedge-shaped and pointed at the posterior side, where a sharp
keel runs obliquely from the beak to an acute angle at the
extremity of the posterior slope : byssal sinus long and wide :
beaks small, slightly recurved, and widely separate from each
other owing to the extent of the ligamental area : ligament
thin, of a golden-brown tint, lozenge-shaped and composed of
several strips or bands placed diagonally; ligamental cavity
very large and deep, usually smooth, but occasionally striated
by the impression of the ligament : hinge-line straight, forming
nearly a right angle at each extremity, its length equalling
the entire breadth of the shell : hinge-plate broad and strong,
considerably wider at the posterior extremity : teeth 40-50,
arched, perpendicularly striated on both sides and having their
crests consequently notched ; those on the posterior side are
the longest, and many of them are double : inside porcellanous,
partly stained with reddish-brown and green blotches ; margin
slightly crenulated, especially on the anterior side : pallia!
scars flexuous : muscular scars oval, very large and conspicuous.
L. 0-85. B. 1-5.

Habitat : Rocky, stony, and shelly ground on all
our coasts and at all depths. In Bantry Bay it is not
uncommon at low water, closely wedged in the chinks
of slate-rocks, the shape being distorted and the surface
scraped in consequence of the confined position. The
abrasion is perhaps caused by the uneasiness of the
animal, through its continual endeavours to extricate
itself or change its place. In deeper water (20-90
fathoms) it occupies the crevices of large stones and the
hinge-cavities of old bivalve shells. In all cases it is
firmly attached by its byssus, and not a slight degree of
force will suffice to dislodge it. It is a Red and Coral-
line Crag fossil. The foreign distribution of this species
extends from Finmark to the iEgean Sea on the east,
and to the Azores and Canaries on the west. Asbjorn-

182 ARCID.E.

sen has dredged it on the coast of Norway in 10-20
fathoms, and Malm on the coast of Sweden in 80-100
fathoms. * M f Andrew has taken it alive on the Spanish
shore ; and Forbes has recorded its range of depth in
the iEgean as 30-80 fathoms.

The valves of this curious shell are so deep, that
Lister mistook them for sessile Barnacles, and called
them Balanus Bellonii. The animal is very shy and
sensitive. According to Mr. Clark a glutinous fluid
appears to exude from a special gland to supply the
byssus, which is moulded by the foot. Capt. Brown
says the shell " burrows in hard clay and limestone
rocks " ; but this does not accord with my observation
of its habits.

In all probability this is the Norwegian shell men-
tioned by Linne, in his i Systema Naturae/ as like A.
tortuosa but of much smaller size. That species in-
habits the Indian Ocean. Miiller applied the above
name, in his ( Prodromus/ to what appears to be the
present species, and Pennant did the same in his ' British
Zoology/ Lamarck called it A. cardissa. Montagu
and subsequent writers on British conchology considered
it was the A. fusca of Solander's MS., although Bru-
guiere's species of that name is different. Turton, in
his s Conchological Dictionary/ mistook it for A. Noce
of Linne, a well-known Mediterranean shell, which has
never been authenticated as a native of the British seas.
Philippi and Loven adopted Bruguiere's name, navi-
cularis ; but that species is stated to inhabit the coast
of St. Domingo, and is very unlike our shell. Mr. Reeve
has added another name (Britannica) to this long list.
Weinkauff has, on the other hand, proposed a reduc-
tion of the catalogue, by uniting the present species
with A. Noce. He says that he has found specimens at

ARC A.

183

Algiers showing the transition of one of these species
from the other.

The accentuation of the name tetragona has also
perplexed many conchologists. There is no question
that, if it were formed into a Latinized-English word,
the accent would lie on the second syllable, as is the
case in pentagonal and hexagonal, and Dr. Latham was
quite right in saying that English quantities are not
Latin quantities. But tetragona being a Latin word, it
seems to me that the classical mode of accentuating
words written in that language, according to their
correct or accustomed quantity, ought to be used in
pronouncing such names as the present. This name
being derived from ycovla " an angle/' and having
been adopted by the Romans, as well as the Greek
combination of the same root with other numerals, the
penultimate syllable is long, and I have therefore placed
the accentuating mark over it.

I have now before me the original specimen of Turton's
A. reticulata, which he said was found in Lough Strang-
ford by his son-in-law, Dr. Macgee. It is not the A.
reticulata of Gmelin, but the A. barbata of Linne, and is
a rather common Mediterranean shell. Mr. Dillwvn
gave me two single valves, in a much worn state, received
by him from Miss Hutchins, as having been collected by
her in Bantry Bay, and which he sent to Montagu for
his inspection. The paper in which they were wrapped
still bears the name " A. barbata " in the handwriting of
the latter naturalist. I do not consider this evidence
sufficient to include the species among our indigenous
mollusca. Collard des Cherres, however, has enumerated
it in his list of shells living on the coast of Brittany, and
it may therefore be looked for in the Channel Isles.

The Turtonian collection also contains a specimen of

184 GALEOMMIM.

A. imbricata, or an allied species from the West Indies,
enclosing the dried remains of the animal, and marked
in his handwriting " Area rostrata, Plymouth." Mr.
Leckenby found a dead specimen and an odd valve of
the same species in a mass of Filograna compleoca, which
was brought to him by a fisherman from the Dogger
bank. I merely notice the occurrence of these shells
with a view to further inquiry.

Family VII. GALEOM'MIDJE, Gray.

Body oval, compressed, thick and fleshy: mantle closed,
except in front for the passage of the foot, and at each end,
where a tube is formed for alimentary and excretal purposes ;
it has two lobes, one of which is folded externally over the
shell, and the other is internal, and has its margin fringed
with cirri or filaments and is studded with ocelli : gills two on
each side : foot large and flexible : byssus strong.

Shell oblong, equivalve, nearly equilateral, pearly and
reticulated, gaping widely in front : cartilage internal : hinge
toothless.

This curious and anomalous family consists of only
one genus and one species, so far as concerns the British
mollusca ; and neither the family nor that genus is well
represented abroad. It is related to the last family
through Area, and to the next family (Kelliida:) through
Lepton; but it cannot be placed in either, consistently
with the ordinary principles of classification. The ani-
mal of Galeomma has ocelli, like some species of Area ;
and the shell of each has a straight hinge-line, and a
large opening on the opposite side — for the passage of
the foot in the one case, and of the byssus in the other.
But the shell of Galeomma is covered by a fold of the
mantle, instead of by an epidermis, and for the external
ligament of Area is substituted an internal cartilage ;

GALEOMMA. 185

and, moreover, it wants the characteristic feature of the
last-mentioned genus, viz. the numerous cardinal teeth :
the hinge of Galeomma has no tooth of any kind. Its
habit of active locomotion, the structure of its shell, and
its internal cartilage connect it with Lepton; but in
that genus the shell is capable of being completely
closed, and it is furnished with both cardinal and lateral
teeth. Forbes and Hanley united the present family
with KelliidcB ; and Clark placed it, as well as the genus
Lepton, in the Area family. Gray proposed to make
one family of Galeomma, and another of Lepton; but
the latter does not form an isolated or aberrant group,
like the former ; and if every genus is to be raised to
the rank of a family, the organization of natural history
may be compared to an army consisting of officers only.
The members of this family, although by no means
numerous, are widely distributed over the globe, except
towards the north pole. Our single European species
does not seem to have travelled to a higher latitude than
the southern coasts of Great Britain.

Genus GALEOM'MA*, Turton. PI. IV. f. 6.

Characters described above, as belonging to the
family.

The singular shell which represents this genus in the
European fauna was discovered by Dr. Turton nearly
forty years ago ; and its no less remarkable animal was
first noticed by Scacchi, a Neapolitan conchologist.
In 1834? Quoy and Gaimard published an account of
another species, which they referred provisionally to
Psammobia, and which constitutes one of the numerous
additions to science made in the course of their cele-

* Cat's eye.

186 GALEOMMIDiE.

brated voyage in the ( Astrolabe/ France, Russia, Austria,
and even the comparatively poor kingdom of Sweden,
as well as the United States, have excelled us in such
enterprises ; and all that our own wealthy nation has
undertaken in this way of late years has been more
owing to a spirit of commercial enterprise than to a
desire of promoting philosophical knowledge. Surely
some of our numerous smaller ships of war and their
hardy crews might be advantageously employed in sci-
entific expeditions to various parts of the world, instead
of the vessels rotting in harbour, and our seamen be-
coming discontented by an irksome and monotonous
routine of discipline. The stale question of cui bono
might be easily answered by pointing to such men as
Sabine, Fitzroy, Darwin, Joseph Hooker, Busk, Hux-
ley, Jukes and others, who were formerly educated in
similar voyages of research. The influence of their
works on the mind and character of the people has been
eminently and notoriously beneficial ; and we should all
have deep cause for regret, were this race of great
masters to become extinct and be superseded by a class
of political economists who could only teach us where
cotton might be best obtained, or what effect a gold
instead of a paper currency may have on the material
prosperity of the next generation. No thinking person
will deny that science ought to be an important branch
of national education. If any part of the public money
is to be so applied, teachers of natural history must be
instructed — not as at present by skimming books of
doubtful authority and superficial information, but by a
course of sound and practical lessons, such as would be
acquired by means of voyages of discovery. The notion
that science can take care of itself, and that its votaries
can provide their own amusement, is only another

GALEOMMA. 187

form of the dangerous maxim laissez faire. The great
masses are like children, and ought to be educated as
well as protected ; and if proper tuition is not afforded,
their minds may be occupied with other and less inno-
cent thoughts, and deplorable consequences may result
to their short-sighted governors from a want of timely
precaution. As Montaigne aptly says, " Fame descharge
ses passions sur les objets faux quand les vrais luy de-
faillent."

Let us, however, return from politics to Galeomma.

Its nearest ally is Area. Both have the same shape,
the ventral gape is similar, the hinge-line is nearly as
straight, and the mantle is equally furnished with ocelli.
But here the analogical resemblance ends. The animal
of Area has no tube, and the shell is of a different tex-
ture. That of the present genus has an internal carti-
lage instead of an external ligament, and it entirely
wants the peculiar teeth of the Area family. Mr. Clark
must have been mistaken in supposing he saw " oblique,
though nearly obsolete teeth on the ligamental line in
Galeomma Turtoni" Owing to the thinness and trans-
parency of its shell, the oblique striae which ornament
the external surface are indistinctly perceptible through
the hinge-plate of its outer edge; and I believe this
appearance may have misled my usually most accurate
friend : I have carefully and closely examined, with dif-
ferent powers of a first-rate microscope, the hinge-appa-
ratus of many fresh specimens, and never could detect
the slightest vestige of any tooth. In the ' Proceed-
ings ' of the Zoological Society for 1855 is contained an
excellent paper by M. Deshayes on this genus. He has
there described no less than twelve new species, in addi-
tion to G. Turtoni and (provisionally) the Psammobia
vitrea of Quoy. Eleven of these new species, however,

188 GALEOMMIDJE.

are said to be provided with teeth ; so that either the
generic character in that respect requires alteration, or
the species in question may belong to Lepton or an
allied genus.

The Galeommata inhabit rocky ground, and are found
at various depths, from low- water mark to the coralline
zone. An account of their habits, so far as they are
known, will be given presently, among other particulars
of our unique species.

Galeomma Turto'ni *J Editors of the c Zoological

Journal/

G. Turtoni, Turton in Zool. Journ. ii. p. 361, tab. xiii. f . 1 ; F. & H. ii.
p. 105, pi. xxsv. f. 11, and (animal) pi. O. f. 5.

Body pure white : mantle partly closed in front, with an
opening for the foot, of a thin texture, except at the edge,
which is muscular and forms a tumid cord extending beyond
the shell ; from this cord is thrown off a double wavy margin,
one flake of which is stretched like an extremely thin skin
and covers the shell, and the other or inner margin is marked
with equidistant frosty-white tubercles or ocelli, 8 or 9 on
each side, with fine white intermediate filaments : incurrent
tube at the anterior side, wide, irregularly sinuous, and not
always present: excuvrent tithe at the posterior side, small,
with a plain orifice : gills of equal size : lips 2 on each side,
more coarsely pectinated than the gills, of which they appa-
rently form a continuation : foot worm-like, cylindrically
tapering to a point ; the byssal groove is at its heel, close to
the body.

Shell transversely oblong, much compressed towards each
end, thin, opaque except when held up to the light, of a glis-
tening aspect : sculpture, numerous and delicate ribs, which
radiate from the beak to the margins, curling round towards
the back or hinge-area, and branching off (especially in front)
at irregular intervals ; these ribs are crossed by still more
numerous and fine transverse or concentric striae, and by their

* Named in honour of Dr. Turton, the well-known author of several
works on British Conchology.

GALLOMMA. 189

intersection the angles are slightly nodulous : colour snow-
white : epidermis not visible and apparently replaced by the
pallial membrane : margins obliquely truncate and wedge-
shaped at the anterior side, the end of which is rounded, gently
curved in front for the entire breadth of the shell, with an
extremely long and wide ventral gape, more decidedly trun-
cate and somewhat longer at the posterior side, which is also
wedge-shaped and has a rounded end : heals slightly pro-
minent, and appearing like small nipples, placed nearer the
anterior side : hinge-line nearly straight, occupying more than
half the breadth of the shell : cartilage oval, yellowish-brown,
lying close to the beaks on the posterior side : hinge-plate in-
curved, somewhat thickened, terminating on the anterior side
in an obtuse angle, and merging in the slope on the other side :
inside pearl-white and glossy, with the edges finely crenulated
by the projection of the longitudinal ribs, and slightly grooved
on each side below the hinge-plate : muscular scars oval.
L. 0-2. B. 0-4.

Habitat : Rocky and stony ground, from low- water
mark to 20 fathoms, on some of our southern shores ;
but it is very local. It is not uncommon in the little
island of Herm, where it was probably discovered by
Dr. Turton ; single valves are not unfrequently dredged
off Guernsey ; Mr. Clark obtained it alive in the same
way off Exmouth ; and Mr. W. Thompson has taken it
in Eschar a foliacea, thrown up on the beach at Wey-
mouth after a storm. The single valve mentioned by
Turton in his original description, on the authority of
Dr. Goodall, was formerly in the collection of Mr. George
Humphreys, and is said to have come from Ireland. It
is now in my cabinet. Cailliaud has found it on the
coast of Brittany, D'Orbigny at Noirmoutiers in La
Vendee, M f Andrew in Vigo Bay j and several others have
noticed it as inhabiting the Mediterranean, from the
Gulf of Lyons to Sicily, as well as the Adriatic. The
only occurrence of it in a fossil state was observed by
me at Biot near Antibes, where I found a single valve

190 GALEOMMID.E.

in a raised beach, at the distance of about a league from
the sea, with other shells belonging to species that are
still living in that part of the Mediterranean.

Mr. Clark informed me that he gave his dredger,
Branscombe, a guinea for the first specimen taken at
Exmouth. Branscombe's account was that he captured
the same day a second specimen, and laid it on one of
the thwarts of his boat, until the jar which contained its
intended companion in captivity could be got ready,
but that in the mean time the free specimen crawled
away and escaped overboard. This is like Mr. Stutch-
bury's story of the once rare Trigonia pectinata, several
specimens of which he unaccountably lost, before he was
aware of its habit of taking a long leap, and he wrongly
accused his dredger of secreting them. As, however, it
was not Branscombe's interest to keep back any shell
from his liberal employer, who paid him much better
than any one else, the disappearance of the Galeomma
in the mode above related seems very probable. Scacchi,
Philippi, Deshayes, Mittre, and Clark have severally
described the animal. The last-named author says,
" A fasciculus of fine filaments issues from the byssal
fissure in the foot, which fix the animal so firmly to
whatever it is placed on, as to require some force to dis-
turb it ; in fact the byssus is discarded, by being alto-
gether withdrawn from a slit in the foot, whenever an
attempt is made to remove the animal by force ; but
though we repeated the operation several times, the
little creature did not appear to be injured or less lively,
but, as soon as it had crawled to some distance, we had
the good fortune to witness the formation of a new
byssus, which was effected by the discharge of a light-
green gelatinous opake matter from the fissure at the
heel of the foot, which by its ponderosity resolved itself

GALEOMMA. 191

into delicate fibrous filaments that instantly adhered to
the saucer : we detached the animal several times ; the
byssus was always left, and a new one formed. On
leaving it for the night, in a marked position, we found
in the morning that it had detached itself by abandon-
ing the byssus, and had formed another at a consider-
able distance. The animal marches with great rapidity,
by flatting the valves into the form of a circular disk ;
it then, by the foot, aided by the muscular margins of
the mantle, makes rapid progression. It marched across
the saucer before ten could scarcely be counted." Mr.
Alder noticed a peculiar expansion of the mantle, which
invests the shell like a membrane. Philippi had pre-
viously remarked that this membrane resembles the
true skin of vertebrate animals ; but Alder has given a
farther explanation of its structure. He says " it is a
continuation of the true skin, and consists of two layers ;
the lower of which is slightly muscular, and under the
microscope the muscles may be seen interlacing each
other in all directions. The outer layer is granular, and
is covered with tubercles, which possibly, when the ani-
mal is alive, may rise into papillse. The want of an
epidermis appears to be thus supplied." The interesting
particulars above given of its organization make us
anxious to know more about this wonderful mollusk ;
and it is to be hoped that the investigation will be con-
tinued by Mr. Alder, or prosecuted by some other ob-
servant naturalist. The animal is hardy, and could be
safely sent by post, packed in Chondrus crispus or some
stiff sea- weed, to any place within reach of the sea. The
number, position, and nature of the siphonal tubes have
not yet been satisfactorily made out. Philippi describes
one only, Mittre two (besides an anomalous organ re-
sembling the large tentacle of Lepton squamosum), while

192 kelliid^:.

Clark does not mention any. Nor do we know what it
feeds on. According to Mittre it lives on the roots and
leaves of fuci; but at Herm these sea- weeds are not
found in the spots frequented by the Galeomma. He
observes that they look like beautiful pearls, when seen
beneath the water at a depth of from three to four
fathoms. Mr. Dennis remarks, in a note with which he
has kindly favoured me, " How surprisingly tough the
animal of Galeomma Turtoni is— quite like a limpet !
They occurred at Herm in little colonies, invariably
where a large loose piece of granite rested against the
solid rock, and never under stones which lay flat." The
shell resembles that of Lima in its composition and
structure. Mr. Norman's cabinet contains a specimen
having a longitudinal fold in the middle of the front
margin, and resembling in that respect a monstrosity of
Pisidium fontinale, which I noticed in page 26 of the first
volume of the present work.

This species is the Hiatella Poliana of Costa, H. striata
of Delle Chiaje, and Parthenope formosa of Scacchi.
Nardo states that it is the Tellina aperta of Renier.

Family VIII. KELLI'IME, {Kelliadce) Forbes

and Hanley.

Body oval or suborbicular, gelatinous : mantle open in front,
as well as in most genera on the posterior side to form an ex-
cretal tube ; it has only a single lobe, the margin of which is
fringed with cirri : gills 2 on each side : foot long and exten-
sile : byssus slight.

Shell triangular, oval, oblong or subglobose, equivalve,
more or less inequilateral, thin, variously sculptured, com-
pletely closed : epidermis slight : beaks calyciform : cartilage
internal: hinge furnished with cardinal or lateral teeth, or
with both.

LEPTON. 193

All the KelliidcB are of small size. They are also
upstarts in a conchological point of view, none having
been known to Linne, or described by any writer until
near the close of the first decade of the present century.
But the family came into this country long before the
Conqueror. Many of our recent species flourished in
the time of the Coralline Crag ; and the history of their
existence in these dark and remote ages has been duly
chronicled. They now inhabit both hemispheres : one
kind of Montacuta is found in the Arctic seas, and
species of that and other genera are diffused over all the
vast tract of sea which lies between Cape Horn and

" The gulfy coast of Norway ironbound."

A peculiarity of this family consists in some of them
being viviparous. This is certainly the case with Mon-
tacuta substriata, Lasaa rubra, and Kellia suborbicu-
laris. The Sphariida? resemble these members of the
present family in the above-mentioned peculiarity, as
well as in shape.

Genus I. LEPTON * Turton. PI. IV. f. 7.

Eodt voluminous : mantle protruded, and furnished with
long tentacular cirri : foot capable of being expanded into a
disk -like form.

Shell roundish-oval or triangular : cartilage small : hinge
furnished with a single cardinal tooth and two strong lateral
teeth in each valve.

This genus closely resembles Galeomma ; but the
animal has no ocelli, the shell does not gape in front,
and the hinge exhibits a goodly array of cardinal and
lateral teeth. Mr. Clark has, by his careful observa-
tions, completely dispelled the commonly received idea

* Tliin as a scale.

194 KELLIID.E.

that the shell gapes. It can be completely closed on all
sides at the will of the animal. A species (L. loripes),
half an inch long, found on the coast of Florida has
a singular habitat. According to Mr, Stimpson, the
discoverer, " it lives in sand or mud, on the flats, near
low-water mark, at the depth of a foot below the surface,
and generally occupies the holes of marine worais and
fossorial Crustacea."" This might warrant a supposition
that the animal of Lepton is predacious.

Three species of Lepton are enumerated in Dr. Philip
Carpenter's list of mollusca from the west coast of
North America. The genus Scintilla of Deshayes ap-
pears to be closely allied to the present genus.

A. Shell pit-marked.
1. Lepton squamosum *, Montagu.

Solen sqvarao&is, Mont. Test. Brit. i. p. 565. L. squamosum, ~F. & H. ii.
p. 98. pi. xxxvi. f. S, 9, and (animal) pi. O. f. 6.

Body clear white : mantle very large, having its margins
flexuous and often puckered into two or three folds ; the
margins extend considerably beyond the shell, and from them
springs, on each side of the ventral range in the middle, a row
of 25 rather long, slender and pointed milk-white tentacular
filaments : the pallial margin has also at its sides 40 long,
strong, close-set, blunt, frosty-white cirri of different lengths,
one of these last filaments being much larger and longer than
the others, and resembling one of the tentacles of a Gastero-
pod : excurrent tube short : foot bluish-white, and transparent,
with a broad streak of intense snow-white running down the
middle, and a still more conspicuous Hake at the anterior end :
it is fixed to the centre of the body by a moderately long-
pedicle. (Clark.)

Shell roundish-oval, with a tendency to a square outline
in consequence of the front margin being nearly straight and
of the hinge-line being unusually broad ; it is very much

* Scaly.

LEPTON. 195

compressed and almost flat, thin, seniitransparent and glossy :
sculpture, numerous and minute circular pit-marks, which are
caused by the intersection of a close network of fine longi-
tudinal and transverse ribs, the former radiating from the beaks
and curved towards the back and sides ; there are also distinct
lines of growth, which vary in their distance from each other :
colour snow-white : epidermis exceedingly thin, and only
shown by an iridescent hue in young specimens : margins ob-
liquely truncate on both sides, with the angles rounded, some-
what incurved in front, and slightly curved outwards at the
•back : beaks small, somewhat prominent, placed a little nearer
to the anterior than to the posterior side : hinge-line gently
curved, occupying nearly one-third of the circumference of the
shell : cartilage triangular, yellowish -brown, close to the beaks
on the posterior side : hinge-plate broad, incurved, excavated
in the middle for the reception of the cartilage : teeth, one
small and slight but upright cardinal, lying directly under the
beak and close to the cartilage, and a long laminar lateral on
each side of the cavity containing the cartilage ; the lateral
teeth are placed at a little distance within the hinge -line : in-
side iridescent, striated lengthwise but irregularly ; margin
plain : pallial and muscular scars usually indistinct, owing to
the thin texture of the shell. L. 0-575. B. 0-45.

Habitat : Shelly gravel and sand, in 8-20 fathoms,
on the coasts of Cornwall, Devon, and Dorset, as well as
at Guernsey, and in the south and west of Ireland. It
is recorded in the ' British Mollusca ' as having been
found bv Lvons and Hanley at Tenbv, bv M f Andrew at
Anglesea, and by Barlee at Oban ; but another locality
there given on my authority (" off Skye ") must have
originated in a mistake. Searles "Wood found a single
specimen in the Coralline Crag at Sutton. Its foreign
range appears to be limited or little noticed. Lillje-
borg has taken it at Christiansund in Norway, Malm
and Loven on the coast of Bohuslan in Sweden (the
former in 12-20 fathoms), I found it at Etretat in Nor-
mandy, Cailliaud in the Departement of Loire-inferieure,
and M f Andrew dredged it at 8 fathoms in Vigo Bay.
It may be decidedly considered a local species.

k2

196 KELLIID.E.

This curious shell was discovered by Montagu, and
described by him from a single valve. Although quite
aware that it did not belong to any of the Linnean
genera, he was much more averse than naturalists of the
present day to travel out of the beaten path, and he
therefore provisionally placed it in Solen. Its shape is
not very dissimilar from that of a Solenicurtus. Its
nearest comparison, however, would be to a fish-scale ;
and its sculpture is equally beautiful, and resembles the
finest Jace laid out on cambric. The pit-marks which
cover the surface of the shell are like those which ladies
so often see on the top of their thimbles, but without
admiring or noticing the ornamentation, their thoughts
perhaps being occupied with something else. The re-
fraction of light through the punctures makes the silver-
white shell appear under a microscope to be studded
with glittering dew-drops. Nor is the animal less
curious or lovelv than the shell. Two excellent ob-
servers, Alder and Clark, have published some interesting
details of its peculiarities and habits. Mr. Alder says
that the single filament noticed in my description is
waved to and fro like a tentacle when the animal is
crawling, and apparently enables it to feel its way as it
goes. The other filaments are comparatively motionless,
floating loosely in the water, though capable of being
thrown out or withdrawn at pleasure. The edges of its
large foot can be either closed or expanded so as to
form a disk, as in Nucula. As may be imagined from
the size of the foot, the Lepton crawls about very freely ;
and sometimes it swims in an inverted position on the
under surface of the water, in the manner of some Gas-
teropods, the hinder part of the foot being then unfolded
and disk-shape ; but its favourite posture is that of
repose, suspended perpendicularly, with the beaks of its

LEPTON. 197

shell downward, by three or four threads, which are so
fine that they cannot be seen by the naked eye ; and
even by the aid of a magnifier they can only be observed
when the light falls upon them at certain angles. When
the animal withdraws into its shell, the latter can be
completely closed; but usually the valves are kept a
little open, and the mantle protruded beyond them.
Mr. Clark kept a specimen alive for thirty-four days in
a glass of sea- water, changed daily, and it was seemingly
as vigorous all that time as when first placed in captivity.
He states that when it was in motion and had made a
step, the long tentacular filament curled inwards, like
the fore-finger of an open hand bent down to the palm,
but immediately afterwards it resumed a straight posi-
tion to await another step ; all the other filaments were
either retractile or contractile, separately or together.
The foot can form a disk at each end. According to his
account, a glutinous red filamentous matter is copiously
poured out by the byssal gland. But I would venture
to surmise that this phenomenon may be connected
with the reproductive functions. Mr. Clark goes on to
sav, " The animal is vivacious, and allowed itself to be
examined many times daily; it marched with quick-
ness, but I only once saw it progressing in a vertical
position ; the usual posture of the shell is to rest on one
of the disks, which is frequently changed for the other ;
the adductors did not appear to allow of a greater open-
ing of the valves than the ordinary extent. The animal,
when placed at the bottom of a glass, always crawled
up and moored itself by a filament at the side ; some-
times, however, it slipped its moorings and floated free
on the surface of the water with the umbones down-
wards, and after an interval refixed itself by spinning a
byssal thread." He subsequently succeeded in obtain-

198 KELLIIDiE.

ing another lively specimen, which, he adds, " on being
placed in water, at once unfurled its ]ong and beautiful
fringes, and exserted the ample niveous mantle and foot.
This is certainly the prince of British bivalves; the
snow- white colour of both animal and shell sheds over
this interesting creature the inexpressible charms of
purity and elegance. " I can fully sympathize with the
enthusiasm of my old friend, although I have not been
equally fortunate in seeing the paragon he has so well
described. But I hope some of my readers will endea-
vour to realize the truth of his description by their own
experience ; and it will be more satisfactory, for, as our
best of poets says,

" Beauty itself does of itself persuade
The eyes of men without an orator."

Dr. Leach has named this species Eupoleme cancellata.
2. L. ni'tidum *j Turton.

L. nitidum, Turt. Conch. Dith. p. 63. Kellia nitida, F. & H. ii. p. 92.
pi. xxxvi. f. 3, 4, and (L. nitidum) App. iv. p. 255.

Body clear white and gelatinous : mantle having its edges
protruded beyond the shell as far in proportion as in L. squa-
mosum ; it is closely fringed with cirrous filaments, which are
more developed in front than behind, each of them bein^
studded at the point with four or five white cilia, so sharp and
minute as to require a high power to see them, and that only
in certain lights : tube formed by a fold or projection of the
mantle at the anterior end, being contrary to the position of this
organ in the last species : foot pale azure, marked with intense,
but irregular flake-white minute blotches ; each end from the
pedicle or stalk is of equal length and finely pointed. (Clark.)

Shell subrhomboid-oval, somewhat compressed, not very
thin, semitransparent, and glossy: sculpture, a few minute pit-
marks near the beaks, which are only perceptible by the aid
of a high magnifying power, besides faint and irregular con-
centric striae which traverse the whole surface, and are visible

* Shining.

LEPTON. 199

with an ordinary lens : colour varying from pale yellowish to
clear white : epidermis slight, bnt brilliant and prismatic :
margins rounded at each end, much broader at the side
furthest from the beak, very slightly curved in front, and
somewhat angular at the back : beaks prominent and projecting
beyond the dorsal margin, placed nearly in the middle, but a
little towards the narrower end of the shell : hinge-line curved,
occupying about one-fourth of the circumference : cartilage
small and slight, light horncolour, placed close to the beaks on
the narrower or posterior side : hinge-plate narrow, incurved
or excavated in the middle : teeth as in L. squamosum, but they
are more developed and lie more compactly, the cardinals are
more oblique, and the laterals are smaller, and placed nearer
the hinge-line in consequence of the groove which contains
these teeth being narrower and deeper in proportion to the
size of the shell : inside highly iridescent, and microscopically
striated lengthwise; margin plain: scars distinct. L. 0*1.
B. 0-125.

Var. 1. convexa. Shell rather more convex, and coarsely
pit-marked throughout. L. convexum, Alder, Cat. Moll. ISorth.
k Durh. p. 93 ; F. & H. ii. p. 102, pi. xxxvi. f. 10.

Var. 2. lineolata. Shell rather natter than usual, and marked
with minute longitudinal lines.

Yar. 3. ^>?s*Y?z'«7?s. Shell triangular and convex, resembling
in shape Pisidium pusillum (var. obtusalis), marked with ex-
ceedingly minute wavy ribs, which are formed by the con-
fluence of the pit-marks.

Habitat : Gravelly sand on most parts of our coast
from the Shetland to the Channel Isles, in from 10 to
90 fathoms : although local, it is not uncommon. It is
a Coralline Crag fossil. Var. 1. Equally diffused in a
recent state. Var. 2. Loch Fyne (M'Nab) ; Exmouth
(Clark) ; Guernsey (J. G. J.). Var. 3. Torbay (Web-
ster). The typical form has been found by Malm on the
Swedish coast in 20-50 fathoms, and by myself in the
Gulf of Spezzia in 18 fathoms. Sars has noticed its oc-
currence in postglacial beds in the Christiania district.

According to Mr. Clark the anterior part of the animal

200 KELLIIDiE.

occupies the broader side of the shell, contrary to what
is the usual rule in bivalves and even in this genus, taking
L. squamosum as the type. His remark seems to be
confirmed by the position of the cartilage in the present
species being different from that in L. squamosum. The
characteristic sculptmie of L. nitidum is extremely varia-
ble, but never absent. In apparently the smoothest and
most glossy specimens the pit-marks may always be
discerned near the beaks oculo bene armato. In all
probability Dr. Turton had not used a microscope when
he described the shell to be without punctures. From
this state to that of the variety convexa the gradations
of sculpture are almost endless. The pit-marks usually
are circular, but sometimes they are oval, elliptical,
or polygonal, and occasionally they are confluent and
form undulating wrinkles towards the front margin.
Not unfrequently one half only, or a greater or less por-
tion, of the surface is thus marked, the other part being
quite smooth. Perhaps the most elegant kind of orna-
mentation is that which combines the impressions exhi-
bited by the first variety with the radiating lines of the
second. The shell may readily be distinguished from
the young of the last species by being much less com-
pressed and comparatively more solid, by its beaks and
hinge-line being more prominent, and the teeth in-
finitely stronger and more compact. Mr. Clark says
that it is a far more active creature than L. squamosum,
creeping up a glass as easily as a Gasteropod ; the shell
is generally carried on one side, with the foot in the
same position, but is sometimes held upright when the
animal is on the march. This little gelatinous mol-
lusk, enclosed in its pellucid valves,

" A liquid prisoner, pent in walls of glass,"

and having the borders of its cloak fringed with tufted

LEPTON. 201

hairs, which are so delicate as to be almost invisible, is
not less worthy of admiration than its larger and more
showy congener.

B. Shell concentrically grooved, or marked with fine longitu-
dinal lines.

3. L. sulca'tulum *, Jeffreys.

L. suleatulum, Jeffr. in Ann. Nat. Hist. 3rd ser. Jan. 1859, p. 34, pi. '1.
f. 2 a-g.

Body of a light yellowish -brown colour.

Shell nearly circular, the contour being interrupted only
by the prominence of the beaks, somewhat compressed, thin,
semitransparent and glossy: sculpture, broad, numerous and
regular concentric ribs, which are equally strong and distinct
throughout the surface, and still more numerous and line lon-
gitudinal lines, which are not perceptible by the naked eye :
colour clear white : epidermis filmy : margins rounded at the
sides and in front, with a gentle fall from the beak to each
end : beaks projecting a little beyond the dorsal margin, slightly
inclined towards the narrower and shorter side : hinge-liae
obtusely triangular, occupying scarcely one-fourth of the cir-
cumference : cartilage small, placed close to the beak on the
shorter side : hinge-plate broad and thick, not much excavated
for the reception of the cartilage : teeth, one strong and erect
cardinal in the left valve, and a much smaller one in the right
valve, besides a remarkably strong and triangular lateral on
each side of the beak in both valves ; that on the broader side
is longer than the other ; the grooves into which these lateral
teeth lock are correspondingly deep : inside nacreous and
glossy, with a plain margin : sears rather distinct. L. 0-055.
B. 0-06.

Habitat : Rather plentiful among corallines in the
laminarian zone at Guernsey. I also found it at
Etretat on the coast of Normandy, as well as among
some small shells from Sardinia which I received from
M. Hupe for examination j and I noticed specimens in

* Slightly furrowed.

K 5

202 KELLIID.E.

Mr. M 'Andrew's collection, dredged by him off Orotava
and Lancerote in the Canary Isles.

This is certainly not the young of any other shell, as
might be hastily imagined on account of its minute size.
I have a series of all ages from the fry to the adult.
Nor does it resemble any other British shell. In some
respects it is even abnormal as a Lepton. The regular
concentric ribs and the inclination of the beaks to one
side do not occur in any of the above-described species.
The dentition, too, is peculiar. The cardinal tooth in
the left valve is united by a ledge with the lateral tooth
on the longer and broader side of the shell, so as to make
1)oth appear in, one point of view like the same tooth.
The cardinal tooth in the other valve is not discernible
unless in fresh specimens, and by means of a Coddington
lens or an equally strong microscopical power. Even
this pigmy shell, barely exceeding half a line in length,
is sometimes found to have been drilled by one of the
smaller Muricida.

4. L. Clar'kijs *, Clark.

L. Clarkia, Clark, in Ann. Nat. Hist. 2nd ser. March 1852 ; F. & H. iv.
p. 255, pi. cxxxii. f. 7.

Shell triangularly oval, with an oblique outline, much com-
pressed, not very thin, semitransparent and rather glossy:
sculpture, slight and numerous but irregular concentric stria?,
which are stronger and more crowded in front and at the sides,
and usually a few snow-white lines or streaks, radiating from
the beak towards the margins and more or less interrupted ;
the surface is also slightly scabrous or rough in fresh speci-
mens : colour yellowish-white : epidermis extremely thin :
margins abruptly truncate but rounded at the smaller end,
with an oblique slope to the ventral margin, which is likewise
rounded, very broad, and wedge-like at the larger end, and
forms a blunt angle behind : beaks small, projecting beyond

* Named out of compliment to Mrs. Clark, the wife of the distin-
guished British conchologist.

LEPTON. 203

the dorsal margin, placed considerably nearer to the posterior
or narrower side, which is not half the size or breadth of the
anterior side : hinge-line obtusely triangular, occupying about
one-third of the circumference : cartilage rather large, situate
close to the beaks on the narrower side: hinge-plate rather
narrow but thick, deeply excavated in the middle : teeth, in the
left valve a strong and oblique cardinal, and a long laminar
pointed lateral on each side of the beak ; in the right valve a
very minute cardinal, with strong lateral teeth as in the other
valve ; all the laterals are nearly of equal size, and diverge a
little inwards from the hinge-line : inside nacreous and
glossy, with a plain margin : scars not very distinct. L. 0*085.
B. 0-1.

Habitat : Gravelly sand, at depths of from 18 to 80
fathoms, on various parts of our coast, but not every-
where. The localities being few, I will enumerate
them. Shetland, Arran Isle, co. Gal way, Fowey (Bar-
lee) ; Exmouth (Clark) • Plymouth (Rouse) • Skye, Bar-
mouth, Lulworth, Torbay, Guernsey (J. G. J.). Al-
though this appears at present to be rather a scarce
species, it is hoped that something will be sooner or
later known of its distribution in other parts of the
European seas, as well as of the animal. The proba-
bilities are much against any of the marine inverte-
brata being exclusively confined to the line of soundings
round our own sea-girt coasts.

The shell differs from that of any of its congeners in
the obliquely rounded outline, and especially in the
sculpture, which consists of fine and irregular con-
centric striae, instead of pit-marks or regular transverse
and parallel ribs. It is also marked with longitudinally
radiating lines, and the beaks are much nearer one end.
The structure of the hinge agrees better with that of
L. sulcatulum.

204 KELLIID^E.

Genus II. MONTACU'TA * Turton. PL V. f. 1.

Body oval, rather thick : mantle protruded, and fringed with
short cirri : eoccurrent tube sessile : foot large, tongue -shaped.

Shell triangularly oval or oblong : cartilage proportionally
large, placed underneath the beak on the smaller and narrower
or posterior side : hinge furnished with two strong lateral teeth
in each valve.

Montagu preeminently deserves to have his name
commemorated in the present genus, because all the
known British species were discovered and admirably
described by him. Two out of the three are dwellers
in mud : the other has a singular habitat, being inva-
riably found attached to the spines on the under side
of Spatangus purpureus and other Echinoderms of the
same kind.

The founder of this genus, Turton, says that the
hinge is furnished with cardinal teeth but with no lateral
ones. This appears to be a mistake ; at least I con-
sider the scheme of dentition to be exactly the reverse
of the above. The entire space under the beak in the
hinge of each valve is occupied by the cartilage ; and
this is the only place where cardinal teeth must be
looked for. The teeth in all the British species of Mon-
tacuta are long and laminar, one on each side of the
cardinal area, and diverging obliquely inwards. A deep
cavity or indentation is thus formed in the hinge, resem-
bling the letter V reversed, and enclosing the cartilage.
The sides of this letter represent the usual shape and
position of lateral teeth. Cardinal or hinge teeth lie
immediately under the beak, and are either tubercular
or short. The cartilage is in some species calcined at
its point of attachment, and in consequence of its com-

* Dedicated to the memory of Colonel Montagu, one of our best zoo-
logists.

MONTACUTA. 205

position not being homogeneous, the base becomes
hardened to such an extent, that a cup -shaped process
or "ossicle" is formed, which can be separated from
the shell. It can only be detected in fresh specimens
before the cartilage has dried up; and the latter is
seldom preserved, owing to its elastic nature and slight
attachment to the pit, which is fixed and forms part of
the shell. The genus Thracia has nearly the same kind
of process.

Gould was of opinion that the present genus and
Kellia ought to be united, or else that the one might
merge in Ungulina of Daudin, and the other in Erycina
of Lamarck. Nyst referred Mont acuta to the last-
mentioned genus. But although Lamarck states that
the ligament in Erycina is internal, the hinge is de-
scribed as having cardinal as well as lateral teeth. The
structure of the hinge in Ungulina is very different from
that in Kellia.

Several species are noticed by Dr. Philip Carpenter
as inhabiting the Gulf of California.

1. Montacuta substria'ta *J Montagu.

Ligula mbstriata, Mont. Test. Brit. Suppl. p. 25. M. sv.bstriata, F. & H.
ii. p. 77, pi. xviii. f. 8, 8 a, and (animal) pi. O. f. 2.

Body whitish and nearly transparent: mantle having its
margin simple, and largely open in front for the passage of the
foot : gills large and conspicuous : foot muscular, transparent,
very much longer than the shell, issuing from the broader end,
tapering to a disk-like point, and furnished at the heel with a
byssal groove.

Shell varying in shape from a long to a short oval, with an
oblique outline, rather convex, not very thin, semitransparent,
usually of a dull aspect, but sometimes glossy : sculpture,
about a dozen very slight and indistinct ribs, which radiate
from the beak but do not quite extend to the front margin ;
there are also a few white longitudinal streaks, and concentric

* Slightly striated.

206 KELLIIDJE.

lines of growth : colour yellowish -white : epidermis extremely
thin : margins abruptly truncate but rounded at the smaller or
posterior end, with an oblique slope to the ventral margin,
which is also curved and rather deeply indented for the
byssus, very broad, wedge-shaped, and rounded at the anterioi
end, and forming an obtuse angle behind : beaks small, blunt,
and nearly straight, protruded beyond the dorsal margin ; they
are placed very much nearer to the posterior side, which is
not one-fourth the size of the other : hinge-line slightly curved,
occupying about one-fifth of the circumference : cartilage
yellowish-brown and semicylindrical, clasping the hinge-line
on the posterior side of the beaks : hinge-plate short and
narrow, but strong, not deeply excavated in the middle : teeth
triangular and pointed, that on the anterior side in each valve
being longer and rather larger than the other ; the teeth in one
valve lock into sockets in the other, but not in the correspond-
ing valve of every specimen — it apparently being indifferent
whether the right or left valve contains the more prominent
teeth or the sockets : inside nacreous and glossy, with a plain
margin : pallial and muscular scars indistinct, the former being
more perceptible than the latter. L. 0*115. B. 0*125.

Var. Icevis. Shell smooth and destitute of the radiating
striae.

Habitat : On the ventral spines of Spatangus pur-
pur eus, and occasionally of Amphidetus ovatus (A. roseus,
Forbes), in sandy ground, at depths ranging from 8 to
90 fathoms, on every part of our coasts. Capt. Beechey
took it alive on the Spatanyus in 110-140 fathoms off
the Mull of Galloway. The variety is from deep Avater
in Shetland. It is a Coralline Crag species. Loven,
Sars, Asbjornsen, M'Andrew, and Malm have recorded
it as inhabiting the Scandinavian seas from Finmark
southwards, Petit as found in the north of France, and
Recluz, Verany, and Mace as Mediterranean. The last-
named conchologist informs me that it occurs in the
Gulf of Lyons on Cidaris hy stria;. Sars mentions that
at Naples it attaches itself to Spatangus meridionalis ;
and Malm says that on the coast of Bohuslan not only
S. purpureus and A. ovatus, but also Brissits lyrifer, are

MONTACUTA. 207

favoured with its company. An ally, if not a variety,
of the present species of Montacuta was described by
Recluz in the ( Revue de Zoologie' for 1844 under the
name of Erycina seminulum, and stated to have been
discovered by M. Caron in the Mediterranean on the
spines of different kinds of sea-urchins, principally
Echinus esculentus. I mention these cases to show that
it is not confined to S. purpureus, or the " purple-heart
urchin," as is commonly supposed.

The byssal threads by which this curious mollusk
attaches itself are exceedingly strong and coarse. Mr.
Clark observed it in active motion after he had sepa-
rated it, still adhering to the spines, from a Spatangus.
He savs, "When the animal marches, its foot is ex-
tended, and its rounded termination is instantly fixed
to the vase in which it is deposited ; then by the re-
tractor muscle it is drawn forward, making such rapid
progression as to cross a watch-glass in a minute, and on
the passage turns itself several times by a twist of the
foot from side to side/' In another description which
he has given of this operation, he uses the appropriate
expression " iterumque, iterumque/' to show the toil-
some march of the little creature, which evidently would
have preferred remaining on the sea-egg from which it
was so unceremoniously dislodged to taking a long
walk across and round Mr. Clark's watch-glass, in a
vain search for fresh quarters of the accustomed sort.
The gills and green liver are visible through the shell
in some specimens which are more transparent than
others, the former crossing it diagonally. The shape
and position of the cartilage is very remarkable. Some-
times the shell is partly incrusted with a ferruginous
deposit. The number of fry, with their shells com-
pletely formed, which are found in some individuals, is

208 KELLIID.E.

astonishing. Many hundreds of them, packed close to-
gether, and glittering like microscopic pearls, might be
counted. They occupy at least two-thirds of the space
enclosed within the valves of their parent ; and its own
body seems to be atrophied and dwindled to a mere
skeleton. The shell is in fact turned into a crowded
nursery. Perhaps the parent dies, like some insects,
immediately after all its progeny have been developed.
I do not concur in the general belief that M. substriata
is parasitic. In one sense only can it be said to live on
Echinoderms. The food of Spatangus purpureus, on
which it is usually found, appears to consist of ani-
malcula ; and for that purpose it swallows large quan-
tities of shell-sand, causing thereby a strong and fre-
quent current in the neighbourhood of its mouth. The
Montacuta probably avails itself of this indraught, and
partakes of the sustenance intended for the Spatangus,
placing itself in the way, with its alimentary tube or
opening turned in the right direction. No exudation
from the Spatangus has been noticed ; and its excretions
would scarcely be produced in sufficient quantity for
the support of the Montacuta, or perhaps be suitable to
it. The latter has no suctorial organ, such as is pos-
sessed by all animal parasites : it never attaches itself
to the pedicellarise or any other soft part of the echino-
derm; nor has it once been detected on the back or
sides, or elsewhere than in the ventral region, of its
associate. It is only found on the spines close to their
points.

2. M. bidenta'ta *, Montagu.

Mya bidentata, Mont. Test. Brit. p. 44, tab. 26. f. 5. Montacuta bidentata,
F. & H. ii. p. 75, pi. xviii. f. 6 & 6 a.

Bout clear white : mantle having a bluish tinge ; its margins

* Two-toothed.

MONTACUTA. 209

protruded considerably beyond the shell and fringed with bril-
liant silvery, close-set, symmetrical, blunt, short but distinct
indented points, which extend on both sides to near the beaks :
tube scarcely perceptible, lying within the posterior margin of
the shell : foot very large, long, broad, subtriangular, hyaline,
sprinkled with flake-white spots ; it is slightly bent or genicu-
late, and has a conspicuous byssal groove.

Shell triangularly oval, or of a somewhat rhomboidal
figure, compressed, rather solid and opaque, of a more or less
dull aspect : sculpture, irregular lines of growth, and (occa-
sionally) white longitudinal lines or streaks as in the last
species : colour milk-white : epidermis not very thin, pris-
matic, and marked with numerous minute concentric striae
which impart to it a silky appearance under the microscope :
margins abruptly truncate at the smaller or posterior end,
nearly straight or slightly curved in front, expanding and
rounded at the anterior end, and very gently sloping behind
from the beak to that side : beaks small and blunt, promi-
nent, somewhat incurved, with an indentation below ; they
are placed very much nearer the posterior side, which is not
one-third the size of the other : hinge-line nearly rectan-
gular, occupying about one-third of the circumference : car-
tilage yellowish, smooth, thick and globular, contained in a
triangular pit lying directly under the beak in the left valve,
and forming a cup-shaped process or ossicle at its base : hinge-
plate narrow but strong, deeply excavated in the middle for
the reception of the cartilage, which sometimes encroaches on
the beak to such an extent as to make the latter appear broken
or eroded : teeth, in the right valve rather short, leaf- like, and
diverging inwards ; in the left valve longer, and parallel with
the hinge-line ; those on the anterior side are the largest in
both valves : inside nacreous and glossy, with a plain margin :
scars obscure. L. 0-125, B. 0*14.

Habitat : Muddy gravel and in the crevices of old
bivalve shells, from 10 to 70 fathoms, everywhere from
Unst to Guernsey. As an upper tertiary fossil it is
recorded by Grainger from Belfast, by James Smith from
Bridlington, and by Searles Wood from the Red and
Coralline Crag. Its foreign range extends from Norway
to Sicily. Malm has dredged it on the Swedish coast in
10-25 fathoms, M f Andrew at Vigo in % and. off Sicily

210 KELLIID^E.

in 8 fathoms, and I have taken it at Spezzia in 18
fathoms. According to Sars it is found in the post-
glacial beds of Christiania.

Clark's account of the animal is that it is "lively,
marches with rapidity, and in its course turns from side
to side, sometimes resting the shell on the ventral range
in an upright posture." Montagu, having found it
apparently burrowing in old and thick oyster- shells, be-
lieved that it was partly the cause of the small round
holes so frequently seen on those shells. Such perfora-
tions, however, are attributable to a sponge (Cliona
celata), that fills the cylindrical tubes of which the holes
are the outlet, and branches off in every direction — a
course never known to be taken by any mollusk. The
relative proportions of length and breadth in the shell
of M. bidentata are very variable. The young are more
triangular than the adult, and somewhat resemble in
shape the fry of Nucula nucleus. My largest specimen
is a line and a half long, and a third more in breadth.

This small shell has been bandied about by different
conchologists from one genus to another, and received
various names. Montagu referred it provisionally to
My a. Brown in 1827 placed it in the genus Anatina
of Lamarck, and Clark did the same in 1855. Gray
and Hanley called it a Petricola. It is the Erycina
faba of Nyst, E. nucleoid of Recluz, and Mesodesma
eociguum of Loven. The Montacuta elevata of Stimpson,
which Gould supposed was our shell, differs in the posi-
tion of the beaks and in other particulars.

3. M. ferrugino'sa *, Montagu.

Mya ferruginosa, Mont. Test. Brit, p. 44, tab. 26. f. 5. Montacuta ferru-
ginosa, F. & H. ii. p. 72, pi. xviii. f. 5, 5 a & 5 b (as M. ferruginea).

Body clear white : mantle having its margins on the ante-

* Covered with iron -rust.

MONTACUTA. 211

rior side produced considerably beyond the shell, and forming
a kind of frill, which becomes gradually smaller and more
even as it passes along the front of the shell towards the pos-
terior side ; it is fringed with very delicate, rather short, and
blunt filaments, which extend completely round the edges of
the valves, with the exception of a small space at the umbones :
tube consisting of a small inconspicuous excretory orifice : foot
very large and muscular, slightly bent in the middle, tapering
to a blunt point in front and abruptly truncate behind ; its
base or sole is somewhat wavy and grooved through its entire
length.

Shell oblong, convex, thin, rather opaque, glossy : sculp-
ture, irregular lines of growth and occasionally a few exceed-
ingly slight longitudinal scratches : colour greyish-white :
epidermis as in the last species, but it is usually obscured by
a thick ferruginous crust : margins somewhat truncate but
rounded at the smaller or posterior end, thence obliquely
slanting and slightly curved in front, expanding and rounded
at the anterior end, and very gently sloping behind from
the beak to that side, with a short ledge on the other side
which forms an obtuse angle at the posterior extremity : beaks
small, blunt, and rather tumid, not very prominent, and nearly
straight; they are placed at about one-third the distance
from the posterior end : hinge-line almost straight, occupying
about one- third of the circumference : cartilage large and
solid, light yellowish- brown or horn colour, obliquely twisted
and clasping the hinge-plate on each side, lying close to the
beaks at the posterior side ; the pit or groove containing it
slants abruptly and obliquely down towards the posterior side,
and has its walls and base much thickened : hinge-plate nar-
row but thick : teeth, in the right valve one on the anterior
side, which runs from the cartilage at nearly a right angle to
the hinge-line and so far resembles a cardinal tooth, but it
then takes a sharp twist in the direction of the hinge -line,
where it becomes laminar and is gradually attenuated to a
sharp point ; the other tooth in the same valve on the posterior
side is shorter, triangular and pointed, placed on a lower level
and parallel with the posterior slope ; in the left valve the
tooth on the anterior side is pointed near its commencement
and forms a rather long laminar ridge in a parallel line with
the hinge, the other tooth being of the same shape as the corre-
sponding one in the right valve and taking a similar direction :
inside partly nacreous but mostly of a dull hue, with a plain

212 KELLIID.E.

and somewhat thickened margin, sometimes marked with faint
lines which radiate from the beak : scars remarkably distinct,
the muscular impression on the anterior side being larger and
much longer than the other. L. 0-2. B. 0-3.

Var. oblonga. Shell narrower, and having the front and
dorsal margins nearly straight. M. oblonga, Turt. Conch.
Dith. p. 61, tab. 11. f. 11, 12.

Habitat : Muddy ground, from 7 to 85 fathoms, on
all our coasts. It is, however, a local species, and is
seldom found in a perfect state. The variety is not un-
common, and occurs with the typical form, as well as
with intermediate gradations. Grainger has recorded
this shell from the Belfast deposit, and Searles Wood
from the Coralline Crag. Loven and Malm have de-
scribed it as Swedish, the latter giving a depth of 18-50
fathoms ; Recluz found a single valve in the stomach of
a turbot on the French side of the English Channel ;
Lamarck mentions Cherbourg as the locality for his
Amphidesma pur par as c ens, which is probably our spe-
cies ; and I noticed it in M. Martin's collection of
shells from the Gulf of Lyons.

Professor Loven published, in the ' Proceedings * of
the Royal Swedish Academy of Sciences for 1848, some
important information as to the production and deve-
lopment of the fry of this species (as well as of M. biden-
tata) ; and in the c Annals of Natural History ' for March
1850 (2nd ser. v. p. 210) is contained an excellent paper
by Mr. Alder on the same subject, and also with respect
to the habits of the adult. My description of the ani~
mal is taken from Mr. Alder's notes. He mentions that
the specimen which he observed was taken from " the
stomach of a haddock — a very unpromising locality cer-
tainly for meeting with anything in a living state ; but
the little creature on being placed in sea-water appeared
quite lively, and not visibly the worse for the uncom-

MONTACUTA. 213

fort able quarters from which it had been extracted. In
a short time it protruded the mantle beyond the shell,
extended its large foot, and began to crawl about." And
as to the fry he says, " After having kept my specimen
for some days in sea- water, I found one morning that
the bottom of the glass was covered with a minute
white dust, which I immediately concluded would be
the spawn, and on placing a small portion under the
microscope I found that such was the case. I sub-
sequently had it removed into a separate glass with a
fresh supply of water, in order to observe its develop-
ment. Though nearly round at first, the ova soon
assumed a subtriangular shape, and about the third day
strong cilia were observed on one of the sides, and they
began to rotate very quickly. One after another assumed
the rotatory state, till nearly the whole were in motion.
After rotating for about a day, they apparently burst
the envelope, and swam freely about in all directions
by means of their vibratile cilia, and at the same time
assumed more or less of a bell-shape — a slender style
or thread projecting from the centre of the ciliated base.
This organ, which has been observed in the embryos of
other species, has been described as a kind of byssus, by
which the little creature can fix itself securelv to other
bodies. This, however, I did not observe to be the
case in the present instance. It soon appeared to be
absorbed ; the animal became gradually elongated, and
the cilia were withdrawn into the shell, which then
began to appear; but at what time it was actually formed
I could not make out, as, from its extreme transparency
and similarity of colour to the rest of the animal, it was
very difficult of detection. The cilia could be seen
vibrating within the shell for some time after the ani-
mal became quiescent — a few isolated cilia at one of the

214 KELLIIDiE.

extremities, not observed before, being the only ones
that remained to perform their functions externally.
These produced a partial current without propelling the
animal through the water, as at this stage it gave up its
natatory habits and took to a quiet life. The internal
portion, the parts of which conld not be very distinctly
made out, appeared to be nndergoing a process of deve-
lopment. The mass was continually changing its form,
the separate parts being extended alternately in different
directions, and a portion, probably the incipient foot,
was occasionally pushed beyond the margin of the shell.
At this point of development further observations were
unfortunately arrested by the death of the whole colony
in consequence of the water beeoming impure, and my
situation at a distance from the sea preventing my get-
ting an immediate fresh supply. The whole period that
I had kept them was not above five or six days ; so that
their development had been pretty rapid. After the
death of the animals the shells remained at the bottom
of the glass. They were of an elliptical form, straight
at the upper margin, where they were attached, though
the hinge did not appear to be yet formed ; the whole,
excepting in the elongated form, had very little resem-
blance to the adult shell "

I am sure my readers will not regret my having
reproduced such a faithful and striking picture by one of
our great masters of British zoology. It agrees on the
whole with the account furnished by Loven, and espe-
cially with his observations as to the development of
the embryo of Modiolaria marmorata and Lascea rubra.
The metamorphosis in Modiolaria is stated to have
commenced about the third day after the spawn was
deposited, being the same period as that which Alder
noticed in Mont acuta ferruginosa. The shell is apt to

MONTACUTA. 215

become coated with a thick but irregular layer of hard
ochreous dirt, like iron-rust. I suspect that this in-
crustation is caused by a continual deposit and accumu-
lation of faecal matter from the animal, which is not
carried off in consequence of its sedentary habits and of
the water in which it lives being free from currents.
The same remark applies to species of Pisidium and
other freshwater shells, as well as to many of the ma-
rine bivalves. Forbes and Hanley observe that M.fer-
ruginosa is " a scarce shell." This of course is only
in comparison with other species; but the common
notion of rarity is not quite correct. I consider that
" local" would be a more appropriate word than "scarce"
with regard to the occurrence of marine testacea. The
difficulty of procuring some particular kinds may en-
hance their value to collectors ; but probably all kinds
are prolific, and differ in that respect from many of the
larger land mammals. There certainly cannot exist a
" unique" specimen of any shell in nature. In the
present case single valves may be found in tolerable
plenty on several of our sandy beaches, and perfect spe-
cimens may be got by dredging in the sheltered lochs of
the west of Scotland and in rather deep water off our
southern coasts. The beaks are often fissured or notched
from their being squeezed close together by the strong
and elastic cartilage, the shell being too fragile to resist
such pressure.

The proportions of length and breadth vary greatly
in specimens, which may account for the diversity of
names which this species has from time to time re-
ceived. As I have already incidentally noticed, it ap-
pears to be the Amphidesma purpurascens of Lamarck ;
Brown called it Tellimya elliptica and T. glabra,
S. Wood T. ovata, Leach Amphidesma Goodalliana,

216 KELLIID.E.

Recluz Erycina Franciscana, and Loven Montacuta
tenella.

Among some small shells sent to me by Mr. Robert
Dawson, and collected by him on the Aberdeenshire
coast, is a minute single valve, which I cannot identify
with any known species, whether recent or fossil. Its
shape is obliquely triangular, with rounded margins ; it
is compressed, rather solid, glossy, and smooth or marked
only by the lines of growth ; the beaks are blunt and
not prominent; the hinge-line is small and straight;
the teeth somewhat resemble those in the right valve of
Montacuta bidentata, but they are much shorter and
nearly on a level with the hinge -line, the tooth on the
broader side being considerably larger and stronger than
the other; the inside is nacreous, with a plain margin.
The shell appears to be full-grown ; but its size is barely
one-fifteenth of an inch in length, and rather less in
breadth. If more specimens are found, I would propose
for this species the name of Dawsoni, as a fit compli-
ment to its discoverer, a zealous and intelligent con-
chologist.

When dredging at Falmouth in 1839 I obtained a
recent single valve of the species, which Searles Wood
described and figured in his Monograph of the Crag
Mollusca (Palaeont. Soc. Trans. 1850, p. 131, tab. xi.
f. 3 a-c) as Montacuta donacina, from the Coralline
Crag at Sutton. I am, no less than Mr. Wood, quite
unable to say in what genus this curious shell should be
placed. My specimen is a right valve, and it has a
minute tubercular tooth on the longer side of a small
cartilage-pit. In shape it is a miniature Zenatia (a
genus founded by Dr. Gray), but having an external
ligament.

LASJEA. 217

Genus III. LAS^E'A*, Leach. PL V. f. 2.

Body oval : mantle folded on the anterior side (being the
longer and larger end of the shell), so as to form a wide, but
incomplete, incurrent tube : the excurrent tube is very short and
inconspicuous, placed on the opposite side : foot long, tongue-
shaped, protruding when in motion through a slit in the ex-
current tube at its base.

Shell roundish-oval : beaks straight : cartilage long and
cylindrical, divided or split lengthwise, and clasping the
hinge-plate, in each valve, on the smaller and narrower side
of the shell, being the posterior end : hinge containing in the
left valve a minute thorn-like cardinal tooth, and in each
valve two remarkably strong lateral teeth.

The late Captain Brown proposed this genus in 1827,
on the authority of Dr. Leach, for the Cardium rubrum
of Montagu ; and although he says nothing about the
animal, and not much more about the shell, I think the
genus is a good one, and I therefore adopt the name
above given to it. M. Recluz, apparently unaware of
his having been anticipated, gave in 1843 another name
(Poronia) to the same genus; but his description is
positively incorrect. He says of the animal, that it has
on the posterior side two lobes, and two tubes which are
disunited ; and of the shell, that the hinge has two cardi-
nal teeth in each valve, besides lateral teeth, and that
the cartilage is placed in an oblique groove. It will be
seen that my description of the generic characters is
very different from that of M. Recluz : and were it not
for the certainty that we both mean not only the same
genus, but also the same species, I could not believe
that our respective descriptions had been drawn from
the same object. The present genus is intermediate
between Mont acuta and Kellia, and partakes of the

* A meaningless name ; possibly a corrupt derivation from Xaiai)iov, s
little shield.

218 kelliidjE.

leading characteristics of each. With the former it
agrees in having the cartilage placed at the shorter end
of the shell, a position contrary to that in Kellia, and
with the latter in the mantle being folded on the ante-
rior side, though not so completely as in that genus.
The position of the cartilage or ligament is by no means
unimportant, because it indicates the posterior side ; and
the empty shell thus serves to determine the place, and
often the nature, of the organs which had composed the
frame of its late occupant.

It is very probable that the shell which Adanson
called " Le Poron " belongs to this genus ; but his
notice of it is unusually brief and obscure. He says that
it has two small triangular teeth in each valve, which
form the hinge, that it is at most only two lines in dia-
meter, and that it is whitish and sometimes of a violet
colour, chiefly towards the hinge. He evidently did not
know the animal, for he included the Poron among the
species of his genus Chama, which he described as having
three openings in the mantle, two of which take the form
of a rather long tube. It would be a waste of etymolo-
gical research were we to endeavour to trace the derivation
of the word " Poron." Adanson tells us, in the preface
to his most admirable work on the Mollusca of Senegal,
that he preferred inventing such chance names as had
the least meaning, and had no relation to other names
or known objects. Perhaps Dr. Leach had the same
idea in selecting some of his generic names. However
that may be, in his posthumous work on the Mollusca
of Great Britain he seems to have changed Lascea for
the more classically correct name of Autonoe, placing it
in the family Veneridce, although calling the species (after
describing it) " Lasea rubra. 33

The Lascea are of a minute size, and usually inhabit

LASyEA. 219

the littoral zone, where they congregate in vast num-
bers, at the roots of small seaweeds, as well as in the
crevices of rocks and in the empty shells of Balani. On
some coasts they live as much out of the sea as in it,
a sufficient supply of water being retained within the
close-fitting valves to keep the gills moist until the
return of the tide ; and in many cases they must fast for
a long time, because they are found in places which are
covered by the sea at high springs only. A little fresh-
water bivalve (Pisidium pusillum) is also occasionally
amphibious. We have but one species of Lascea, and
that is viviparous. Other species, however, have been
noticed in various parts of the world :

" Prythee, think

There's livers out of Britain."

1. Las^ia rtj'bra*, Montagu.

Cardium rubrum, Mont. Test. Brit. p. 83, tab. 27. f. 4. Kellia rubra,
F. & H. ii. p. 94, pi. xxxvi. f. 5-7 (as Poronia rubra), and (animal)
pi. O. f. 3.

Body white : mantle having its margin apparently plain and
without tentacles : excurrent tube sessile and concealed within
the mantle : foot broad at the base, the extremity being rather
rounded than pointed ; its bluish-white and transparent hue
is variegated by a line of dull but intense flake-white, which
runs from one end to the other.

Shell oval, with often a circular or triangular and rather
oblique outline, ventricose, not very thin or glossy : sculpture,
distant lines of growth and close-set wavy concentric striae,
besides more numerous but much finer longitudinal striae,
which are so excessively minute as only to be seen with a
powerful lens : colour milk-white, tinged more or less deeply
with purplish-red, especially towards the hinge : epidermis
yellowish, rather thick : margins somewhat truncate and
rounded at the smaller or posterior end, slightly curved in
front, with sometimes a byssal sinus or indentation in the

* Eed.

220 kelliid.i:.

middle, produced or wedge-like and rounded at the anterior
end : beaks broad, blunt, prominent, and contiguous ; they are
placed about two-fifths nearer to the posterior end : hinge-Vine
curved, occupying rather more than one-fourth of the circum-
ference : cartilage large, yellowish -horn colour, attached to the
shell below the hinge-plate and lodged on an oblique shelf:
hinge-plate very broad, thick, and strong: teeth, in the right
valve two triangular laterals with sharp points, the anterior of
which is a little more raised than the other ; in the left valve
similar laterals, besides a minute cardinal and erect tooth
directly below the beak ; the laterals in each valve lock into
corresponding grooves in the other : inside partially nacreous,
but otherwise of a dull hue ; margin plain : pallia! scar scarcely
visible, but evidently existing on account of the adhesion of
the mantle inside the front margin : muscular scars oval and
distinct. L. 0-85. B. 0-1.

Var. pallida. Shell yellowish -white and nearly trans-
parent, without any tinge of purple or red.

Habitat : Everywhere in crevices of rocks, inside the
empty cups of Bcdani and among the tufts of Lichina
pygmcea, near high-water mark, and at the roots or
footstalks of CoralYina officinalis and other seaweeds,
and on mussel-beds, between tide-marks ; sometimes it
is found at depths varying from 3 to 20 fathoms. The
variety is not uncommon. This species is a Coralline
Crag shell. Steenstrup has found it in Iceland, and
Lilljeborg at Grip in Upper Norway ; but I am not
aware of anv other northern locality. It is widely
diffused southwards from the north of France to the
Canary Isles, and throughout the Mediterranean. Spe-
cimens for which I am indebted to the kindness of
Mr; Cuming (so renowned for his unrivalled collection
of shells, as well as for the extent of his conchological
experience), and taken by him on the south-western coast
of America, cannot be distinguished from the European
species ; and Dr. Philip Carpenter is of opinion that a
species from the Gulf of California is the same as ours.

LAS.EA. 221

L. rubra has been recorded by Sars among arctic shells
occurring in newer tertiary strata in the diocese of
Christiania.

Dr. Turton was the first who noticed the curious fact
that this minute mollusk is viviparous. It does not
appear to be prolific, as seldom more than twenty young
ones are to be seen at any one time in the shell of the
parent. They are fully formed while in this stage of
growth, and their shells have even a tinge of purplish-
red on each side of the beaks. Mr. Clark says the
ovary contained no young in specimens which he pro-
cured in the winter. The same may perhaps be said of
most mollusca, whether viviparous or oviparous, as well
as of other animals the season of whose loves in a state
of nature does not commence until

" species patefactast verna diei,

Et reserata viget genitabilis aura favoni."

A discussion took place some years ago, between
Mr. Clark on the one side, and Messrs. Alder and Han-
cock on the other, as to the use of the anterior tube in
this species and in Kellia sub orbicularis, both of which are
viviparous. Mr. Clark contended that it was an organ
of reproduction, in consequence of his having observed
the fry ejected through it. His opponents disputed this
uterine function, and showed that the tube serves to
convey water to the gills. My own observations induce
me to believe that it has various uses — one for obtaining
food, another for aerating the gills, and a third for the
expulsion of the fry. The tube seems to be expanded
or contracted at the will of the animal, being formed
merely by an overlapping of the folds of the mantle. Its
sides are never united. The present species is rather
active in its habits. According to Mr. Clark, it imme-

222 KELLIID^.

diately fixes itself, when placed in a basin of sea- water,
by its threadlike byssus. The foot protruded, but not
in action, occupies a central position : it is usually pushed
through the slit at the base of the tube on the anterior
side when the animal wishes to move forwards, and, fixing
itself by a kind of suction, rapidly draws the shell after
it ; and it can also execute a similar movement backwards,
but more slowly. The animal never remains long with-
out forming a byssal attachment ; but when inclined to
move, it seems to have no difficulty in slipping its cable,
which is always discarded and left in situ. The surface
of the shell is sometimes coated with confervoid spores,
giving it a greenish appearance. My largest specimens
are from Shetland.

Walker first noticed and figured this species in his
account of minute and rare shells from Sandwich; but
his description was excessively meagre, and no specific
name was added. It is in all probability the Amphi-
desma nucleoid of Lamarck, Erycina violacea of Scacchi,
Cycladina Adansonii of Cantraine, Erycina Fontenayi of
Mittre, and Bornia seminulum of Philippi. Stimpson
remarks that the Kellia rubra of Gould is not our spe-
cies, having a more compressed form and much smaller
beaks. He therefore gave the name of planulata to the
North- American species. Gould's figure seems to re-
present Mont acuta bidentata.

Genus TV. KEL'LIA*, Turton. PI. V. f. 3.

Body globular : mantle folded on the anterior side (being the
shorter and smaller end of the shell), so as to form a bag-shaped
incurrent tube, and folded on the opposite side into an excur-
rent tube, which is more prominent but shorter : gills two, sym-

* Named after the Rev. J. M. O'Kelly of Dublin, a conchological asso-
ciate of Dr. Turton.

KELLIA. 223

metrical, and nearly triangular : lips two, of a similar shape :
foot long, tongue-shaped and bent, placed in the middle of the
front margin.

Shell globular : beaks incurved : cartilage cylindrical, placed
on the hinge-plate at the posterior side (being the broader and
larger end of the shell) : hinge containing in the left valve a
thick, erect cardinal tooth, and in each valve two remarkably
strong laminar teeth which are partly cardinal and partly
lateral.

This genus diners from Lascea in the incurrent tube
being more complete and the excurrent tube conspi-
cuous, in the foot being placed in the middle of the
ventral margin (instead of on the anterior side and pro-
truding through a slit at the base of the larger tube),
but especially in the position of the cartilage, which
lies on the broader and larger side of the shell, sup-
porting the hinge-plate, and outside of the lateral teeth,
and not (as in the last genus) placed on the narrower
and smaller side of the shell, nor clasping the hinge-
plate inside and below those teeth. The habits of the
present genus are also different from those of Lascea.
This is not amphibious, and probably cannot exist if
constantly left high and dry by the receding tide. It
usually inhabits comparatively deep water, and prefers a
muddy ground. Both are viviparous : but at least one
species of Montacuta has the same mode of reproduc-
tion. In the shape of its shell Kellia resembles Sphce-
rium; but that genus has an external ligament and
differs from this in the number and arrangement of the
teeth. The position of the tubes is also very dissimilar
in these genera. In Kellia, as well as in Lasted, it is
somewhat anomalous, the larger and incurrent tube
being placed at one end, and the smaller and excurrent
tube at the other. In Sphmrium and most other genera
which have two tubes, both are placed on the same side ;

224 kelliidtE.

and the Sphariidce possess the peculiarity of their tube
or tubes being situate at the shorter and smaller side of
the shell, which may therefore be considered the pos-
terior end, the ligament being situate at the other end.

Philippi described the present genus under the name
of Bornia, though not without some suspicion of its being
identical with Kellia. He remarks that he had no
means of seeing Turton's work on the British bivalves.
One character of his genus he conceives to be of very
great importance; and that is the absence of any mark
of a fold of the mantle — " sinus palliaris nullus." There
must be some mistake in this. The character exists in
Mediterranean as well as in British examples of the
typical species. Perhaps Philippi meant to say that the
pallial scar in Kellia is not sinuated as in the Veneriche
and allied families.

It may be well here to say that, in describing the right
and left valves, I have followed the rule laid down in
Dr. Gray's " Conchological Observations" (Zool. Journ.
i. p. 208), viz., "When a bivalve shell is placed on its
basal margin, with the ligament towards the observer,
the right and left valve will correspond with his own
sides." Some rule of this kind is indispensable, in
order to ensure a uniform method of description \ but it
appears of late years to have been left to the caprice of
every author.

Many species of Kellia are known in a recent and
fossil state. During the formation of the Crag strata,
within the area which is bounded on the west by the
counties of Norfolk, Suffolk, and the adjacent comer of
Essex, several kinds flourished ; but of these one only is
known to have survived, and still exists in the British
seas.

KELLIA. 225

1. Kellia suborbicula'ris #, Montagu.

My a saborbieularis, Mont. Test, Brit. p. 39, tab. 26. f. 6. K. suborbicularis,
F. & H. ii. p. 87, pi. xviii. f. 9, 9 a & 9 b, and (animal) pi. O. f. 4.

Body white and nearly transparent : mantle protruding be-
yond the shell in front, and having its margin fringed with a
few thornlike or triangular tentacles : incwrent tube varying
in length and diameter even in the same individual ; its oriiice
plain, but uneven : excurrent tube short : gills pale yellow and
striated : lips thick, strong, and coarsely striated : foot com-
pressed, flexible, and hyaline.

Shell usually globular, but sometimes inclined to an oval or
triangular outline, ventricose, rather thin, and more or less
glossy: sculpture, distant lines of growth, and close-set and
irregular concentric striae, besides some slight longitudinal
lines : colour milk-white, with a faint tint of yellow : epidermis
thin and beautifully iridescent: margins somewhat truncate
but obliquely rounded at the larger or posterior end, a con-
tinuous curve being formed by the ventral and anterior sides :
beaks circular and calvciform, incurved and twisted towards
the anterior or smaller end, close together, but not contiguous ;
they are placed nearly in the centre of the dorsal margin, and
there is a depression or incomplete lunule formed below them :
hinge-line curved, occupying nearly one-third of the circum-
ference : cartilage triangular, yellowish-brown, attached to the
hinge-plate close to the inner margin of the dorsal side, and
doubled on itself : hinge-plate narrow, but strong : teeth, in the
right valve two strong laterals, the one on the anterior side
being at first erect and resembling a cardinal tooth, and then
(as in Montacutaferruginosa) becoming laminar and attenuated,
that on the posterior side being obliquely triangular ; in the left
valve a recurved cardinal tooth, and two laterals similar to
those in the other valve, the cardinal and anterior lateral form-
ing a double tooth for the reception of the corresponding lateral
in the right valve ; dental sockets deep : inside like frosted
silver, with a slight prismatic lustre : pallial scar indistinct :
muscular scars large and conspicuous. L. 0*4. B. 0-45.

Var. lactea. Shell somewhat compressed and oval, of a
thinner texture and rather more glossy ; front margin nearly
straight, and dorsal margin raised more to a level with the

* Nearly globular.

L O

226 kelliidjE.

beak, Tellimya lactea, Brown, 111. Rec. Conch, p. 106, pi. xlii.
f. 10, 11.

Habitat : Fine mud in the cavities of dead bivalves
from deep water, and occasionally under stones at the
lowest verge of spring tides, sometimes occupying the
excavations made by other animals in hard rocks. Its
bathymetrical range extends to the line of soundings
round our coasts. The variety is not so common : it is
the K. Cailliaudi of Recluz. The typical form occurs in
the Clyde beds (Smith), and in the Red and Coralline
Crag (S. Wood). It is found in the Scandinavian seas,
as far north as Finmark, in 10-50 fathoms, and also
throughout the Atlantic and Mediterranean, the Canary
Isles and Sicily being its southernmost known limits.
The Rev. P. Carpenter has enumerated it as a Califor-
nian species.

Montagu discovered this pretty shell in hard lime-
stone ; and he remarked that the opening of the excava-
tions which it inhabited was smaller than the shell, so
that it must have entered in a younger state, and never
could have got out. It is, however, not a borer. I
have often found it in the tortuous and deserted galle-
ries made by Annelids; and its shape is sometimes
altered or even distorted in consequence of its confined
position. The shells of such specimens are thicker
than usual, and the epidermis is in a great measure
abraded. Both Alder and Clark have published some
excellent observations as to the habits of the animal.
The former says it moves freely by means of its strap -
shaped foot, which is frequently protruded in all direc-
tions. Its progress is usually forward ; but sometimes
it crawls backwards or sideways, especially when it is
ascending a perpendicular surface, which it frequently
does for the purpose of suspending itself by its byssus.

, KELLIA. 227

The byssal sinus is about halfway up the foot on the
posterior side ; and from it the animal produces a very
delicate thread, and suspends itself freely (with the beaks
of its shell downward) by a single almost inconspicuous
fibre, which is strengthened by a double attachment at the
top. In this posture it appears to rest for some time, with
both tubes open, and the foot partly withdrawn! into the
shell. According to Mr. Clark, the byssus spun by the
kind which is found in rocks consists not merely of
delicate filaments such as free individuals of the ordi-
nary form throw r out when placed in a saucer, but of a
membranous plate which cannot be detached without
some force. He also says that the larger tube in free
specimens (having a thinner shell) is marked with flake-
white longitudinal lines, which do not appear in the
rock specimens. He found in the ovary of one indi-
vidual ova in an advanced state, together with fully-
formed testaceous fry. M. Recluz has lately announced
the same fact with regard to the variety lactea. The
ova mentioned by Mr. Clark, and which through his
kindness I have had an opportunity of examining, are
bean-shaped, and closely resemble a minute form of
Cy there. They are very different from the fry, which
are perfectly spherical. Dr. Gordon has remarked that
K. suborbicularis is occasionally seen as part of the food
of the haddock. Sometimes the shell is extremely thin,
and so transparent that the gills are distinctly visible
through it, causing the surface to appear obliquely
striated. The cartilage is always ruptured and divided
when the shell is fully opened, one half being left in
each valve. The teeth vary somewhat in shape and
relative position.

This species is the Erycina pisum of Scacchi, Bornia
inflata of Philippi, and Oronthea Montaguana of Leach,

228 KELLIIDiE.

who placed it in the Mya family. The Tellimya tenuis
of Brown seems to have been constituted from a speci-
men which had lost one of its cardinal or front teeth.
It must have been knocked out after death. Any one
but a conchologist may well ask why these hinge-pro-
cesses are called " teeth," seeing that they are not
homologous to the teeth of Vertebrate animals, and
that they are always placed at the back, instead of in
front, of a headless creature. But the word, whether
rightly or wrongly used, has now become " household "
and unchangeable. I hope those out of the scientific
pale will accept this explanation : if they are not satis-
fied, the Hudibrastic distich may serve their purpose —

" To them we leave it to expound
That deal in sciences profound."

To the present genus must be referred provisionally
the K. cycladia of Searles Wood, a rare Coralline Crag
shell. To this species I am now inclined to refer a
shell which I found in the Shetlands and named Po-
romya subtrigona. A description and figure of it will
be found in the ' Annals and Magazine of Natural
History/ 3rd series, January 1858, p. 42, pi. ii. f. 1.
I had then only a single (the left) valve, which I sent
to my friend Mr. Barlee for his inspection; but un-
fortunately the box containing it was crushed on
being returned to me through the post, and a few frag-
ments are all that remain of the original specimen.
Since that time I have fortunately discovered another
(the right) valve in my dredgings on the same ground,
and I have no doubt that more specimens will hereafter
be found. However, I do not at present consider the
species, or even its generic position, sufficiently esta-
blished to warrant its redescription . The cartilage is in-
ternal, and lies on the narrower and smaller side of the

LUCINIILE. 229

shell, as in Lascea. The right valve has a small tuber-
cular cardinal tooth, a strong lateral tooth on the ante-
rior side, and a very indistinct one on the posterior side.
The hinge of Poromya is differently constructed ; and I
was wrong in placing the Shetland shell in that genus.
The form is peculiarly oblique ; but otherwise it has
somewhat the appearance of Axinus flexuosus. Searles
Wood thought his species might be the Scacchia ovata
of Philippi ; but I cannot agree with him that there is
even any resemblance between them.

Family IX. LUCI'NIDjE, D'Orbigny.

Body nearly globular : mantle closed, except in front, where
there is a large opening for the egress of the foot and to admit
water to the gills, and also at the posterior side, where there
are usually one or two tubes or orifices for alimentary and
excretal purposes ; its edges are thickened and adhere closely
to the inside of the shell : gills (in all the genera but Asemus
and Diplodonta) one only on each side : lips (or labial palps)
short, and (except in those genera) two in number : foot ex-
tremely long, tubular and extensile.

Shell more or less circular, equivalve in all cases but an
exceptional one, nearly equilateral, of different degrees of
solidity, in some instances almost smooth and in others curiously
sculptured, completely closed : epidermis thin : beaks incurved :
lunule usually distinct : ligament (except in Loripes) more or
less external : hinge furnished with cardinal and lateral teeth
or with some of them, but occasionally toothless : pallial scar
entire : muscular scars very conspicuous, that on the anterior
side unusually elongated and extending far within the shell in
a parallel line with the front margin.

Poli, Valenciennes, Clark, and Deshayes devoted
much labour to the elucidation of this familv as a
natural group, and have published some important ob-
servations on the animal. But we still need further
information, especially as to the branchial apparatus.

230 LUCINIM.

According to Valenciennes, the animal of Lucina has but
a single gill-leaflet on each side. Forbes and Hanley
state that there can be little doubt that two lamellse
on the same side are so united as to appear like a single
gill. Deshayes has shown that the two gills when
divided contain four rows of vessels, and that they
occupy as much space as all the gills in other Con-
chiferous mollusks. As I do not pretend to be, like
Sidrophel, " old dog at physiology," I can say no more
than that I hope the question may be sooner or later
set at rest. The foot is a remarkable and peculiar
organ. When at rest and contracted, it looks like a
shrivelled worm, and is doubled up within the shell ; but
when the period for action has arrived, the wrinkles
disappear, and in a marvellously short time the foot
expands and is drawn out to three times the length of
the whole body. It is thus rendered firm and more
capable of muscular exertion. This distention is effected
by means of aquiferous ducts or canals, which permeate
the tissue of the foot, the water being introduced at its
base through a wide funnel opening directly into the
visceral cavity. A similar organization of the foot has
been noticed in the Cephalophorous mollusks, especially
in some of the Muricidce, Naticida, and Bullidae, which
have the same habit of burrowing as the Lucinidce.
Another peculiarity which characterizes the present
family is the elongation of the anterior adductor muscle ;
and it is easy to recognize the fossil species by the nature
of the scar or mark inside the shell. The ligament is
more or less external in all the genera but Loripes,
which has an internal cartilage concealed within the
hinge-line and occupying an oblique groove, as in Kellia.
The Lucinida inhabit sandy mud and gravel, in which
they shelter themselves. Very many recent species of

LUCIN1D.E. 231

different genera have been described from various parts
of the world ; and fossil species are still more abundant.

The " family likeness " is unmistakeable, and this
constitutes part of the value of the Luciniclce as a
natural group. After much consideration and study of
the question, and with great respect for the opinion of
the authors of the ' British Mollusca' and of M. Des-
hayes, I cannot agree with them that the long-esta-
blished genera of Loripes and Axinus ought to be
merged in Lucina. The great French conchologist has
lately made a strong protest against the dismemberment
of the last-mentioned genus; and he wishes it to be
retained, like the once glorious republic of his own
country, " une et indivisible." To use his own words,
it forms " une grande unite." It may, however, be
questionable if the characters on which he lays so
much stress do not apply not only to the genus, but to
the family which has sprung from it, and whether there
are not other characters, although perhaps of inferior
value, that may serve to distinguish several genera. I
believe that such characters exist, and I will endeavour
to point them out in the proper place. It can hardly
be disputed that each group of natural objects, whether
we call it a kingdom, class, order, family, genus, species,
or variety, has some peculiar feature of its own, although
we may not be able to detect it. The imperfection of
our knowledge has hitherto combined with the limited
capacity of our intellect in keeping us but partly en-
lightened ; and this must ever continue to be the case,
until the whole scheme of Nature, past and present, has
been unfolded to our view. Perhaps, even to the greatest
philosopher of modern days,

" Science appears but what in truth she is,
Not as our glory and our absolute boast,
But as a succedaneum, and a prop
To our infirmity."

232 lucixid^.

Genus I. LO'RIPES * Poli. PL V. f. 4.

Body somewhat compressed : mantle having the margin
notched : incurrent tube rather long and wrinkled : excurrent
tube sessile : foot awl-shaped.

Shell almost equilateral, irregularly cancellated, or sculp-
tured by nexuous striae : lunule short : ligament (or rather the
cartilage) quite internal : teeth, one cardinal in the right, and
two in the left valve ; laterals remote and sometimes indistinct.

The celebrated Neapolitan eonchologist, Poli,, who
founded this genus, described the shell under another
name — that of Loripoderma — a hybrid compound, or
" Babylonish dialect/' which fortunately we are not
obliged to use. It may be known from Lucina by the
different position of the ligament or cartilage, which is
external in that and internal in this genus. Deshayes
is of opinion that the structure of the ligament is of
more consequence than its position; but the structure
or composition of every kind of ligament or cartilage is
the same, and it appears to me that the position of this
apparatus deserves to be considered in any scheme of
classification. Any one character, if certain and not
liable to vary in the same genus, is as good as another
for this purpose.

Searles Wood says that " this is a recent genus, and
its age, as far as it is known to me, does not extend
bevond the middle tertiaries." It is difficult to distin-
guish the genus Ungulina of Daudin from Loripes. Ac-
cording to Chenu, the ligament in Ungulina is external ;
but its exact position is in a groove on the hinge-plate,
within the dorsal margin.

* So named from the thong-shaped foot.

LORIPES. 233

A. Shell concentrically ribbed and slightly decussated by lon-
gitudinal striae ; lateral teeth indistinct.

1. Loripes lac'teus *, Linne.

Tellina lactea, Linn. Syst. jSat. p. 1119. Lucina leucoma, F. & H. ii.
p. 57, pi. xxxv. f. 2 (as L. lactea).

Body whitish : foot cylindrical, and swollen in the upper
part.

Shell usually of a somewhat globular form, but varying in
comparative length and breadth, rather solid and opaque, not
glossy: sculpture, distant lines of growth and fine, irregular
and close-set concentric striae, as well as equally fine and irre-
gular but less numerous longitudinal striae or scratches, which
radiate from the direction of the beak, and cause the surface to
be partly decussated : colour white, with a tinge of yellow :
epidermis forming a mere film, and slightly iridescent : margins
rounded and sometimes indented or sinuous on the anterior
side, curved in front, and slightly truncate although rounded on
the posterior side : beaks small, rather prominent, much in-
curved and close together ; they are placed very nearly in the
middle of the dorsal margin : lunule deep and heart-shaped :
hinge-line flexuous, occupying about one-fourth of the circum-
ference : cartilage yellowish-brown, shaped like a lance -head,
divided into two semicylindrical portions, each of which fills a
groove on the hinge-plate in either valve, sloping obliquely
downwards from the beak within the line of the posterior
lateral tooth, and terminating abruptly in the interior of the
shell : hinge-plate broad and strong : teeth, in the right valve
one triangular cardinal, and occasionally a small denticle, be-
sides two indistinct laterals (one on each side), which are more
or less raised and pointed at the end ; in the left valve a
double cardinal, which receives that of the opposite valve in
an intermediate socket, and two laterals as in the other valve ;
the posterior lateral is much the longer : inside somewhat
nacreous, but of a dull hue ; margin smooth and plain : scars
large and remarkably distinct. L. 0*7. B. 07.

Yar. Desmarestii. Shell flatter and thinner. Lucina Des-
marestii, Payraudeau, Cat. Moll. Corse, p. 44, pi. i. f. 19, 20.

Habitat : Muddy gravel and sand on the coasts of

* Milk-white.

234 LUCINIDiE.

our southern, south- western, and south-eastern counties,
and in the south and west of Ireland ; Llyn, Carnarvon-
shire (Pennant) ; Scarborough (Bean) ; Seaton, Dur-
ham (Hogg, fide Alder) ; and Mr. Dawson has dredged
a single valve off Buchan in Aberdeenshire at some
distance from land. In the Channel Isles it lives in the
sand at low tides ; and it is usually found elsewhere at a
depth of only a few fathoms. The locality " Scalloway/'
given in the ( British Mollusca ' on my authority, is
incorrect ; and Mr. M f Andrew informs me that a similar
mistake must have occurred in quoting him as having
taken this species in Zetland. The variety is from
Southampton and Bantry Bay. I am not aware that
this species has ever been found in the north of Europe.
South of Great Britain it is widely distributed through
the Atlantic, Mediterranean, and iEgean seas \ its fur-
thest limit appears to be the Canary Isles.

The shell varies considerably in the degree of globose-
ness, and in the proportions of length and breadth, as
well as in the development of the teeth. Very young
specimens have an oblique contour and are much broader
than long.

Philippi was of opinion that this species is not the
Tellina lactea of Linne, because the latter is described
as " gibba." Believing, moreover, that the present spe-
cies is that which Lamarck designated lactea, he pro-
posed the name of frag His for Linnets species. Forbes
and Hanley subscribed to Philippics view, but changed
the specific name of our shell to leucoma. I do not
see any necessity for this shifting nomenclature. The
Lucina leucoma of Turton, if we may trust his descrip-
tion and typical specimens, is scarcely a variety of the
shell commonly called L. lacteus. Lamarck appears not
only to have made two species out of the old one, but

LORIPES. 235

to have placed them in different genera, one in Lucina
as L.lactea, and the other in Amphidesma as A. lucinalis.

B. Shell marked by flexuous striae ; lateral teeth distinct.
2. L. divarica'tus * } Linne.

Tellina divaricata, Linn. Syst. Nat. p. 1120. Lucina divaricata, F. k H.
ii. p. 52, pi. xxxv. f. 3.

Shell resembling that of L. lacteus in shape, bnt more
tumid and having an oblique outline, thick and opaque, rather
glossy : sculpture, numerous imbricated and flexuous striae,
which bend from the middle of the shell to each side with a
gentle curve, the highest point or centre of the curve being in
the direction of the beak ; the striae are irregularly concentric
in the umbonal area, and become flexuous in the subsequent
stage of growth ; the surface is also marked by minute close-
set longitudinal striae or lines as in the last species : colour
white with a slight tinge of yellow : epidermis so thin as to
be scarcely visible : margins rounded on all sides, except where
the beak projects ; the posterior is the highest and forms a
kind of shoulder : beaks very prominent, gibbous, close toge-
ther, and twisted towards the anterior side : lunide deep,
heart-shaped, and defined on each side by a strong ridge :
hinge-line curved, occupying not quite one-fourth of the cir-
cumference : cartilage light horncolour, narrower than in L.
lacteus, but similar in shape and position : hinge-plate rather
broad and strong : teeth, in the right valve one strong blunt
cardinal, and a long, sharp and raised lateral on each side ; in
the left valve two cardinals, one of which is strong and blunt,
and the other very much smaller and on a lower level, besides
two laminar laterals on each side, receiving between them the
single lateral on the corresponding side of the other valve ;
the posterior laterals are the longest : inside slightly nacreous
but of a dull hue ; margin finely crenulated : scars large and
distinct, that left by the anterior adductor muscle being not
much longer than the other. L. 04. B. 0-4.

1 & X

Habitat : Sonth coast of England, but exceedingly

* Spread out, with reference to the different directions exhibited by
the markings on the shell.

236 LUCINID^.

rare. Montagu obtained a single valve from dredged
sand at Falmouth; Turton records it from the Land's
End and Teignmouth, although the only specimen in
his collection appears to be from the first of those locali-
ties; and I fortunately obtained in 1839 two valves
(right and left, but not a pair) by dredging in muddy
sand, at a depth of about 15 fathoms, off St. Mawe's
Creek near Falmouth, some miles outside the harbour,
and where no ballast had ever been deposited. Mytilus
Adriaticus occurred on the same ground ; and a living
specimen of Tellina balaustina has since been got there
by trawling. Another locality is, according to Dr.
Leach (on the authority of Dr. Knox), " southern seas
of Scotland, between Arran and Bute and the Mull of
Cantire f* but the length and height of a specimen said
to have come from that quarter are suspicious, "one
inch and threequarters." It must have been the com-
mon West-Indian shell generally known as the Lucina
divaricata of Lamarck and L. quadripartita of D'Or-
bigny. Searles Wood has described the present species
from the Mammalian and Red Crag. Collar d des
Cherres states that it has been found alive at Quelern
in Brittany ; and it unquestionably inhabits all the seas
of Southern Europe, as well as the coasts of Madeira
and the Canaries. Dr. Gould included it in his list ;
but Stimpson considers the Massachusetts shell to be a
distinct species, and has called it Lucina strigilla.

This is the Lucina digitaria of Poli, Cardium discors
of Montagu, Lucina undularia of Searles Wood's Cata-
logue, and L. commutata of Philippi.

A valve of a much smaller species, which is fre-
quently seen in parcels of West-Indian shells, was sent
between forty and fifty years ago by Mr. Dillwyn to
Col. Montagu for his opinion. It was marked " foreign,"

LORIPES.

23:

and returned by the latter with a note in pencil, " not
C. discoid" The specimen and memorandum are close
beside me while I am writing. I mention this because
there seems to have been some confusion as to what
species Montagu intended by his Cardium discors.
Nearly the whole of his priceless collection of British
shells, which he presented to the National Museum, has
unluckily been lost to science : and even some of the
few specimens that are still preserved were many years
ago removed from the original tablets, no care having
apparently been taken in the course of rearrangement to
retain the names affixed by the donor to his types. No
similar neglect, however, has happened of late years;
and all that can now be desired by the public to ensure
proper care being taken of our unrivalled store of scien-
tific wealth, and its being made available for the instruc-
tion and amusement of the people, are more space and
a larger staff.

Dr. Pulteney, Mr. Bryer, and Dr. Maton are reported
to have found the Venus tigerina of Linne (a species of
Loripes) on several parts of the Dorset coast. There
is no likelihood, much less satisfactory evidence, that
it is indigenous. It inhabits tropical seas.

Another species, the Venus orbiculata of Montagu,
said to have been found by Laskey at Dunbar, is also
spurious. It is the Lucina squamosa of Lamarck, and
West Indian.

I was assured by Dr. Lukis that the Tellina carnaria
of Linne had been taken alive at Guernsey ; and I have
noticed it on the Continent in collections of Mediter-
ranean shells. Most writers on British and European
conchology have given it a place in their lists ; and Mid-
dendorff asserts that it is a native of the Caspian Sea.
But although I may be over-sceptical, I must hesitate

238 lucinidjE.

before I can recognize its claim to be admitted into the
British fauna. It is so common a West-Indian shell that
the circumstance of its appearing on any of our shores
(particularly those which are much frequented) is no
proof of its inhabiting the adjacent sea. Shipwrecks,
ballast, sailors returning home from foreign voyages, or
children playing on the sands, might account for any
exotic shells being found in such places. One thing,
however, ought to be noticed with regard to the spe-
cies in question, viz. that the Tellina Balthica (or soli-
dula) was mistaken for it by some of the old writers.
After describing that species, Lister gives the following
locality, " In brevibus Lancastriensibus." Linne cites
Lister, and uses the same word " brevibus " (shallows)
coupled with " oceani ff in denoting the habitat of his
T. camaria. Gmelin tried to improve this, and says, as
to the last-named species, u Habitat copiosissima in An-
gliee sinubus et insularum oceani Americani littore."
Da Costa and Donovan followed suit, the former making
a further emendation by altering the name to " Cardium
carneosum." Whether the Tellina camaria of Linne
belongs to the present genus has not yet been satis-
factorily determined.

The Tellina pisiformis of Linne may possibly be Bri-
tish. Montagu described it as Cardium arcuatum, and
said that it had been dredged up in Falmouth Harbour
with sand for manure. I have a single valve that was
found in Cornish shell-sand. It is a well-known Medi-
terranean species ; and De Gerville records it, by the
name of C. discors, from Querqueville on the coast of
Brittany. Gmelin called it Tellina digitaria, and La-
marck Lucina digitalis. The sculpture is very different
from that oihoripes divaricatus. In that species the
stride are arched in the line of growth and thence diverge

LUCINA. 239

to each side. In the present species the striae run ob-
liquely from one side to the other, curling upwards at
each end. L. divaricatus is very convex, white with a
tinge of pale yellow, and rather glossy, while L. pisi-
formis is compressed, and has a rosy tinge and dull hue.
The markings on the latter shell are such as may be seen
on the tip of a finger, and from these the names digitaria
and digitalis have been derived. It occurs in the Red and
Coralline Crag. In consequence of the anterior mus-
cular impression being simple, Searles Wood placed this
shell provisionally in Astarte ; and Deshayes has lately
formed out of this and other allied fossil species the
genus Woodia, a just compliment to our distinguished
palaeontologist.

Genus II. LUCI'NA* Bruguiere. PL V. f. 5.

Body somewhat compressed: mantle having the margin
waved : incurrent as well as excurrent tube sessile : foot tongue-
shaped.

Shell rather inequilateral, concentrically ridged: lunule
long and well denned : ligament for the most part external :
teeth, one or two cardinals in the right, and always two in the
left valve, one of which latter is often cloven ; laterals long
and laminar : inside chalky and pit-marked.

Although this genus has been divided, it must be
borne in mind that very nearly three-fourths of a cen-
tury have elapsed since it was first instituted. The
progress of conchological discovery has been unusually
rapid during the last twenty years, owing in a great
measure to the impulse and encouragement given to the
study of the Mollusca by publications specially devoted
to it, as the ' Zeitschrift fur Malakozoologie/ f Malako-
zoologische Blatter/ and ' Journal de Conchyliologie/

* An epithet of Juno.

240 lucinice.

and not less to the continual and successful labours of
Deshayes, Dunker, PfeifFer, Hanley, Reeve, H. & A.
Adams, Morch, Fischer, and other writers on the subject.
New forms are every day being brought to light, and re-
quire the former system of classification to be modified.
The old tree has put forth a greater number of new
shoots than the branches which have been severed from
it, and it is not less vigorous for the pruning ; even the
loppings, that have been planted and carefully tended,
are flourishing, and bid fair to rival their parent stem.
Species of Lucina abound in tropical seas, and Dr. Philip
Carpenter has enumerated no less than seventeen as
inhabiting the west coast of North America. Lamarck
asserted that in certain species the teeth become obli-
terated by age and disappear, which statement has been
repeated by subsequent writers. The British species
present no such anomaly ; on the contrary, their teeth
are developed in the course of growth, and become
stronger and more conspicuous in the adult than in the
young.

1. Lucina spini'fera*, Montagu.

Venus spinifera, Mont. Test. Brit. p. 577, pi. 17. f. 1 . L. spinifera, F. & H.
ii. p. 49, pi. xxxv. f. 1.

Body clear white : foot very slender, and not swollen.

Shell obtusely triangular, with a somewhat oblique out-
line, compressed, solid and opaque, not glossy. Sculpture,
about 30 fine, plate-like concentric ridges, which are slightly
imbricated, their edges forming sharp spines on the dorsal
margin ; these ridges are more regular and equidistant in the
young than at a later stage of growth ; between them are
extremely numerous and fine, but irregular concentric striae ;
and there are here and there a few longitudinal lines which
are not visible to the naked eye : colour pale yellowish-white :
epidermis fibrous and not very thin : margins slightly incurved

* Prickly.

LUCINA. 241

on the anterior side, which joins the ventral margin at almost a
right angle, rounded in front, somewhat truncate on the poste-
rior side, and sometimes indented by a slight furrow running
nearly parallel with the margin to the ligamental area, which
is very gently curved : beaks small and pointed, not project-
ing, slightly recurved, placed so close together as to touch, and
considerably nearer to the anterior side : lunule deep, abruptly
denned by the edges of the anterior margin : corselet, or liga-
mental area, also deep and well denned : ligament very long
and straight, horncolour, sunk within the dorsal margin, but
visible outside, with the exception of a small portion on the
sides, which is overlapped by a thin layer of shell : hinge-live
representing an obtuse angle, and occupying much more than
one-third of the circumference : hinge-plate rather broad and
strong : teeth, in the right valve one triangular and pointed
cardinal, and on each side of it a ridge-like lateral which is
raised at the end ; in the left valve two cardinals, one of which
is much smaller than the other, the laterals being less distinct
than in the other valve : inside nacreous and partly iridescent,
salmoncoloured in the centre ; margin bevelled off and plain :
scars large and distinct. L. 0-85. B. 1.

Yar. minor. Shell smaller and flatter, with stronger and
more regular ridges.

Habitat : A muddy and gravelly bottom, from 8 to
90 fathoms, on nearly all our coasts, but locally distri-
buted. It is much more common in the west of Scot-
land and Ireland than it is on the southern coasts of
England. Captain Beechey dredged it in 145 fathoms
off the Mull of Galloway. The variety occurs in deep
water off Shetland ; and there is a remarkable coinci-
dence in size between it and the southern specimens.
The geographical range of L. spinifera extends from
Nordland to the iEgean and Canary Isles. It occurs in
the upper miocene tertiaries of the South of France.

Scotch and Irish specimens are far larger than those
from the south of England and the Mediterranean.
Young shells are exquisite objects, with their snow-
white complexion, occasionally suffused with a pale

M

242 LUCINID^.

orange tint, and their delicate flounces almost equalling
the ornamentation of the once-prized Venus Dione. The
fry are quite smooth and glossy.

This constituted the type of Turton's genus Myrtea,
and of Leach's genus Cyrachcea. It is the Venus hia-
telloides of Delle Chiaje; and Philippi at first adopted
that specific name, not being aware that the species had
been long previously described by Montagu. Macgilli-
vray considered it to be only the young of L. borealis ;
but it may be readily distinguished from that shell by
its shape, which is triangular instead of circular, by its
beaks being much less prominent, and by the row of sharp
spines on the dorsal margin.

2. L. borea'lis *, Linne.

Venus borealis, Linn. Syst. Nat. p. 1134. L. borealis, F. & H. ii. p. 46,
pi. xxxv. f. 5, and (animal) pi. M. f. 6.

Body clear white : mantle open from the anterior adductor
to near the posterior muscle, where it is contracted and nearly
closed : labial palps one on each side of the mouth, short, coarse,
thick, nearly cylindrical, and striated : foot placed in the middle
of the ventral area, very narrow, and lancet-shaped at the ex-
tremity.

Shell roundish, more or less tumid, solid and opaque, of a
dull chalky hue : sculpture, numerous concentric ridges or
ribs, which are not much raised although tolerably sharp ; they
become closer, irregular, and even confluent towards the front
margin in adult specimens, and are somewhat laminar towards
the posterior margin ; the only other markings appear to be a
few slight and minute concentric fines between the ridges :
colour white : epidermis rather thick, fibrous, puckered, and
fight yellowish-brown : margins obliquely truncate on the an-
terior side, and forming nearly a right angle with the dorsal
margin in consequence of the line from the beaks along the
lunule being almost straight, rounded in front, with a slight
tendency to obliquity, and somewhat truncate on the poste-

* Northern.

LIJCINA. 243

rior side, which is indented by an indistinct furrow running
nearly parallel with the ligamental area : beaks very small and
pointed, rather prominent, much recurved, almost contiguous,
considerably nearer to the anterior side : lunule deep and ex-
cavated : corselet level : ligament very long and straight, yel-
lowish-brown, seniicylindrical, slightly projecting outside ; its
sides are covered by a shelly strip, which is usually found
broken in small pieces by the action of closing the valves :
hinge-line curved, occupying not quite one-third of the circum-
ference : hinge-plate broad and thick : teeth, in the right valve
two strong cardinals, the anterior one being double, and the
posterior much smaller and set more obliquely, and on each
side of the beak a plate-like lateral, the anterior one being
slightly raised at the end, and the posterior much longer than
the other ; in the left valve two similar cardinals, but nearly
of equal height, and corresponding laterals : inside chalky-
white, but in places irregularly tubercular from an internal
deposit of nacre : margins bevelled off and plain, sometimes
grooved longitudinally : sears remarkably large and distinct.
L. 1-4. B. 1-5.

Yar. 1. depressa. Shell natter and thinner, with fewer ribs
and the beaks less prominent.

Yar. 2. gibba. Shell much smaller, with a more oblique
outline, the valves protuberant, ribs closer together, epider-
mis iridescent, and the beaks more prominent. L. 0-45.
B.05.

Habitat : On all our coasts, in muddy gravel and sand,
from the low- water mark of spring tides to 82 fathoms.
Captain Beechey has dredged it off the Mull of Gallo-
way in 110-145 fathoms. The late Wm. Thompson and
II . Ball found it in lakes of brackish water at Arran.
Dr. Lukis informed me that this species was compara-
tively rare in the Channel Isles, and that the numerical
proportion which it bore there to Loripes lacteus was as
1 to 50. He added, " Lucina borealis was wrongly stated
by Forbes and Hanley (vol. ii. p. 48) to occur ' abun-
dantly near St. Peter's Port in Guernsey/ We do not
meet with it excepting at Herm. I have never found a
single specimen on the Guernsey coast, although I have

m 2

244 lucinidjE.

digged much in nearly every bay." He suspected that
Loripes lacteus (single valves of which are exceedingly
plentiful near St. Peter's Port, Guernsey) must have been
mistaken for the present species. Var. 1. Many places,
in deep water. Var. 2. In shallow water, Guernsey and
Scalloway (J. G. J.) ; Bantry Bay (Norman). This
species occurs in the tertiary beds of the Clyde (Geikie),
Belfast (Hyndman and Grainger), Sussex ( Godwin -
Austen), and the Mammalian, Red, and Coralline Crag
(S.Wood). Abroad it ranges from Iceland (Steenstrup)
to Messina (Sars). Brocchi and Philippi enumerate it
as an Italian fossil. I have found it in the upper mio-
cene tertiaries of the South of France, as well as in the
Uddevalla and Christiania beds. Gould describes it as
a Massachusetts shell, and Stimpson from the Boston
coast ; but the latter now denies that it is our species,
and distinguishes it by the greater size, by the ribs
being more distant and regular, and by the colour, which
Gould says is white : Stimpson has therefore named it
filosa. However, if the claim to distinction rests only on
these comparative characters, I do not see any reason
for separating the Atlantic and Transatlantic species.

Montagu states that this shell is "particularly abun-
dant at Falmouth, amongst the sand dredged from the
harbour for the purpose of manure; by which means
it is common in the arable fields about that place." I
hope geologists may not be misled, and consider it
fossil, if they find it in such situations. They need as
much caution as antiquaries in the exercise of their
pursuit, although they are not so liable to be wilfully
deceived. It may be worth while to fabricate coins,
flint knives, and similar relics of historic and prehistoric
times ; but fossil shells have no such marketable value,
they are not so easily forged or imitated, nor would even

AxiNtrs. 245

Palissy's workmanship impose on a palaeontologist of any
experience. The shell of L. borealis has a considerable
tendency to vary in respect of the remoteness or proximity
of the striae. In some Guernsey specimens the ribs
nearly disappear towards the front. A specimen from
Exmouth has a minute pearl lodged between the pallial
impression and the inner margin. The young are ob-
liquely triangular, and marked with a few irregular
white streaks which radiate from the beaks. The frv are
almost globular, perfectly smooth, and glossy. Speci-
mens of an extraordinary size are got at Tenby. My son
picked up a single valve on the sands there, measuring
two inches in breadth and nearly as much in length.

Petiver first noticed this species as British, and called
it the " thread- girdled white Cockle." Donovan recog-
nized it as the Venus borealis of Linne. It is also the
V. spuria of Gmelin (from the figures of Lister and
Chemnitz), Tellina radula of Montagu, and Venus cir-
cinnata of Brocchi. The type of Turton's Lucina alba
is composed of two odd and much-worn valves of
L. borealis. The L. lactea and L. leucoma of Macgilli-
vray also belong to the present species.

Genus III. AXI'NUS * J. Sowerby. PL V. f. 6.

Body convex : mantle having the margin thickened, with-
out tubes : gills two on each side, an outer and inner pair :
foot nearly cylindrical and very slender.

Shell globular, with somewhat of a triangular outline,
smooth ; posterior side longitudinally furrowed, or angulated :
heaks much recurved : lunule short and sometimes indistinct :
ligament usually and to a certain extent external, placed in a
groove or excavation on the hinge-line, and outside the hinge-
plate : teeth altogether wanting.

* Hati-het-shaped.

246 LUCINID.E.

If Lucina has been properly made the type of a sepa-
rate family, and is no longer to be regarded as a genus
containing many sections or subgenera, the validity of
the present genus can hardly be questioned. A com-
parison of the characters above given with those of
Lucina, as now sought to be restricted, will, I think,
suffice to convince most conchologists that Axinus is a
good genus. Those who are of opinion that the family
has no substantial or natural basis are of course at
liberty to adopt the old genus Lucina in its original in-
tegrity. I do not propose any new genus. Axinus has
already attained the respectable age of forty years. It
is at present in some danger of being set aside as obso-
lete or unfashionable ; but

Multa renascentur quae jam cedidere, cadentque
Quae nunc sunt in honore vocabula, si volet usus,
Queni penes arbitrium est et jus et norma loquendi.

These mollusks are of small size, and dwellers in mud
and sand at various depths of water. The species are
by no means numerous. Three of them are British and
European, and another is Cuban. Mr. Searles Wood
says, " Species strictly belonging to this genus have not
been described from any formation of an older date
than the tertiaries : the shell called Axinus obscurus,
from the Magnesian limestone, belongs to a different
group, and has already been made a genus of by Pro-
fessor King, under the name of Schizodus." The shell
of Axinus has no tooth. What has been taken for such
is merely the point of the hinge-plate, near the beak,
which becomes thickened, and even projects a little, in
full-grown specimens. This process is unlike the tooth
of any bivalve. The connexion of the valves depends
wholly on the ligament, and is therefore slight. Sowerby,
in proposing the present genus, instanced A. anyulatus

axinus. 247

of the London Clay as the type. This exhibits all the
essential generic characters, except in respect of the
hinge, which is not visible in consequence of the matrix
in which the shell is imbedded being too hard and com-
pact to be removed. It is remarkable, however, that
Sowerby added to his description of Axinus, " I suspect
it has no teeth."

Several names for this genus have been attributed to
Leach, viz. Thyasira, Thiatira, Thiatisa, and Bequania.
The first only is classically correct. Turton called it
Cryptodon, Philippi Pty china, and I gave another generic
name (Clausina) to one of the species. All these are
mere synonyms and superfluous.

I would recommend those of my readers who are
acquainted with the Danish language to read a very
interesting account by Professor Sars of the animal of
A. Sarsii, contained in his Report of a zoological ex-
cursion to the Loffoden Isles and Fimnark in 1849.
He observes that Axinus differs from all other Con-
chifera in the position of its generative organs, which
lie outside the stomach, and not within it ; and he com-
pares this genus to the Brachiopoda in that respect.
He found by a microscopical examination that some
individuals were male and others female.

1. Axinus flexuo'sus *, Montagu.

Tellina flexuosa, Mont. Test. Brit. p. 72. Lucina flexuosa, F. & H. ii. p. 54,
pi. xxxv. f. 4.

Body clear white : mantle somewhat contracted on the pos-
terior side, so as to form a round hole : gills thick, of a red-
brown colour : foot placed in the middle of the ventral area.

Shell roundish-oval, tumid, thin, usually opaque but some-
times more or less transparent, scarcely glossy : sculpture, irre-

* Flexuous.

248 LUCINID^.

gular lines of growth and microscopical frost-like markings :
colour white : epidermis filmy and inconspicuous : margins ob-
liquely truncate on the anterior side, and forming nearly a
right angle with the dorsal margin, which is almost straight or
slightly incurved, rounded in front, and flexuous on the pos-
terior side, which is deeply indented by a wide furrow or
groove running from the beaks at an angle of about 30 degrees
and gradually enlarging outwards, as well as by another smaller
and parallel furrow close to the ligamental area : beaks small
and pointed, but not prominent, much recurved, almost con-
tiguous, a little nearer to the anterior side : lumde rather deep
and heartshaped : corselet prominent, well defined by the upper
furrow, and forming two sharp and pouting lips : ligament
rather long, yellowish-brown or light horncolour, not pro-
jecting beyond the lips of the corselet, but distinctly visible
outside ; ligamental groove narrow and shallow : hinge-line
obtusely angular, occupying not one-fourth of the circumfe-
rence : hinge-plate rather broad and thick, nearly flat, almost
all of it lying on the posterior side ; immediately below the
beaks it is indented in the right valve and slightly reflected in
the left, which gives that valve the appearance of having an
indistinct or obscure cardinal tooth : inside highly glossy and
iridescent, sometimes slightly striated lengthwise ; margin thin
and plain: pallial scar broken in a zigzag line, in conse-
quence probably of a corresponding structure in the edge of
the mantle: muscular scars large. L. 0375. B. 0*35.

Var. polygons,. Rather longer in proportion to the breadth,
marked by three or four longitudinal ridges, giving the shell
an angular form, the grooves on the posterior side being much
deeper than usual.

Monstr. Having a longitudinal groove down the middle,
which is longer and deeper in the left valve than in the right.

Habitat : Gregarious in soft mud and sand on all
the British coasts, from Shetland to the Channel Isles,
in 3-87 fathoms. The variety is from the deepest water
on the " outer haf/' about forty miles east of the
Whalsey Skerries, and the monstrosity from Falmouth
and Tenby. This species is rather plentiful in the
" alluvial" deposits at Belfast (Hyndman and Grainger);
Clyde beds (Smith); Coralline Crag, Sutton (S. Wood).

axinus. 249

It is widely distributed through the North Atlantic
from Spitzbergen (Torell) to the Canary Isles (M'An-
drew), and likewise through the Mediterranean and
JEgean. The greatest bathymetrical limit recorded is
that by Danielssen, viz. 180 fathoms, at Vadso in Fin-
mark. "Postglacial" beds in the Christiania diocese
(Sars). Gould has described it as a Massachusetts
shell ; but in a review of his work by Philippi, in the
' Zeitschrift ' for 1846, the North- American species is
stated to differ in several respects from ours, and the
name Lucina Gouldii was therefore given to it. Morch
refers the Greenland shell to this last species, and says
it is the Tyatira hyalina of Beck. I confess that I have
not been able to make out anything more than a varietal
difference between the Greenland specimens and those
of A. flexnosus from our own seas.

Young shells are globular, and the principal fold on
the posterior side is visible in every stage of growth.
The liver is of a beautiful purple colour. The attach-
ment of the ligament to the hinge is slight, which
accounts for single valves being so frequently thrown
up on the shore, or taken by the dredge in sandy bays.
Lamarck described this species in his ( Histoire na-
turelle des Animaux sans Vertebres/ both as Amphi-
desma fleoniosa and Lucina sinuata. It is the Crypt odon
bisinuatum of S. Wood's Catalogue, and the Pty china
biplicata (afterwards changed to Axinus sinuatus) of
Philippi. The Venus sinuosa of Pennant and Donovan
(thus characterized, "Thin, convex, a deep obtuse sinus
or bending in the front") appears to be Thracia distorta,
which is often contracted in this way ; and Donovan's
figure confirms that idea. S. Wood, however, considered
it identical with the present species. The A. Sarsii of
Philippi, described by Loven in his admirable ' Index

m 5

250 LVQimi)m>

Molluscorum litora Scandinavian occidentalia habitan-
tium/ is not uncommon on the coasts of Norway and
Sweden; but it has not been found in our seas. I
venture to regard it as a large variety of A. flexuosus.
Some remarks will be found on the subject when I come
to treat of the next species.

2. A. Croulinensis $, Jeffreys.

Clattsina Crov.linensis, Jeffr. in Ann. Nat. Hist. vol. xx. p. 19; ser. 3. ii.
p. 122, pi. v. f. 2, a-c (young).

Shell obliquely oval, tumid, of a moderate thickness,
opaque except in the young state, rather glossy : sculpture,
numerous and fine but irregular concentric strise : colour white :
epidermis slight : margins rounded on the anterior side, as
well as in front, and slightly angular on the posterior side,
which is indented by a double but short furrow : beaks small
and prominent, much more recurved than in the last species,
almost . contiguous and central : lunule indistinct : corselet
narrow but well defined by the upper furrow : ligament slight,
not visible outside ; ligamental groove sloping inwards : liinge-
l',ie obtusely curved, occupying not one-fifth of the circum-
ference : hinge-plate rather narrow but thick, almost all of
it lying on the posterior side ; the tooth-like folds are as in

A. flexuosus, but very much stronger and more conspicuous :
inside highly glossy, iridescent, and smooth ; margin thin and
plain: pallial scar indistinct : muscular scars oval. L. 0*15.

B. 0-135.

Habitat : Skye and Shetland, in muddy sand, from
45 to 85 fathoms ; rare.

This shell, compared with specimens of A. flexuosus
of a similar size and age, is longer and more oblique, as
well as proportionally more solid ; the margin of the
anterior side is curved, instead of being nearly straight
and truncate; the furrows on the posterior side are
scarcelv visible when viewed in front : the beaks are

* From its having been first found near Croulin Island, in the He-
brides.

AXIXUS. 251

much more recurved; and the tooth-like folds are
stronger and more prominent. I at one time thought
it might be the young of A. Sarsii ; but having been
favoured bv mv kind friends in the North with a series
of specimens from several localities, I am enabled to
express a positive conviction that my shells are not the
young of that species or variety. The shell of A. Sarsii
in all states of growth is even more globular than A.
flexuosus, the furrows are equally strong (except in
large specimens, when they are less conspicuous), and
the tooth-like folds are wanting or indistinct. A. Sarsii
is usually found in deeper water than A. flexuosus, and
I am not aware that both forms have ever been taken
together. Asbjornsen gives different localities for each
on the coast of Norway ; and Malm informs me that
on the Swedish coast he always finds A. flexuosus on
softer ground and in shallower water than the other.
A. Sarsii attains a much larger size ; and Lilljeborg
showed me a comparatively gigantic specimen, which
was upwards of an inch long. It occurs in the Udde-
valla beds. The authors of the ' British Mollusca ' in-
advertently placed A. Croulinensis with A.ferruginosus.
The outline of each will be sufficient to distinguish
them, independently of other characters. The shell of
the former is obliquely oval, and that of the latter
almost globular.

3. A. ferrugixo'sus*, Forbes.

Kellia ferruginosa, Forbes, iEgean Invert., Brit. Assoc. Rep. 1843, p. 192.
Lucina ferruginosa, F. & H. ii. p. 60, pi. xxxiv. f. 1 .

Shell nearly globular, but more tumid towards the beaks,
covered with a thick ferruginous crust or coating like the rust
of old iron, beneath which it is thin, opaque, and rather glossy :

* Covered with iron-rust.

252 LUCINID/E.

soalpture, irregular lines of growth and intermediate micro-
scopical striae: colour reddish-brown outside, and milk-white
inside the crust: epidermis thin and obscured by the outer
covering : margins rounded on the anterior side and in front,
obliquely truncate or sloping on the posterior side, which is
slightly nexuous and marked by a broad but shallow furrow
radiating from the beak, as in the last species : beaks small
and tubercular, rather prominent, much recurved, not so close
together as in A. flexuosus, and nearer to the anterior side:
lunule imperfectly defined : corselet indistinct : ligament short,
reddish-brown, sunk within the lips of the corselet and hardly
visible outside ; ligamental groove very slight and narrow :
hinge-line obtusely angular, deeply excavated in the centre
on the posterior side of the beak, and occupying about one-
third of the circumference : hinge-plate narrow and sharp,
reflected and projecting below the beak on the anterior side, so
that the edge appears like a blunt cardinal tooth ; by far the
greater part of the hinge-plate lies on the posterior side : inside
rather glossy ; margin plain : pallial scar slight, entire : mus-
cular scars conspicuous and round. L. 0'125. B. 0*125.

Habitat : Muddy ground and sand in 30-50 fathoms,
Sound of Skye; 20-100 fathoms, Loch Fyne ; and 70-
80 fathoms, off the west coast of Shetland. Close to
Crouiin Island, in the first of these localities, it is
remarkably plentiful. Captain Hoskyn has lately taken
specimens off the west coast of Ireland at a depth of
210 fathoms. Glacial beds, Aberdeenshire (Jamieson);
Coralline Crag, Sutton (S.Wood). Torell has dredged it
in 250 fathoms off the coast of Greenland ; Loven and
other writers have mentioned it in their lists as Scan-
dinavian, from Finmark to Bohuslan ; and Forbes first
described it, as inhabiting the ^Egean at a depth of 119
fathoms.

The young are oval and transparent. Some speci-
mens of a larger size than usual have a snout-like
process which projects from the angle of the posterior
side, and is caused by an excessive accumulation of the
ferruginous crust in that part. This induces me to

DIPLODOXTA. 253

think that the coating arises from a deposit of faecal
matter in still and deep water, and not from any pecu-
liar secretion of the animal, or from a mineral or che-
mical deposit.

It is the Cryptodon rotundatiim of Searles Wood's
' Catalogue of the Crag Mollusca/ Judging from an
examination of a single valve so named by Forbes, his
Kellia abyssicola from the iEgean appears to be only
the decorticated state of the present species.

Genus IV. DIPLODON'TA *, Brown. PI. V. f. 7.

Body nearly globular, but compressed : mantle thick, having
a plain margin : tubes none : gills two on each side : labial
palps the same : foot lancet-shaped.

Shell squarish, convex, and smooth: beaks not much re-
curved: h.mule inconspicuous : ligament quite external : teeth,
two cardinals in each valve, the anterior of which in the right
valve is simple, and the other bifid or cloven, the contrary being
the case in the left valve ; laterals laminar and indistinct.

The peculiarity of this genus consists in there being
two separate gills and as many labial palps on each side,
instead of a single gill and palp as in all the other genera
of the same family, and also of the ligament being alto-
gether external, and the cardinal teeth more numerous
and symmetrical. In adult specimens the anterior
muscular impression is elongated, like that of Lucina.

The Diplodonta inhabit every part of the marine
world ; and many fossil species have been described.
Torell has lately dredged at Spitzbergen a new species,
which is nearly allied to the only one we have in the
British seas.

It is the genus Mysia of Leach, and (according to
AYoodward) Spharella of Conrad.

* Double-tooth.

254 LUCINID.E.

Diplodonta rotunda'ta*, Montagu.

Tellina rotundata, Mont. Test. Brit. p. 71, tab. 2. f. 3. D. rotundata,
F. & H. ii. p. 66, pi. xxxv. f. 6, and (animal) pi. M. f. 7.

Body clear white : gills laminar, somewhat elongated and
angular, folded or puckered at the edges, pectinated, and fixed
as usual to the dorsal range, the upper plate being little more
than half the depth of the lower one : palps short, pointed,
pectinated, and somewhat triangular : orifice at the posterior
end very small and inconspicuous : foot central, rather long,
and conical, minutely perforated at the point.

Shell obliquely quadrilateral, gibbous, not very thin, opaque,
moderately glossy: sculpture, strongly marked and irregular
lines of growth, and (under the microscope) exceedingly fine
and close-set, regular longitudinal lines on the umbonal area,
which radiate from the beak and are only perceptible in fresh
specimens, as well as equally fine and numerous, but irre-
gular and often wavy or confluent, transverse lines on the
rest of the surface : colour milk-white : epidermis fibrous and
yellowish, usually rubbed off except in front : margins obtusely
angular on the anterior side, where the slope to the beak and
front is nearly equal, obliquely rounded in front, somewhat
produced and very much broader on the posterior side, which
is also rounded at the end, and straight behind : beaks small,
scarcely projecting beyond the dorsal line, and not contiguous :
lunule very small, but deep, not well defined, and hidden by the
beaks : ligament short, semicylindrical, yellowish-brown or of
a golden hue, projecting beyond the dorsal margin ; ligamental
groove rather deeply cut : hinge-line slightly curved, occupy-
ing nearly one-third of the circumference : hinge-plate broad
in the middle and tapering gradually to each end ; the pos-
terior side is the longer: teeth, in the right valve two erect
cardinals, the posterior of which is double and placed more
obliquely than the other, as well as a plate-like lateral on each
side, the anterior of which is distinct ; in the left valve the
same number and kind of cardinals and laterals, but the posi-
tion of the former is reversed : inside marked by slight longi-
tudinal lines, frost-like in the centre and at the back, but
glossy towards the margin, which is plain : pallial scar distinct,
broad, and entire : muscular scars large and well marked, the
anterior one irregularly elliptical, and the posterior oval.
L. 0-9. B. 1.

* Rounded.

DIPLODONTA. 255

Habitat : Not uncommon on the southern coasts of
England and in the Channel Isles, and also in the
south and west of Ireland, in 12-20 fathoms, sandy
mud. Being elsewhere local, I may mention that it has
been taken by Forbes and M 'Andrew in 7-25 fathoms
off Lundy Island, by Lyons at Tenby, by myself in 20
fathoms at Fishguard, and by M' Andrew in 12 fathoms
off Anglesea. Sir W. C. Trevelyan and the Rev. G. C.
Abbes are reported to have found it at Seaton and
Whitburn; but Alder suspects these specimens were
<c derived from ballast." Possibly Lucinopsis unclata
may have been mistaken for it. The present species is
a Coralline Crag fossil. Its foreign distribution is alto-
gether southern, viz. Vannes (Mittre) ; Nice (Risso) ;
Sicily (Philippi) ; iEgean (Forbes) ; Madeira and the
Canary Isles (M f Andrew).

I have a distorted specimen, which is so much con-
tracted in the middle as to look like a kidnev bean.
Occasionally the anterior side is much shorter than
usual, making the shell decidedly inequilateral. Young-
shells are flatter ; and the fry are triangular also, and
in fact so different in shape that I described and figured
it in the ' Annals of Natural History' for January 1858
as a distinct species under the name of Diodonta Bar-
leei. The portly and protuberant form of the adult,
compared with the slim figure of the young, reminds
one of

" the Justice

In fair round belly with good capon lined."

Good living will doubtless tell upon the Diplodonta, as
well as upon his Worship.

This species is the D. dilated a of Philippi and Gloco-
mene Montaguana of Leach.

256 CARBIT1D.E.

Family X. CARDITDXE, Gray.

Body oblong or roundish -oval : mantle thin, open in front,
and folded behind into a short excretal tube : foot tongue-
shaped and extensile, byssiferous.

Shell shaped like the animal, equivalve, inequilateral :
ligament external: hinge strong, furnished with one or two
cardinal teeth, which are set more or less obliquely, and with
a laminar posterior lateral tooth in each valve : pallial scar in
nearly every case entire : muscular scars large, round, and
deep.

I give this family provisionally as British, not know-
ing where else to place the abnormal genus Cyamiwn,
as well as a species of Cypricardia, which at present I
am not sure is indigenous. The present members of this
family are dispersed over the ocean, but chiefly confined
to the southern zone : their ancestors flourished in the
northern hemisphere, and multiplied exceedingly during
the tertiary epoch.

With respect to the shape of the pallial scar, being
the impression produced by the adhesion of the mantle
to the inside of the shell near the front margin, I think
an undue importance has been attached to this cha-
racter. When it is sinuous or indented, it certainly
shows that the animal has two distinct tubes springing
from a common sheath, at the posterior side ; but when
it is simple, or even flexuous, we cannot learn from it
whether there are two such tubes, or only one, nor
what their length may be, nor even whether there is
any tube at all. Cardium and Venus have each a double
tube on the posterior side ; but the pallial scar in the
former is simple or entire, and in the latter sinuous.

CYAMIUM. 257

Genus CYA'MIUM *< Philippi. PI. V. f. 8.

Body somewhat compressed : ecccurrent tube scarcely pro-
jecting beyond the posterior side of the shell : gills large : foot
slender.

Shell oblong, very inequilateral : teeth, in the right valve
one strong and large double cardinal (appearing like two single
teeth in immature specimens), and in the left valve two cardi-
nals ; each valve has an indistinct lateral tooth on the poste-
rior side.

The type of this genus is a small shell from the Falk-
land Isles, which Philippi described in 1845 as Cyamium
antarcticum. This is the only species known, unless
the British shell which I am about to mention belongs
to the same genus. The ligament in both species is
external. Loven adopted Philippics genus for our shell,
which has a wide European range ; but he did so with
some doubt, because it was supposed that the ligament
in Cyamium was internal. Forbes and Hanley seem
also to have entertained the latter idea : and thev con-
sequently proposed a new genus, Turtonia, for the re-
ception of the northern species. Messrs. H. and A.
Adams, in their most useful and elaborate work, ' The
Genera of recent Mollusca/ at first united Turtonia with
Cyamium ; but in the appendix they expressed a different
opinion, and separated them, on the ground that " the
shell of the former is closed at both ends, the ligament
is more exposed than in Cyamium, and it is also pro-
vided with slightly prominent elongated lateral teeth
which are absent in Cyamium" Having several times
examined minutely a series of specimens of C. antarcti-
cum in the British and Stockholm Museums, I have
arrived at a different conclusion; and, after carefully
weighing the reasons stated by the able systematists

* A little bean.

258 CARDITIDyE.

above-named, I feel satisfied that the two species from
the extremities of the Atlantic Ocean ought to be in-
cluded in the same genus. Perfect specimens of C. ant-
arcticum are closed at both ends ; and the ligament is as
much exposed, and the lateral teeth are as fully deve-
loped, in that species as in the other.

There is, however, a much greater difficulty as to the
position and relations of this anomalous genus, in con-
sequence of the following description of Turtonia in the
'British Mollusca' (vol. ii. p. 80) : "Animal with the
mantle widely open anteriorly, a single very slender
siphonal tube at the shorter end, and an ample and
strong foot angulated at its posterior base proceeding
from the longer." The authors also state in the descrip-
tion of the species, t( all we know of the animal is con-
tained in the generic character, due to the observations
of Mr. Alder." The representation of the animal, given
in pi. O. f. 1. of that work, corresponds with the above
description. In the ( Supplementary Notes on the
Acephala' (vol. ii. p. 375), and in the description of the
plates (vol. i. p. 480), a material error is noticed as to
the engraving, viz. in the ic siphon projecting from the
short, instead of the long, end of the shell." The de-
scription remains uncorrected. Mr. J. de C. Sowerby
assured me that he accurately made the engraving from
a sketch furnished by the late Professor Forbes, whose
name as the draughtsman appears on the plate. I
thereupon wrote to Mr. Alder for further information ;
and in reply he says, " I am quite certain of Turtonia
minuta (the species in question) having a small slender
siphonal tube, which is occasionally exserted, but at the
longer end. I have hunted out my sketches of the
animal, which after some search I have found in an old
memorandum-book of 1838, and herewith send you a

CYAMIUM. 259

tracing of them. You will see that in two of the figures
the tube is exserted : but the animal is rather shy in
extending it, and it can only be seen by watching the
opportunity. It is probably the anal siphon, as is sup-
posed to be the case in Lucina [Loripes], — the branchial
siphon being either very short or only formed by a fold
in the open mantle, as in some other genera." I have
myself failed to detect any slender tube such as Mr.
Alder has described, although during the last two years
I have examined a great number of living and active
individuals on the spot and under extremely favourable
circumstances. Subjoined is the result of my observa-
tions, which were noted at the time of their being made,
with respect to the shape and position of the tube and
foot. The excretal or anal tube is small, button- shaped,
and almost sessile. It is situate on the upper part of
the posterior or broader side of the shell. This process
is formed out of a fold or contraction of the mantle, and
slightly separated by a raised edge from the long ventral
opening. It is occasionally protruded, but never to a
greater extent than the one-hundredth part of an inch.
When t