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CONCHOLOGIST'’S TEXT-BOOK./

EMBRACING THE ARRANGEMENTS OF |

LAMARCK AND LINNAUS,

WITH A GLOSSARY OF TECHNICAL TERMS. |

TO WHICH IS ADDED

A BRIEF ACCOUNT OF THE MOLLUSCA.

Ninth ditton.

CORRECTED AND ENLARGED

BY WILLIAM MACGILLIVRAY, ESQ.,

PROFESSOR OF NATURAL HISTORY IN MARISCHAL COLLEGE, ABERDEEN.

ILLUSTRATED BY ENGRAVINGS Bevo: al!
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FULLARTON, MACNAB & 00., NEW YORK.

EDINBURGH:
FULLARTON AND MACNAB, PKINTERS, LEMPEH WALK

PUBLISHERS’ ADVERTISEMENT TO THE
SIXTH EDITION. / & 45"

Tue ConcHotoaist’s Text-Book, of which a revised and
improved edition is now offered to the Public, has been
so favourably received as to have passed through five
editions since its first appearance in 1833. In the
present edition—the Sixth—several alterations have
been made on the translations of Lamarck’s generic
and specific characters; the descriptive portion has
been revised, and a chapter on the Mollusca, with two
illustrative plates, has been added from the ‘ Klemens
de Zoologie’ of M. Milne Edwards. For these, and
any other alterations on, or additions to, the text of
preceding editions, the editor of the present edition,

Professor MaceiLiivray, is alone responsible.

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PREFACK.

Tuer study of Conchology has, by many, been considered
as trifling, and tending to no useful purpose; but such
an opinion could emanate only from persons ignorant
of its great importance in a geological point of view:
fossil shells, coral, and wood, with other organic re-
mains, being the only true remaining MeEpats oF
Creation—as Bergman elegantly expresses himself.
These often retain the exact figure of their primitive
state. By their aid, therefore, we are enabled to
identify strata, both of the older and more recent
formations, that may present themselves to view in
different parts of the globe. Few of these fossil species
now exist in a living state, most of them having per-
ished in the wreck of the former world. “ By these
medals,” says Parkinson, “we are taught, that in-
numerable beings have lived, of which not one of the
same kind does any longer exist; that immense beds,
composed of the spoils of these animals, extending for

many miles under ground, are met with in many parts

Vill ' PREFACE,

of the globe; that enormous chains of mountains,
which seem to load the surface of the earth, are vast
monuments in which these remains of former ages are
entombed ; that, though lying thus crushed together,
in a rude and confused mass, they are hourly suffering
those changes, by which, after thousands of years, they
become the chief constituent parts of gems,—the lime-
stone which forms the humble cottage of the peasant,
—or the marble which adorns the splendid palace of
the prince.” From the connected examination of fos-
sils, and of the strata which contain them, much
valuable information may be expected to be obtained
respecting situations in which useful substances may
be found.

To trace the structure, and investigate the uses, of
animals which inhabit shells, is not the least amusing
and instructive part of the study of Conchology. As
the Almighty has formed nothing in vain, these crea-
tures, so low in the scale of being, must have particular
uses allotted them in the plan of creation.

Conchology has ever been a favourite pursuit, from
the beauty and elegant structure of shells, and the
ease with which they can be preserved.

The method of Lamarck, the father of modern Con-
chology, is the basis of the following pages; only that,
instead of describing the lowest or least organized beings

first, as he has done, we have pursued the descending

fifo .

PREFACE. 1x

scale, and enlarged his system by the additional genera
of other Testaceologists. The arrangement of Lamarck
is strictly preserved in the orders and families, and the
new genera have been placed as nearly as possible in
the situations which they would naturally occupy in
his system.

The Linnean arrangement was long followed as the
best, and is still adopted by many naturalists. Since
his time, however, the immense accumulation of new
species, with characters which are likewise new, ren-
ders the task of classifying them according to his
method, extremely difficult, if not impracticable. We
have, nevertheless, given his arrangement, as well as
that of the modern school, leaving it to the decision of
the student which he will adopt.

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CONTENTS.

ADVERTISEMENT, ; - 5 E . °
Preface, . F : - ° : ° °
Introduction,

Explanation of the Basis of Shells,
Multivalve Shells,
Bivalve Shells, :
Description of Plate [V.—Hinges of the Lineean
Genera of Bivalves, . ‘
Univalve Shells, ; ° P ;
Of the Linnzan Genera, . ‘ E A
Order I.—Multivalve Shells,
IJ.—Bivalve Shells,
I1I.—Univalve Shells, :
Table of the Linnzan Genera of Shells, with Madices s
Divisions, : : d
Lamarck’s Genera of Shells, : ‘ ; : 4

Cuiass First.—Testaceous Mouuusca,
Order I.—Heteropoda,
I1.—Cephalopoda,
IiI.—Trachelipoda,
1V.—Gasteropoda,
V.—Pteropoda,

Crass SEcOND.—CONCHIFERA,
Order I.—Monomyaria, é °
1I.—Dimyaria, ‘ :

xll CONTENTS.
Page
| Cuass THirp.—CrmRIPEDA, . : <A as 167
Order I.—Pedunculata, : : . . 0 eS
| IT.—Sessilia, } : : : zO. |
Mt Division (E.— Ariewlates: 80d io ae eae
| Cuass Firra.—ANNULOsA, : . : ‘ 173
| Order I.—Sedentaria, . ; ‘ : ee Vie ok
| 1I.—Antennata,. s : é 180
| WT Aragiis oes ek ea a ee
| On the Structure of the Mollusca, ; 4 ; 181
|| Cxuass 1.—CEPHALOPODA, . : ; : 2° 187
Crass IJ.—PrEeropopa, . 4 : 5 . 189 |
|| Crass III].—GasTERoPoDA, ‘ 5 ai) 400) |
| Order I.—Gasteropoda Pilmotets, : 191 |

II.—Gasteropoda Pectinibranchiata, . 193
11I.—Gasteropoda Tubulibranchiata, 196
{| 1V.—Gasteropoda Scutibranchiata, . 196
V.—Gasteropoda Cyclobranchiata, 197
VI.—Gasteropoda Inferobranchiata, . 197
VII.—Gasteropoda Tectibranchiata, 198
VIII.—Gasteropoda Nudibranchiata, 199

1X.—Gasteropoda Heteropoda, Meer ty ts 2)

|| X.—Gasteropoda Cirrobranchiata, . 199

Criass I1V.—AcEPHALA, or LAMELLIBRANCHIATA, 200

Cuiass V.—BRACHIOPODA, . e : : ~ . 203

Cxiass VI.—TunicaTa, . : ¢ ; : 204

| Explanation of the Figures, . 206
Directions for ee Cleaning oe Airanpia

Shells, : : ‘i 28

Glossary of Terms HS in Gintiningy : ‘ 221

ludex to the Classes, Orders, and Genera, : ae)

aa

THE

CONCHOLOGIST’S TEXT-BOOK.

INTRODUCTION.

ConcHoLocy, TrsTAacrEoLocy, or MaLacoxoey, is that
department of Natural History which treats of animals with
a testaceous covering or shell.

The richness and variety of colours, the fine polish, the
beauty and elegance of form, exhibited by shells, have always
excited admiration, and procured for them a conspicuous
place in the cabinet of the curious collector. But what-
ever interest the pursuit of this branch of knowledge may
have excited, in this point of view, and however highly rare
and beautiful shells have been prized, this is the least impor-
tant feature of their history. Other and more rational con-
siderations render the study of Conchology an agreeable
pursuit. The animals of many kinds of testaceous shells
furnish an excellent and nutritious food. Some tribes sup-
ply the table with a delicate luxury. Other shells, as those
of mother-of-pearl, afford materials for ingenuity and art, in
preparing it for various purposes: and the pearl itself, often
the rival of the most precious gems in the estimation of
mankind, is the production of several species of testaceous
animals. Its nature and mode of formation, therefore, can-
not fail to be objects of curious investigation. Even the
pernicious effects of some species of this tribe of animals,
demand the attention of man, in studying their nature,
tracing their history, and in providing a remedy against their

poisonous properties. The Snail ravages the garden and
: B

14 INTRODUCTION.

the field, and marks its progress by the destruction of some
of the fairest forms and most useful products of the vege-
table kingdom; and the Ship-worm, the dread of the mariner,
appears an insignificant instrument in the hand of Provi-
dence, in humbling the glory and pride of man, in demolish-
ing, by its unseen labours, the noblest efforts of his ingenuity
and skill.

Conchology, or the study of shells, has been sometimes
confounded with Crustaceology, or that of Crabs; but the
slightest attention to the subject will at once discover the
obvious difference which exists between these two classes.
Nature has not only well-defined them by the composition of
the shells, but also by a manifest difference in the construc-
tion of the animals which inhabit them. Shells, properly so
called, are composed of carbonate of lime, combined with a
small portion of gelatinous matter; while those of the Crus-
tacea are composed of phosphate of lime, along with the
animal matter. Shells are, in general, permanent coverings
for their inhabitants; and the animal is of a soft and simple
nature, without bones of any kind, and attached to its domi-
cile by a certain adhesive property or power, possessed by
some of the muscles. On the other hand, shells of crustaceous
animals are cast, and renewed annually. These animals are
of a fibrous texture, with articulated limbs, and covered, as
it were, ina coat of mail. Besides, the shells of crustace-
ous animals are produced all at once; those of the Testacea,
are evidently formed by the animal gradually adding to them
either annually or at least periodically; as may be distinctly
seen in the common muscle: and all shells, strictly so called,
are composed of layers, which is not the case with the cover-
ings of Crabs and their congeners. This may be easily
proved by taking a shell and filing it slowly, when the
different layers are very perceptible; or put a Muscle-shell
into the fire, when it will shortly begin to crackle and
divide into separate lamin. We have numberless instances
of shells, both sea and land, which having been accidentally
broken, have been repaired by the animal: almost every
collection affords specimens of such mended shells.

INTRODUCTION. 15

The terms Conchology and Testaceology, which are syno-
nymous, refer to all animals which have a testaceous or
shelly covering, whether they inhabit the sea, the land, or
fresh-water.

Some chemical writers have divided shells into two classes.
The first are usually of a compact texture, resembling por-
celain, with an enamelled surface, and are in general beauti-
fully variegated. Those composing this class are called
porcelaneous shells, of which kind are those of the genera
Conus, Cyprea, Voluta, &c., of the Linnean arrangement.

The second class consists of shells generally covered with
a strong epidermis or skin, below which lies the shell in
layers, and composed entirely of the substance well-known
by the name of mother-of-pearl. In this class are the fresh-
water Muscles, (the Mytilus Cygneus and Anatinus of Lin-
neus,) the genus Haliotis or ear-shells, the genus Turbo,
and several of the Trochus tribe, &c.

The porcelaneous shells contain a very small portion of
soft animal matter, and those of the second class a very
large proportion;* but otherwise there is no real distinction
between them.

Shells, then, are only the habitations of soft animals called
Vermes, or Worms, which constitute the third order of
Linneus’s sixth class of animals. According to that author,
the animals which inhabit them may be arranged into ten
genera, as follows:

1. Limax; 2. Doris; 3. Spio; 4. Amphitrite; 5. Tere-
bella; 6. Nereis; 7. Ascidia; 8. Tethys; 9. Triton; 10.
Sepia.

1. Liwax.—Body oblong, creeping, with a fieshy kind of
shield above, and a longitudinal flat disk beneath; aperture
placed on the right side, within the shield; feelers four,
situate above the mouth, and an eye at the tip of the largest
ones.

This genus is what is generally termed the slug, or snail.

2. Doris.— Body creeping, oblong, and flat beneath ;
mouth placed below, on the fore-part; vent behind, on the

* See Thomson’s System of Chemistry, vol. v. p. 507.

B2

|

16 INTRODUCTION.

back, and surrounded by a fringe; feelers, two or four,
seated on the upper part of the body in front, and retractile
within their proper receptacles.

3 Spro.—Body projecting from a tube, jointed and fur-
nished with dorsal fibres; peduncles, or feet, rough with
bristles and placed towards the back; feelers two, long,
simple; eyes two, oblong.

4, AmpuiTRITeE.—Body projecting from a tube and an-
nulate; peduncles, or feet, small, numerous; feelers two,
approximate, feathered ; no eyes.

5. TEREBELLA.—Body oblong, creeping, naked, often
enclosed in a tube, furnished with lateral fascicles or tufts,
and branchie; mouth placed before, furnished with lips
without teeth, and protruding a clavate proboscis; feelers
numerous, ciliate, capillary, seated round the mouth.

6. Nerets.—Body long, creeping, with numerous lateral
peduncles or feet, on each side; feelers simple, rarely
wanting; eyes two or four, rarely none.

7. Ascrp1a.—Body fixed, roundish, and apparently issuing
from a sheath; apertures two, generally placed near the
upper end, one beneath the other.

8. TeTHys.—Body detached, rather oblong, fleshy, with-
out peduncles; mouth with a terminal cylindrical proboscis,
under an expanded membrane or lip; apertures two, on the
left side of the neck.

9. Trrron.—Body oblong; mouth with an involute spiral
proboscis; tentacula or arms, twelve, six on each side,
divided nearly to the base, the hind-ones cheliferous.

10. Sepra.—Body fleshy, receiving the breast in a sheath,
with a tubular aperture at its base; arms eight, beset with
numerous warts or suckers, and in most species two pedun-
culated tentacula; head short; eyes large; mouth resembling
a Parrot’s beak.

It is exclusively upon the shape of the shell, and not upon
the structure of the animal inhabitant, that the Linnzan
arrangement of Conchology is founded.

In early periods, naturalists were in much doubt whether
to found their Conchologieal arrangements on the animal,

gee

antes Oo eee

or the shells; but at last it was determined that it should
be on the latter; because few of the marine shells that were
then found had the animal in them, prior to the time when
dredging was resorted to. The greater part of shells in
many collections at the present day, have been found upon
the beach, divested of their animal: they having been cast
ashore by the agitation of the sea in storms, and the inhabi-
tant decayed before they were picked up.

Many shells are very different in their young and adult
states, both in form and colour; the student ought, there-
fore, to make himself well acquainted with the generic

characters, to enable him to discriminate the difference.

But, indeed, this is often a difficult matter, even to those
who have studied the science for many years.

In almost all the species of the genus Cyprza, there is con-
siderable difficulty in distinguishing them from the Volute
and Bulle, in their young state; the denticulated lip being
the last part of the shell which the animal forms. The
Strombus genus wants the expanded lip in the young shell:
from which circumstance it is frequently taken for a species
of the genera Buccinum or Murex.

The Linnean arrangement of shells consists of three
orders, viz. Multivalve, Bivalve, and Univalve.

The first order, Multivalve, is made up of shells consist-
ing of more shelly parts or pieces than two. Every part of
a shell which is connected with a corresponding part by a
cartilage, ligament, hinge, or tooth, is called a valve of such
shell.

The second order, Bivalve, is made up of shells having
two parts or valves, generally connected by a cartilage: for
example, the Cockle and Muscle.

The third order, Univalve, is made up of shells complete
in one piece: for example, the Periwinkle and the Whelk.
This order is subdivided: first, into shells with a regular
spire, and those without a spire.

The first order consists of three genera: Chiton, Lepas,
and Pholas.

The second order contains fourteen genera: Mya, Solen,

INTRODUCTION. 17 |

18 INTRODUCTION.

Tellina, Cardium, Mactra, Donax, Venus, Spondylus, Chama,
Arca, Ostrea, Anomia, Mytilus, Pinna.

In the third order there are nineteen genera: Argonauta,
Nautilus, Conus, Cyprea, Bulla, Voluta, Buccinum, Strom-
bus, Murex, Trochus, Turbo, Helix, Nerita, Haliotis, Pa
tella, Dentalium, Serpula, Teredo, and Sabella.

It will now be proper, before proceeding to a description
of the generic characters of the Linnzan system, to make
the student acquainted with the terms used in Testaceology,
as far as regards the different parts of shells.

EXPLANATION OF THE PARTS OF SHELLS.

MULTIVALVE SHELLS.

VaLveEs oF CuiTons.—Chitons in general have eight
transverse, broad, but very short valves, placed on the back
of the animal, and inserted at their sides into a marginal
tough ligament. Plate I. fig. 6, a, a, a.

Operculum consists of four small valves on the summit
of the Lepas, which shut up the superior orifice; it is in a
certain degree stationary, and different from the operculum
of univalve shells, which will hereafter be described. Plate I.
fig. 1, a. Fig. 2. represents a profile view of the operculum
removed from its place, A the front valves, B the back
valves. Fig 3. a front view of the operculum.

Base is that part of the shell by which it is fixed to rocks
and other bodies. Plate I. fig. 1. and 5, BB B.—H is a piece
of stone to which the base is fixed, and G a piece of wood to
which the shells of the particular kind here represented are
generally attached.

Ligament is the membraneous or tendinous substance by
which the valves or parts of the shell are attached. Some
multivalve shells are connected, by the parts of one valve
locking into another. Plate I. fig. 6, a,a,a. The liga- :

2 reTESS!

EXPLANATION OF THE PARTS OF SHELLS. 19

ments vary considerably in their texture, being scaly, prickly,
smooth, or punctated.

Ridges are certain convexities in many of the Lepas
tribe, sometimes longitudinal and sometimes transverse.
Plate I. fig. 1, FF.

Peduncle.—A sort of stem by which the shells of the
second division of Lepas are attached to wood, &c. It is
composed of a membranaceous tube, filled with a liquid
which perhaps affords nourishment to the animal. Plate I.
fig. 5, cc. The peduncle is usually affixed to a piece of
wood as represented at G, or to some other solid body.

Feelers are those ciliated arms, evolved from the upper
or hind part of the Lepas anatifera, and other shells of the
genus Lepas. While the animal is in the water it con-
tinually moves its feelers, evidently for the purpose of
entangling minute marine insects, as food. Plate I. fig. 5, EE.

Accessory Valves are small plates which cover the apex
at the hinge of the Pholades, or are situated below the
hinge. Plate I. fig. 4, A.

Margin.—A fleshy or cartilaginous border in which the
valves are encased in the genus Chiton. Plate I. fig. 6, 6, b.

BIVALVE SHELLS.

Bivalve shells consist of two parts or valves, connected
by a cartilage, and a hinge which is generally composed of
teeth, those of the one valve locking into corresponding
cavities in the other.

The valves of some bivalve shells are formed exactly
alike, but those of others are very different; the one being
smooth, the other rugose; one flat, and another convex;
and often one is shorter than the other.

The shells of the genera Mya, Solen, Tellina, Venus, and
others, have in general both valves alike, while those of the
genera Spondylus, Ostrea, Anomia, and Pinna, have in gen-
eral dissimilar valves. The first of these kinds are called
equivalve, and the latter inequivalve.

Equilateral shells are those of which the sides are alike,

20 INTRODUCTION,

as in the shells of the genus Pecten, commonly termed
Scallop shells in England, or those shells worn by pilgrims
in former times:

« And fix’d the Scallop on his hat before.” —PARNELL.

Plate II. fig. 2, and Plate VII. fig. 14. This is also exem-
plified in the Pectunculus. Plate XVI. fig. 8.

Inequilateral Valves are shells whose sides are unequal,
and of different shapes, as in the Mactra, Donax, &c. Plate
RoE. fies 0:

Summit, or Umbo, is the most elevated point of that part
of the shell in which the hinge is placed. Plate I. fig. 7.
and Il, aa.

In naming this the summit, we do not follow the axiom
of Linnus, but because we consider it more properly the
summit of the shell than the opposite extremity.

Base is the reverse of the above, or that part of the shell
immediately opposite the summit. Plate I. fig. 9. and 10, dd.

Sides, the right and left parts of the valves. Plate I.
fig. 9,2,

Anterior slope is that part of the shell in which the liga-
ment is situated. In viewing the anterior slope in front,
the beaks of the shell retire from view. Plate I. fig. 7, 7.*

Posterior slope, that part of the shell opposite the ante-
rior slope; in viewing it in front, the beaks point to the
observer. Plate I. fig. 7, k.*

Disk, the convex centre of a valve, or most prominent
part of the valve, suppose it with its inside lying undermost.
Plate I. fig. 7, o. :

Inside, the concave part of a valve. Plate IV. fig. 11, n.

Cicatrix, or Tongue, is the impression left on the inside
of the valves, by the adhering muscles of the animal. It
differs in most shells, according to the shape of the muscle,
as semi-ovate, round, lunate, elongated, &c. As a specific
distinction, it is often of great use; being, with a very few

* But what is thus commonly named anterior, is in fact posterior,

as is known by examining the animal, of which the mouth is placed
toward k, and the siphons toward 7. j

EXPLANATION OF THE PARTS OF SHELLS. 21

exceptions, alike in shells of the same species. Some shells
have only one cicatrix, as the Edible Oyster, and Muscle ;
others have two, and some few more; the Tellina Fausta,
for example. Plate I. fig. 9. and 11, eeee.*

Lunule.—The lunated depressions, situated in the anterior
and posterior slopes. In different species of Venus they
are prominent, characteristic marks, often of much service
in ascertaining a species. Plate I. fig. 7, 5d.

Ligament perforation.—The circular aperture, or per-
foration, through which the ligament passes; by which the
animal of the Anomia attaches itself to stones, and other
marine extraneous bodies; it is in general situated in the
flat valve, though there are a few exceptions to the con-

‘trary. Plate I. fig. 10, m.

Hinge is the point at which bivalve shells are united.
It is formed by the teeth of one valve inserting themselves
between those of the other, or by the teeth of one valve
fitting into the cayities or sockets of the opposite one.

It is on the peculiar construction of the hinge that the
generic character of bivalve shells is principally founded,
together with the general contour of the shell. Plate II.
fig. 1. and 3, qqq.

Teeth of the Hinge.—Upon the number and relative
situation of the teeth, principally depend the generic distinc-
tions; they are of various forms, and very differently placed ;
some are single and large, others numerous and small, orbi-
cular, spatuliform, laminated, &c. Some hinges have no
visible teeth, and are termed inarticulate.— When a primary
tooth has a groove or hollow in its centre, it is called com-
plicated. Plate IV. fig. 6, «. Those with few teeth are
termed articulate. Plate IV. fig. 1. and 12, and those with
many teeth multiarticulate. Plate IV. fig. 2, 3, 4, &e.
Plate I. fig. 6. and 8, gygqq-

Primary Tecth are those teeth in general situated in the

* Two distinct things are confounded in this definition. The cica-
trix, or sinus, is a mark left by the siphon-tube, as in Fig. 11, and the
eto the right. Muscular impressions are the marks left by the adduc-
tor muscles, as in Fig. 9, e, e.

22 INTRODUCTION.

centre of the hinge, and for the most part broad, large, and
distinet, often elevated, and usually inserted in a cavity in
the opposite valve. ‘They however differ very much in
some shells, but may easily be distinguished. Plate IV,
fig. 1,3, and 7, aaaaa. ‘These are also termed the Car-
dinal Teeth, or the Central Teeth.

Lateral Teeth, Plate IV. fig. 10, are teeth which diverge
from the umbo, or are situated at a distance from it, and
are in general long and flat, often double and divided
by a groove or hollow. Plate IV. fig. 2, 4, 6, and 7,
bbbb.

Double Teeth, or teeth formed of two lamine. Plate IV.
hel ee.

Ineurved Teeth are those which are bent round, as in the
single tooth of the Solen Siliqua. Plate IV. fig. 2.

Recurved Tecth are those which are bent backwards, as
in the hinge of the Fanopea. Plate XVIII. iB. 9; and
Spondylus, Plate IV. fig. 8, ff.

Middle Teeth, Plate IV. fig. 4, dd. Another term for
the Primary, Central, or Cardinal teeth.

Numerous Teeth are those small upright teeth, set in
rows, of which the hinges of all the species of the genus
Arca are formed. Plate IV. fig. 10, & A.

Covity cf the Hinge.—The hollow depression in which
the ligament of the Ostrea is situated, generally of a tri-
angular form. Plate IV. fig. Il, g.

Ligament of the Hinge, or the Cartilage, is that elastic
fibrous substance by which the valves are united, and the
hinges kept in their proper places; always situated under
the beaks of the Shell. Plate IL. fig. 1, 3, and 4, J//;
Plate IV. fig. 3, n.

Beak is the extreme point of the summit of bivalves,
which in many species turns spirally downwards, or to the
one side, as in most species of Venus, &c. From this cir-
cumstance it is seldom the highest part of the shell. Plate
Pi fie. \5, rire

Seam.— When the valves are closed, the tine of separation
between them is so called. Plate II. fig. 6, tt.

EXPLANATION OF THE PARTS OF SHELLS. 23

Umbo.—That part situated immediately under the beak.
Plate I. fig. 9, w; and Plate II. fig. 4, w. It is properiy
the most prominent part of the shell, near the hinge, and of
which the beak is the tip.

Ears.—The processes on each side of the beak, in most
species of that division of Ostrea, called scallops; some
have one ear very large, and the other small; and some are
scarcely observable on one side. Plate IL. fig. 2, hh.

Superior Ear.—Plate IV. fig. 11, h.

Inferior Ear.—Plate IV. fig. 11, 2.

Margin.—The extreme edge of the whole shell, or the
circumference of either valve, all round. Plate I. fig. 7, p;
and Plate II. fig 1, p.

Crenulated Margin.—When the margins are notched, or
marked with alternate prominences and depressions, which
often interlock in the opposite valves, as in Cockles. It is
by no means uncommon in other shells, particularly those
of the genus Donax. Plate IV. fig. 6, mm.

Stri@ are fine thread-like lines, generally on the exterior
surface of shells. and are sometimes both longitudinal and
transverse. When the strie of shells appear indistinct, as
if worn out, they are termed obsolete strie@. In some in-
stances the insides of shells are striated; for example, the
Murex Tulipa. (Fasciolaria tulipa, Lamarck.) The char-
acter of the strie is often of much use in distinguishing
species. Plate II. fig. 2, f-

Right Valve is that valve which, when viewed with the
inside uppermost, has the anterior slepe pointing to the right
hand. Plate I. fig. 11; and Plate IV. fig 5. and 6, 6.*

Left Valve.—The opposite of the above; the anterior
slope points to the left hand, when viewed from the inside.
Plate IV. fig. 3, 6, 7, 9, &c.*

Length of the Shell is taken from the ligament, or the

* But the only sure way of knowing which is right or left is to
examine the animal, and place the shell in its natural position, that is,
with the hinge above and the ventral margin, Plate I. fig.7, P, beneath ;
in which case the ligament is behind the umbones, so that what is
usually termed right is actually left. -

24 INTRODUCTION.

beak, to the opposite margin. For example, the common
muscle: it is longer than it is broad, and the solens are
broader than long. Plate I. fig. 5, wu; and Plate II. fig.
4, uu.

Breadth is measured from the most extreme edge of the
anterior and posterior slopes, being in a contrary direction
from its length. Many shells are broader than long, such
as most of the Myz, Solenes, Telline, &c. ; and the genera
Mytilus, Ostrea, Pinna, &c., are in general longer than
broad. Plate I. fig. 5,vv. Plate II. fig. 4, vv. *

Byssus, or beard, is an appendage composed of filaments
of a silky texture, by which some of the Bivalves fasten
themselves to their beds, such as the Muscles, Pinner, &c.
Plate IT fig. 6, s.

DESCRIPTION OF PLATE IV.

HINGES OF THE LINNZ AN GENERA OF BIVALVES.

Fig. 1.—Hinge of the Mya pictorum. (Unio pictorum,
Lamarck.) a. Primary tooth, c¢ double teeth.
Fig. 2._Hinge of the Solen Siliqua. 6. Lateral teeth.
Fig. 83.—Hinge of the Jellina Radula. (Lucina radula,
Lamarck.) aa. Primary teeth, n. cartilage.
Fig. 4.—_Hinge of the Cardium eculegtum b. Lateral
tooth, dd. middle teeth, //. spines.
Fig. 5 —Hinge of Mactra hians. (Lutraria hians, La-
marck.)
Fig. 6.—Inside of both valves of the Donax Trunculus.
A is the right valve, and B is the left valve; db. lateral
teeth, e. primary complicated tooth, or cleft in the middle,
mm. crenulated margin.

* The true length of the shell, however, is in the direction of the
length of the animal, or from the anterior to the posterior extremity
of the shell, and its height, from the ventral margin to the umbones, is
what is above called the length.

SS Se Sa ee See
\

EXPLANATION OF THE PARTS OF SHELLS. 25

Fig. 7.—Hinge of Venus Gallina.( Ortygia gallina, Leach.)
aa. Primary teeth, 0b. lateral tooth.

Fig. 8.—Hinge of Spondylus gederopus, f f. incurved
teeth. .

Fig. 9.—Hinge of Chama Cor. (Isocardia Cor, Lamarck. )

Fig. 10.—Hinge of Arca pilosa. (Pectunculus pilosus,
Lamarck.) & &. numerous small teeth; the distinguishing
characteristic of the genus Arca.

Fig. 11.—Hinge of Ostrea varia. (Pecten varius, La-
marck.) g. cavity of the hinge, A. superior ear, 2. inferior ear.

Fig. 12.—Hinge of Anomia Ephippium.

UNIVALVE SHELLS.

The shells composing this order are far more numerous
than those of the two preceding, both in genera and species.
It requires a considerable degree of attention to discrimi-
uate many of the species, as they often closely resemble
each other; and they are divested of the strong and distinct
character afforded by the teeth of bivalves; besides many
of the species present several varieties.

In the examination of shells of this order, the general
contour or outline of the whole shell is the first particular
to be attended to, as this leads to those distinctions neces-
sary in the definition of simple, spiral, or turbinated shells;
or, more strictly according to the Linnzan method of dis-
crimination, Univalves with a regular spire, and those with-
out a regular spire. The genera of this order are formed
principally from the shape of the aperture, taken in con-
junction with the general shape of the shell; from the spire
being lengthened or depressed, being with or without a
canal; the length of the heak and its direction, together
with the particular form of the outer lip. The colour of
shells only serves as a specific distinction, and cannot in
this respect, in all cases, be depended upon, although in
others it is an unvarying test. The particular manner in
which the spots are disposed, frequently characterizes spe-
cies.

26 INTRODUCTION.

Apex.—The summit, tip, or highest part of the spire
Plate IL. fig. 7, 8,9, A AAs

Base is the opposite extremity from the apex or tip of
the spire. In shells with a beak or rostrum, it implies the
tip of such beak; Plate IT. fig. 11, 6. In shells without a
beak it is understood to be the lower part, as before-men-
tioned, opposite the apex; Plate II. fig. 8and 9, BB. In
the Patella and some others, the hase of the shell is that
part oun which it rests when it is laid on its mouth. In the
Dentalium and Teredo it is the wider end.

Body of the shell is the first or lower whorl of the spire,
in which the aperture is situated, and is in general longer
than the remaining whorls. Plate II. fig. 10 and 12, FF;
and Plate III. fig. 7 and 9, FF.

Front of the shell, is that side where the aperture is
situated. Plate II. fig. 7, 7; and Plate III. fig. 8, 7.

Back is the opposite side to that in which the aperture
is placed or turned directly from the observer. Plate III
fig. 5 and 10, GG.

The venter, or belly, is the most prominent part of the
lower whorl or body, generally situated in the vicinity of
the lip over the aperture; and formed by the convexity of
the aperture. It is in general only made use of in describ-
ing shells, whose body is large in proportion to the size of
the spire. Plate III. fig. 5 and 10, H A.

Sides.—The extreme edges of the shell, when viewed
either in front or from the back. Plate II. fig. 11,
KKKKKKKK. Right side is, when the shell is viewed
in front, that side next the observer’s left hand. Left side,
the side with the aperture in it.*

Ap-rture, or mouth, is that part of the lower whorl or
body, by which the animal protrudes itself. It affords the
principal generic distinctions of Univalve shells, and differs
very much in shape; some apertures being rounded, others
semilunar, angular, &c. Plate Il. fig. 9 and 11, CC; and

* But when the shell is placed in its natural position, with the mouth
below, the right side is what is here called the left.

- = — = SS — —

EXPLANATION OF THE PARTS OF SHELLS. 27

Plate III. fig. 1, 3, and 14, CCC. Some apertures have
a canal at their base, as in Plate XII. fig. 5, 6, 7, and
others are devoid of it, as in Plate XIII. fig. 1, 2,3. In
various genera it extends the whole length of the shell,
as in the Cyprea, and some of the Cones with depressed
spires. It is either entirely open, or it is closed by an
operculum or lid, which is usually affixed to the foot of the
animal,

Canal, or gutter, is the inside of the elongation of the
aperture, or both lips of the shell of those species with a
beak, in which it forms a concave channel or gutter, run-
ning from its commencement in the aperture, to the extrem
ity or base, Plate II. fig. 10 and11, Q Q; Plate III. fig. 8, Q.
Some species are furnished with two canals, one situated
at the junction of the outer lip and body, as in the Murex
I ampas, &e.

Beak, or rostrum, is that lengthened process in which the
canal is situate; it commences a little higher up, on the
outside, than the insertion of the canal in the inside, which
is always distinctly marked by the line of the aperture.
Plate Il. fig. 1], p. This process is not so conspicuous in
some of the species of Voluta, but is more marked in the
genera Murex, Fusus, Pyrula, &e.

Pillar, or columella, is that part which runs through the
centre of the shell in the inside, from the base to the apex
in most univalve shells, and appears to be the support of
the spire; or it may be defined the axis of the shell, round
which the whorls are continued from the apex to the base.
It is in general grooved or folded; but, as it is situated in
the interior of the shell, a minute description 1s unnecessary.
Plate II. fig. 10 and 12, MMMMM;; and Plate IIL.
fig. 9, 2 MM. The internal edge of its base is frequently
described as having plaits, &c.

Plaited Columella, having upon it those folds, or plaits,
which are the distinguishing characteristic of the Volute
and other genera. Plate II. fig. 7, z.

Pillar Lip is a continuation of the glossy process with
which the aperture is lined, and expanded on the columella.

c2

28 INTRODUCTION.

Plate III. fig 7 and 8,OO. This is termed the Jnner
Lip by some authors.

Outer Lip.—The expansion, or continuation of the body
of the shell, on the left margin of the aperture, also lined
with the glossy process of the aperture. Plate II. fig. 7, VV;
and Plate III. fig. 8, WN MN. The latter is an example of
the alated or winged shells.

Operculum, or lid. This is only an appendage to the
turbinated or spiral shells affixed to the foot of the animal,
sometimes of a testaceous, in other cases of a horny or car-
tilaginous substance. It acts as a door or lid, and is calcu-
lated for the protection of the animal, when it retires within
its dwelling from the intrusion of its enemies, it being
adapted to the shape of the aperture, which it closes nicely
up. As exemplified in the horny operculum of the common
Periwinkle, (the Turbo littoreus of Linneus,) it is of a
brown horny appearance; it is also to be found in the large
Whelk, which is common in our seas, and sold in fish-
markets as food. Plate III. fig. 4.

Spire consists of all the whorls of the shell, except the
lower one, which, as before observed, is termed the body of
the shell. Plate IL. fig. 12, D; and Plate III. fig. 7 and 8,
DD.

This spire is a prominent feature of the Univalve; and
upon its being lengthened or elevated, shortened or de-
pressed, &c. depends much of the generic and specific
definition. Adanson, in his ‘ Natural History of Senegal,’
printed at Paris in 1757, says that the external character of
the spire varies according to the plane it turns upon, which,
he observes, may be horizontal, cylindrical, conic, or ovoid.
At the same time, he admits that there are a great many
intermediate forms, which cannot properly be defined.

It is a remarkable circumstance, that many of the young
shells have not the same number of turns or wreaths as the
adults; from which it would appear, that the part of the
animal nearest the apex, never increases in size. The num-
ber of wreaths cannot at all times.be depended upon. A
full-grown shell may, however, be known from the outer-

—— en ee j
|
|

EXPLANATION OF THE PARTS OF SHELLS. 29

tip, which has generally an unfinished appearance in young
shells. Indeed, in all the land and fresh-water shells, it is
a distinct criterion, as they are never complete in the form
of the outer-lip, till full grown.

Whorl is one of the turns, wreaths, or volutions of the
shell. Plate IL. fig. 8, Z; and Plate III. fig. 10, Z.

Depressed Spire is when the spire is very flat, as in the
shells of the genus Planorbis, &c. Plate II. fig. 12, d; and
Plate III. fig. 5, s.

A flat shell is figured in Plate III. fig. 14.

Involuted Spire, in those shells which have their whorls,
or wreaths, concealed in the inside of the first whorl or
body, as in some of the Nautili and Cypree. Plate IIL.
fig. 3, £; Plate VII. fig. 19; and Plate VIII. fig. 21.

Suture of the Spire, is a fine spiral line, which separates
the wreaths or whorls from each other; it is sometimes
crenulated, undulated, or sulcated, and not unfrequently
elevated or projecting. Plate Il. fig. 9, e e.

Reversed, or Heterostrophe Spire, is when the volutions
of the spire revolve in the same manner as a common cork-
screw, or when the aperture is placed downwards, the suture
of the spire runs upwards from the right hand to the left;
as in Plate III. fig. 13. Such shells are also called Sznis-
trose, or turned to the left.

In some of the more depressed species of Helix, or Nau-
tilus, great attention is requisite in order to ascertain which
is really the upper side of the shell, for it is on that side
the spiral turns are to be taken from the centre or apex;
and, in most instances, this is to be determined by the
oblique direction of the aperture to the under part, where
the lip rarely extends so far as on the upper part. In fixed
shells, such as Serpule, there is no difficulty, as the side
which is sessile must be considered as the base, or under
part. Thus, in the Serpula lucida the fixed part is some-
times very small, and the mouth protends spirally upwards,
in a contrary direction to the sun; and therefore it must be
considered a reversed or heterostrophe shell, the same as if
the volutions nearest the mouth had turned laterally upon

ESS

30 INTRODUCTION.

the centre or fixed ones. This shell, indeed, is most fre-
quently found with regular lateral volutions; and though
subject to great variety, with respect to contortions, it in-
variably turns the aperture one way.

In some species of Nautilus, however, there can be no
rule to ascertain whether the shells are dextral or sinistral;
for when the aperture is exactly central, the lip embraces
the body equally, and the sides of the shell are similar, as
in the Nautilus Calear, which cannot be thus defined. In
others of that genus, as in N. Beccariiand N. Beccarii per-
versus, two shells, the principal distinction of which is the
contrary turn of their volutions, it is easily determined by
the convexity of the upper side, and, of course, the aperture
being placed somewhat beneath.

Chambers are the cavities divided by partitions, at regular
or irregular intervals; as in the Nautilus. Plate III. fig.
ll, wwww w.

In some of the Serpule there are also divisions, but they
are not regular as in the Nautili; and besides, they differ
from them in being devoid of a siphunculus or communica-
tion between the chambers; the animal forms a complete
partition and adds to its shell, which it would appear to be
obliged to do, from its body growing too large for its abode.

Several of the Patella have chambers formed of laminar
partitions, subspiral cells, or processes; these in general lie
horizontally, and are quite open at one end, as in the Patella
testudinaria, &c. of Linneus, and the prickly Crepidula,
and Chinese Calyptrea, Plate XIV. fig. 16 and 19; and
Plate III fig. 6, w, or funnel shaped, as in the Sipho
striatus. Plate XIV. fig. 21.

Umbilicus is in general a circular perforation in the base
of the lower whorl, or body, of many univalve shells, and
extending internally in the direction of the axis. This is
common to most of the Trochi, in some species of which it
penetrates. from the base to the apex; widest at the base,
and gradually tapering to the top. Plate III. fig. 1, wu.

Sub-umbilicated shells are those which have the umbilicus
covered ina greater or less degree by a thin process; which,

EXPLANATION OF THE PARTS OF SHELLS. 31

in some, almost entirely closes the opening or mouth. This
character is most commonly to be met with among species
of Buccinum and Murex.

Shells which have no umbilicus are termed imperforate.

Siphunculus is that small round perforation which forms
a communication between the chambers of the Nautili, and
penetrates through the whole spire of the shell. Plate III.
Ag. 11...

Varices are transverse ribs which cross the whorls of
shells in some species of Buccinum, Murex, and Tritonia;
as exemplified in the Cassis Areola. Plate XI. fig. 21.
Varices are formed by the periodical growth of the shells,
they being the thickened margin of the outer lip, to which
the animal has attached its periodical enlargements. In
some species they have more the form of sutures than ribs;
this is owing to the margin of the outer lip being but slightly
developed.

Ribs are those longitudinal or transverse protuberances
which are seen in many of the univalve shells. Plate III.
hel ersrr.

Teeth of univalves, according to Colonel Montagu, are
not properly denticles, or tooth-shaped protuberances, but
are fine white lamin, or ridges, running spirally backwards,
in a parallel direction to each other; those on the exterior
lip may, in most instances, be traced through the outside of
the shell, and are nearly alike in length. Plate III. tig. 13, a.

Epidermis is a kind of cuticle, or membrane, covering the
exterior surface of many shells of all the orders, destined by
nature to protect their surface from being injured. This
substance is the production of the animal inhabiting the
shell; it is always present in certain species, and not at all
in others. Shells with a rugged or uneven surface have
almost always this epidermis. In some it is strong, lami-
nated, velvety, fibrous or rough, often beset with long hairs,
and in others very thin, smooth, and pellucid, and admits
the colours of the shell to shine through it. In some species
it is so dusky, that it entirely obscures the beautiful colour-
ing of the shell beneath. Although many shells are very

INTRODUCTION.

beautiful, even with this cuticle on them, they are much
| more so when it is removed; but I would by no means ad-
vise the collector of shells to remove it, unless he may have
several duplicates of the same species; and then he may do
it by way of variety. It is always preferable, however, to
keep shells in their natural state.

| A shell with epidermis is represented in Plate III. fig. 2,
X; and the effect of the epidermis removed at J.

All other circumstances relative to the forms and mark-
ings of shells, will be described at the end of the work, in
the Glossary of Terms used in the Science.

We may now proceed to give an account of the Linnean
genera composing the three orders of shells. |

OF THE LINNHAN GENERA.

ORDER FIRST.
MULTIVALVE SHELLS.

Animals soft, of a simple structure, and covered with a
calcareous habitation or shell, formed of several pieces.

Genus 1.—CHITON.

Animal a Doris; shell consisting of several segmeuts or
valves, placed transversely on the back of the animal, and
lying upon each other at their anterior edge.

Chiton marginatus. —THE MARGINATED CuIToN. Plate
V. fig. 1. With eight carinated valves, projected over each
other in the form of a beak; very finely shagreened, and
having a broad margin, of a dusky or ash-coloured brown;
3ths of aninch long. Inhabits the British seas, upon stones.

The animals of this genus are marine, adhere to rocks and stones,
in general near low water-mark, and are, at first view, very like an

Oniscus, or the small crustaceous animal called a Slater, or Wood-
louse.

Genus 2.._LEPAS.

Animal a Triton; shell affixed at the base, and consisting
of many unequal erect valves.

Lepas rugosa.—Tue Rovucu Lepas. Plate I.-fig. 1.
(Balanus rugosus, Lamarck.) With a sub-cylindric shell,
having usually six furrows, which frequently widen towards
the top, and terminate in angulated points, sometimes as
wide as at the base; compartments sulcated, often striated
longitudinally; of a yellowish colour; operculum consisting
of four rough, angulated, erect valves

SS aa

34 LINN AN GENERA.

Lepas Tintinnabulum. — Tue Lirrte Berti Lepas,
Plate V. fig. 2. (Balanus Tintinnabulum, Lamarck.)
Shell conical, with the valves strongly and irregularly
ribbed, interstices delicately striated transversely; colour
purple. Inhabits the West Indies.

Those described above are termed Acorn Shells in Britain. This
genus consists of two families or divisions, very different in their
shape. The fist of these is composed of the Balani, or Acorn shells,
of a subconic form, with an operculum or lid, consisting of either four
or six valves ; the body of the shell with six valves. The second family
is that of the Anatiferous, or Barnacles, which are connected with,
and supported at the base by, a tendinous tube or pedicle, of a flexible
nature, allowing the animal to writhe about in quest of food; it has
no operculum, is wedge-shaped, and consists of five or more unequal
valves.

Lepas anatifera.--THe Common Smootu Lepas. Plate I.
fig. 2. (Anatifa levis, Lamarck.) Shell compressed with five
obsoletely striated valves ; the lower valves somewhat tri-
angular; the superior ones long, and tapering to an obtuse
point; connected by an orange-coloured cartilage; base affixed
to a peduncle of a colour between yermilion and orange.

This shell generally adheres to pieces of rotten wood or the bottoms
of vessels, and is found in almost all seas.

Linnzeus founded the name of this shell on the circumstance that
it was from it that the Barnacle Goose was supposed to have had its
origin. Gerard’s account of this transformation, as it affords a re-
markable instance of the credulity of the times, is too curious to be
omitted. “There are found in the north parts of Scotland, and the
islands adjacent called Orchades, certain trees whereon do grow cer-
tain shells tending to russet, wherein are contained little living crea-
tures, which shells in time of maturitie do open, and out of them grow
those little living things, which falling into the water do become
fowles, which we call Barnacles ; in the north of England Brant Geese ;
and in Lancashire, Tree Geese ; but the others that do fall upon the
land perish and come to nothing. Thus much from the writings of

others, and also from the mouths of people of those parts, which may —

very well accord with truth.

“ But what our eyes have seene and hands have touched we shall
declare. There is a small island in Lancashire called the Hill of
Flounders, wherein are found in the broken pieces of old ships, some

whereof have been cast thither by shipracke, and also the trunks and .

bodies with the branches of old and rotten trees, cast up there like-
wise: whereon is found a certain spume or froth that in time breedith
into certain shells, in shape like those of the Muskle, but sharper

.? *

MULTIVALVE SHELLS. 35

pointed, and of a whitish colour, wherein is contained a thing in form
like a lace of silk, finely woven as it were, together, of a whitish colour,
one end whereof is fastened into the inside of the shell, even as the
fish of Oysters and Muskles are; the other end is made fast unto the
belly of a rude mass or lumpe, which in time commeth to the shape
and form of a bird; when it is perfectly formed the shell gapeth open,
and the first thing that appeareth is the foresaid lace or string; next
comes the legs of the bird hanging out, and as it groweth greater it
openeth the shell by degrees, tili at length it is all come forth, and
hangeth only by the bill; in short space often it cometh to full matu-
ritie, and falleth into the sea, where it gathereth feathers, and groweth
to a fowl bigger than a Millard, and lesser than a Goose, having black
legs, bill or beake, and feathers black and white, spotted in such a
manner as is our Magpie, called in some places a Pie-annet, which the
people of Lancashire call by no other name than a Tree Goose; which
place afuresaid, and those parts adjoining, do so much abound there-
with, that one of the best is bought for three pence. For the truth
hereof, if any doubt, let them repaire unto me, and I shall satisfy them
by the testimonie of good witnesses.”—Gerard’s Herbal, p. 1558.

The shells of this genus adhere in clusters to rocks, shells, floating
wood, and other extraneous marine substances, and being incapable
of changing place, are supposed to be true hermaphrodites.

Genus 3.—PHOLAS.

Animal an Ascidia; shell bivalve, divaricate, with several
lesser, differently shaped, accessary pieces, at the hinge;
hinge recurved, united by a cartilage; in the inside, beneath
the hinge, is an incurved projecting tooth.

Pholos crispata.— Tue CurLED Puotas. Plate V. fig.
3. Shell oval, gibbous, pale ochreous-yellow; part next
the hinge cbtuse, gaping at both ends; a longitudinal furrow
near the centre of each valve; one half covered with muri-
cated waved strie and wrinkles, the other substriated.
2 inches long, and 3 broad. Inhabits the British coasts.

Pholades are found below high water-mark, burrowed in hard clay,
limestone, and wood, which they perforate in their younger state, and
as they increase in size enlarge their habitation.

The phosphorescent property of the Pholades is very remarkable.
They contain a liquor which shines with uncommon splendour in the
dark, and illuminates whatever it touches, or happens to fall upon.*

“ There is,” says Dr. Priestley, “a remarkable shell-fish called Pholes,
which forms for itself holes in different kinds of stone. This fish ila

* See Memoirs of the French Academy, 1712.

36 LINNEZAN GENERA.

minates the mouth of the person who eats it; and it is remarked, that
contrary to the nature of other fish, which give light when they tend
to putrescence, this is more luminous the fresher it is ; and when dried,
its light will revive on being moistened either with salt water or fresh ;
brandy however immediately extinguishes it.”*

It is to be regretted, that the experiments made by chemists on those
animals, which have a luminous appearance in the dark, have not
been sufficiently decisive, to enable us to state the true cause of it; but
there is every reason to believe that it proceeds from phosphorus, which
is abundant in all animal bodies. ’

ORDER SECOND |

BIVALVE SHELLS.

Genus 4.—MY A.

Animal an Ascidia; shell bivalve, generally gaping at one
end; hinge, in most of the species, with a broad, thick,
strong, patulous tooth, not inserted in the opposite valve.

Mya arenaria.—Tue Sanp Mya. Plate V. fig. 4.
Transversely ovate, rounded behind; tooth very broad,
thick, obtuse, projecting, and erect; with a small lateral
tooth.

The Mye are to be found both in the sea and in rivers. The marine
kinds generally live under sand or sludge, and the place where they |
lie is betrayed by a small hole, out of which they occasionally protrude
their siphon, which is placed at the posterior or upper end. Those
which inhabit rivers, are generally found in the mud at its bottom. In
some places the animals are used for food; but what makes them of
considerable importance is, the quantity of pearls which they some-
times produce. As illustrative of the value of pearls produced by the
Mya margaritifera, (Unio margaritifera, Lamarck,) it may be men-
tioned that according to Camden, Sir John Hawkins had a patent for
fishing that shell in the river Irt in Cumberland. This shell is well
known in Britain, by the name of the Pearl Muscle. We are informed
in the Philosophical Transactions, that several pearls of great size
have been procured from the rivers in the counties of Tyrone and
Donegal in Ireland. One of them weighed 36 carats, and would have

been worth £40, but owing to its being impure, it lost much of its value.
Other pearls from the same places have sold from £4 10s., to £10 each.

* Priestley’s Optics, page 567.

n<rventnare peers

BIVALVE SHELLS. 37

One of the latter price was sold a second time to Lady Glenlealy, whe
had it placed in a necklace, and refused £80 for it, which she was
offered by the Countess of Ormond. There was also a great fishery for
pearls in the river Tay, which extended from Perth to Loch Tay; and
it is said that the pearls sent from thence, from the year 1761 to 1764,
were worth £10,000. It is not uncommon in the present day, to find
pearls in those shells, which bring from £1 to £2. It is said that those
in the Scottish Crown which forms part of the regalia now exhibited
in the Castle of Edinburgh, are the produce of the river Tay.

Genus 5.—SOLEN.

Animal an Ascidia; shell bivalve, oblong, open at both
ends; hinge with a subulate reflected tooth, often double,
and not inserted in the opposite valve.

Solen Siliqua.—TuE Pop Soxen. Plate I. fig. 5. Shell
linear, straight; in one valve two teeth, and one in the
other, having a lateral inclined tooth corresponding with the
opposite lamina; the exterior covered by a fine olivaceous
brown epidermis, very glossy, and transversely striated, the
strie taking a longitudinal direction across the shell. One
inch long, and from seven to eight broad. Common on most
sandy shores of Europe.

uu Length of the shell, » v breadth of the shell.

Solen Ensis.—Tuer Sapre Soven. Plate V. fig. 5.
Linear, a little bent like a sabre; with a single tooth and
lateral lamina, in one valve, locking into two teeth, and
double laminz in the other; covered with a fine olivaceous,
glossy epidermis; one inch long, and from five to seven
broad. Inhabits the coasts of Europe.

Solen antiquatus.—Tue ANTIQUATED SoLen. Plate
Il. fig. ]. Shell thin, white, and subpellucid; moderately
glossy, with concentric strie; ends rounded and gaping:
hinge near the centre, furnished with a single tooth in one
valve locking in between two in the opposite; the teeth are
erect, oblique, and stand beyond the margin; outside covered
with an umber-coloured epidermis. Found on the Cornwall
and Dorsetshire coasts.

l The cartilage, n inside, p margin or limb, g hinge.

The Solens inhabit the ocean ; they are generally found buried about

D

:

38 LINNEAN GENERA.

six inches deep in the sand, into which they penetrate with great facility;
their residence is known by a small dimple on the surface. In some
places they are used as food.

Genus 6.—TELLINA.

Animal a Tethys; shell bivalve, generally bent at one end;
in the fore-part of one valve a convex, of the other a concave
fold; hinge with usually three teeth, the lateral ones smooth
in one side.

There are three families of the Tellin: ovate and thickish,* ovate
and compressed,** suborbicular.***

Tellina Fabula.—THE OBLIQUELY-STRIATED TELLINA.
Shell very thin, pellucid, and oval, generally white or yel-
lowish, and darker towards the umbo; which is nearly cen-
tral, pointed, and turned a little to one side; the anterior
side slopes to an obtuse point; the posterior side is large
and rounded; hinge furnished with three teeth in one valve
and two in the other; one valve obliquely striated.

Tellina Donacina.—THE Donax-LIKE TELLINA. Plate
V. fig. 6. Suboval, flattish, much sloping on the anterior
side, semi-striated, and semi-pellucid; hinge with two teeth
in one valve, and one in the other; pale yellow, longitudinally
radiated with pink; half-an-inch long and three-fourths of
an inch broad. Inhabits the coasts of Britain.

The Tellinz inhabit the ocean, rivers, and lakes. Those of the ocean
lie buried in the sludge, near the shore, and make two apertures in the
sand ; when the tide has receded, they may be easily found by looking
for these marks.

Genus 7.—CARDIUM.

Animal a Tethys: shell bivalve, nearly equilateral, equi-
valve, generally convex, longitudinally ribbed, striate or
grooved, the margin dentated; hinge with two alternate
teeth in the middle, near the beak; one of them commonly
incurved; and larger remote lateral teeth on one side, each
locking into hollows in the opposite valve.

Cardium edule.—Tue Ep1isLtE Carpium. Plate V. fig.
7. With about twenty-six antiquated longitudinal ribs; of |

BIVALVE SHELLS. 39

a cream yellow colour; the posterior end a little elongated.
Usual diameter one inch; but they are found in Orkney
two and a half inches in breadth, and two and a fourth in
length; in which case the posterior extremity is considerably
produced. When young the cockle is nearly orbicular, and
pure white.

The cockles, with few exceptions, inhabit the ocean only; they, in
general, burrow just under the surface of the sand, being but barely
covered, owing to the shortness of their tube, by which they draw in
and throw out the water. They are used as a wholesome and nourish-
ing food ; and abound on most sandy shores.

Genus 8.—_MACTRA.

Animal a Tethys; shell bivalve, with unequal sides, equi-
valve ; middle tooth of the hinge complicated, with a small
hollow on each side, laterai teeth remote, and inserted into
each other.

Mactra Lutraria.—TueE mup Macrra. (Lutraria ellip-
tica, Lamarck ) Plate VI. fig. 8. Transverse oblong-oval,
smooth, with irregular concentric strie, and an olive, or
yellowish epidermis, glossy white within; gaping at both
ends. Two and a half inches long, and from four to six
broad. Inhabits the British coasts.

Shells of this genus are never found in fresh water, but lurk in the
sand or sludge, most commonly in the estuaries of rivers, or near
them.

Genus 9.—DON AX.

Animal a Tethys; shell bivalve, with generally a crenu-
late margin, the frontal margin very obtuse; hinge with two
teeth, and a single marginal one placed a little behind, rarely
double, triple, or none.

Donax Trunculus.—Tut Truncatep Donax. Plate
IV. fig. 6, and Plate VI. fig. 9. Transverse, oblong, glossy,
finely striated longitudinally, and transversely banded and
radiated with purple; white, clouded with purple within;
internal margin crenulated. Inhabits the British coasts.

The shells of this genus are transverse, triangular, inequilateral, flat-
tened, truncated before, and wedge-shaped. They inhabit the ocean ;

D2

4() LINNAZAN GENERA.

lurking in the sand of the shore, where they may be found on the reflux
of the tiae ; but also in rather deep water.

Genus 10.—VENUS.

Animal a Tethys; shell bivalve, the frontal margin fiat-
tened, with incumbent lips; hinge with three teeth, all of
them approximate, the lateral ones divergent from the tip.

This genus is divided into two sections: pubentes* and impu-
bentes.** This latter section is subdivided into three families: sub-
cordate,+ orbicular,t+ and oval.ttt

Venus Chione.—TuHE CHIONE VENUS. Plate L. fig. 4.
(Cytherea Chione, Lamarck.) Shell strong, sub-cordated,
somewhat concentrically wrinkled, margin entire, covered
with a smooth, glossy, chestnut-coloured epidermis ; some-
times a little radiated; beneath which the shell is of a beau-
tiful pale purple; apex turned sideways, with a cordiform
depression; umbo placed nearest one end. Inhabits the sea
at Falmouth in Cornwall.

aa Summit, bb lunule,? anterior slope, k posterior slope, o disk, p
margin or limb.

Venus compressa.—THE CoMPRESSED VENUS. Plate I.
fiy. 9. (Crassina compressa, Leach.) Shell strong, thick,
suborbicular, compressed, and slightly suleated or irregularly
wrinkled; colour white, but is usually covered by a thick
yellowish-brown epidermis; umbo prominent, turning to one
side, beneath which is a small cordiform depression; hinge
with two teeth in one valve, and a transverse one. Inhabits
the British seas.

c Sides, d base, e € cicatrix, g g teeth of the hinge, w the umbo.

Venus decussata.—_TurE DecussaTED VENUS. Plate I.
fig. 11. Shell ovate, with decussate striae, angular before ;
apex turned to one side; umbo placed nearest one end;
hinge furnished with three teeth in one valve; posterior
slope very minute and retuse; anterior slope long and narrow,
with generally an inner blue margin. The outside is com-
monly of a plain rusty brown, and marked with purple zigzag
lines. Two inches long and three broad. Inhabits the
British seas.

BIVALVE SHELLS. 4]

a Summit, ¢ ¢ cicatrix, g g g teeth of the hinge, 1 the inside.

Venus aurea.—TuE GOLDEN VeENus. Plate VI. fig. 10.
Suborbicular, inequilateral, transversely striated, and striated
concentrically; of a fine golden-yellow. One inch long, one
and a half broad. Inhabits the British seas.

The shells of this genus inhabit the ocean. They in general lurk in
the sand; and many of the larger species are only to be found in very
deep water.

Genus 11.—SPONDYLUS.

Animal a Tethys: shell hard, solid, and ridged, with un-
equal valves; one valve in general convex, and the other
rather flat: hinge with two recurved teeth, separated by a
small hollow.

Spondylus Gederopus.—TuE G#£DEROPUS SPONDYLUS.
Plate VI. fig. 11. Upper valve red, under one white with
longitudinal striz and ribs, rough granulations, and some-
what tongue-shaped, truncated spines, which are rather
short. Three inches long. Inhabits the Mediterranean,
and is considered excellent food by the Italians. It is sold
in the markets at Nice, and other towns on the Mediter-
ranean.

Some of the Spondyli have ears, and others are devoid of
them; they are in general strong, rugose shells. This genus
requires considerable attention, as some of the species are
subject to such variety, that they are frequently mistaken for
distinct shells.

The shells of this genus inhabit the ocean. They adhere to rocks
in deep water, and require considerable force to tear them from their
retreats.

Genus 12.._CHAMA.

Animal a Tethys; shell bivalve, rather coarse; hinge with
a callous gibbosity, obliquely inserted into a slanting cavity ;
anterior slope closed.

Chama Cor.—Tue Heart Cuama. Plate IL. fig. 5, and
Plate VI. fig. 12. (Isoreardia Cor, Lamarck.) Shell sub-
globose, beaks recurved; anterior slope with a gaping fent,

dD 3

42 LINN.EBAN GENERA.

slightly wrinkled transversely, covered with a terra-sienna- |
coloured epidermis; umbo large and prominent, much con-
torted or incurvated, turned to one side, and not touching
when the valves are closed; hinge strong, teeth flattish ;
inside smooth, white, margin plain. This is a very scarce |
British shell; but has been found off the North Foreland, ly.
the Hebrides, and in the Irish Channel, of large size.

o Disk, rv beak. Plate II. fig. 5.

The shells of this genus inhabit the ocean ; they live only in very
deep water.

The Chama Gigas, (Tridacna Gigas, Lamarck,) Giant Chama, is the
largest and heaviest shell yet discovered, an individual having been
seen of the amazing weight of 532 pounds, and the animal inhabitant

so large as to furnish one hundred and twenty-two men with a meal ;
it is said to be very palatable. This species inhabits the Indian Ocean.

Genus 13.—ARCA.

Animal a Tethys; shell bivalve, equivalve; hinge with
numerous sharp teeth, alternately inserted between each

other.
Arca Noe.—Noau’s Ark. Plate VI. fig. 12. Shell rhom-

bic, reticulated, beaks near one end, incurved, very remote
and separated by a deep groove; of a deep umber colour, or
whitish, with brown bands; orifices brown; and margin cre-
nated. ‘Two inches broad. Inhabits the West Indian seas,
the Mediterranean and also Britain, but there of a small size.

Linneus divides this genus into two families: * with the margin
entire; ** with margin crenulated; and has subdivided them as fol-
lows: + beaks recurved ; and ++ beaks inflected.

Some of the Arce are affixed by the foot of the animal to rocks ; and
others lurk in the sand or mud near the sea-shore, generally between
high and low water-mark.

Genus 14.—OSTREA.

Animal a Tethys; shell bivalve, generally with unequal
valves, and slightly eared; hinge without teeth, but fur-
uished with an ovate hollow, and for the most part lateral
transverse grooves.

The Ostrez are divided into three families: * valves radiated and
eared, as in scallops ; ** rugged or rough, as in the oyster; *** hinge

BIVALVE SHELLS. 43

with a perpendicular furrowed line, as in the species of the genus
Perna, The first family is again subdivided into three sections:
t valves equilateral, and ears equal; tt ears unequal, and having one
of them generally ciliated with spires within ; +tt valves gibbous on
one side.

Ostrea levis.—TueE SmootTH OstreEa. Plate II. fig. 2.
(Pecten Levis, Lamarck.) Shell thin, flat, suborbicular,
and pellucid, longitudinally and transversely striated; one
ear considerably larger than the other; colour various, some-
times orange, dark pink, &c. Not uncommon on the coast
of Northumberland. The striz on this shell are so minute,
that they can seldom be seen with the naked eye.

F Longitudinal and transverse striz, H H ears or auricles.

Ostrea opercularis.—TuE Lip OstrEA. Plate VIL. fig.
14. Ears nearly equal; shell with about twenty rounded
ribs finely striated longitudinally and transversely; beauti-
fully variegated with red, orange, purple, or brown; upper
valve somewhat convex. Inside pure white. Three inches
long. Inhabits the British seas.

The Ostreze inhabit the ocean; some lurk in the sand in large beds,
others adhere to rocks, and some to the mangrove trees which overhang
the sea on the shores of the West Indies.

The Edible Oysters of Britain are said to be superior to those of all
other countries, and are common on many of our coasts. Indeed, this
country has been noted for oysters from the time of Juvenal, who flour-
ished in the beginning of the second century. In satirizing Montanus,
an epicure, he says:

He, whether Circe’s rock his oysters bore,
Or Lucrine lake, or distant Richborough’s shore,
Knew at first taste.

The luxurious Romans were very fond of oysters, and had their layers
or stews for them as we have at the present time. Sergius Orata was
the first inventor, as early as the time of L. Crassus the orator. He
did not make them for the sake of indulging his appetite, but through
avarice, and enjoyed great profits from them. Orata got much credit
for his Lucrine oysters, for, says Pliny, the British were not then
known,

The oyster is a very entertaining object to those who are fond of
microscopic investigation. In the clear liquor around the animal, many
minute, round, living animalcules have been found, whose bodies being
conjoined, form spherical figures with tails, not changing their place
otherwise than by sinking to the bottom, being heavier than the fluid;
these have been frequently seen separating, and coming together again

44 LINNEAN GENERA.

In other oysters, animalcules of the same kind were found not con-
joined, but swimming by one another, where they seemed in a more
perfect state, and were judged ‘by Leeuwenhoek to be the animalcules
in the roe or melt of the oyster.

A female oyster being opened, incredible numbers of small oysters
were seen, covered with little shells, perfectly transparent, and swim-
ming along slowly in the liquor; and in another female, the young
ones were found of a brown colour, and without any appearance of life
or motion.

In the month of August oysters are supposed to breed, because young
ones are then found in them. Leeuwenhoek, on the 4th of August,
opened an oyster, and took out of it a prodigious number of minute
oysters, all alive, and swimming nimbly about in the liquor, by means
of certain exceeding small organs extending a little way beyond their
shells; and these he calls their beards. In these little oysters he could
discover the joinings of the shells; and perceived that there were some
dead ones, with their shells gaping. These, though so extremely
minute, are seen to be as like the large oyster, as one egg is like
another.

As to their size, he computes, that 120 of them in a row would extend
an inch; and consequently, that a globular body, whose diameter is an
inch, would, if they were also round, be equal to 1,728,000 of them. He
reckons 3,000 or 4,000 are in one oyster, and found many of the embryo
oysters among the brairds ; some fastened thereto by slender filaments,
and others lying loose ; he likewise found animalcules in the liquor 500
times less than the embryo oysters.

Genus 15.—ANOMIA.

Animal an emarginate ciliate strap-shaped body, with
bristles or fringes affixed to the upper valve; arms two,
linear, longer than the body, connivent, projecting, alternate
on the valve and ciliate on each side, the fringe affixed to
each valve; shell bivalve, inequivalve, one of the valves
flattish, the other gibbous at the base with a produced beak,
generally curved over the hinge; one of the valves often
perforated near the base; hinge with a linear prominent
cicatrix, and a lateral tooth placed within, but in the flat
valve on the very margin; two bony rays for the base of the
animal. Plate VII. fig. 15.

Anomia undulata.—THort Wavep Anomta. Plate VII.
fig. 15. Suborbicular, with fine irregular, undulated, longi-
tudinal, smooth striz, crossing transverse curved ones; in-

BIVALVE SHELLS. 45

side pearly shining green. One and a half inch wide. In-
habits the British seas

Anomia Ephippium.—Tue Sappie Anomta. Plate I.
fig. 7. Shell suborbicular, irregularly wrinkled, and waved ;
upper valve convex, under flat and perforated at the hinge,
through which the ligament passes by which it is affixed to
other bodies; inside perlaceous, and of various changing
colours; green, purple, violet, or yellow.

Often to be met with adhering to the common oyster, or Ostrea
maxima.

a Base, m ligament perforation.

The Anomiz inhabit the ocean. The animal attaches itself to fuci,
shells, stones, and other extraneous bodies at the bottom of the sea:
they are generally affixed by a testaceous plug, which adheres to one
of the muscles of the animal and passes through the perforation in
the flat valve.

Genus 16.—MYTILUS.

Animal allied to an Ascidia; shell bivalve, rough, gener-
ally affixed to other bodies by a byssus or beard of silky
filaments; hinge mostly without teeth, having a subulate,
excavated, longitudinal line. Plate VII. fig. 16.

The Linnzan Mytili are divided into three families: * parasitical,
affixed as it were by claws, as exemplified in the Mytilus Crista Galli ;
** flat or compressed into a flattened form, and slightly eared; as in
the Mytilus margaritiferus ; *** elongated, ventricose, or convex, as
in Mytilus edulis.

Mytilus edulis—_Tue Eprste Mouscre. Plate II. fig.
4 and 6. Shell oblong, pointed at the beak, sides much
sloped; ‘anterior side a little angulated; smooth, and radi-
ated with deep blue or purple; covered with an umber-
coloured epidermis; inside, round the margin, of a fine blue,
which grows gradually lighter towards the centre; cicatrix
very distinct and glossy; beneath the beak are several
crenulations, which some have supposed to be teeth.

This is the most common shell we have, and well known
by the name of Muscle or Mussel. It forms a pleasant and
nutritious food. They have, however, in some localities,
proved poisonous, and fatal consequences have followed

\

46 LINNEZAN GENERA.

eating them. The true nature of this poison has not yet
been satisfactorily determined.

Plate II. fig. 4 and 6. a The cartilage, v v length of the shell, u «
breadth of the shell, o disk, r x the beak.

Mytilus incurvatus.—T ue INcuRVATED Mytitus. Plate
VIL. fig. 16. Oblong oval, nearly smooth, both valves much
inflated, and curved on one side near the ligament, apex
acute, and base much widened. Inhabits the British coasts.
Probably it is only a variety of the Mytilus edulis.

It is to the Mytilus margaritiferus, (the Meleagrina margaritifera of
Lamarck,) Plate X. fig. 10, that we are indebted for that precious gem,
the oriental pearl. Itis an inhabitant of the Indian Ocean; where it
is regularly fished for by men who dive to the bottom of the sea, in
places where it frequents. In this perilous employment the divers are
often attacked by sharks, and not unfrequently lose their lives.—
Mother-of-pearl ornaments are made from the shell itself.

The Mytili inhabit the ocean, lakes, rivers, and ponds. Marine
muscles adhere to rocks or beds by a thin but very tenacious byssus,
consisting of extremely fine and tough filaments, and some to the
Gorgoniz by a kind of claws. Some penetrate calcareous and argil.
laceous rocks, where they reside without changing place, others adhere
to rocks or clay on the shore. They are much used for bait or food,
and as such they are esteemed by many. The fresh-water muscles are
generally found on the surface, or a little way under the mud. Most
species of muscles produce pearls.

Genus 17.—PINNA.

Animal a Limax; shell sub-bivalve, fragile, upright, gaping
at one end, and furnished with a silky byssus or beard: hinge
without teeth.

Pinna pectinata.—Tue PecTINATED Pinna. Plate VII.
fig. 17. Thin, pellucid, light horn coloured; longitudinally
ribbed, and spinous for half its width, obliquely striated,
transversely on the other half. Six and a half inches long
and three broad. Inhabits the British seas.

The Pinnz, which frequently grow to a large size, only inhabit the
ocean. They are generally found standing erect in the smoother water
bays, with the broad end or base of the shell uppermost. They are
sometimes affixed by their byssus or beard, to rocks or other bodies,
and so firmly attached, that they can by no means be disengaged but
at the will of the animal.

In Italy, the byssus of the Pinna is woven into a sort of silk, The

BIVALVE SHELLS. 47

hbres or filaments of which it is composed, are very tough, and of a fine
glossy brown colour. The ancient Romans highly esteemed articles
made of this byssus ; and at Naples and Palermo there are still manu-
factories of it. Stockings, gloves, and even a fabric resembling sarsnet,
are made from it; and also an imitation of broad cloths. This latter
stuff is very expensive, a coat being about the value of ten pounds of
English money.

The Pinna has obtained among the Italians a little reputation for
the practice of some of the moral virtues, in treating a small species of
crab with hospitality and friendship, by receiving it into the shell, and
defending it against its enemies. In return for this kindness, the crab,
like the jackal with the lion, acts the part of a provider and monitor,
by warning its host of the presence of its prey, or the approach of an
enemy. But this friendly intercourse, like the fabulous account of the
lion and the jackal, accords ill with the nature of the animals between
which it is practised. The crab, it is far more probable, is a trouble-
some intruder; and, notwithstanding all the service he can repay, is
considered a very unwelcome guest, and is indebted for his lodging to
his activity and instinctive sagacity in providing for his own persona:
safety, retaining possession from the sluggish nature of his host, rather
than to his kindness and hospitality.

Genus 18.-ARGONAUTA.

Animal a Sepia or Clio; shell univalve, spiral, involute,
membranaceous, and unilocular, or consisting of a single
apartment or cell.

Argonauta Argus.—TuE Arcus ArconauTa. Plate
VII. fig. 18. Involute, extremely fragile, white, ribbed,
and obsoletely striated; the keels approximate and tuber-
culated, from six to eight inches in diameter. Inhabits the
Mediterranean.

The Argonauta Argus, or Paper Nautilus, is the Nautilus so famous

amongst the ancients, and frequently mentioned in the writings ot
Pliny and others.

The singular structure and wonderful economy of this animal very
early attracted the attention of naturalists. To its progressive motion
on the surface of the ocean mankind are indebted, it is said, for the
first hint of using sails in navigation. This is alluded to by Pope, in
the following lines:

Learn of the little Nautilus to sail,
Spread the thin oar, and catch the driving gale.

What the particular organization is which enables this animal to

rise to the surface, or to sink to the bottom of the ocean at pleasure
has not yet been satisfactorily accounted for by naturalists; whether

48 LINNEAN GENERA.

it is by throwing out a quantity of water, by which it becomes specifi-
cally lighter than the element in which it lives, or by taking in a quan-
tity of air, which will produce the same effect. It is only when the sea
is calm and unrufiled, that the Argonauta, with his feeble bark, ap-
pears on the surface. In rising through the water, the shell is reversed,
the sharp edge of the keel presenting less resistance to the liquid, and
when it reaches the surface, the animal, by exserting its arms, restores
it to a proper position for its voyage. A quantity of water is taken
into the shell to balance it ; the animal then employs its arms as oars ;
or if a gentle breeze sweep the surface, it erects an ovate extensible
membrane, at the extremity of the tentacula, in the manner of a sail,
while its arms serve as oars to direct its course, or to keep the shell
steady, as well as part of the body which hangs over the shell and
serves to act the part of a rudder. Thus equipped, the solitary navi-
gator, in his little galley, impelled by the breeze, glides smoothly along
the bosom of the ocean. But on the approach of the smallest danger,
it instantly retires within its shell, and, taking in a quantity of water,
or ejecting a volume of air, quick as thought it sinks to the bottom. In
fine weather this shell is frequently to be met with in the Mediter-
ranean and has obtained amongst seamen the name of “ Portuguese
man-of-war,” under which name, however, are confounded two or more

very distinct animals.

Genus 19.—NAUTILUS.

Animal unknown. Shell univalve, divided into several
compartments, communicating with each other by a siphun-
culus or aperture. F

The Linnzan Nautili are divided into two families: * spiral and
rounded, ** elongated and straight. Of the former there are two
sections: + whorls contiguous, t+ whorls separated.

Nautilus Pompilius.—'THe Prarty Navuriuus. Plate
VII. fig. 19. With the aperture heart-shaped, the spire

involute and concealed, pale yellow with mixed streaks and
undulations of bright chestnut; aperture pearly and shining,
within from five to eight inches in diameter. Inhabits the
East Indian ocean. Plate III. fig. 3, represents this shell
with the lip cut straight, and a piece removed from the
side, to show the involuted spire. ¢ aperture, ¢ involuted
spire.

Nautilus Spirula.—Tue Sprrat Navurtixvs. Plate III.
fig. 1]. (Spirula Peronii, Lamarck.) Aperture of the
shell orbicular; whorls cylindrical, separated, and gradually
decreasing inwards, the first a little straight; siphunculus

UNIVALVE SHELLS. 49

contiguous to the walls of the shell; outside of a pale cream
colour, perlaceous within.
Inhabits the American and Indian oceans.

v Siphunculus, w ww w w chambers.

The curious structure of the shell of the Nautilus Pompilius, (which
also runs, with some variation, through the whole genus,) cannot be
contemplated without admiration, each cell or camera communicating
with the next by a small and short tube, the first or principal cell being
far larger than the rest, and appearing destined to contain the chief
part or body of the inhabiting animal, the nature of which is not yet
properly understood. It appears, however, to be in some degree allied
to the genus Sepia, but is destitute of long arms or claspers, instead of
which it is furnished with several rows of short, broad, subdivided or
palmated tentacula, spreading in a radiated direction round the mouth
or beak: it is also provided with a concave expansile hood or process,
which it is supposed occasionally to extend by way of a sail.

The animal is figured in Shaw’s Nat. Misc. Plates 579 and 580. But
it has been more correctly described and figured by Professor Owen
and other anatomists of the present day.

With a very few exceptions the Nautili have only been found to in-
habit the ocean.

Genus 20.—CONUS.

Animal a Limax; shell univalve, convolute, turbinate ;
aperture effuse, longitudinal, linear, without teeth, entire
at the base; pillar smooth.

This genus in the Linnzan System is divided into five families:
*having the spire or turban nearly truncate or flat; **pyriform, with
the base rotundate, and sub-cylindrical, the cylinder one half longer
than the spire; ***elongate, with the base rotundate, cylinder twice
the length of the spire; #***yentricose in the middle, and narrow at

each end; *#****ventricose, and emits a tinkling sound when thrown
on its back upon a table.

Conus striatus.—TuHE StriaTeD Cone. Plate VIII.
fig. 20. Ovate, oblong, gibbous, clouded, and with strong
transverse striez. Four inches long. Inhabits Africa and
India.

Conus varius. Plate II. fig. 12. Rubbed through to
show the internal structure of the shell. pb Spire, Fr body,
M MM pillar or columella.

The Cones inhabit the ocean, and are generally found on rocky

shores.
. E

50 LINNAAN GENERA.

Many of the Cones are very beautiful. Some of them bring the
highest prices of all shells, from their great rarity. One species, the
Cedo Nulli of Lyonet, is valued at one hundred guineas. Cones are
covered with an epidermis, and it is not till this is removed that their
beauty can be seen. Their surface is highly polished, contributing
much to heighten the delicate and glowing tints which are diffused
over some of the finer species in an infinite variety of undulations,
clouds, spots, and bands.

Genus 21.—CY PRA.

Animal a Slug; shell univalve, involute, sub-ovate,
smooth, obtuse at each end; aperture effuse at both ex-
tremities, linear, extending the whole length of the shell,
and dentated or toothed on each side.

Linnzeus divides the genus Cypreea into four families: *mucronate,
or pointed ; **obtuse, and without any manifest spire; *#**#umbili-
cated, or with a small perforation ; ****marginated.

The genus Cyprza consists of beautifully coloured, and very highly
polished shells. It is said, that they leave their shells annually, and
construct new and larger ones. But we have not been able to ascer-
tain this point as a fact.

They live in sand at the bottom of the sea; the animals are provided
with a membrane, which they throw over their shells, and which pre-
serves the fine polish, and prevents other testaceous bodies from fixing
on them. The Cyprez have only been found to inhabit the ocean.

Cyprea Uropea.— THE European Cyprma. Plate
VIII. fig. 21. With numerous transverse furrows, tumid
on the back, pale purple or whitish, and generally with
three dark blackish-brown spots. Half an inch long. In-
habits the British seas.

Genus 22.—_BULLA.

Animal a Limax; shell univalve, convolute, and unarmed
with teeth; aperture a little straitened, oblong, longitudinal,
very entire at the base; pillar oblique and smooth.

Bulla Catena.—Tue Cuain Butua. Plate VIII. fig.
22. (Bullea Catena, Lamarck.) Ovate, white, pellucid,
with minute chain-like transverse striz; aperture extremely
large, obtuse at the top, with a singie volution, and one-
fourth of an inch long. Inhabits the British seas.

f UNIVALVE SHELLS. 5]

The shells composing the gents Bulla inhabit the ocean, lakes,
rivers, and ditches. The marine species are found a few inches under
the sand. Some of the species may be frequently taken alive in littie
pools, between high and low water-mark, in which they are often seen
sporting, with a very rapid motion, in the sunbeams.

The animal inhabiting the Bulla is considerably too large for its
shell, and cannot contract itself wholly within it, as most other animals
which have a testaceous covering can do.

Genus 23.—_ VOLUT A.

Animal a Limax; shell single celled and spiral; aperture
without a beak and somewhat effuse; pillar twisted or
plaited, generally without lips or perforation.

Linnzeus divides this very extensive genus of shells into five distinct
families: *aperture or opening entire; **somewhat cylindrical and
emarginate ; ***obovate, effuse, and emarginate; ****fusiform ;
¥****Ventricose, spire papillary at the top.

Voluta episcopalis._Tur Episcopan Votorta. Plate
VIL fig. 29. (Mitra episcopalis, Lamarck.) Emarginated,
smooth, margin of the volutions entire; lip denticulated;
columella with four plaits. Five inches long. Inhabits
the Indian ocean. Variously spotted with orange.

Voluta Oliva.—Tue Oxtve Votuta. Plate II. fig. 7.
(Oliva, Lamarck.) Shell smooth and glossy; spire re-
flected at the base; pillar with four plaits; clouded, or
covered with zigzag or waved lines of a pale brown colour.
Found in the Indian seas, in endless varieties of colours and
markings.

A Apex, 1 front, n outer lip, z plaits of the pillar-lip or columella.
The Volutes have only been found in the ocean, and are most com-
mon in inter-tropical climates.

Genus 24..-BUCCINUM.

Animal a Limax; shell univalve, spiral, gibbous; aperture
ovate, terminating in a short canal, leaning to the right, with
a retuse beak or projection; pillar-lip expanded.

The Buccina are divided by Linnzus into nine iamilies: *inflated,
rounded, thin, sub-diaphanous, and brittle; **with a short, exserted,

reflected beak, lip unarmed outwardly; ***lip aculeated on the out-
side of the posterior part; in other respects resembling the last divi-

E2

cp ian

52 LINN/AN GENERA.

sion ; ****pillar-lip dilated and thickened ; *****pillar-lip appearing
as if worn flat; ******smooth, and not enumerated in the former
divisions ; ****#%**aneular, and not included in the former divisions ;
KEKKKKEE tapering, Subulate, and smooth.

Buccinum Lapillus.—Turt Common Wurte Buccinum,
Plate VIII. fig. 24. (Purpura Lapillus, Lamarck.) Oval,
pointed, spirally ridged, and faintly striated; columella
broad, flattish, and impressed near the top; yellow, white,
chestnut, orange or brown, sometimes with spiral bands;
aperture oval, acute, lip thin, and slightly crenate. One
inch long. Inhabits the European seas.

This is one of the shells from which the ancients are supposed to
have extracted their indelible purple dye, called the Tyrian purple.
The part containing the colouring matter, is a longitudinal vein, just
under the skin on the back, behind the head, appearing whiter than
the rest of the animal. If the vein is laid open with a needle, a tena-
cious yellow matter will flow, which being applied with a hair pencil
to linen, silk, or paper, will in a short time become of a bright yellow,
will soon change to pale green, then assume a bluish cast, and after-
wards a deep and brilliant purple. These changes are more or less
accelerated by the presence or absence of the solar rays: but even
without the influence of the sun, it will go through all these changes
in two or three hours. Neither air, light, nor washing can afterwards
alter its hue.

The Buccina generally inhabit the ocean, or its shores.

Buccinum undatum.—TuHe Wavep Buccinum. Plate
II. fig. 10. Shell with from seven to eight ventricose volu-
tions, and undulated ribs; transversely striated, and crossed
with fine longitudinal strie; pillar-lip reflected, and glabrous.
Inside white, or deep yellow in some. Four inches long.

A common shell on most of the British shores.

F Body, mo the pillar or columella, @ canal or gutter.

Genus 25.—STROMBUS.

Animal a Limax; shell univalve and spiral; aperture
much dilated; the lip expanding and produced into a groove
leaning to the left.

Linnzeus divides the Strombi into four families: *lip projecting into

linear divisions or claws; **lobed; ***dilated; ****tapering, with
a very long spire.

i .

UNIVALVE SHELLS. 53

Strombus Pes-Pelecani.—PEtican’s Foot STROMBUS.
Plate VIII. fig. 25. (Rostellaria Pes-Pelecani, Lamarck.)
Volutions surrounded by a row of tubercles; lip expanded
into four palmate angular claws; body with two rows of
tubercles, gray or reddish-brown. Two inches long. In-
habits the British coasts.

The shells composing this genus inhabit the ocean, and are in gen-
eral found on rocky shores.

Strombus pugilis—_Tue Ficutinc Strompvus. Plate
III. fig. 8. Anterior lip prominent, rounded, smooth; spire
spinous; beak three-lobed, obtuse, flesh-coloured, reddish
or brownish, within paler and polished; back smooth; first
whorl of the spire crowned with spines, which in the others
grow gradually less; the outermost whorl cancellate; pillar-
lip much reflected; three and a half inches long.

Inhabits South America, and the shores of the West
India islands.

D Spire, 1 front, NNN the outer lip, o pillar-lip, @ canal or gutter.
The young shells of this genus want the dilated lip, which is one of

the most essential characters of the Strombi, and are in consequence
liable to be confounded with the genera Buccinum and Murex.

Genus 26.._MUREX.

Animal a Limax; shell univalve, spiral, rough, with
membranous sutures; aperture oval, ending in an entire
straight or slightly ascending canal.

Linnzus divides the Murices into six families: *spinous, with a pro-
duced beak; **sutures expanding into crisped foliations; beak ab-
breviated ; ***ventricose, with thick protuberant rounded sutures ;
****more or less spinous, and without manifest beak; *****with
a long, straight, subulate, closed beak, and unarmed with spines ;
******tapering, subulate, with a very short beak.

Murer antiquus.— THe ANTIQUATED Murex. Plate
VIIL. fig. 26. (Fusus antiquus, Lamarck.) Oblong, trans-
versely striated; beak rather elongated; spire with seven
or eight convex volutions: yellowish white, aperture saf-
fron-yellow, with margin of outer lip acute, and entire.
From six to eight inches long. Inhabits the British coasts.

E3

54 LINNZAN GENERA.

Murex muricatus.—The MuricaTep Murex. Plate II.
fig. 11. Shell strong and rough, with from six to seven
ventricose, tuberculated volutions, tapering to a fine point;
the tubercles are formed by interrupted, longitudinal ribs,
srossed by strong elevated striz, and in some parts are
pointed or angulated; apex smooth; aperture oval, termi-
nating in a long slender canal; outer lip sharp and dentated
at the edge, margin within crenulated; pillar-lip smooth.
Inhabits the British seas, rather a local shell.

B Base, c aperture, KK, Wc. sides, Pp the beak or rostrum, @ canal or
gutter.

The Murices are only found in the ocean. They in general frequent
rocky shores, and some of them burrow in the sand.

Genus 27.—TROCHUS.

Animal a Limax; shell univalve, spiral, more or less
conic; aperture somewhat angular or rounded, the upper
side transverse and contracted; pillar placed obliquely.

Linnzeus divides the Trochi into three families: *umbilicated, erect,
with pillar perforated ; **imperforate, erect, with the umbilicus closed ;
**#tapering, with an inserted pillar, and falling on the side when
placed upon the base.

Trochus papillosus.—THE PimpLeD Trocuus. Plate
VIII. fig. 27. Conic, imperforate at the base, spirally
granulated, and not marginated at the edges of the volu-
tions; body tumid, and spire tapering abruptly to an acute
apex; flesh-coloured; one and a half inch long.

Trochus umbilicatus.— THe UmBinicATED TRocuvus.
Plate III. fig. 1. Shell conico-convex, flattish, rounded at
the top; apex depressed, volutions five, slightly emarginate,
defined by a fine line; spirally striated, rather whitish, with
zigzag lines of purple; aperture compressed and angulated;
with a large umbilicus which extends to the apex. Found
on the Northumberland and Yorkshire coasts.

c Aperture, v umbilicus.

The Trochi inhabit the ocean, with the exception of a few land

species. They generally frequent pools, which are wet when the tide
recedes; some few of them live in very deep water.

|

a

UNIVALVE-SHELLS. 55

Genus 28.— TURBO.

Animal a Limax; shell univalve, spiral, and solid; aper-
ture contracted, orbicular, entire.

The shells composing this genus are divided into five families: *with
the pillar-margin of the aperture dilated and imperforate; **solid
and imperforate ; ***solid, perforated ; ****cancellated ;*****tapering.

Turbo rudis.—Tur Rustic Turso. Plate IX. fig. 28.
Sub-oval, faintly striated transversely, with five tumid volu-
tions; outer lip thick, glossy within; dull yellow, drab,
or fawn coloured; volutions separated by a deep suture.
Three-fourths of an inch long. Inhabits the British coasts.

Turbo Terebra.—Tue Aucer Turpo. Plate III. fig. 9.
(Turritella terebra, Lamarck.) Taper, pointed, with twelve
or-sixteen volutions, and numerous strong, spiral striz, the
intermediate spaces prominent and acute; white, reddish,
or cream coloured; one and a half inch long. Inhabits the
British seas.

This figure represents the shell sectioned, to show the in-
ternal structure of the columella, F body, m mm columella.

Turbo costatus.—Tue RisBeD Torso. Plate III. fig.
12.. (Pyramis costatus, Brown.) Shell sub-pellucid, white,
and subturreted; volutions five, with prominent, longitudinal
ribs, a little oblique; apex obtuse; aperture suborbicular,
with a thick sulcated margin.

Found on the coasts of Pembrokeshire, Dorsetshire, and
Northumberland.

RRER Ribs.

Turbo labiatus.—Tur Lippep Turso. Plate III. fig.
13. (Clausilia labiata, Lamarck.) Shell with nine re-
versed volutions or whorls, tapering to a fine point; colour
light brown, with strong, regular, longitudinal striz; volu-
tions flat, and separated by a fine obsolete line; aperture
suborbicular and white, with a sinus at the upper end, and
two teeth-like lamine on the inner lip; margin reflected,
broad and thick. Found in Hyde Park, and the osier grounds
at Battersea in Surrey.

56 LINNEAN GENERA.

Plate III. fig. 13. B Reversed or heterostrophe spire, a teeth of a
univalve.

The shells of this genus inhabit the sea, land, and fresh water ; they
adhere to rocks near the shore; and some of them live in very deep
water.

The Turbo scalaris, or wentletrap, is very much esteemed by collec-
tors, and is rather a scarce shell.

Genus 29.—HELIX.

Animal a Limax; shell univalve, spiral, subdiaphanous,
brittle; aperture contracted, semilunar or roundish.

Linnzus divides the Helices or Snails into six families: *angulated
on both sides; **whorls with a carinate acute margin; ***whorls

rounded and umbilicated; ****rounded and imperforate; *****#taper-
ing; ******ovate and imperforate.

Helix arbustorum.—TueEe Grove HeEtrix. Plate IX. fig.
29. Sub-globose, sub-pellucid, with five volutions; mottled
with ash-colour, and streaked with deep chestnut zigzag
lines; a single deep brown band commences at the edge of
the outer lip, and continues round the middle of the body
and the volutions to the apex; 3ths of an inch in diameter.
Inhabits groves, thickets, hedge-banks, and places covered
with strong herbage, in Britain.

Helix vivipara.—Tue Viviparous Hexix. Plate II.
fig. 8. (Paludina vivipara, Lamarck.) Shell with six
ventricose whorls, separated by a deep depressed line; sub-
ovate and obtuse; of an olive-green, with generally three
fascize or bands on the body of the shell, and two on the
superior volutions, which become obscure in the fourth;
slightly wrinkled transversely; aperture suborbicular ; pil-
lar-lip reflected; sub-umbilicated. Found in the Thames
and New River.

A Apex, B base, L a whorl, 8 R oands or fascize.

Helix polita.—Tue Porisnep Hexrx. Plate II. fig. 9.
(Pyramis politus, Brown.) Shell strong, white, glossy
and smooth, with from nine to twelve volutions, scarcely
defined by a separating line, slender and gradually tapering
to a point; aperture oval, outer lip thick, but not margin-

UNIVALVE SHELLS. 57

ated, inner or pillar-lip replicated. Found in Devonshire,
Dorsetshire, Northumberland, and at Dunbar, and on the
coast of Aberdeenshire, in Scotland.

A Apex, B base, EE suture of the spire or whorls, c a>erture.

Helix nemoralis.—Tue Woop Hetrx. Plate IIL. fig. 2.
Shell imperforate, sub-globose, thin and sub-pellucid, colour
various; volutions five, with from one to five dark brown
bands or fascie; aperture pyriform; inner margin of the lip
dark-reddish brown. This shell is very common in England
and the south of Scotland, at the roots of hedges, on grassy
banks, or by walls.

n Outer lip, x epidermis, y epidermis removed.

Helix glutinosa.—Tue Guutinous Hetrx. Plate III.
fig. 5. (Lymnea glutinosa, Lamarck.) Shell suborbicular,
thin, and diaphanous, of a glossy, pale horn-colour, smooth,
but sometimes with obsolete wrinkles; the body very large;
spire very small; volutions three; aperture very large, ex-
tending nearly to the apex. Found by Mr. Montagu, in
the marshes at Deal.

&@ The back, H the venter, L whorl or volution.

Helix putris—Tue Dircw Hetrx. Plate III. fig. 10.
(Lymnza ovata, Lamarck.) Shell sub-pellucid, and horn-
coloured; spire with four volutions; the body tumid and
large; wrinkled longitudinally ; apex very small, fine, and
pointed, aperture oval and large, outer-lip very thin; out-
side covered with a dusky epidermis, inside pale yellow, and
very glossy.

Common in most ponds, ditches, brooks, and rivers.

Helix planorbis.—Tue FLATTENED HeEtix. Plate III.
fig. 14. (Planorbis earinatus, Lamarck.) Shell depressed
and sub-pellucid, horn-coloured, rufous, or light chestnut
brown; generally with a light umber-coloured epidermis;
volutions five, placed laterally on each other, gradually
decreasing to the centre, making the shell concave at top,
rounded and defined by the suture; striated across the
whorls; a carinated ridge round the margin at the base;

—

58 LINNZAN GENERA.

aperture angulated, and slanting towards the base. Inhabits
ponds, rivers, and ditches in Britain.
Helix subulata.—Tuer Awui-SHAPeED HEtrx. Plate III.
fig. 7. (Pyramis subulatus, Brown.) Shell tapering and
subulate, very smooth, and glossy; whorls about ten, and
scarcely defined; colour white, with two _ pale-chestnut
spiral lines running from the body to the apex, becoming
very faint on the upper whorls; aperture ovate, and rather
contracted. Length three quarters of an inch. Inhabits
the sea at Weymouth, the Frith of Forth, and the coast of
Aberdeenshire.
D Spire, F body, o pillar-lip.
Habitation. The Helices are found in the ocean, in lakes, rivers,
and on the land. They are inhabitants of almost all countries of the
globe, and are in general very numerous. On land they are found to
inhabit trees, old walls, mossy banks, and rocks, as well as under stones.
The animals of this genus are termed snails in Britain ; they feed on
vegetables. It has been asserted, and on apparently good authority,
that snails have been known to revive after remaining in torpidity for
a number of years; snails are possessed of very considerable repro-
ductive powers, and are capable of reproducing the head after it is
taken off.

Genus 30.—NERITA.

Animal a Limax ; shell univalve, spiral, gibbous, flattish
at bottom; aperture semi-orbicular, or semilunar ; pillar-
lip transversely truncate, flattish.

This genus is divided into three families: *umbilicate ; **imperfo-
rate, with the lips toothless ; ***imperforate, with the lips toothed.

Nerita littoralis. Tur SuHore Nerira. Plate IX. fig.
30. (Neritoides littoralis, Brown ) Globular, thick, smooth ;
spire flat; yellow, covered with an olive epidermis, beneath
which the shell is either yellow, orange, or red, frequently
with elegant zigzag lines of red or brown. Three-fourths
of an inch long. Inhabits the British coasts.

The Neritze inhabit the sea, lakes, and rivers. The marine species
are found near the shore, and several are attached to marine plants ;

some are only found in deep water so that live specimens can only be
had by trawling for them.

4

SHELLS WITHOUT A REGULAR SPIRE. 59

Genus 31.—HALIOTIS.

Animal a Limax; shell ear-shaped; univalve and dilated,
with a longitudinal row of orifices opening on the surface;
spire lateral, and nearly concealed.

The animals composing the shells of the genus Haliotis, inhabit the
sea only. They adhere closely to rocks, and can only be removed by
suddenly snatching them from their hold. In some places the animal
is esteemed good eating. One species, the Haliotis tuberculata, is very
common in Guernsey, and sold in the market as food.

Haliotis tuberculata.— Tue TupsercuLtaR HALtioris.
Plate IX. fig. 31. Dull reddish brown on the outside,
sometimes clouded or mottled with a deeper shade: longi- |
tudinally striated, and transversely wrinkled, with a few
raised tubercles; inside perlaceous, reflecting the most beau-
tiful shades of pink, blue, green, and yellow; aperture open
the whole length of the shell, outer-lip irregular. From
three to four inches long. Inhabits the sea at Guernsey.

It is asserted, that as a new hole is added by the animal to the shell,
it carefully closes up the next open one to the spire ; by which means
the number of orifices is, in general, the same in all shells of one {|
species.

DIVISION SECOND.—_SHELLS WITHOUT A REGULAR SPIRE.

Genus 32.—PATELLA.

Animal a Limax; shell univalve, subconic, shaped like a |
bason; without a spire.

Linnzus divides this genus into five families: *furnished with an in-
ternal lip; shell entire; **with the margin angular or irregularly |
toothed ; ***with a pointed recurved tip or crown; *#***very entire, ||
and not pointed at the tip or vertex ; *****with the crown perforated.

Patella vulgata.—Tue Common Patents. Plate IX.
fig. 32. Subject to great exterual variety; ribbed from the
vertex to the margin in some specimens, and with divergent
strie; others striated merely, without ribs; of a dark brown
or olive green on the outside, and the inside blue, shining |
with deep purple radiations; and presenting a great variety

60 LINNEAN GENERA.

of colour; apex obtuse, and placed towards the narrow end
of the shell, which is usually ovate. From one to two
inches long. Inhabits the shores of Northern Europe.

Patella Chinensis —Tue Cutnesé PatTetia. Plate III.
fig. 6. (Calyptreea sinensis, Lamarck.) Shell sub-conic,
sub-pellucid, and very thin, colour whitish, much compressed,
rounded at the margin; vertex central, terminating in a sub-
spiral volution, with usually a number of concave scales.
Inside white, glossy, and smooth, with a sub-spiral colu-
mella or pillar-lip, extending from nearly the margin to the
end, and forming the external sub-volution ; it is broad, flat,
and oblique. Found in Helford harbour, Cornwall; in Sal-
comb bay, Devonshire, by Col. Montagu; and near Dunbar,
by Captain Laskey.

The shells of this genus inhabit the sea, lakes, and rivers. Those of
the sea in general adhere to rocks and stones on the shore; and are
so tenacious, that they cannot be removed without great force, unless
taken by surprise. Those inhabiting fresh water are generally found
attached to stones or aquatic plants. The Patelle are called Limpets
in Britain.

w Chamber.

Genus 33.—DENTALIUM.

Animal a Terebella; shell univalve, tubular, straight, or
slightly curved, with the cavity undivided, and open at both
ends.

Dentalium Entalis.—Tue Tooth Dentatium. Plate
IX. fig. 33. White or yellowish, slightly curved, and taper-
ing toa fine point; slightly striated. One and a half ‘inch
long. Inhabits the British seas.

The shells of this genus are only found in the ocean. They are soli-
tary, and lie in the mud, in an oblique or perpendicular position,

Genus 34.._SERPULA.

Animal a Terebella; shell univalve, tubular, generally
adhering to other substances; often separated internally by
divisions at uncertain distances.

Serpula vermicularis.—THE WoRM-LIKE SERPULA. Plate
IX. fig.34. White, cylindrical, tapering, and variously curved

eee ees |

SHELLS WITHOUT A REGULAR SPIRE. 61

and twisted ; always affixed to other substances. Inhabits
the British seas.

The Serpulze inhabit the ocean. They generally adhere to stones,
shells, or plants; sometimes a plurality of species is found on one
stone or shell. There are also several species of Serpula which are
unattached.

Genus 35.—TEREDO.

Animal a Terebella, with two calcareous, hemispherival
valves cut off before, and two lanceolate ones: shell taper-
ing, flexuous, and capable of penetrating wood.

Teredo navalis.—TueE Suite TEREDO. Plate IX. fig. 35.
Cylindrical, taper; smooth, white, and flexuous, finely stri-
ated longitudinally.

The shells of this genus inhabit the bottoms of ships; and poles or
planks, which are under water in harbours and docks. One species
| has been found in the mud, at the bottom of the ocean. This last
mentioned shell is the Teredo gigantea, and has been described to
consist of a tube, five feet four inches in length, nine inches in cireum-
| ference at the larger, and two and one half inches at the smaller end.
It is the longest of all testaceous shells.

The Teredo navalis, or ship-worm, insinuates itself into the bottoms
of ships, even although the oak is perfectly sound, and in a very short
time perforates or even completely destroys it. This destructive crea-
ture was, it is said, originally brought by our vessels from tropical
climates ; but it has now become an inhabitant of most of the harbours
of this island, and is very common in Plymouth Dock.

It was first proved by that learned and very indefatigable naturalist,
Colonel George Montagu, in his supplement to Testacea Britannica,
that the animal inhabiting the Teredo, was not a Terebella, but an
Ascidia. More recently, however, it has been found to be neither.

Genus 36.—SABELLA.

Animal a Nereis, with a ringent mouth, and two thicker
tentacula behind the head; shell tubular, composed of par-
ticles of sand, broken shells, and vegetable substances, united
to a membrane by a glutinous cement.

Sabella tubiformis.—Plate IX. fig. 36.

These shells (if they can be called so) inhabit thesea. The Linnean
Sabelle are not testaceous shells, but merely coverings made up of
extraneous substances; and may therefore fairly be expunged from
the collection of the Conchologist. They are included in Lamarck’s

class Annelides, the formation of the animal being different from that
of the true Mollusca,

E

‘ae

62

I. Cu1Ton,

II. LEPAs,

III. PHOLAS,

IV. Mya,

V. SOLEN,

VI. TELLINA,

Vil. CarDiIvum,

VIII. Mactra,

IX. Donax,

Chiton.
Chitonellus.

Tubicinella.
Coronula.
Balanus.
Acasta.
Creusia.
Pyrgoma.
Anatifa,
Pollicipes.
Cineras.
Otion.

Pholas.

Gastrochena.

Panopea.

Glycimeris.

Mya.

Anatina.

Lutraria,
art.

Pp
, Amphidesma,

Unio.
Vulsella.

Solen.
Anatina, part.
Sanguinolaria

| Hiatella.
Mya, part.

Amphidesma,

part.
Pandora.
Psammobia.
| Psammotea.
Tellina.
Lucina.
Cyclas.
| Cyrena.
Cardium.

Lutraria,
nearly all.
Mactra.

part.

Rea aide aia.

Crassatella,
part.

( Petricola, part.

Sasa

Venerupis,
part.

rioteens
Capsa.

X. VENUS,

XI. SponDrtus,

XII. CHama,

XIII. Arca,

XIV. OstREA,

XV. ANOMIA,

XVI. Mrrizts,

XVII. Pinna,

XVIII. Areo-
NAUTA,

LINNZ AN GENERA OF SHELLS.

TABLE OF THE LINNAAN GENERA OF SHELLS, WITH
LAMARCK’S DIVISIONS OF THESE GENERA.

Petricola,
part.

Venerupis,
part.

Sanguinolaria,

Lucina, part.
Donax, do.
Crassina,
yrena, part.
Galathea.
Cyprina.
Cytherea.
Venus.

Plicatula.
Spondylus,

( Cardita.
Cypricardia.
Tsocardia.
Chama.
Tridacna.
Hippopus.

Nucula.
Pectunculus.
Arca.

( Cucullza.
Perna.
Malleus.
Pedum,
Lima.
Pecten.
Gryphiea.
Ostrea.

Placuna,

Anomia.

Crania.

Orbicula.

Terebratula.
| Hyalea.

Saxicola.
Anodonta.
Modiola.
Mytilus.
Avicula.
Meleagrina.
LOstrea, some.

Pinna.

Limacina.
Argonauta,
Carinaria,

XIX. Navurtitvs,

XX. Conus,
XXI,. Crpr@a,

XXII. Butta,

XXIII. Voruta,

XXIV. Buccinum.

XXV. Stromsus,

Orthoceras.
Nodosaria.
Spirula.
Cristellaria.

| Nautilus.
(| Polystomella.

Conus.
Cyprea.

Bullea.
Acera.
Bulla.
Bulimus.
Achatina.
Physa, part.
Ovula

Terebellum.

Auricula.
Ancilla.
Tornatella.
Turbinella.
Cancellaria.
Columbella.
Mitra.
Voluta.
Marginella.
Volvaria.
Achatina.

(Oliva.
Concholepas.

Achatina,
part.
Phasianella.
Pleurotoma.
Turbinelia,
part.
Cancellaria,

part.

Pyrula, part.
Murex, do.
Triton.
Cassidaria,
Cassis.
Purpura.
Monoceras,
Harpa.
Dolium.
Buccinum.
Eburna.

( Terebra.

( Pirena.
Cerithium,

part.
Pleurotoma,
part.
Rostellaria,
Pteroceras.
Strombus.
Cassidaria,
rt

part.
Purpura.

ah aa

XXVI. Murex,

XXVII. Trocuvus,

XXVIII. Torso,

(2 $$ $$

XXIX. Hetrix,

XXX. NERITA, }

XXXI. Hatroris,
F2

63

Cerithium. |
Pleurotoma.
Turbinella,
part.
Fasciolaria.
Fusus.
Pyrula.
Struthiolaria.
Ranella,
Murex.
Triton.
Ricinula.
Purpura, part,

Pyramidella,
Solarium.
Rotella.
Trochus. i
Monodonta,
part.

Turbo, part.
Cerithium,

Auricula, part.
Cyclostoma. —
Planorbis, part
Paludina.
Scalaria.
Delphinula.
Trochus, part.
Monodonta,

Helix.
Carocolla.
Anostoma.
Helicina, some
Pupa, some.
Bulimus.
Succinea.
Auricula.
Cyclostoma.
Planorbis.
Lymneza.
Welania,
Melanopsis.
Paludina, part
Valvata.
Ampullaria,
Natica.
Tanthina.
Sigaretus.

Navicella.
Neritina.
Nerita.
Natica.
Stomatia,
Haliotis,

64 LINNEAN GENERA OF SHELLS.
Lingula. XXXIII. DEn- .
bat laa TALIUM, i Dentahure:
i mbrella. ,
Parmophorus. f ee ea
Emarginula. eat =
ey: | KX KIV.S veraill
XXXII. PaTELxA, ¢ Pileopsis. - SERPULA, 4 bes ail
Calyptrea. | Sentact SS
Crepidula. Seplae
Ancylus. LVermetus.
Navicella, Fistulana.
part. XXXY. TEREDO, < Septaria, part.
LStomatella. Teredo,

LAMARCK’S GENERA OF SHELLS.

ARRANGED ACCORDING TO THE DESCENDING SCALE, WITH
THE ADDITION OF SOME RECENTLY FORMED GENERA.

TESTACEOUS MOLLUSCA.

ANIMALS soft, inarticulated, provided with an anterior
head, which is more or less projecting, or salient; most
frequently furnished with eyes and tentacula, or sometimes
having arms disposed in the form of a coronet; their mouth
short, elongated, or tubular, extensile and usually armed
with hard parts. Mantle diversified, having its edges free
on the sides of the body, or the lobes united, forming a sac
or bag, which partly envelopes the animal; gills or organs
of respiration various, rarely symmetrical; circulation double,
one partial, the other general; heart unilocular, sometimes
with the auricles separated, and very distant, no continuous
medullary cord along the body, but a few scattered nerves
and ganglions; body sometimes naked, either unprovided
with solid internal parts, or enclosing a shell or other hard
substance; but generally provided with an external shell
covering the body, or sheathed in it, and which is never
coraposed of two opposite valves.

ORDER I—HETEROPODA.

Head distinct, with two eyes, but destitute of arms
wranged around the head; body free elongated, fitted for
F3

66 CEPHALOPODA.

swimming horizontally; no foot under the abdomen or
throat for walking; one or more fin-like expansions, with-
out any regular order, and not arranged in pairs as in fishes.

Genus 1.—PHILLIROE; and Genus 2._PTERO-
TRACHEA, are soft animals without any testaceous cover-
ing or shell.

Genus 3.—CARINARIA.—LZamarck:

Generic Character.—Head distinct, provided with two
tentacula, a contractile elongated mouth, and two eyes;
heart and branchiz united into a single mass, projecting from
the abdomen, contiguous to the tail, and enveloped ina shell;
body elongated, gelatinous, pellucid, with a tail at its pos-
terior extremity.

Shell univalve, conical, compressed, unilocular, ex-
tremely thin, hyaline; apex convoluted into a spire; back,
in some species, forming a notched keel; aperture oblong
and entire.

The shells of this genus are distinguished from those of
the Argonauta, by the spire never entering the aperture.

Carinaria fragilis.—Tue Fracite Cartnarta.—Plate
X. fig. 1. Shell excessively thin, hyaline, striated longi-
tudinally, destitute of a dorsal keel. Inhabits the African
seas.

ORDER I1—CEPHALOPODA.

Head emanating from a bag-shaped mantle, and surmount-
ed by inarticulated arms, which are provided with suckers,
and surround the mouth; two sessile eyes; mouth provided
with two horny mandibles; three hearts; the sexes in sepa-
rate individuals,

CEPHALOPODA. 67

Sus-Division I.—CErEPHALOPODA SEPIARIA-

Animals without any internal or external covering or
shell, but with an internal cartilaginous or calcareous
plate. This subdivision embraces four genera of Sepiz or
Cuttle fish.

Sus-Drvision II.—CrerpHALoPopDA MoNoTHALAMA.

Having unilocular shells, entirely external, and envelop-
ing the animal.

Genus 5.—ARGONAUTA.—Linneus.

Generic Character.—Shell spiral, univalve, unilocular,
very thin, doubly carinated, with the spire entering the

aperture.
Argonauta Argos.—TueE Arcus ARGONAUTA, or PAPER

Nautitus.—Plate X. fig. 2. Shell white, involute, ex-
tremely thin and fragile, sides with undulated ridges, and
obsoletely striate; keel with small tubercles, partly reddish-
black. Inhabits the Mediterranean.

Sus-Drviston III].—CrryHaLopopa PoLyTHALAMA.

Shell multilocular, partly or wholly internal, and en-
veloped in the posterior part of the body.

FAMILY I.—AMMONACEA.

With the septa sinuous, lobed and cut at the margin,
meeting upon the inner wall of the shell, and articulated by
acutely notched sutures.

Genus 6.—BACULITES.—Lamarck.

Generic Character.—Shell straight, cylindrical, some-
times a little compressed, slightly conical; with the walls
articulated by sinuous sutures; dissepiments transverse ;
little distant, imperforate, lobed and subdivided at the
margin.

68 CEPHALOPODA.

Baculites Faujasti.—Fausacian Bacu.ites. Plate X.
fig. 3. Erect, cylindrical, opposite sides smooth and de-
pressed ; sutures lobed and denticulate.

Genus 7.—TURRILITES.—Lamarck.

Generic Character.—Shell spiral, turreted, volutions con-
tiguous, and all conspicuous ; walls articulated with sinuous
sutures; septa transverse, lobed, and lacinated at the margin ;
aperture nearly round.

Turrilites costulata.—THE RiBBED TuRRILITES. Plate
X. fig. 4. Erect, turreted; volutions convex, with trans-
verse ribs each with a tubercle at its base.

Genus 8.—_AMMONOCERATITES.—Lamarcek.

Generic Character. —Shell horn-shaped, arcuated, scarcely
forming half a turn; the walls articulated with sinuous,
laciniate, branched sutures; septa transverse, sinuous, im-
perforate; their margins lobed, laciniate; having a marginal
tube or siphon, which does not perforate the septa.

Ammonoceratites ylossoidea.— THE GLossorp AMMONO-
CERATITES. Plate X. fig.5. Large, thick, cylindrical, ar-
cuated, flattish on the sides, inside somewhat concave; apex
compressed, tongue-shaped. Twenty inches long. Fossil,
East Indies, and in Mount St. Catherine, near Rouen.

Genus 9.—ORBULITES. —Lamarck.

Generic Character.—Shell subdiscoid, spiral, with the
yolutions contiguous; the last enveloping the rest; the in-
ternal parietes articulated by sinuous sutures; septa trans-

verse, lobed at their circumference, perforated by a marginal

tube,

Orbulites striata—Tue STRIATED OrRBULITES. Plate
X. fig. 6. Suborbicular, umbilicated; volutions transversely
and minutely striated and ribbed; back rather acute. One
and a half inch in diameter. Fossil.

|

CEPHALOPODA. 69

Genus 10.—AMMONITES.—LZamarck.

Generic Character.—Shell discoid, spiral; volutions con-
tiguous, wholly visible; inner parietes articulated by sinuous
sutures; septa transverse, lobed at the circumference, and
without siphon at the disk, but perforated by a marginal tube
near the margin. /

Ammonites armatus.—THE ARMED AMMONITES. Plate
X. fig. 7. Subcarinated, volutions depressed at their inner
margins; with strong transverse strie and clavate 'ribs.
Fossil.

FAMILY I1.—NAUTILACEA.

Shell discoid, with a central spire, and short cells, which
do not extend from the centre to the circumference.

Genus 11.—_NAUTILUS.—LZinneus.

Generic Character.—Shell discoid, spiral, multilocular,
with simple parietes; volutions contiguous, the last or body
one enveloping the rest; the cells numerous, septa trans-
verse, externally cencave, perforated in the disk by a tube ;
margins entire.

Nautilus umbilicatus.—TuHE UMBILICATED NavrTILus.
Plate X. fig. 8. Suborbicular; the centre of the volutions
umbilicated on both sides; aperture round, heart-shaped
pale fawn-coloured, with chestnut undulated transverse
clouds. Six inches long. Inhabits the Indian Ocean.

Genus 12..__NUMMULITES.—Zamarck.

Generic Character.—Shell lenticular, attenuated at the
margins; spire internal, discoid, multilocular, covered over
by several plates; the outer layers complicated, produced, ex-
tending and uniting on each side to the central disks; cells
very numerous, small, alternate, and formed by transverse
imperforate septa.

70 CEPHALOPODA.

Nummulites complanatus.— Tue Fiat NvuMMULITEs.
Plate X. fig. 9. Orbicular, broad, depressed at the sides,
and smooth; margin undulated. One and a half inch in
diameter. Fossil in France.

Genus 13.—VORTICIALIS.—Lamarck.

Generic Character.—Shell discoid, spiral, multilocular ;
volutions contiguous, but not appearing externally; septa |
transverse, imperforate, but not extending from the centre
to the circumference ; aperture marginal.

Vorticialis strigilata.—'THE CREASED VORTICIALIS.
Plate X. fig. 9. Somewhat depressed, transversely ribbed, |
and spirally striated. Fossil. |

Genus 14._POLYSTOMELLA.—Lamarck.

Generic Character.—Shell discoid, multilocular, with con-
cealed volutions; with numerous transverse ribs; aperture
formed of variously disposed holes.

Polystomella crispa.—THE WRINKLED POLYSTOMELLA
Plate X. fig. 11. Discoid, with both sides convex, the mar-
gin carinated; the last turn of about twenty cells, marked
with flexuous ridges, having their interstices crenated.
Common in shell sand.

Genus 15.—SIDEROLITES.—Lamarcehk.

Generic Character.—Shell discoid, multilocular; volu-
tions contiguous, but not visible externally; the disk con-
| vex on both sides, and studded with tubercular dots; the
| circumference margined with unequal radiating lobes; septa
transverse, imperforate; aperture distinct, somewhat lateral.

Siderolites calcitrapoides.—Tue CuaLK SIDEROLITES.
Plate X. fig. 1. With four lobes, and punctated through-
out. Fossil in the mountain of St. Peter, at Maestricht.

Genus 16.—DISCORBIS.—LZamarck.

Generic Character.—Shell discoid, spiral, multilocular,

anes

CEPHALOPODA. 71

with simple parietes; the voiutions wholly visible, exposed,
and contiguous; with transverse, numerous, and imperforate
septa.

Discorbis vesicularis.— Tue VeEsicuLar Discorsis.
Plate X. fig. 13. Volutions nodulous, subvesicular; the
last volution sometimes closed. Fossil at Grignon.

FAMILY III.—RADIOLACEA.

~ Shell discoid, with a central spire, and elongated radiating
cells, extending from the centre to the circumference.

Genus 17.—PLACENTULA.—Lamarck.

Generic Character.—Shell orbicular, convex above and
below, multilocular; aperture oblong, narrow, disposed like
a radius in the lower disk, or sometimes in both upper and
under.

Placentula asterisans.— THE STAR-SHAPED PLACENTULA.
Plate X. fig. 14. Volutions convex; partitions radiating
from the centre. Fossil.

Genus 18..—_LENTICULITES.—Lamarck.

Generic Character.—Shell sublenticular, spiral, multi-
locular; outer margin of the volutions complicated, and
_ extending on both sides to the centre; septa imperforate,
curved, and lengthened on both sides in the form of rays;
aperture narrow, projecting over the last volution.

Lenticulites rotulata. Tue RotieD LENTICULITEs.
Plate X. fig. 15. Orbicular; margin acute; disks some-
what prominent. Fossil at Mendon.

Genus 19.—ROTULITES.—Zamarck.

Generic Character.—Shell orbicular, multilocular, spiral,
convex, or conical, above; flat, radiated, and tubercular
beneath; aperture marginal, trigonal, and directed upwards.

Rotulites trochidiformis.—Tue Trocuus-sHAPED Ro-

2 CEPHALOPODAs

TULITES. Plate X. fig. 16. Shell conoid; volutions cari-
nated; lower side granulated. Fossil at Grignon.

FAMILY IV.—SPHERULACEA.

Shell globular, spheroidal, or oval; with the volutions
mutually enveloping, or the cells contiguous, curved in the
segment of a circle, and collectively forming a single envelope
to the central cavity.

Genus 20.—MELONIA.—Zamarck.

Generic Character.—Shell subspherical, multilocular ;
spire central; volutions contiguous, convolute, tuniciform ;
cells numerous, narrow; septa imperforate.

Melonites spheroidea.—Tue Rounp MeEtonta. Plate
X. fig. 17. Entirely globular, and divided by depressed ribs.
Fossil.

Genus 21._GYROGONA.—Lamarck.

Generic Character.—Shell spheroidal, concave within,
composed of linear, curved, canaliculate pieces; the external
surface with carinated, parallel, partly transverse ribs; be-
coming spirally curved and uniting at each of the centres or
poles; aperture round, sometimes closed, situated at the in-
ferior pole of the shell.

Gyrogonites medicaginula.—Somewhat spherical, with
transverse keels, spiral at the extremities. Fossil at Mont-
morency.

Genus 22.._-_MILIOLA.—Zamarck.

Generic Character.—Shell transverse, ovate-globular, or
elongated, multilocular; having transverse cells surrounding
the axis, and alternately covering each other; aperture
very small, orbicular or oblong, situated at the base of the
last volution.

Miliola ovata. —TuHE Ovat Miniona. Plate X. fig. 18.

CEPHALOPODA. 1:

Ovate, small, with an oblong-ovate aperture. Fossil at
Grignon.

FAMILY V.—CRISTACEA.

Shell semidiscoid, with an eccentric spire.

Genus 23.—ORBICULIN A.—Lamarck.

Generic Character.—Shell subdiscoid, multilocular; spire
eccentric; volutions contiguous and compound; chambers
short and very numerous ; septa imperforate.

Orbiculina uncinata.— Tue UNcINATE ORBICULINA.
Plate X. fig. 19. Spirally striated, and the volutions sepa-
rated by a deep sinus. Fossil.

Genus 24,—_CRISTELLARIA.—LZamarchk.

Generic Character.—Shell semi-discoidal, multilocular ;
volutions contiguous and simple, progressively enlarging ;
spire ecceutric, sublateral ; septa imperforate.

Cristellaria squammula.—THE ScaLED CRISTELLARIA.
Plate X. fig. 20. Shell externally covered with minute
scale-like marks. Fessil.

Genus 25. RENULINA.—LZamarch.

Generic Character.—Shell kidney-shaped, flat, sulcated,
and multilocular; volutions linear, contiguous, curved
around a marginal axis, those most remote from it being
longest.

Renulites opercularis—Tue Lip-sHaAPED RENULINA.
Plate X. fig. 21. Semilunar, flat, with arcuated concentric
ridges. Fossil at Grignon.

FAMILY VI.—LITUOLACEA.

Shell somewhat spiral; the last volution continuous in a
straight line.
G

74 CEPHALOPODA.

Genus 26.—LITUOLA.—Lamarck.

Generic Character.—Shell multilocular, partially spiral
and discoid; volutions contiguous, the last terminating in a
straight line; chambers irregular; septa simple and trans-
verse, the last one perforated with from three to six orifices.

Lituolites nautiloides.—TuHrE NAUTILUS-SHAPED LiITU-
oLA. Plate X. fig. 22. Discoid, tailed, ribbed; septa with
six perforations. Fossil at Mendon.

Genus 27._SPIROLIN A.—Lamarck.

Generic Character.—Shell multilocular, partly spiral and
discoid ; volutions contiguous, the last one terminating in a
straight line; septa straight, perforated by a tube.

Spirolina clavata. —THE CLUB-SHAPED SPIROLINA.
Plate X. fig. 23. Club-shaped, spiral, smooth, ending in a
lengthened erect body. Fossil.

Genus 28..SPIRULA.—Lamarck.

Generic Character.—Shell cylindrical, thin, subpellucid,
multilocular, spiral, discoid; the volutions apart, with a
straightish termination; septa transverse, and equidistant,
externally concave, with an interrupted lateral siphon; aper-
ture round.

Spirula Peronit.—Perron’s Sprruua. Plate X. fig. 24.
White; very fragile, involute; diameter about one inch.
Inhabits the West Indian seas.

| Lamarck has ascertained that the animal is cephalopodous, and
furnished with a sac, which envelopes the hind part of its body, at
which is seen the shell, having only a portion of its last turn exposed.

FAMILY VII.—ORTHOCERATA.

| Shell straight, or nearly so, without any spiral volutions.

Genus 29.—CONILITES.—Lamarck.
Generic Character.—Shell conical, straight, slightly in-

Pie is ote a eae

—

CEPHALOPODA. 15

flected; outer crust thin, by which the nucleus is invested;
nucleus somewhat separable, multilocular, and divided by
transverse septa.

Conilites pyramidata.—TuHeE PyRAMIDAL CONILITEs.
Plate X. fig. 25. Pyramidal; with the concave bands con-
tracted. Fossil.

Genus 30.—HIPPURITES.—Lamarck.

Generic Character.—Shell conico-cylindrical, straight, or
somewhat arcuated, multilocular, with transverse septa ;
having a lateral internal channel formed by two parallel,
longitudinal, obtuse and convergent piers the last chamber
closed by an operculum.

Hippurites curva.—TuHeE Brent Hippurites. Plate X.
fig. 26. Conical, curved, coarse; lower part truncated
and flat.

Genus 31.—NODOSARIA.—Zamarchk.

Generic Character.—Shell elongated, straight or slightly
arcuated, subconic, nodose, consisting of a series of very
smooth spherical cells; the transverse septa perforated.

Nodosaria Radicula.—TuHeE Suintne Noposartia. Plate
X. fig. 27. Erect, oblong, and attenuated; with five globu-
lar joints. Two lines long. Inhabits the Adriatic.

Genus 32.—OR THOCERA.—Lamarck.

Generic Character.—Shell elongated, straight, or a little
arcuated, subconical; externally striated with longitudinal
ridges; chambers formed by transverse septa, perforated by
a tube, which is either central or marginal.

The shells of this genus resemble a slightly curved horn.

Orthocera Raphanus.—Tue RavisH-RootT ORTHOCERA.
Plate X. fig. 28. Erect, elongated, conical, with longitu-
dinal continuous ribs; the joints tumid, the siphon sublateral ;
white. Inhabits the Mediterranean sea.

G2

76 TRACHELIPODA.

Genus 33.—BELEMNITES.—Lemarck.

Generic Character.—Shell straight, conical, elongated,
capable of being separated into two parts, the outer one a
solid sheath, produced above and excavated with a conical
cell beneath; the inner nucleus conical, and divided by
numerous transverse septa, perforated by a central tube.

Belemnites subconicus.—TuHe Supconic BELEMNITEs.
Plate X. fig. 29. Lower part semi-cylindrical ; upper part
conical and attenuated. Fossil, found in Britain in chalk-
marl.

ORDER IIL.—TRACHELIPODA.

Posterior part of the body spirally convolute, separated
from the foot, and constantly enveloped ina shell; foot free,
depressed, attached to the lower base of the neck, on the
anterior part of the body, and forming an organ of locomo-
tion; shell spiral, and enveloping.

Section I.—ZoopHaGcous TRACHELIPODA.

The animals are entirely marine, having a protruding
siphon, and respiring water only, which reaches the branchize
by this siphon; they are devoid of maxille; provided with
a retractile proboscis; and feed on other animals.

FAMILY I.—INVOLUTA.

Shell destitute of a canal, but having its aperture notched
or effuse at the base, and its volutions compressed, and
convoluted so as that the external one nearly envelopes the
others.

Genus 1.—CONUS.—Linneus.

Generic Character.—Shell turbinate, or of the form of a

TRACHELIPODA. ‘We

reversed cone, aperture longitudinal, linear, toothless, narrow,
and effuse at the base.

Conus generalis.— THE GENERAL Cone. Plate XI. fig.
1. Shell oblong, turbinate, reddish-brown, or orange, black
at the base, with interrupted white bands, the spire flat,
marginate, with the apex acute. Two and a half inches long.
Inhabits the Indian seas.

There are two sections of this beautiful and very extensive
genus.

I. Shells coronate, or provided with knobs, round the
edges of the spiral volutions.

II. Shell not coronate.

Genus 2.—OLIV A.—Lamarck.

Generic Character.—Shell subcylindrical, convolute,
smooth, and glossy; spire short, with canaliculated sutures ;
aperture longitudinal, emarginate at the base; columella
obliquely striated, or plaited.

The volutions of this genus, being separated by a canal, at once dis-
tinguish them from those of the Voluta and Mitra ; the same distinction
separates it also from Ancillaria.

Oliva cruentata.—THE Buioopy Oxtve. Plate XI. fig.
2. Shell pale fawn-coloured with large triangular spots of
purple, edged with deeper fawn; two dark brown spots on
the edge of the outer lip; suture of the spire deep; pillar
plaited to nearly the top. One and a half inch long. In-
habits the Indian seas.

Genus 3.—ANCILLARIA.—Zamarck.

Generic Character.—Shell oblong, subcylindrical ; spire
short, not caniculate at the sutures; aperture longitudinal,
effuse and hardly emarginate at the base; lower portion of
the colume!la with an oblique callosity or varix.

The columella never being plaited distinguishes the shells of this
genus from those of Oliva. The callous oblique band, at the base of
the columella, separates it from Terebellum.

Ancillaria cinnamomea.—Tur CINNAMON ANCILLARIA,
G3

78 TRACHELIPODA.

Plate XI. fig. 3. Shell chestnut-brown, with white bands
above; varix of the columella reddish, and somewhat stri-
ated. One inch long. Inhabits Trincomalee. _

Genus 4.—TEREBELLUM.—Zamarck.

Generic Character.—Shell convolute, sub-cylindrical ;
apex pointed; aperture longitudinal, narrow above; base
emarginate ; columella smooth, truncated beneath.

Terebellum subulatum.—THE AWL-SHAPED 'TEREBEL-
Lum. Plate XI. fig. 4. Shell cylindrical, thin, and glossy ;
spire subulate ; columella smooth, truncate at the base. One
inch long. Inhabits the Indian seas.

Genus 5.—CY PRA A.—Linneus.

Generic Character.—Shell ovate or oblong-ovate, convex ;
margins involute; aperture longitudinal, narrow, dentate on
both sides, effuse at both extremities; spire very small,
generally hidden or covered in the perfect shells.

Cyprea Exanthema.—THE MEASLEY CyprmA. Plate
XI. fig. 8. Oblong-ovate, brown, thickly studded with
round eye-like white spots; dorsal line greyish; marginal
teeth dark brown. Four inches long. Inhabits the West
Indies.

Genus 6.—_OVULA.—Bruguiere.

Generic Character.—Shell turgid, attenuated at both
ends; margins convolute; aperture longitudinal, narrow,
effuse at the extremities; the inner or columellar margin
without teeth.

*Outer lip thickened, or wrinkled.—** Outer lip smooth and without
teeth.

The shells of this genus are distinguished from Cyprea by the want
of a spire, and the columellar lip never having plaits or teeth.

Ovula oviformis.—THeE Eac-sHapeD OvuLa. Plate
XI. fig. 5. Shell ovate, much inflated, ventricose in the
centre, very glossy, pure white; extremities prominent;

TRACHELIPODA. 79

mouth dark orange within. Four inches long. Inhabits the
Indian seas.

FAMILY II.—COLUMELLARIA.

Without a canal at the base of the aperture, but having a
subdorsal more or less distinct notch, and with folds or plaits
on the columella.

Genus 7.—VOLVARIA.—Lamarck.

Generic Character.—Shell cylindrical, convolute; the
spire hardly protruding; aperture narrow, nearly the whole
length of the shell; columella with one or more folds or
plaits near its base.

This genus forms a natural connection betwixt the Columellaria and
the Involuta.

Volvaria cylindrica.—Tue Cy.tinpric Votvaria. Plate
XI. fig. 11. Shell cylindrical, white, with one plait on the
columella. Half an inch long. Inhabits the British seas.

This shell, however, is not an apt representative of the genus Vol-
varia, it being a Bullina.

Genus 8. _MARGINELLA.—Lamarck.

Generic Character.—Shell oblong-ovate, smooth; spire
short, outer lip with an external marginal longitudinal rim
or varix; base slightly notched; columella plaited; folds
nearly equal.

The thickening of the outer lip distinguishes these shells from the
genera Volvaria and Mitra. There are two sections: 1. with the spire
protruded; 2. with the spire not projecting. To the first belongs the
following species.

Marginella cerulescens.—Tutr BuiuisH MARGINELLA.
Plate XI. fig. 6. Shell bluish-white; spire short, and acute;
lip brownish-purple within; columella with four plaits. One
inch long. Inhabits the Indian Ocean.

Genus 9.—VOLUT A.—Linneus.

Generic Character.—Shell ovate, more or less ventricose ;

80 TRACHELIPODA.

apex nipple-like; no canal; columella pticate, the lower
plaits larger and more oblique than the others; no columellar
lamina.

This genus is divided into four sections.—1. Shell ventri-
cose; 2. shell ovate, spinous, or tubercular; 3. shell oval,
and subtubercular; 4. shell elongated, ventricose, nearly
fusiform.—The following illustrates section 2.

Voluta Vespertilio.—TuE Bat Vouute. Plate XI. fig.
7. Shell turbinate, with acute spires on the volutions;
summit slightly obtuse; columella four-plaited. Three
inches long. Inhabits the Indian seas.

Genus 10.—MITRA.—Lamarck.

Generic Character.—Shell turreted, or sub-fusiform, with
the spire pointed; base emarginate, without a canal ; colu-
mella plicate, the plaits being parallel and transverse, the
lower ones smallest; pillar lip thin and adnate. :

Mitra pontificalis Tur Pontirican Mirra. Plate XI.
fig. 9. Turreted, ovate; covered with a yellow-olive epi-
dermis, beneath which are interrupted bands of orange spots ;
spire crowned with tubercles. Two and a half inches long.
Inhabits the Chinese seas.

Genus 11.—COLOMBELLA.— Lamarck.

Generic Character.—Shell oval; spire short; base of the
aperture more or less emarginate, and destitute of a canal ;
columella plicate; outer lip with an internal prominence,
which contracts the aperture.

Colombella mercatoria.— THE COMMERCIAL COLOMBEL-
LA. Plate XI. fig. 10. Ovate, white, sulcated, transversely
clouded with brown, or yellow-orange; outer lip with
internal dentations. An inch long. Inhabits the West
Indian seas.

FAMILY IIIl.——-PURPURIFERA.

Shell with a short canal posteriorly ascending, or with

——

|

TRACHELIPODA. 81

an oblique notch at the base of the aperture, directed
back wards.

Sugs-Diviston 1.— Having an oblique notch directed
backwards.

Genus 12._TEREBRA.— Lamarck.

Generic Character.—Shell elongated, turreted, acumi-
nated; aperture longitudinal, several times shorter than the
spire, emarginate; base of the columella contorted and
oblique.

Terebra vittata._THE FILLETED TEREBRA. Plate XI.
fig. 12. Pale fawn-coloured, smooth; body, and volutions
transversely striated at the top, and with transverse purplish
bands, occupying nearly its lower half. One inch long. In-
habits the Indian ocean.

Genus 13.—EBURNA.—Lamarck.

Generic Character.—Shell ovate or elongated; the outer
lip simple; aperture longitudinal; emarginated at the base;
columella umbilicated above, with a canal below the
umbilicus.

The peculiar character of the umbilicus and of the columella, which
is prolonged at the lower base and forms a canal occupying the remain-
ing part of the left side, is a striking feature in this genus.

Eburna Zeylanica.—Tue Creyton Epurna. Plate XI.
fig. 13. Smooth, white, with irregular large yellowish-brown
spots; apex acute, smooth, white; sutures distinct, canal of
the columella scaly. Two and a half inches long. Inhabits
the coasts of Ceylon.

Genus 14.._BUCCINUM.—Linneus.

Generic Character.—Shell ovate, or ovato-conical ; aper-
ture longitudinal, with the base emarginate; no canal; colu-
mella not flattened, turgid above.

Sub-division.—Nassa. The shells have a callous colu-
mella.

=]

82 TRACHELIPODA.

Buccinum undatum.—Tue Wavep Buccinum. Plate
XI. fig. 14. Ovato-conical, ventricose; obliquely waved ;
grooved and striated transversely, longitudinally striulate ;
covered with a yellow olivaceous epidermis; volutions con-
vex; aperture white or yellow. Four inches long. Inhabits
the European seas.

Genus 15.—DOLIUM.—D’ Argenville.

Generic Character.—Shell thin, ventricose, inflated; fre-
quently subglobose, very rarely oblong; transversely ribbed ;
outer lip dentated or crenated; aperture longitudinal, emar-
ginate at the base.

Dolium Perdiz.—Tue Partripce Dorium. Plate XI.
fig. 15. Ovato-oblong, thin, reddish-brown, clouded and
spotted with white; thickly ribbed and convex; spire short.
Four inches long. Inhabits the Tropical seas.

Genus 16.—HARPA.—Zamarck.

Generic Character.—Shell ovate, more or less turgid ;
with longitudinal, parallei, compressed, inclined ribs; spire
short; aperture longitudinal, emarginate below; no canal ;
columella smooth, flattened, and acute at the base.

Harpa rosea—Tue RoseaTE Harpa. Plate XI. fig.
16. Oblong-ovate, flesh-coloured, with roseate interrupted
bands; ribs remote; columella of a fine rosy hue. Two
inches long. Inhabits the Indian ocean.

Genus 17.—CONCHOLEPAS.—Zuamarck.

Generic Character.— Shell ovate, inflated, semispiral ;
apex inclined obliquely towards the columellar lip; aperture -
very wide, longitudinal, oblique, provided with a notch be-
neath; outer lip with two teeth at its base; aperture fur-
nished with an obleng, thin, horny operculum.

Concholepas Peruvianus.-- THE PERUVIAN CONCHOLEPAS.
Plate XI. fig. 17. Three inches long, and very thick, with

TRACHELIPODA. 83

an umber-brown back, and white inside. Inhabits the coasts
of Peru.

Genus 18.—MONOCEROS.—Lamarchk.

Generic Character.—Shell ovate; aperture longitudinal,
obliquely emarginate at the base; a conical tooth at the
base of the outer lip.

Monoceros cingulatum.— THE BANDED Monoceros. Plate
XI. fig. 18. Ovato-oblong, with raised spiral bands, and
very minutely striated ; the bands black; the whorls angular
above; the aperture pure white. Inhabits the western
coasts of Mexico.

Genus 19.—PURPURA.—LZamarck.

Generic Character.—Shell ovate, either smooth, or tuber-
cular, or angular; aperture dilated, emarginate at the base,
having a subcaniculate oblique sinus; columella depressed,
ending below in a point.

Purpura Persica.—Tue Persian Purpura. Plate XI.
fig. 19. Transversely sulcate, and striated between the
ridges; dark-burnt-umber brown; ridges cream-yellow, with
distant spots of very dark umber brown; upper ridge and
the superior edges of the volutions mucronate ; inside sul-
cated and striated, white with yellow lines, the lip black.
Inhabits the Indian seas.

Genus 20.—RICINULA.— Lamarck.

Generic Character.—Shell ovate, usually tubercular or
spinous externally; aperture longitudinal, furnished with a
short recurvate canal, terminated by an oblique notch; colu-
mella with unequal teeth; the teeth on the interior of the
right lip frequently narrowing the aperture.

Ricinula horrida.—Tue Ruecep Rictinuta. Plate XI.
fig. 20. External surface covered with strong, obtuse, black
tubercles, the interstices being white and transversely stri-

ated; inside of both lips of a rich purple; outer lip with

84 TRACHELIPODA.

five triangular, grooved rays, between which, at their base,
the margin is crenulated. One and a half inch long. In-
habits the East Indian seas.

Genus 21..__CASSIS.—Zamarck.

Generic Character.—Shell gibbous; aperture longitudi-
nal, narrow, terminating in a short canal, abruptly reflected
backwards; columella transversely plicated or rugose; outer
lip usually dentated.

The genus consists of two subdivisions: 1. Spire with
longitudinal varices. 2. Spire without varices.

Cassis Areola.—_THE PatTcueD Cassis. Plate XI. fig.
21. Smooth, shining, white, with square orange tesselated
spots; spire short and conical, with decussated strie; lower
part of columella rugose. Two and a half inches long.
Inhabits the Indian ocean.

Genus 22.._-C ASSIDARIA.— Lamarck.

Generic Character. — Shell obovate, or ovate-oblong ;
aperture longitudinal, narrow, terminating in an ascending
curved canal; outer lip marginated, or folded back at the
margin; inner lip covering the columella, generally rough,
granular, tuberculate, or rugose.

Distinguished from Cassis by the canal being ascendent, and very
little arched, and not suddenly recurved towards the back, as in that
genus.

Cassidaria Thyrrena.— THE TYRRHENE CASSIDARIA.
Plate XI. fig. 22. Ovate, transversely grooved, reddish
fulvous ; volutions convex; the last turn generally with
one tuberculate groove; aperture white; columella rugosely
tuberculate. Three inches and a half long. Inhabits the
Mediterranean sea.

FAMILY IV.—ALATA.

Shell provided with a canal of greater or less extent, at
the base of the aperture; the right lip changing its form as

TRACHELIPODA. 85

the animal advances in age, and provided with a sinus at
the lower part.

Genus 23.—_STROMBUS.—Linneus.

Generic Character.—Shell ventricose, base terminating
in a short truncated, emarginated canal; right lip dilating
with age into a simple, entire wing, lobed or crenulated
above, and provided with a sinus beneath, separated at the
base from the canal or notch; aperture provided with a
long narrow horny operculum.

Strombus Auris-Diane.—D1ana’s Ear Stromsvus. Plate
XI. fig. 23. Oblong-ovate; spire acute, tuberculated, and
transversely striated; base recurved; outer lip thick; an-
terior lobe with a finger-like termination. Three inches
and a quarter long. Inhabits the Indian ocean.

Genus 24.__PTEROCERA.—JZamarck.

Generic Character.—Shell oblong-ovate, ventricose, ter-
minating in a lengthened canal; outer lip dilating with age
into an expanded, rayed, or digitated wing, with a sinus
near the base; spire short.

Pterocera Chiragra.—Tue Knotty PTERocERA. Plate
XI. fig. 24. Ovate, tuberculated, with six digitated, canali-
culated rays, which are closed over in the adult shell; outer
lip internally striated. Six inches and a half long, exclusive
of the digitated lobes. Inhabits the Indian ocean.

Genus 25.—ROSTELLARIA.—Zamarck.

Generic Character.—Shell fusiform or sub-turreted, ter-
minated below by a beaked canal; outer lip entire in some
species, and dentated in others, more or less dilated by age;
with a sinus near the canal.

Rostellaria Pes-pelecaniTur Prwican’s Foot Ros-
TELLARIA. Plate XI. fig. 25. Turreted, flesh-coloured or
white; body and volutions longitudinally ribbed, and crowned
with papille; base of body papillose ; outer lip palmate,

H

86 | TRACHELIPODA.

with three acute, divaricate digitations. One inch and a
half long. Inhabits the European seas.

FAMILY V.—CANALIFERA.

Shell with a canal of greater or less length, situated at
the base of the aperture; the outer lip differing little in the
young and adult states.

Sus-Drviston I.— Having a permanent varix on the outer
lip, and varices on the spire.

Genus 26. _TRITON.—Lamarck.

Generic Character.—Shell ovate or oblong, with a canali-
culated base; having alternate or nearly solitary varices,
which never form longitudinal continuous ridges; aperture
oblong, provided with an operculum.

The varices in this genus are not in continuous rows from the apex
to the base as in Murex and Ranella, but in interrupted alternating
series.

Triton variegatum.—THE VARIEGATED TRITON. Plate
XI. fig. 26. Elongated, conical, trumpet-shaped; suture of
the spire crenulated ; pillar lip grooved obliquely; pale pur-
ple, elegantly clouded and spotted with brown. Sixteen
inches long. Inhabits the Indian and American seas.

Genus 27.—MUREX.—Linneus.

Generic Character.—Shell ovate or oblong, with a canali-
culated base; furnished with rough spinous or tuberculated
varices, on each volution of the spire, the lower ones uniting
with those above, so as to form continuous rows; aperture
with a corneous operculum.

The Shells of this genus are easily distinguished by their having
three or more rows of varices on each whorl; while the Ranellze have

only two, and the Struthiolariz but one, and that situated on the
margin.

TRACHELIPODA. 87

Section * Shells with a slender beak. always longer than the aper-

ture.
—_—*#* Beak thickened, not abrupt, and more or less lengthened.

+ Volutions with three varices.
+ 1 Volutions with more than three varices,

Murex spiralis—_Tue Sprrat Murex. Plate XI. fig.
27. Body roundish; separated from the spire by a narrow
ridge; spire depressed; upper volutions rounded, and ter-
minating in an obtuse apex; canal very long and curved ;
flesh-coloured, substriated, with remote brown irregular
spots. Three inches long. Inhabits the Chinese seas.

Genus 28. _RANELLA.—Lamarck.

Generic Character.—Shell oval or oblong ; sub-depressed
with two opposite continuous varices, and canaliculated at
the base; aperture rounded or ovate; varices straight or
oblique, situated at intervals of half a volution, forming a
continuous longitudinal row on each side.

Ranella spinosa.—Tue Prickty Ranetia. Plate XII.
fig. 1. Ovate, depressed, with acute, short, distinct, muri-
cated tubercles; fawn-coloured ; varices lateral, with elon-
gated spines; beak sulcated; outer lip internally crenated.
Two inches and an eighth long. Inhabits the Indian ocean.

Genus 29._STRUTHIOLARIA.—LZamarck.

Generic Character.—Shell ovate; spire produced ; aper-
ture oval, with a sinus, terminated at the base by a very
short, straight canal without any notch; pillar lip callous,
spreading; margin of outer lip sinuous, with an exterior
ridge.

Struthiolaria nodulosa. Tue Noputous StTruTHIo-
LaRIA. Plate XII. fig. 2. Ovate, grooved, and striated
transversely; top of volutions flattened and nodulous;
cream-yellow, with undulated brownish-yellow longitudinal
lines; lip yellow-orange within. Three inches long. In-

habits New Zealand.
H2

88 TRACHELIPODA.

Sus-Drviston II.— Without a constant ridge on the
outer-lip.

Genus 30.—PYRULA.—Lamarck.

Generic Character. — Shell sub-pyriform; base with a
canal, ventricose above, destitute of external ridges; spire
short, sometimes obtuse; columella smooth; outer lip with-
out a notch.

Pyrula ficus.—Tue Fic Pyrvuna. Plate XII. fig. 3.
Spire very short; volutions rounded above; yellow-brown,
spotted with dark brown; and covered with decussated
strie. Three inches long. Inhabits the Indian ocean.

Genus 31.—FUSUS.—Lamarck.

Generic Character.—Shell fusiform or sub-fusiform, with
a canal at the base; middle or lower part ventricose, with-
out varices; spire produced; margin of the outer lip with-
out a notch; columella smooth ; aperture oval, with a horny
operculum.

Fusus corneus.—THE Horny Fusus. Plate XII. fig. 5.
Elongated, with eight convex volutions, striated spirally,
and covered by an olivaceous epidermis; beak long, oblique.
Three inches long. Inhabits the seas of Northern Europe.

Genus 32.—_FASCIOLARIA.—Lamarchk.

Generic Character.—Shell sub-fusiform, with a canal at
its base; without varices; columella with two or three
oblique plaits.

Fasciolaria Trapezium.—THE QUADRANGULAR Fascro-
LARIA. Plate XII. fig. 6. Ventricose, obtusely angled ;
volutions nodulous; reddish fawn-coloured, with transverse,
double, slightly undulated lines; inside of aperture with
reddish striz. Six inches long. Inhabits the Indian ocean.

Genus 33. CANCELLARIA.— Lamarck.

Generic Character.—Shell oval or turreted; base of the
aperture sub-canaliculated ; canal very short, almost none ;

TRAOHELIPODA. 89

columella plicate, the plaits varying in number; usually
transverse ; lip internally furrowed.

Cancellaria reticulata. —Tue RETICULATED CANCEL-
LARIA. Plate XII. fig. 4. Oval, strong, ventricose, with
distant, coarse, reticulated striz; sometimes with yellow
or orange bands; pillar with three plaits; aperture white
Two inches long. Inhabits the Atlantic ocean.

Genus 34.—TURBINELLA.—Zamarchk.

Generic Character.—Shell turbinated or sub-fusiform ;
with a canal at the base; columella with from three to five
oblique, transverse, and compressed plaits.

Somewhat allied to both Murex and Voluta, but differing from the
former in the want of varices, and from the latter, in having no canal ;
although also somewhat like Fasciolaria, it can be distinguished from
that genus by the position of the plaits on the columella.

Turbinella Pyrum.—TuHe PEAR-SHAPED TURBINELLA.
Plate XII. fig.8. Pear-shaped; yellowish-white, with irregu-
lar reddish-brown spots ; spire short, mucronate; apex mam-
milliform ; beak long; columella with four plaits; in adult
specimens, the shell is covered with a very thick opaque
yellow-brown epidermis. Six inches long. Inhabits the

Indian ocean.

Genus 35.—PLEUROTOMA.—Zamarch.

Generic Character.—Shell turreted or fusiform, termi-
nated below by a straight canal, of greater or less length;
outer-lip with a notch or fissure at the upper part; aperture
with a small horny operculum.

Pleurotoma nodifira.—'THE JAVANESE PLEUROTOMA.
Plate XII. fig.’7. Fusiform, turreted ; volutions somewhat
angulated, upper ones smooth; under volutions and body
transversely striated with angulated oblique nodules at the
suture; outer lip deeply crenulated, with a large notch;
reddish-yellow. One inch and a half long. Inhabits the
seas around Java.

H 3

90 TRACHELIPODA.

Genus 36.—CERITHIUM.—Bruguiere.

Generic Character.—Shell turreted; aperture oblong,
oblique, terminated at the base by a short, truncated, re-
curved canal, without a notch; the outer lip with a groove
at its upper extremity; aperture provided with a small
horny operculum.

This genus is allied to Pleurotoma, but the aperture is without the
slit on the right margin.

Cerithium semigranosum.—THE SEMIGRANULATED CERI-
THIuM. Plate XII. fig.9. Fusiform, turreted; apex acute ;
transverse minute strie, and sulcated granulations; the suture
with double spiral rows of large granules; colour reddish-
brown. One inch and a half long. Inhabits the seas of
New Holland.

Section I].—PHYTIPHAGA.

Without a projecting siphon, generally respiring by an
orifice; provided with jaws, and usually feeding on vege-
table substances; shell having the aperture entire, and des-
titute of a notch or canal.

FAMILY I.—TURBINACEA.

Shell turreted, or conical, with an oblong or rounded
aperture, not expanding, and the margin disunited.

Genus 37.—TURRITELLA.—Lamarck.

Generic Character.—Shell turreted, not pearly ; aperture
rounded, entire; margin disunited above; the outer lip
with a slight sinus, and the aperture furnished with a horny
operculum. *

The genera Scalaria, Turbo, and Cerithium, are nearly allied to this
genus, but may easily be distinguished from them by a sinus on the
right margin of the aperture, which is only visible when the mouth is
quite perfect, and which does not exist in any other shells.

TRACHELIPODA. 91

Turritella Terebra.—THE AUGER TURRITELLA. Plate
XII. fig. 11. Greatly turreted, with acute, spiral strie ;
yellowish-brown or whitish; apex usually reddish. Two
inches long. Inhabits the European seas.

Genus 38.._PHASIANELLA.—JZamarck.

Generic Character.—Shell ovate or conical, solid; aper-
ture entire; longitudinally ovate; the lips disunited above;
the outer sharp-edged, but not reflected; columella smooth,
compressed, and attenuated at the base; aperture provided
with a calcareous or horny operculum.

Mr. Swainson has pointed out a highly distinctive character in the
shells of this genus, namely, that of a slightly projecting or salient
angle, running along the columella.

Phasianella Pullus. Tue CuHtIcken PHASIANELLA.
Plate XII. fig. 12. Smooth, glossy; volutions inflated ;
skin-coloured, with spots of crimson or rich reddish-brown.
One quarter of an inch long. Inhabits the coasts of
Britain.

This species however is not characteristic, and has even been referred
to a different genus. The finest species belong to New Holland.

Genus 39.—_PLANAXIS.—JZamarck.

Generic Character.—Shell ovate or conic, solid ; aperture
ovate, or somewhat elongated; columella depressed and
truncated at the base, separated from the outer lip by a
compressed sinus; lip interiorly sulcated, having a callosity
running under the superior portion.

Somewhat allied to the genus Phasianella, but distinguished by the
base of the columella being truncated as in the genus Melanopsis.

Planazis suleata.—Tuet Furrowep Puanaxis. Plate
XII. fig. 16. Imperforate, transversely furrowed; grayish-
white, and spotted with black, forming oblique longitudinal
fascia ; outer lip internally crenulated and striated. One
inch long. Inhabits the American seas.

92 TRACHELIPODA.

Genus 40.—TURBO.—Linneus.

Generic Character.—Shell conoid, or sub-turriculated ;
aperture entire, round, margin of outer lip disunited; colu-
mella arcuated, depressed, but not truncated at the base;
aperture provided with a testaceous operculum.

This genus has recently been subdivided into a great number of
genera, one of which contains our common Periwinkle, Littorina lit-
torea.

Turbo setosus.—TueE BristLy Turpo. Plate XII. fig.
17. Thick, transversely and deeply sulcated, and longi-
tudinally striated; spire short; volutions rounded; lip
crenulated ; variegated with white, green, and brown; in-
side perlaceous. Two inches long. Inhabits the Indian
seas.

Genus 41.—_MONODONT A.—Lamarck.

Generic Character.—Shell ovate or conoid; aperture round
and entire; outer lip disunited from the body at top; colu-
mella arcuated and truncated at the base ; aperture provided
with an operculum.

Monodonta coronaria.—TuEe THICK-LIPPED Monopon-
TA. Plate XII. fig. 10. Covered with numerous, small,
scabrous, acute, turbercles; outer lip very thick; apex
blunt, white; the columella reddish. One inch and a quar-
ter long. Inhabits the Chinese seas.

Genus 42.—TROCHUS.—Linneus.

Generic Character.—Shell conical; spire elevated, some-
times abbreviated ; aperture transversely depressed; margin
of outer lip disunited from the body at the upper part;
columella arcuated, more or less oblique at the base; aper-
ture provided with a horny operculum.

Trochus Zizyphinus.— THE ZIZYPHINE TrRocuus. Plate
XII. fig. 2. With strong transverse strie; colour livid,

Pe i ls

————

TRACHELIPODA. 93

with undulated streaks of reddish flesh-colour, or brownish
carnation. One inch long. Inhabits the European seas.

Genus 43.—ROTELLA.—Lamarck.

Generic Character.—Shell orbicular, glossy, destitute of
epidermis ; spire short, subconic; lower parts convex and
callous ; aperture half round.

Rotella vestiaria.— THE ORNAMENTAL ROTELLA. Plate
XII. fig. 18. Pale skin-coloured, or citron-coloured, the
upper part of body and spire spotted with dark brown.
Half an inch long. Inhabits the Indian ocean.

Genus 44.—SOLARIU M.—Lamarck.

Generic Character.—Shell orbicular, in the form of a
depressed cone; largely umbilicated; internal margins of
the volutions, which are visible in the umbilicus, crenu-
lated; aperture wide; mouth quadrangular, destitute of a
columella.

Solarium perspectivum.—THE PERSPECTIVE SOLARIUM.
Plate XII. fig. 23. Cream-yellow, with brown or chestnut
and white bands near the sutures of the volutions; umbili-
cus ample, and crenulated. Two and a half inches broad.
Inhabits the Indian ocean.

FAMILY II.—SCALARIDEA.

Shell devoid of plaits or folds on the columella; margins
of the aperture united in a circular form.

Genus 45.—DELPHINULA.—Lamarck.

Generic Character.—Shell subdiscoid or conical, umbili-
cated, solid; volutions of the spire rough or angular; aper-
ture entire, round, sometimes trigonal, with the edges united,
and generally provided with a fringe, or a thick marginal
ridge; spire depressed.

Delphinula laciniata. —TuHe FriInceED DELPHINULA.
Plate XII. fig. 22. Umbilicus large, surrounded by large

94 TRACHELIPODA.

vaulted scales, in spiral rows; also with strong waved spiral
strie; brownish-red, variegated with white. Two inches
long. Inhabits the Indian seas.

Genus 46.—SCALARIA.—LZamarck.

Generic Character.—Shell subturreted, with longitudinal,
elevated, thin, interrupted ribs; aperture rounded; margins
united in a circle, and edged by a reflected ridge.

Scalaria pretiosa. — THE WENTLETRAP, or PRECIOUS
Scanarra. Plate XII. fig. 20. Conical, smooth, cream-
yellow; volutions disjoined, connected by longitudinal ribs;
body extremely ventricose; a deep umbilicus. One and a
half inch long. Inhabits the Indian ocean.

Genus 47.—VERMETUS.—Lamarck.

Generic Character.—Shell thin, tubular, loosely spiral in
the lower part, the three or four upper volutions regularly
spiral; attached to other substances by the apex of the
spire; aperture orbicular, margins united, and provided with
an operculum.

These shells are remarkable on account of their adhering or being
affixed to marine bodies by the attenuated and pointed extremity of
the spire.

Vermetus lumbricalis. —'THE WorM-LIKE VERMETUS.
Plate XII. fig. 24. Variously twisted; reddish-brown,
sometimes clouded with darker brown. Two to four inches
long. Inhabits the African seas.

FAMILY IIIl.—PLICACEA.

Shell with the aperture somewhat contracted, and the
columella plaited.

Genus 48.—P YRAMIDELLA.—JZamarck.

Generie Character.—Shell turreted, destitute of epider-
mis; aperture entire, semi-ovate, the outer lip with a sharp

TRACHELIPODA.

edge; columella produced at the base, subperforated, and
provided with three transverse plaits.

Pyramidella Terebellum.—Tue WimMBLE PYRAMIDELLA.
Plate XII. fig. 26. Smooth, glossy, white, with reddish-
brown fascie ; columella recurved ; inside of the lip smooth.
One and one-fourth inch long. Inhabits the American

seas.

Genus 49.—TORNATELLA.—Lamarck.

Generic Character.—Shell convolute, ovate-cylindrical,
usually transversely striated, and destitute of epidermis ;
aperture oblong, entire, with the margin of the outer lip
thin; one or several folds at the base of the columella.

Tornatella fasciata. THE BANDED ToRNATELLA. Plate
XII. fig. 27. Covered with fine transverse strie; spire
produced, apex acute; aperture straitened, columella with
one plait; purplish-red, with two white transverse fascie-
Inhabits the coast of Britain.

FAMILY IV.—MACROSTOMA.

Shell ear-shaped, with the aperture very wide, and the
margins disunited; without any columella or opercu.um.

Genus 50.—HALIOTIS.—Zinneus.

Generic Character.—Shell ear-shaped, usually depressed;
spire short, sometimes depressed, and nearly lateral; aper-
ture extremely large, oblong-ovate, and entire in the adult
state ; disk perforated with holes, disposed in a line paralle}
to the left margin, which commences by a notch.

Haliotis asinina.—Tue Astntne Hatiotis. Plate XII.
fig. 28. Shell elongated, narrowish, somewhat curved,
smoothish, green, marbled with brown; pearly and irides-
cent within; marked with oblique undulated strie, and
having the spire very short. Two and a half inches long.
Inhabits the seas of China and the Moluccas.

=

96 TRACHELIPODA.

Genus 51 —STOMATIA.~ Lamarck.

Generic Character.—Shell ear-shaped, imperforate; spire
prominent; aperture entire, oblong, and large; outer lip
elevated as much as the pillar; back with a transverse sub-
carinated tuberculated rib.

Stomatia phymotis.—THE TUMOURED StomatTtA. Plate
XII. fig. 29. Ovate oblong; back convex, striated, nodu-
lous, and white; spire small, contorted; lip thin and acute.
Three and a fourth inches long. Inhabits the Indian ocean.

Genus 52.—_STOMATELLA.— Lamarck.

Generic Character.—Shell orbicular or oblong, ear-shaped,
imperforate; aperture entire, large, elongated; outer lip
effuse, dilated, and open.

This shell is distinguished from Stomatia, by its never having the
transverse rib of the species of that genus.

Stomatella imbricata.—THE ImBRICATED STOMATELLA.
Plate XII. fig. 30. Suborbicular, convex, somewhat de-
pressed, rough, having thick-set transverse ribs, covered
with imbricated scales; grayish-brown. More than an inch
and a half long. Inhabits the Indian ocean.

Genus 53.—SIGARETUS.—LZamarch.

Generic Character. — Shell subaurtform, suborbicular ;
outer lip short and spirally intorted; aperture entire, very
expanded, ovate oblong; the margins disunited.

Sigaretus somewhat approximates the genus Natica, and much re-
sembles a depressed shell of that genus, from which, however, the
extraordinary width of the aperture, and its spiral short columella
render it quite distinct.

Sigaretus concavus.—THE CoNCAVE SicaRETus. Plate
XII. fig. 25. Ovate, back convex, covered with transverse
undulated striae; reddish-yellow, spire white, somewhat
prominent ; aperture expanded, concave; umbilicus deepish.
Inhabits the Indian ocean.

TRACHELIPODA. 97

FAMILY V.—IANTHINEA.

Shell not floating, having the aperture very wide; no
columella.

Genus 54.—IANTHINA.—Lamarck.

Generic Character.—Shell ventricose, somewhat conical,
thin, and pellucid; aperture triangular; columella straight,
produced beyond the base of the outer lip, which has a
sinus in the middle aperture without an operculum.

Lanthina communis.—TuHE Common IantTuina. Plate
XII. fig. 19. Extremely fragile, of a beautiful violet hue;
aperture triangular, with a small notch on the margin of
the outer lip. One inch long. Inhabits the Atlantic and
Mediterranean.

FAMILY VI.—NERITACEA.

The shells are both marine and fiuviatile; semiglobular
or oval; destitute of a columella, with the aperture edged
and transverse, and provided with an operculum.

Genus 55.—NATICA.—Adanson.

Generic Character.—Shell subglobose, umbilicated; aper-
ture entire, and half rounded; inner lip oblique, without teeth;
but having a callosity, which partly covers the umbilicus,
and in some species entirely conceals it; outer lip sharp,
smooth within; aperture provided with an operculum.

Natica Canrena.—TuHeEe CANRENE NatTica. Plate XII. *

fig. 15. Subglobular, smooth; fawn-coloured, with bands
and interrupted rays of reddish-brown, and zigzag lines and
streaks; base of body and inner lip white, deeply umbili-
cated ; spire a little prominent. One inch and three-fourths
long. Inhabits the West Indian ocean.

I

98 TRACHELIPODA.

Genus 56.—NERIT A.— Lamarck.

Generic Character.—Shell solid, semiglobose, flattened
below, without an umbilicus; aperture semi-orbicular and
entire; inner lip depressed, septiform, thin-edged, and fre-

quently dentated or crenated; outer lip obtuse, and often |

provided internally with teeth.

Nerita peloronta.—Tuer Bioopy-TootH Nerita. Plate
XII. fig. 13. Thick, transversely sulcated; gray or red-
dish-yellow, with variously coloured bands ; inner lip with
two teeth or crenulations, having a bloody mark at their
base. One inch long. Inhabits the seas of South America
and the West Indies.

Genus 57.—NERIT OIDES.—Byown.

Generic Character.—Shell strong, thick, subrotund; spire
depressed; aperture nearly round; lip almost continuous,
having a slight groove only at its junction with the body;
no umbilicus.

NNeritoides litoralis.—'TuHe Snore NeriroreEs. Plate
XIII. fig. 24. Smooth, covered with an olive-green, yel-
low, brown, or otherwise coloured epidermis, sometimes
beautifully banded or chequered beneath it; inside generally
purplish-brown; body very large; spire very short and de-
pressed. Five-eighths of an inch long. Inhabits the shores
of Northern Europe.

This shell is the Turbo neritoides, and Turbo retusus of Lamarck.

Genus 58.—NERITIN A.—Jamarchk.

Generic Character.—Shell rather thin, semiglobose, or
ovate, flattened below; without an umbilicus; aperture
semicircular; inner lip flattened, and reflected on the colu-
mella, sometimes slightly crenated; outer lip destitute of
teeth or crenulations on its internal face; aperture provided
with an operculum, having a lateral point.

Neritina fluviatilis. —Tae FREesuH-wATER NERITINA.

TRACHELIPODA. 99

Plate XII. fig. 14. Shell small, oval; back convex, smooth,
white, variously speckled with red, black, or dark brown;
spire inclined, lateral; lip slightly denticulate. One-third
of an inch long. Inhabits the rivers and streams of Europe.

Genus 59.—NAVICELLA.—Zamarck.

Generic. Character.—Shell elliptical or oblong, convex
above, concave beneath; spire lowered to the margin; inner
lip flattened, acute, narrow, and destitute of teeth; aperture
provided with a solid flat operculum, having a lateral acute
point.

Navicella elliptica. — Tue Ovau Navicetua. Plate
XIII. fig. 1. Smooth, shining, spotted and streaked with
purple, blue, or brown; covered with an olivaceous epider-
mis; spire curved, prominent, extending beyond the margin.
One inch Jong. Inhabits rivers in the Isle of France, India,
and the Moluccas.

FAMILY VII.—PERISTOMIDA.

Shell conoid or subdiscoid, with the margins of the aper-
ture united; aperture protected by an operculum; fluviatile,
and the animal respiring water.

Genus 60. —AMPULLARIA.—LZamarck.

Generic Character.—Shell globular, ventricose, umbili-
cated; inner lip without a callosity; aperture oblong, entire ;
margins united; outer lip acute, but not reflected; an oper-
culum.

Ampullaria Guyanensis.—Tue GuIaANA AMPULLARIA.
Plate XII. fig. 2. Globular, thick, with unequal longi-
tudinal strie; covered with a fuscous-brown epidermis ;
inside golden-yellow. Three inches in diameter. Inhabits
the rivers of Guiana.

Genus 61. =P ALUDIN A.— Memarch:

Generic Character.—Shell conoid; volutions rounded or

100 TRACHELIPODA.

convex, modifying the spiral cavity; aperture subrotund,
ovate, or oblong, angulated above; margins of outer and
inner lips united, acute, but not reflected; an orbicular
horny operculum.

Paludina vivipara.—T ue Viviparous Patupina. Plate
XIII. fig. 3. Thin, ovate, ventricose, wrinkled longitudi-
nally ; body with three or four brown bands; covered with
an oliyaceous epidermis. One inch and a half long. Inhabits
the rivers of Europe.

Genus 62.—VALVAT A.— Muller.

Generic Character.—Shell discoid or conoid, umbilicated ;
volutions cylindrical, not modifying the spiral cavity ; mar-
gins united and acute; operculum orbicular.

Valvata piscinalis.—Tue Ponp VatvaTa. Plate XIII.
fig. 4. Globular, conoid, somewhat trochus-shaped, deeply
umbilicated ; apex obtuse; longitudinally wrinkled; covered
with a greenish-yellow epidermis. One-fourth of an inch
long. Inhabits the rivers and lakes of Europe.

FAMILY VIII.—MELANIACEA.

Fluviatile, operculated shells; with the margins of the
aperture disunited; the outer lip always thin-edged; the
animals respire water only, and are provided with two
tentacula.

Genus 63.—PIREN A.— Lamarck.

Generic Character.—Shell turreted; aperture longitudi-
nal; outer lip acute, with a distinct sinus at the base, and
another at its junction with the body; base of the columella
turned towards the right; a horny operculum.

Pirena terebralis.—THE WIMBLE Prrena. Plate XIII.
fic. 7. Subulate, dongitudinally striated; outer lip expanded;
covered with a deep blackish-brown epidermis ; aperture
white. Three inches long. Inhabits the rivers of India.

TRACHELIPODA. 101

Genus 64..-MELANOPSIS.—Lamarck.

Generic Character. — Shell turreted; aperture ovato-
oblong, entire; columella with a callosity above, truncated
at the base and incurvated; the outer lip separated from
the inner by a sinus; aperture with a horny operculum.

Melanopsis is distinguished from Melania, by the columella being
callous at the upper part, and the base truncated as in Achatina; it
differs from Pirena in having only one sinus, or a widened opening at
the base of the shell.

Melanopsis levigata. — THE PotisHED MELANOPSIS.
Plate XIII. fig. 28. Ovate, conical, smooth, of a chestnut

colour. Three-fourths of an inch long. Inhabits the rivers

of the Archipelago.

Genus 65.—MELANIA.—Lamarck.

Generie Character. — Shell turreted; aperture entire,
ovate or oblong, effuse at the base; columella smooth, and
incurvated ; a horny operculum.

Melania amarula.— THE CRownNED Menanta. Plate
XIII. fig. 8. Ovate-oblong, thick; longitudinally wrinkled ;
transversely striated at the base of the body; upper margin
of the volutions crowned with triangular tubercles, from
which emanate straight slender spines; colour deep chest-
nut, covered with a black epidermis; aperture bluish-white.
One and a half inch long. Inhabits the rivers of India.

FAMILY IX.—LYMNAACHEA.

Animals amphibious, usually without an operculum; and
having flattened tentacula; shell spiral, generally smooth
on the external surface; the margin of the outer lip is
always acute, and not reflected. They live in fresh water,
but come to the surface to respire.

Genus 66.—LYMN Hi A.—Brugwere.

Generic Cheracter.—Shell oblong, sometimes turreted,
ey

102 TRACHELIPODA.

with the spire produced; aperture entire, oblong; the outer
lip acute; the lower part of the outer lip rising on the colu-
mella, and there forming an oblique plait, which enters into
the aperture ; destitute of an operculum.

Lymnea stagnalis—Tue Ponp Lymnza. Plate XIII.
fig. 9. Ovato-acuminate, with the last turn ventricose, and
subangulate above; the spire tapering to a point; the aper-
ture large; the outer lip spreading, thin, transparent, and
horn-coloured. Two inches long. Inhabits the ditches
and ponds of Europe.

Genus 67.—PHYSA.—Drapernaud.

Generic Character.—Shell generally sinistral, convolute,
oval, or oblong; spire prominent; aperture longitudinal,
contracted above; columella twisted; outer lip very thin,
acute, partly obtruding above the plane of the opening ;
destitute of an operculum.

Physa fontinalis— Tue Fountain Puysa. Plate XIII.
fig. 6. Volutions reversed, oval, diaphanous, glossy, horn-
coloured ; spire very short and rather acute. Half an inch
long. Inhabits the ditches and streams of Europe.

Genus 68.—LUTEA.—Brown.

Generic Character.— Shell globular; spire short, sub-
acute; aperture ovate; outer lip not continuous, slightly
inflected at the top, and acute at the base; a little reflected
on the base of the columella, and subumbilicated.

Lutea lacuna.—Tue Lake Lurea. Plate XIII. fig. 10.
Very diaphanous, slightly wrinkled, and of a greenish horn-
colour. Half an inch long. Inhabits ditches in Britain.

Genus 69.—_PLANORBIS.—Lamarck.

Generic Character.—Shell discoid; spire depressed or

’ flat; the volutions apparent on both sides ; aperture oblong,

semilunar, very distant from the axis of the shell; margin
not reflected; no operculum.

TRACHELIPODA. 103

Planorbis carinatus.—THE KEELED PLANoRBIS. Plate
XIII. fig. 11. Depressed ; upper side concave, with a keel
round the middle of the last volution. Three-fourths of an
inch in diameter. Inhabits the ditches and lakes of Europe.

Genus 70.—PLANARIA.—Brown.

Generic Character. —Shell discoid, depressed on both
sides; the volutions conspicuous on either side; spire
slightly produced above, and concave beneath; aperture
ovate ; edges of outer lip acute; no operculum.

Planaria alba.—Tue Waite Puanaria. Plate XIII.
fig. 17. White, slightly wrinkled transversely ; outer lip
with a narrow margin behind. One-fourth of an inch in
diameter. Inhabits the coast of Dunbar, Scotland.

FAMILY X.—COLIMACEA.

Shell spiral, but without any exterior projections, except
the additions of growth; outer lip frequently reflected ;
tentacula of the animal cylindrical; no operculum. Ter-
restrial.

Section I.— Animals with two tentacula.

Genus 71.—CYCLOSTOMA.—Lamarck.

Generic Character.—Shell variable in shape; volutions
rounded ; aperture circular, entire, and reflected in the adult
state ; a horny operculum.

Cyclostoma elegans. —T HE ELEGANT CycLosToma. Plate
XIII. fig. 12. Ovate, conical, umbilicated; with elegant
transverse striz; volutions five, very convex; ash-coloured,
with three bands of brown spots. Half an inch long. In-
habits Europe.

Genus 72.—AURICULA.—Zamarchk.

Generic Character. — Shell suboval, or ovato-oblong ;
aperture longitudinal; entire at the base and contracted

104 TRACHELIPODA.

above, or with the margins disunited; columella with one
or more plaits; outer lip sometimes reflected, and in other
species simple.

Section * Right lip outwardly reflected.

** Right lip plain and sharp.

Auricula Jude.—Jupas’ AuricuLa. Plate XIII. fig.
13. Oblong, conical, cylindrical, thick, with minute de-
cussated striz and granulations; whitish-brown; columella
with three plaits; aperture contracted in the middle. Two
and a fourth inches long. Inhabits the East Indies.

Section I].—Animals with four tentacula.

Genus 73.—SUCCINEA.—Draparnaud.

Generic Character.—Shell ovate, or ovato-conical ; aper-
ture very wide, entire, and longitudinal; outer lip acute,
but not reflected, united below to the columella, which is
smooth and thin-edged ; no operculum.

The shells of this genus neyer have their lip reflected or thickened,
and are thus distinguished from those of the genus Bulimus, to which
they bear a strong resemblance.

Succinea amphibia.—Tue Ampuisious SuccinEa. Plate
XIII. fig. 14. Amber-coloured; excessively thin and pel-
lucid; spire short; aperture expanded beneath, nearly ver-
tical. Three-fourths of an inch long. Inhabits the sides
of ditches and lakes in Europe.

Genus 74.—_ACHATIN A.—Lamarck.

Generic Character.—Shell ovate or oblong; aperture
entire, elongated; outer lip acute, never reflected; columella
smooth, with its base truncated.

Achatina virginea. —'THE VirnciIn AcHATINA. Plate
XIII. fig. 15. Smooth, grayish-white, with red and black
transverse bands; the columella with one plait, rose-col-
oured; volutions ventricose ; inside of the lip bluish. One
and a half inch long. Inhabits South America and the
West Indies.

TRACHELIPODA. 105

Genus 75.—BULIMUS.—Zamarck.

Generic Character.—Shell ovate, oblong, or turreted ;
aperture entire, longitudinal; margins very unequal, and
disunited above ; columella straight, smooth, entire at the
base, and not effuse.

Bulimus montanus.—THE Mountain Butimus. Plate
XIII. fig. 16. Ovate-oblong, umbilicated, slightly striated
longitudinally ; of a brownish horn-colour; with seven con-
vex volutions; aperture semi-oval; outer lip white and re-
flected. Five-eighths of an inch long. Inhabits mountair-
ous situations in Savoy, and other parts of Europe. 2

Genus 76.—CLAUSILIA.—Zamarck.

Generic Character.—Shell sinistral, generally fusiform,
slender; summit somewhat obtuse; aperture irregular,
rounded, oval; margins united, free, and externally re-
flected.

Clausilia papillaris -THe PimpLeD CLausiLia. Plate
XIII. fig. 18. Pellucid, finely striated longitudinally, horn-
coloured brown; the margins of the volutions papillose ;
aperture with two plaits. Three-fourths of an inch long.
Inhabits dry situations in Europe.

Genus 77.—PUPA.—Lamarck.

Generic Character.—Shell cylindrical, generally thick ;
aperture irregular, semi-ovate, rounded, and subangulated
beneath; margins nearly equal, reflected outwards, uncon-
nected at their upper parts; the plait of the columella in-
terposed between them.

Pupa muscorum.—TuHe Moss Pura. Plate XIII. fig.
21. Very small, cylindrical, obtuse, and smooth, brownish
horn-coloured; volutions convex; sutures much sunk; aper-
ture with one tooth; outer lip white and reflected. One-
eighth of an inch long. Inhabits moss, generally in shaded
places, in Britain, France, and other countries of Europe.

106 TRACHELIPODA.

Genus 78.—HELICIN A.— Lamarck.

Generic Character.—Shell subglobose, imperforate; aper-
ture entire, and semi-oval; columella callous, transverse,
flattened, and forming an angle at the base of the outer lip;
a horny operculum.

The shells of this genus are distinguished from the Helices, by their
transverse callous columella, depressed and diminished in thiekness
at the lower part.

Helicina major.—Tue GReaT Heticina. Plate XIII.
fig. 22. Citron-coloured, inside pink; pillar and outer lip
white; the former broadly reflected on the columella.

Genus 79.—ANASTOMA.—Lamarck.

Generic Character.—Shell suborbicular; spire convex
and obtuse; aperture rounded, dentated within, turned up-
wards and grinning ; margin of the outer lip reflected.

Anastoma globulosa.—TuE GLOBULAR ANASToMA. Plate
XIII. fig. 25. Suborbicular, obsoletely. carinated, smooth,
and white; aperture with six teeth; reddish-brown.

Genus 80.—CAROCOLLA.—Lamarck.

Generic Character.—Shell orbicular, more or less convex
or conoid above, with the circumference acutely angulated ;
aperture transverse, contiguous to the axis of the shell;
outer lip subangular, frequently dentated below.

Carocolla lapicida.—TuHE STONE-CUTTING CAROCOLLA,
Plate XIII. fig. 26. Depressed above, convex beneath,
broadly umbilicated, and transversely striated ; reddish horn-
coloured; body-volution carinated. Seven-eighths of an
inch in breadth. Inhabits dry situations in Europe.

Genus 81.—HELIX.—Linneus.

Generic Character.—Shell orbicular, convex or conoid
above; sometimes globular, with the spire somewhat ele-
vated ; aperture entire, transverse, very oblique, contiguous

wy

GASTEROPODA. 107

to the axis of the shell; having the margins disunited by
the projection of the last volution. The Helices, or Snails,
which are very numerous, and present considerable differ-
ences in the form of the shell, have by several more recent
authors been arranged into various subgenera,

Helix arbustorum.—TuEe Grove Heuix. Plate XIIL
fig. 27. Subglobular, subumbilicated, finely striated longi-
tudinally ; greenish-yellow or reddish, beautifully mottled,
and streaked with reddish-brown, and a broad brown band
running throughout the middle of the volutions. One inch
in diameter. Inhabits the thickets and woods of Europe.

ORDER IV.—GASTEROPODA.

Animals with straight bodies, and never spiral, nor en-
veloped entirely in a shell, having a foot or muscular disk
under the abdomen, attached to the body nearly its whole
length, and serving for progressive motion.

Section I].— PNEUMOBRANCHIZ.

Branchize constructed like a vascular net, on the wall
of a particular cavity, opening by a perforation which the
animal has the power of contracting and dilating at pleasure.
They respire air.

TRIBE I.—LIMACINEA.

The animals almost wholly naked, with elongated bodies ;
and creeping by means of a ventral disk; branchie in the
form of a vascular network, lining a cavity, of which the
aperture is a hole capable of being contracted or dilated at
will.

Genus 1.—VITRIN A.—Lamarck.

Generic Character.— Body creeping, elongated, snail-
shaped, nearly straight; posteriorly separated from the foot,

108 GASTEROPODA.

and spirally bent; posterior appendages of the mantle dis-
played over part of the shell; four tentacula; the anterior
very short. Shell small, extremely thin, depressed, spire
very short; body very large; aperture ample, rounded, and
oval; the left margin slightly inflected.

Vitrina peliucida. —_Tue Pretitucip VitTrina. Plate
XIII. fig. 5. Extremely thin, pellucid, and glossy; de-
pressed, with the spire very short; of a pale yellowish
green; aperture large and oval. Four lines long. Inhabits
dry places of Europe.

Genus 2.—_TEST ACELLA.—Lamarckh.

Generic Character.— Body creeping, elongated, snail-
shaped, having a shell on the posterior extremity; four
tentacula, the two longest with the eyes at their tips; vent
and respiratory aperture behind. Shell very small, external,
somewhat ear-shaped ; the apex obsoletely spiral; aperture
very large, oval, with outer lip inflected.

Testacella haliotidea. —_Tur HALiIoTIs-SHAPED TEs-
TACELLA. Plate XIII. fig. 23. Shell oblong-ovate, auri-
form; left margin slightly reflected; exceedingly thin,
transparent, and yellowish. Inhabits the middle provinces
of France.

Genus 3.—LIMA X. —Linneus.

Generic Character.—Body oblong, naked, and creeping;
back convex, provided with a coriaceous slightly wrinkled
shield; and having a flat longitudinal disk beneath; tentacula
four, retractile, the two posterior the largest, with eyes at
their tips; branchial cavity placed under the shield; orifice
for respiration and vent on the right side. Shell very small,
internal, extremely thin, oblong, ovate, flattened. :

Limax rufus.—'THe Rep Limax. Plate XIII. fig. 29.
Shell ovate-oblong, both margins reflected; very thin, dia-
phanous, slightly wrinkled, and of a pale straw-yellow
colour; animal with the body longitudinally sulcate, red

: GASTEROPODA. GS

above, white beneath. Inhabits gardens in Britain and
France.

Genus 4.—PARMACELLA.—Zamarch.

Generic Character.—Body creeping, oblong; middle of
the back moderately cenvex, and shield-shaped; the hind
part in the form of a tail, laterally compressed, and acute
above; shield ovate, fleshy, adhering at its posterior part,
and free before, enveloping a shell, and having a notch in
the centre of its right margin; four tentacula, the two pos-
terior the largest; respiratory and anal orifices under the
notch of the shield, and the orifice for generation placed
between the two tentacula of the right side.

Parmacella calyculata, — THe Cup-sHAPED Parma-
cELLA. Plate XIII. fig. 31. Ovate; left margin broad
and reflected, right margin reflected at top and acute be-
neath ; exceedingly thin, transparent, and of a pale yellow-
isli-brown.

Genus 5.—ONCHIDIU M.—Lamarck.

Generic Character.—Body oblong, creeping, marginated
on all sides ; head projecting, the lower part with a promi-
nent margin; two rectractile, cylindrical tentacula; two
auriform appendages at the sides of the mouth, which is
destitute of maxillary processes; the respiratory and anal
orifices distinct, placed under the posterior extremity of the
body. Destitute of a shell.

Annals du Museum, vol. v., p. 38, plate 6.
Section I].—HypRoBRANCHIZ.
The branchie formed of filaments or lamine, and pecti-
nated or tufted. The animals respire in water.
TRIBE II.—LAPLYSIACEA.

The branchiz placed in a particular cavity, situated near
the posterior region of the back, and covered by an oper-
cular shield; the animals possessing tentacula.

i ae

110 GASTEROPODA.

Genus 6.—_DOLABELLA.— Lamarck.

Generic Character.—Body creeping, oblong, narrowed in
front, posteriorly widened, and there truncated obliquely by ©
an orbicular inclined plane; the margins folded over the
back; four somewhat tubular tentacula, disposed in pairs;
branchial operculum enclosing a shell; anal orifice situated
on the back, near the branchia, in the middle of the orbicu-
lar disk. Shell oblong, slightly arcuated, thicker, callous,
and somewhat spiral, on one side.

Dolabella Rumphiit.—Rumputus’s DoLaBetia. Plate
XIII. fig. 30. Base thick, callous, and subspiral; dilated
above, thin, and wedge-shaped. Inhabits the Indian ocean,
the Isle of France.

Genus 7.—LAPLYSIA.—JLinneus.

Generic Character. — Body creeping, oblong, convex
above; bordered on each side by a broad mantle, which
covers the back when the animal is quiescent; head and
neck elevated; with four tentacula, of which the two upper
ones are ear-shaped; the eyes situated near the mouth
before the ear-shaped tentacula; the dorsal shield semi-
circular, sub-cartilaginous, adhering on one side, and cover-
ing the branchial cavity; anal orifice placed behind the
branchie.

Laplysia radiata.—Tue RapiaTep Laptysta. Plate
XIV. fig. 25. Nearly round, left margin somewhat re-
flected; outer lip acute; yellowish horn-coloured, with
brown radiations, and two concentric bands.

TRIBE III.—BULLACEA.

The branchie situated in a particular cavity, near the
posterior region of the back, and covered by the mantle;
no tentacula.

GASTEROPODA. ltl |
|
|
|
|

Genus 8.—BULLA.—JLinneus.

Generic Character.—Body oblong-ovate, slightly convex;
divided into two transverse portions above, and having the
mantle slightly folded posteriorly ; no apparent tentacula;
branchiz on the fore part of the back, and covered; anal
opening placed in the right side. The posterior part of the
body covered by an involute shell, with neither pillar nor
spire; aperture extending the whole length of the shell.

Bulla lignaria.—Tue Woop-.ikEe Buia. Plate XIV.
fig. 25. Narrowed towards the top, where it is slightly
umbilicated; yellowish-brown, with numerous transverse
pale strie. Two inches long. Inhabits the British seas,
and those of Europe generally.

Genus 9.—BULL A.—Lamarck.

Generic Character.—Body ovate-oblong, somewhat con-
vex above, and divided transversely into two parts; the
lateral lobes of the foot thickened and bent upwards; head
indistinct, and without tentacula; branchie placed on the
back. Shell concealed in the mantle; thin, somewhat in-
volute on one side, and destitute of a columella or spire ;
aperture large and wide.

Bullea aperta.—TueE Oren Butitma. Plate XIV. fig.
23. Suborbicular, pellucid, white, faintly striated, and
slightly wrinkled ; almost entirely open. Half an inch long.
Inhabits the British seas, and those of Europe generally.

Genus 10.—RETUSA.—Brown.

Generic Character. — Animal unknown. Shell small,
oblong-ovate, spiral, outer lip nearly the whole length of
the bedy,- and entire; spire very short, volutions promi-
nent.

Retusa plicata.—Tue Puarrep Retusa. Plate XIV.
fig. 27. White, opaque, subcylindrical; spire produced ;
aperture elongated, straitened at top; two transverse plaits,
K 2

112 GASTEROPODA.

and several oblique ones, at the base of the columella; outer
lip thin, slightly inflected. One-third of an inch long. In-
habits the sea at Dunbar.

Genus 11.—A KER A.—Brown.

Generic Character.—Animal not described. Shell elas-
tic, convoluted; apex obtuse, canaliculated, the volutions
even with the body ; aperture wide at the base, contracted
at top, and extending the whole length of the body; colu-
mella visible to the end.

Akera flexilis—_THE FLEXIBLE AKERA. Plate XIV.
fig. 29. Oval membranaceous, excessively thin and flexible;
horn-coloured, with a convolute truncated channelled spire;
pillar lip a little thickened and white. Three-fourths of an
inch long. Inhabits the British seas.

Genus 12.—_DIAPHANA.—.Brown,.

Generic Character.— Animal unknown. Shell small,
spiral, fragile, somewhat orbicular; aperture encompassing
the body, wide; pillar lip slightly reflected, behind which
is a subumbilicus; spire very short, never exceeding two
volutions, and hardly rising above the body, which is con-
cave at top.

Diaphana candida.—THe Waite DiapHana. Plate
XIV. fig. 30. Pure white, ventricose; aperture whole
length of the shell, narrowed at top; spire short; sub-
umbilicated. One-sixth of an inch long. Inhabits the
Frith of Forth.

Genus 13.—~ACER A.—Lamarck.

Generic Character.—Body ovate, convex, transversely
divided above into two parts; the foot with dilatations in
the form of fins or wings below; head indistinct; branchie
situated on the back, far behind, and covered by a mantle;
no shell.

GASTEROPODA. 113

Acera carnosa.—TuHe FiesHy AcerA. Cuvier in An-
nales du Musée, vol. xvi. p. 10. Plate I. fig. 15, 16.

TRIBE IV.—CALYPTRACEA.

The branchie are situated in a dorsal cavity near the
neck, and elevated within the cavity, or even projecting
beyond it; shell invariably external, and covering the ani-
mal.

Genus 14. _ANCYLUS.—Draparnaud.

Generic Character. — Body creeping, enveloped in the
shell; two thick, sub-cylindrical tentacula, with the eyes
situated at their internal base; foot large, elliptical; some-
what narrower than the body. Shell thin, obliquely coni-
cal; aperture oval, with a pointed apex, which is inclined
backwards; margins simple.

Ancylus oblongus.— THE OBLone ANncytus. Plate XIV.
fig. 18. Aperture elongated, vertex turned to one side;
with fine concentric striz; pale horn-colour above, inside
bluish. One-third of an inch long. Inhabits the fresh
waters of Europe.

Genus 15.—CREPIDULA.— Lamarck.

Generic Character. —Head of the animal anteriorly forked,
having two conical or nearly cylindrical tentacula, with the
eyes placed at their exterior base; mouth simple, destitute
of jaws, and situated in the bifurcation of the head; bran-
chi with long filaments, and projecting from the large
branchial cavity; the mantle never bordering the shell; foot
minute; anal orifice lateral. Shell ovate, or oblong-ovate,
convex on the back, and concave beneath; spire inclining
to one side; aperture with a horizontal partition next the
spire, extending to nearly the middle of the shell.

Crepidula aculeata.— Tur PrickLy CrepipuLa. Plate
XIV. fig. 16. Oval. brown, with acute rough strie; vertex
K 3

114 GASTEROPODA.

recurved; inside with a chamber, and of a bluish or purple
colour. One inch long. Inhabits the American seas.

Genus 16.—CALYPTRAA.—Lamarck.

Generic Character.— Animal. oval or suborbicular, more
or less depressed, not spiral; head broad, with distant lateral
tentacula, having the eyes on the middle of their outer bor-
der; foot nearly circular, very thin. Shell conical, base
orbicular, and summit vertical, imperforate, and acute; in-
ternal cavity with a spiral septum.

Calyptrea Sinensis.—-THE CHINESE CALYPTRZEA. Plate
XIV. fig. 19. Orbicular, subconic, smooth; vertex ending
in a small volution; margin entire; cream-yellow; very
glossy within, and provided with a laminar plate. Three-
fourths of an inch in diameter. Inhabits the Chinese seas.

Genus 17.—PILEOPSIS.— Lamarck.

Generic Character.—Animal with two conical tentacula,
and the eyes at their base externally; branchie formed in
a row under the anterior margin of the cavity, near the
neck. Shell obliquely conical, anteriorly recurved, with
the apex curved and somewhat spiral; aperture of a round-
ish oval; the anterior margin shortest, and the posterior
one large and rounded; the muscular impression elongated,
arcuated, and transverse, situated under the posterior mar-
gin.

Pileopsis Ungarica.—T ue HUNGARIAN PiLeEopsis. Plate
XIV. fig. 31. Conical, vertex slightly spiral; longitudinally
striated, and transversely wrinkled; covered with a fawn-
coloured hairy or filamentous epidermis; inside smooth,
glossy, white, or rose-colour. Two inches in diameter.
Inhabits the seas of Europe.

Genus 18.—FISSURELLA.—Zamarek.

Generic Character.—Animal with the head truncated in
front; two conical tentacula, with eyes at their exterior

base; mouth simple, terminal, and destitute of jaws; two
pectinated branchie projecting from the cavity; mantle
large, protruding beyond the shell. Shell shield-shaped,
conically depressed; concave within; the vertex perforated ;
destitute of a spire.

Fissurella Greca.— Tue GREEK FissurELLA. Plate
XIV. fig. 20. Ovate-oblong, convex; the vertex with an
ovate perforation; strie cancellated and elevated, and the
sections tuberculated; opening oblong-ovate, white or
bluish; outside yellowish-brown, sometimes clouded. Half
an inch long. Inhabits the European seas.

Genus 19.—SIPHO.—Brown.

Generic Character.— Animal unknown. Shell subconic,
vertex turned to one side, slightly spiral, with a small fis-
sure near the apex; inside having a rhombic funnel-shaped
siphon, corresponding with the external fissure; ovate.

Sipho striatus—TuHe STRIATED SrpHo. Plate XIV.
fig. 21. White, with strong divergent striz and faintly
striated concentrically; margin slightly crenulated; the
fissure triangular. Three-eighths of an inch long. Inhabits
the sea at Greenock.

This is the Fissurella Noachina of Sowerby and Lyell; Patella
Noachina of Linnzeus.

Genus 20.—EMARGINULA.—LZamarck.

Generic Character.—Body creeping; having two conical
tentacula, with the eyes placed at their external base ;
mantle very large, partly covering the margin of the shell
by its replicate borders; foot broad and very thick. Shell
conical, shield-shaped; vertex inclined to one side; internal
cavity simple; the dorsal margin with a fissure.

Emarginula fissura.—Tue Stir Emarcinuta. Plate
XIV. fig. 17. Oval, with reticulated striz, and ribs radiat-
ing from the vertex, which is obtuse and slightly recurved;
margin with a fissure, which extends nearly half-way to the
vertex; inside glossy white. Three-eighths of an inch

116 GASTEROPODA.

long. Inhabits the British seas, as well as those of other
parts of Europe.

Genus 21.—PARMOPHORUS.—Lamarck.

Generic Character.—Body creeping, very thick, oblong-
ovate, broad behind, obtuse at the extremities; border of
the mantle cleft before, and suspended vertically around ;
back shell shield-shaped, and partly covered; head distinct,
and slit below; two conical contracted tentacula, at the
base of which are placed the eyes, which are somewhat
pedunculated; mouth below, funnel-shaped, oblique, trun-
cated, and concealed; branchial cavity opening anteriorly
behind the head by a transverse fissure. Shell oblong,
somewhat in the form of a paralielopiped; slightly convex
above, with a small sinus before; apex minute, pointed,
inclined backwards.

Parmophorus Australis. —TuHe AUSTRALIAN ParMo-
pHorus. Plate XIV. fig. 22. Shell oblong, depressed ;
vertex slightly recurved; concentrically striated; the pos-
terior margin rounded, and the anterior truncated. Two
inches long. Inhabits the Australian coasts.

TRIBE V.—SEMIPHYLLIDIA.

Branchie situated under the margin of the mantle, and
set in a longitudinal series, on the right side of the body.
The animals respire water.

Genus 22.-_UMBRELLA.— Lamarck.

Generic Character.— Body of the animal very thick,
somewhat oval, and provided with a dorsal shell; foot very
large, smooth, and flat underneath, surrounded by a border,
anteriorly notched, attenuated behind; head indistinct; four
tentacula, the two upper ones thick, short, and truncated,
the other two thin, and shaped like pedunculated crests;
foliaceous branchie, between the foot and the slight margin
of the mantle, along the right side. Shell external, orbicu-

GASTEROPODA. LEZ

cular and somewhat irregular; slightly convex above, with
the vertex towards the centre; internal cavity but slightly
hollowed, with a coloured, callous disk, impressed in the
centre.

Umbrella Indica. —TueE INDIAN UMBRELLA. Plate XIV.
fig. 24. Ovate, slightly convex above; the vertex towards
the centre; whitish, with the summit yellow; longitudinally
striated, and concentrically wrinkled; inside with radiating
strie. Four inches in diameter. Inhabits the Indian seas.

Genus 23.—PLEUROBRANCHUS.~—Lamarck.

Generic Character.—Body creeping, fleshy; mantle and
foot expanded; branchie placed on the right side; cloak
enveloping the shell; neck short, contracted in some spe-
cies, with an emarginate front, exhibiting the commence-
ment of the inferior tentacula, the upper ones tubular and
hollow; branchize at the edge of the dorsal plait, in front
of which are the generative and anal orifices; mouth pro-
vided with a short retractile proboscis. Shell dorsal and
internal, thin, flat, and obliquely oval.

Pleurobranchus plumula.—Tue Ptumep PLEUROBRAN-
cuus. Plate XIV. fig. 14. Ovato-oblong, depressed,
pellucid, yellowish-white, concentrically wrinkled, almost
entirely open, rounded, and convoluted ; the vertex with a
single turn. Half an inch long. Inhabits the Devonshire
coast.

TRIBE VI.—PHYLLIDIACEA.

The branchiz situated beneath the margin of the mantle
in a longitudinal series around the body. Animals respiring
water.

Genus 24.—_PATELLA.—LZinneus.

Generic Character.—Body completely covered by the
shell; head with two pointed tentacula, having the eyes
situated at their exterior base; branchie placed in a series

——

118 GASTEROPODA.

under the mantle and around the body; anal and generative
orifices situated on the right anterior side. Shell univalve,
not spiral, concave within, simple, entire, with the vertex
anteriorly inclined, and imperforate.

The anterior side of the shell, is that to which the summit is in-
clined, and the impression of the animal’s head can easily be distin-
guished internally on that side.

Patella vulgata.—Tue Common PaTELLa, on LIMPET.
Plate XIV. fig. 15. Oval, conic, or a little depressed ;
outside green or brown, sometimes radiated with various
colours; having divergent striz and concentric wrinkles ;
inside glossy, iridescent, with yellow or fawn-coloured,
purple, blue, or brown radiations. Two inches long. In-
habits the coasts of Europe.

Genus 25.._CHIT ON.—Linneus.

Generic Character.—-Body creeping, ovate-oblong, con- |},
vex, rounded at both extremities; marginated all round
with a coriaceous skin; the back covered by a longitudinal
series of testaceous, transverse, imbricated, and moveable
plates; head anterior, sessile, with the mouth placed below;
destitute of tentacula or eyes; branchie placed in a series,
round the body, under the margin of the skin; anal orifice
at the posterior extremity.

The species of this genus are in much obscurity, and of difficult
solution. The absence or presence of granulations, strix, and punc-
tures, are certainly of much use, but the only certain testis an exami-
nation of the sides of the valves, which, however, cannot be accom-
plished without taking the specimen to pieces. The sides of the valves
are always provided with a certain number of serrated teeth, which
seem to afford permanent characters in each species. See Plate I.
fig. 11.

Chiton fascicularis.-- THE FASCICULATED CuiTon. Plate
XIV. fig. 13. Eight imbricated valves, nearly smooth,
slightly carinated, and rounded at the margins, with thick
tufts of hair between the junctions of the valves, there
being five on the top of the upper valve, and three on the
base of the lower one. Three-fourths of an inch long.

Inhabits the British coasts.

PTEROPODA. 119

Genus 26.—CHITONELLUS.— Lamarck.

Generic Character.—Body creeping, elongated; middle
of the back provided in its entire length with a multivalve
shell, of which the alternate pieces, for the most part longi-

- tudinal, are connected by their extremities, in the form of a
band; sides naked; branchie disposed around tke body;
foot cleft longitudinally by a deep furrow.

The testaceous plates of this genus are never joined like those of
the Chiton, so that the animal can move in every direction. Upon the
contraction of the animal after death, however, these valves become
nearly united.

Chitonellus striatus. —TuHeE STRIATED CHITONELLUS.
Plate XIV. fig. 10. Each valve with strie radiating from
its apex; the margins serrated; the base of the last valve

obtuse. Inhabits the seas of New Holland.

TRIBE VII.—TRITONACEA.

| With external branchie, placed over the mantle on the

back or sides. Destitute of shells, and respiring water.
_ An extensive and highly interesting tribe of slug-like marine
animals, of which the genera, not being furnished with shells,
do not properly enter into a merely conchological arrange-
ment.

ORDER V.—PTEROPODA.

Animals destitute of a foot for locomotion, and of arms
for seizing their prey; but provided with two opposite and
similar fins fitting them for swimming; body free and float-
ing; some of them are destitute of shell.

Genus 1.—CYMBULIA.— Cuvier.

Generic Character.—Body oblong, gelatinous, pellucid,

enclosed in a shell; head sessile; two eyes, and two re-

120 PTEROPODA.

tractile tentacula; mouth with a retractile proboscis; two
opposite, oblong-ovate, branchiferous wings, connate at their
posterior base, being connected by an intermediate lobiform
appendage. Shell gelatino-cartilaginous, transparent, and
oblong; apex truncated; aperture lateral, anterior.

Cymbulia Peroniit.—Prron’s Cympunia. Plate XIV.
fig. 6. Somewhat gelatinous, or cartilaginous; very trans-
parent crystalline; oblong, pointed at the vertex, truncated
| at the base; general shape like a Turkish slipper. Two
_ inches long. Inhabits the Mediterranean.

Genus 2.—_ LIM ACIN A.—LZamarck. |

Generic Character.—Body soft, oblong; two branchial |
fins situated at the base of the neck; posterior part of the
body spiral, and enveloped in a shell. Shell thin, fragile,
papyraceous, spiral, with the volutions connected in a dis-
coid form.

Limacina helicialis. —T we HELIX-LIKE Limactna. Plate
XIV. fig. 11. Thin, fragile, spiral; the volutions united
| ina discoid form. Half an inch in diameter. Inhabits the
| North seas.

Genus 3.—CLEODORA.—Peron.

Generic Character.—Body oblong, gelatinous, contrac-
tile; with a head in front, and two wings; the posterior
part enveloped in a shell; head distinct, projecting, rounded ;
two eyes; mouth in the form of a small beak; destitute of
tentacula; two opposite membranaceous, pellucid, and cor-
dated wings or fins, placed at the base of the neck. Shell
or sheath gelatinoso-cartilaginous, transparent, and in the
form of a reversed pyramid.

Cleodora pyramidata. — THE PyRAMIDAL CLEODORA.
Plate XIV. fig. 9. Pyramidal, triangular; of a gelatinous
or cartilaginous substance, very thin and transparent; aper-
ture obliquely truncated. Inhabits the American seas.

He se a a a

ae eet

CONCHIFERA. 12]

Genus 4, HYALAA.—Lamarck.

Generic Character.—Body enclosed ina shell; two op-
posite retractile, rather large fins, inserted at the sides of
the mouth; head indistinct; mouth terminal, placed at the
junction of the fins; no eyes; branchie lateral. Shell
horny, transparent, oval-globular, with three teeth behind,
open at the summit and the two posterior sides.

Hyalea tridentata.—Tur TuHreEe-TooTHED HyaLma.
Plate XIV. fig. 12. Transparent, horn-coloured, globular;
posteriorly tridentate; summit and two posterior sides open;
very finely striated transyersely. Three-fourths of an inch
long. Inhabits the Mediterranean, and the seas of warm
climates.

CLASS I.—CONCHIFERA.

Animals soft, inarticulated, destitute of head or organs of
vision, and always fixed within a bivalve shell; having ex-
ternal branchiz, situated between the body and the mantle,
which is very large, and forms two thin lobes, enveloping
the whole body; a simple circulation, and a unilocular
heart.

All the animals of this class live in the sea or in fresh
water. None of them have an internal shell. The body
is invariably soft, and the mouth is situated near the hinge
anteriorly.

Lamarck divides this class into the two following orders:
—I. Monomyarta, with one muscle of attachment; shell
exhibiting interiorly but one subcentral muscular impres-
sion.—II. Dimyarta, having at least two muscles of at-
tachment; the shell exhibiting interiorly, two separate,
lateral, muscular impressions.

L

122 MONOMY ARIA.

ORDER I—MONOMYARTIA.

The animal provided with one muscle of attachment,
leaving a nearly central impression in each valve of the
shell.

Section I.—Ligament either unknown, or forming a
tendinous tube, which connects the valves.

TRIBE I.—BRACHIOPODA.

Animal with two opposite, elongated, ciliated arms, situ-
ated near the mouth, and rolled up spirally when the animal
is at rest; mantle having two separate lobes in front, which
envelop the body. Shell bivalve, adhering to extraneous
marine bodies, either by the shell itself being in contact
with them, or attached by a tendinous chord. The shells
are not quite equivalve, and open by a hinge.

Genus 1.—LINGULA.—Lamarck.

Generic Character.—Subequivalve, flat, ovato-oblong,
truncated at the apex, slightly pointed at the base, elevated
on a fleshy tendinous peduncle, attached to marine bodies;
hinge without teeth.

Lingula anatina.—Tur Duck Linevra. Plate XIV. fig.
7. Shaped like a duck’s bill, with a green, shining epidermis,
and having a cylindrical pedicle from two to four inches long.
Inhabits the Indian ocean.

Genus 2.— TEREBRATULA.—Lamarck.

Generic Character.—Inequivalve, regular, subtrigonal ;
attached by a short pedicle to extraneous marine bodies ;
the larger valve with a projecting umbo, frequently curved,
and perforated at its summit by a round hole, or a notch;
hinge with two teeth; two slender osseous processes arising
from the disk of the smaller valve internally.

——

MONOMYARIA. 1233

’

This genus contains two sections :—* Shell without furrows or striz.
** Longitudinally furrowed.

The distinction between this genus and that of Anomia, is that in
the latter the perforation is always in the smaller valve, while in the
Terebratula it isin the larger one. There is, however, a still greater
distinction in the animals.

Terebratula Cranitum.— Tue Sxkutut TEREBRATULA.
Plate XIV. fig. 1. Slightly ovate, ventricose; summit of
the convex valve produced and blunt; with divergent striz,
and the margin crenulated. Half an inch long. Inhabits
the sea at the Zetland Islands.

Genus 3.—ORBICULA.—Lamarck.

Generic Character.—Suborbicular, inequivalve ; without
apparent hinge; under valve very thin, depressed, and ad-
hering to marine bodies; upper valve ‘subconic, with the
vertex acute, and more or less elevated.

Orbicula Norwegica.— Tue NorRWEGIAN ORBICULA.
Plate XIV. fig. 32. Upper valve in the form of a depressed
cone, with.a produced and pointed summit. Inhabits the
Norwegian seas.

TRIBE Il.—RUDISTA.

Animal unknown, as are also the ligament and hinge;
shell with very unequal valves, and having no distinct
umbones.

Genus 4.-CRANIA.—Bruguiere.

Generic Character.—Inequivalve, suborbicular; under
valve flattened, fixed below, and perforated on its inner sur-
face by three unequal oblique holes; upper valve very con-
vex; provided interiorly with two projecting callosities.

Crania personata.—THE Maskep Cranta. Plate XIV.
fig. 5. Orbicular; the upper valve more gibbous and some-
what conical; lower valve flat, with three pits. Inhabits
the Indian ocean.

pe

124 MONOMY ARIA.

Genus 5.—DISCIN A.— Lamarck.

Generic Character.—Inequivalve, of a roundish oval shape,
and depressed; valves equal in size, each provided with an
orbicular and central disk; that of the upper valve not per-
forated, but having a mammillated projection in the centre;
the lower valve divided by an oblong fissure.

Discina ostreoides.—THE OysTER-LIKE Disctna. Plate
XIV. fig. 8; a, the upper valve; 6, the under valve. Upper
valve longitudinally ribbed, crossed by concentric strie. Five
lines long. Inhabits the Zetland and Hebridian seas.

Genus 6.—BIROSTRITES.—Lamarck.

Generic Character.—Inequivalve, with two horns; the
disks of the valves elevated, conical, and unequal, obliquely
diverging, and nearly straight, in the form of horns; the one
valve enveloping the other at the base. Fossil.

Genus 7.—CALCEOLA.—Lamarck.

Generic Character.—Inequivalve, triangular, turbinated,
flattened beneath; the large valve hollowed like a hood, and
truncated obliquely at the aperture; the smaller valve some-
what orbicular, and in the form of a lid, having a furrow in
the centre. Fossil.

Genus 8.—RADIOLITES.—Lamarck.

Generic Character.—Shellinequivalve, striated externally,
the striz radiating from the umbo; lower valve turbinated,
and larger; the upper convex or conical, and lid-shaped.
Fossil.

Genus 9._SPH HZ RULITES.—Lamarck.

Generic Character.—Shell inequivalve, orbiculato-globose,
somewhat depressed above, roughened with large subangular
spreading scales; the upper valve the least, flattened, lid-

MONOMY ARIA. 125

shaped, with two unequal tubercles within; under valve sub-
ventricose, with the scales radiating beyond the margin, its
cavity obliquely conical, and forming a ridge by a replication
of its margin; inside partly striated; hinge unknown.

Section II.—Ligament not marginal, enclosed in a short
hollow under the beak, always perceptible, and not forming
a tendinous chord beneath the shell.

TRIBE I.—OSTRACEA.

Ligament placed either internally or nearly so; shell ir-
regular in form, foliaceous, and sometimes papyraceous.

* Papyraceous, thin shells, with the ligament internal.

Genus 10.—ANOMIA.—LZinneus.

Generic Character.—Shell inequivalve, irregular, opercu-
lated, adhering by the operculum; under valve flattened,
with a perforation or slit near the umbo, through which pro-
trudes a testaceous, straight, elliptical operculum, or plug,
by which the shell adheres to extraneous bodies; upper
valve larger, concave, and entire; ligament large, internal,
and cardinal.

Anomia undulata.a—Tux Wavep Anomta. Plate XIV.
fig. 2. Suborbicular, pellucid, with strong, irregular, undu-
lated, longitudinal striz, and some transverse concentric
ones; outside yellowish dirty green; inside fine green; the
ligament perforation large, ovate; muscular impression star-
shaped. Two inches broad. Inhabits the British coasts.

Genus 11.—PLACUNA.—L£amarch.

Generic Character.—Shell free, subequivalve, irregular,
very flat; hinge internal, with two short longitudinal diver-
gent ribs, in the form of the letter V, which fit into two
grooves in the opposite valve, held together by the ligament.

L3

126 MONOMY ARIA.

Placuna placenta.—Tue PLAceNTA Puacuna. Plate
XIV. fig. 3. Suborbicular, flat, white, and pellucid, with
fine longitudinal striz, slightly decussated. Six inches or
more in diameter. Inhabits the coasts of China, and the
Indian seas.

** Shell foliaceous, frequently ponderous, with a semi-internal liga-
ment.

Genus 12._VULSELLA.—Lamarck.

Generic Character. —Shell longitudinal, subequivalve,
irregular, and free; umbones equal; hinge, with a projecting
callosity depressed above, and a conical obliquely arcuate
hollow for the ligament; within each valve a lengthened
muscular impression.

Vulsella lingulata.—Tue LATCHET VULSELLA-. Plate
XIV. fig. 4. Elongated, depressed, transversely striated ;
pale yellowish brown, with longitudinal undulated darker
stripes. Four inches long. Inhabits the Indian ocean.

Genus 13.—OSTREA.—Linneus.

Generic Character.—Shell adhering to extraneous bodies ;
inequivalve and irregular, with the beaks separated, the
upper valve advancing as the animal enlarges; hinge without
teeth; the lower valve larger, concave, ligament semi-inter-
nal, fixed in the cardinal depressions, of which that of the
lower valve is sometimes prolonged, with the umbo, as the
animal advances in age.

This genus has two sections ; * with a simple margin, and not pli-
cated, ** margins plicated.

Ostrea edulis—Tue EpiBLE OysTEerR. Plate XV. fig.
3. Suborbicular, rugged, with undulated, imbricated scales,
and transversely striated; one valve flat, and the other
convex; outside brownish-green ; inside pearly-white; ex-
ceedingly variable in form and size. Inhabits the coasts of
Europe.

MONOMYARIA. 127

Genus 14.—GRYPHZA.—Lamarck.

Generic Character.—Shell inequivalve, free; lower valve
large and concave, with the beak large, projecting, and spi-
rally curved or involute; upper valve small, flat, and resem-
bling a lid; hinge without teeth; the cardinal hollows
oblong, arcuated; a single muscular impression. Animal
unknown.

This genus is distinguished from Ostrea by the very deep and
crenated lower valve, and by its summit being terminated by a long
spirally incurved beak, slightly turned to one side; and the edge sharp
and angular,

Gryphea angulata.—TuHEe ANGULATED GryYPHZA. Plate
XV. fig. 1. Oblong-ovate, with three longitudinal, cari-
nated ribs below; beak large, somewhat oblique. Four
inches long. Habitation unknown. A specimen of this
rare shell is in the Museum of the Jardin du Roi, at Paris.

Pa

TRIBE II.—PECTINIDES.

Shell for the most part regular, compact, and not foli-
aceous ; the ligament either internal, or partly so.

Genus 15.—PODOPSIS.—Zamarck.

Generic Character.—Shell inequivalve, nearly regular,
adhering by its lower beak; without ears; the lower valve
larger, more convex, and produced at the base; hinge with-
out teeth; ligament internal. Found only in a fossil state.
They nearly approximate the genus Gryphza, from which
they are distinguished by the summit of the lower valve not
being recurved, though much advanced beyond the upper
valve.

Genus 16.—SPONDYLUS.—Linneus.

Generic Character.—Shell inequivalve, adherent, cared,
spined, and rough, with unequal beaks; lower valve with

128 MONOMYARIA.

an external flattened cardinal space divided by a longitudinal
groove, and increasing with the age of the animal; hinge
with two very strong hooked teeth in each valve, and a
central cavity for the ligament, communicating at its base
with the external groove; ligament internal.

Spondylus longispina.— THE LONG-SPINED SPONDYLUS.
Plate XV. fig. 2. Longitudinally sulcated and ribbed,
thickly spined; of a reddish colour; alternate spines, arcu-
ated and tongue shaped; umbones orange. Four inches
long. Inhabits the Indian ocean.

Gone 17.2 PLICATUL A= Lanerek:

Generic Character. — Shell inequivalve, without ears,
attenuated at the base, rounded and plaited at the upper
margin; beaks unequal and entire; hinge with two strong
teeth in each valve, with a central cavity for the ligament,
which is internal.

Plicatula ramosa.—Tue BRANCHED PLIcATULA. Plate
XV. fig. 4. Oblong-trigonal, very thick ; with strong lon-
gitudinal plaits; brown, or yellowish-brown, with rust-
coloured, arrow-shaped markings; inside white. One inch
and a half long. Inhabits the American seas.

Genus 18.—PECTEN.—JLamarck.

Generic Character. —Shell free, regular, inequivalve,
eared; the lower margin transverse, straight; beaks con-
tiguous; hinge without teeth; ligament internal, placed in
a triangular cavity.

It has two sections—* ears equal or nearly so—** ears unequal,

Pecten varius.—THE SPECKLED PEcTEN. Plate XVe
fig. 5. Ears very unequal; having about thirty-two ribs,
covered with transverse prickly suberect scales; variously
clouded and speckled with a variety of colours. 'Two inches
and a quarter long. Inhabits the European seas.

MONOMYARIA. 129

Genus 19.—PLAGIOSTOMA.—Zamarchk.

Generic Character.—Shell subequivalve, free, somewhat
eared; base of the hinge transverse and straight; beaks some-
what remote; hinge without teeth; depression, for the re-
ception of the ligament, conical and partly internal. Species
all fossil.

» Plagiostoma spinosum.— THE THorNyY PLAGIosToMA.
Plate XV. fig. 6. Subarcuated, the umbo of one shell
higher than that of the other, with longitudinal ribs, and
remote concentric rings. Fossil Britain.

Genus 20 —LIMA.—Bruguiere.

Gencric Character.—Shell longitudinal, nearly equivalve,
with small ears; valves gaping at the sides; beaks separate;
cavity for the ligament partly external; hinge without teeth.

Lima vitrina.—Tue Guassy Lima. Plate XV. fig. 7.
Oblong-ovate; extremely pellucid, and pure snowy-white,
with longitudinal distinct strize; lower margin denticulated.
One half inch long. Inhabits the British seas.

Genus 21.—PEDUM.— Lamarck.

Generic Character. — Shell inequivalve, subauriculate ;
the lower valve tumid; beaks unequal, separate; hinge
without teeth; ligament partly external, inserted in an
elongated groove, in the internal surface of the beaks;
lower valve, with a notch near the posterior margin.

Pedum spondyloideum.—TuEe SPoNDYLUS-SHAPED PE-
pum. Plate XV. fig. 9. Ovate, wedge-shaped, flat; the
upper valve with longitudinal striz, white, granulated, and
rough, slightly tinged with purple near the beak. Two
inches and a half long. Inhabits the Indian ocean, and the
seas of the Isle of France

130 MONOMYARIA.

Section IIJ.—Ligament marginal and elongated.

TRIBE I.—MALLEACEA.

With foliaceous shells, more or less inequivalve; having
the ligament marginal, somewhat linear, and either simple
or interrupted by crenulations.

Genus 22._MELEAGRIN A.—Zamarck.

Generic Character.—Somewhat equivalve, rounded and
scaly on the outside: a sinus at the posterior base of the
shell for the passage of the byssus, at which place the left
valve is notched and narrow; hinge linear, and destitute of
teeth; ligament marginal, elongated, and placed nearly ex-
terior, and dilated in the centre.

In many respects resembling Avicula, but differing in being equi-
valve, and always without the elongated transverse base, on the car-
dinal tooth. The sloping sides of the opening, admitting the passage
of the byssus, are perceptible on both valves, which is never the case
with Avicula, where a notch answers the same purpose.

Meleagrina margaritifera.—THE PEARL-BEARING ME-
LEAGRINA. Plate XV. fig. 10. Somewhat square, com-
pressed; undulated, and transversely striated, with a series
of lamelliform longitudinal scales; greenish on the outside
and perlaceous within. Ten or twelve inches long. In-
habits the Indian seas.

Genus 23.—AVICULA.—Lamarch.

Generic Character.—Shell inequivalve, fragile, with the
base straight, transverse, and produced at both extremities,
the anterior of which is caudiform; valves oblique; the left
one emarginate, with a sinus or notch, through which the
byssus passes; hinge linear, with one tooth in each valve,
under the beaks; ligament linear and marginal, placed in a
long narrow groove.

Avicula Anglica.—Tue Eneiisn Avicuta. Plate XV.
fig. 11. Wing moderate, obliquely curved; yellowish fawn-

MONOMY ARIA. 131

eoloured, with dark reddish-brown blotches; inside perla-
ceous and iridescent. One inch and a fourth long. Inhabits
the Devonshire coast.

Conis WME LLEUS — Lamarck.

Generic Character. —Subequivalve, rugged, distorted,
frequently elongated; sublobate at the base; beaks small,
diverging; hinge without teeth, with an elongated conical
furrow under the beaks; ligament subexternal, short, placed
in the sloping area, at the base of the valves.

Approximating in form to Perna, but very different in the structure
of its hinge, and in this respect more nearly resembling Avicula,
though it cannot be mistaken for it, both being without the sulcated
teeth or joints at the hinge; but the conical cavity, situated under the

beaks of the Malleus, and crossing the angle of the slope of the liga-
ment, at once distinguishes it from Avicula.

Malleus albus.— Tue Wuite Mattevs. Plate XV.
fig. 12. Trilobate; lateral lobes of the base prolonged,
sinus none, or not distinct from the pit for the ligament:
white, with transverse undulations. Four inches long.
Inhabits the Australian seas.

G_nus 25.—PERN A.— Lamarck.

Generic Character.—Subequivalve, flattened, slightly
distorted, of a lamellar texture; hinge linear, marginal, and
many toothed; these are furrow-like, parallel, and trans-
verse, not inserted in the opposite furrows, but with the
ligament inserted between them; sinus for the byssus some-
what gaping, and placed under the extremity of the hinge.

The substance of the shell, although solid, is formed of flaky por-

tions, not adhering closely to each other, and giving it a foliaceous
appearance.

Perna Ephippium.—Tue Sappie Perna. Plate XV.
fig. 13. Compressed, suborbicular; hind side produced, the
margin very acute; purplish-brown on the outside, and pearly
within. Four inches long. Inhabits the Indian seas.

132 MONOMY ARIA.

Genus 26.—CRENATULA.—Lamarckh.

Generic Character.—Subequivalve, flattened, somewhat
distorted and lamellar; without any particular opening for
the byssus; hinge lateral, linear, marginal, and crenated ;
the crenulations in a regular series, callous, and hollowed
for the reception of the ligament.

The distinction betwixt this genus and Perna, consists in the hinge
of Crenatula being composed of slightly concave callous crenulations,
which receive the ligament; while in Perna it consists of parallel
truncated linear teeth, corresponding and opposed to the opposite ones,
the ligament being inserted in their interstices only.

Crenatula mytiloides. —Tue MuscLE-sHAPED CRENA-
TULA. Plate XV. fig. 14. Oblong-ovate, oblique; the
base acute; violet-coloured, with obscure radiations. In-
habits the Red sea.

TRIBE II.—MYTILACEA.

Hinge with a subinternal marginal ligament, which is
linear, very entire, and occupies a considerable portion of
the anterior margin; shell rarely foliaceous, generally thin,
and brittle.

Genus 27.—~PINNA.—Linneus.

Generic Character.—Longitudinal, wedge-shaped, equi-
valve, gaping at the end, and pointed at the summit, with
the beaks straight and acute; hinge lateral and without
teeth; ligament marginal, linear, very long, and half internal.

Pinna ingens.—THE Huce Pinna. Plate XV. fig. 15.
Nearly triangular, horn-coloured, smooth, with distant folia-
tions; striated on one side, with rough scaly wrinkles on
the broader end. ‘Twelve inches long. Inhabits the coast
of Britain.

Genus 28..—_MY TILUS.—Zinneus.

Generic Character.— Longitudinal, equivalve, with the

——

MONOMYARIA. 133

base acute, affixed by a byssus; beaks acute, nearly straight,
and terminal; hinge lateral, generally with teeth; ligament
marginal, and partly internal; muscular impression elon-
gated, clavate, and sublateral.

Section * Longitudinally furrowed. ** Without furrows.

Mytilus edulis—_Tue Eprste Myrinus. Plate XV. fig.
16. Oblong-oval, nearly smooth, pointed, and slightly cari-
nated at the beak, truncated on one side, and dilated on the
other; covered with an olivaceous epidermis; beneath which
it is radiated with blue or purple; internal margin blue, the
concave part white. Two to three inches long. Inhabits
the British seas.

Genus 29._MODIOLA.—Zamarck.

Generic Choracter.—Subtransverse, equivalve, regular;
the posterior side very short; beaks nearly lateral, depressed
on the short side; hinge without teeth, lateral and linear;
cardinal ligament placed in a marginal furrow, and nearly
internal; one muscular impression in each valve, which is
sublateral and elongated. *

Distinguished from the genus Mytilus by the beaks not being termi-
nal but placed a little below the apex.

Modiola discors.—TuE Discorpant Mopiona. Plate
XV. fig. 17. Oblong-oval, very convex, produced and nar-
rower at the anterior end; longitudinally striated on both
sides, and transversely in the middle; outside green; inside
white or pale pink, and somewhat pearly; margin crenulated
at the base; beak oblique. One half inch long. Inhabits
the British seas.

TRIBE III.—TRIDACNITES.

Transverse, equivalve, the muscular impressions situated
under the centre of the lower margins, and extended on each
side.

* Both in Mytilus and Modiola there are in reality two muscular
impressions, although one is very small

M

134 MONOMY ARIA.

Genus 30.—HIPPOPUS.—Lamarck.

Generic Character. —Equivalve, regular, inequilateral,
and transverse; lunule closed; hinge with two compressed
unequal teeth; ligament marginal, and external.

Distinguished from the Tridacna, by having the posterior slope
closed, or nearly so, and the inner margin dentated at that part.
The spines which arm the ribs are tubular, and are never arched or
vaulted.

Hippopus maculatus.—TuEe SpotTeD Hipropus. Plate
XV. fig. 18. Transversely ovate, ventricese, with scaly
ribs; and reddish purple spots; lunule heart-shaped, and
oblique; the margins very deeply crenulated. Eight inches
broad. Inhabits the Indian seas.

Genus 31.—TRIDACNA.—Lamarch.

Generic Character.—Shell regular, equivalve, inequilateral
and transverse ; a gaping space near the beaks; hinge with
two compressed, unequal teeth; ligament marginal and ex-
ternal.

A bundle of tendinous fibres passes through the aperture of the pos-
terior slope, by which the animal affixes itself to rocks, where it re-
mains suspended. Although there is no nacreous substance in the
valves themselves, yet the animal sometimes produces very fine pearls,
and of large size.

Tridacna gigas.—Tue Giant Tripacna. Plate XY.
fig. 21. Large, white, transversely ovate; with broad ribs,
provided with vaulted scales; the posterior slope heart-
shaped and gaping. Two feet six inches long, and four feet
six inches broad; the largest of all known shells, sometimes
weighing above five hundred pounds. Inhabits the Indian
ocean.

ORDER IL—DIMYARIA,

Shell having two separate lateral muscular impressions.

DIMYARIA. 135

Section I.—Shell irregular, and always inequivalve.

TRIBE I.—CHAMACEA.

Shell inequivalve, irregular, and adherent; hinge with one
or more teeth; and two distinct, lateral, muscular im-
pressions.

Genus 1.—ETHERIA.—Zamarck.

Generic Character.—Shell irregular, inequivalve, adher-
ing; beaks short, and appearing as if sunk in the base of the
valves; hinge destitute of teeth; waved, somewhat sinuated,
and unequai; with two distinct, remote, oblong muscular
impressions ; ligament external, tortuous, penetrating partly
into the shell.

The shells of this genus differ from those of Chama, in being pearly
in their substance, and lamellar in their texture.

Section * Shells with an oblong callosity on the base of the valve.

#* Shells without an incrusted callosity at their base.

Etheria elliptica.—Tue Ova Etnerta. Plate XV. fig.
19. Oval, flattened, dilated towards the umbones; the
apices remote. Inhabits the Indian ocean.

Genus 2.—CHAMA.—Lamarchk.

Generic Character.—Irregular, inequivalve, adherent ;
beaks incurved, unequal; hinge with one thick, oblique,
subcrenated tooth, fitting into a socket in the opposite valve;
two distant lateral muscular impressions; ligament external,
and depressed.

A strong characteristic mark of these shells is the thick, oblique
transverse tooth, which resembles a lengthened callosity, and is usually
crenated and grooved.

The shells of this genus are always affixed to their bodies Ly the
lower valves.

Section * Beaks twisted from left to right. #* Beaks turning from '

right to left.
M 2

aT

136 DIMY ARIA.

Chama Lazarus.—Tue Lazarus’s CHama. Plate XV.
fig.20. With imbricated, dilated, waved, obsoletely striated
foliations ; of a white, orange, red, or yellow colour; white
within. Two inches in diameter. Inhabits the American
seas.

Genus 3.—DICERAS.—Lamarck.

Generic Character.—Inequivalve, adherent ; beaks conical,
very large, diverging in irregular, spiral contortions; hinge
with a large, thick, concave, somewhat ear-shaped tooth
projecting in the larger valve ; two muscular impressions.

Diceras arietina.—TuHE RAM-HORNED Diceras. Plate
XVI. fig. 7. Somewhat heart-shaped, with divergent beaks.
Fossil.

Section II.—LAMELLIPEDES.— The foot depressed,
lamelliform, and not posterior.

TRIBE I.—NAYADES.

Shells inhabiting fresh waters; the hinge sometimes hay-
ing an irregular, simple, or cleft tooth, and a longitudinal,
prolonged one, sometimes none; some have irregular, granu-
lated tubercles, the whole length of the upper part; a com-
pound posterior muscular impression; umbones often de-
corticated.

Genus 4.—IRIDIN A.—Lamarck.

Generic Character.—-Equivalve, inequilateral, transverse ;
beaks small, turned to one side and nearly straight; two
separate lateral, muscular impressions; hinge long, linear,
and attenuated near the centre, tuberculous or nearly cre-
nated in its whole length; tubercles unequal; ligament ex-
ternal and marginal.

Tridina Nilotica.—Tue Nive Iripina. Plate XV. fig.
22. Shell transversely oblong; dark olivaceous green on
the outside, somewhat wrinkled concentrically; inside fine

oo ——————

DIMY ARIA. 137

pearly, with iridescent reflections. Five inches long. In-
habits the Nile.

Genus 5.—ANODONT A.— Lamarck.

Generic Character.—Equivalve, inequilateral, transverse ;
hinge linear, without teeth; an adnate, smooth, cardinal
lamina, truncated or forming a sinus at the anterior end,
terminating the base of the shell; two lateral, remote, twin,
muscular impressions; ligament linear, external, sunk in a
cleft at the anterior extremity.

The substance of the shell is pearly.

Anadonta cygnea.—THE Swan AnaponTa. Plate XVI.
fig. 1. Ovate, thin, convex, somewhat compressed on the
anterior side; with concentric wrinkles; covered with a
green epidermis, frequently brown towards the umbo; in-
side pearly white; beaks small and ventricose. Three
inches long, and seven broad. Inhabits the fresh-water lakes
in Europe.

Genus 6.—HY RIA.—Lamarck.

Generic Character.—Equivalve, oblique, trigonal, eared,
with the base truncated and straight, hinge with two spread-
ing teeth, the posterior one cleft into numerous divergent
portions; the lateral or anterior tooth strong, elongated, and
lamellar; ligament linear, and external.

What distinguishes the shells of this genus particularly is the car-
dinal or posterior tooth being divided into many lamellar plaits, or
pieces, the centre one being very small. This compound tooth is not
erect, but slopes in an inclined position towards the posterior side.

Hyria avicularis—Tue LittLe-pirp Hyrra. Plate
XVI. fig. 2, Umbones smooth and produced, in the form
of a tail; ears large, with pointed terminations; a greenish-
brown epidermis, and finely striated; inside pearly, and of a
rich reddish golden-yellow. Three inches broad. Inhabits
the rivers of America.

138 DIMYARIA.

Genus 7.—UN10.—Bruguiere.

Generic Character.—Shell transverse, equivalve, inequi-
lateral, free; umbones decorticated, and somewhat eroded ;
posterior muscular impression compound; hinge with two
teeth in each valve; the cardinal tooth short, irregular, cleft,
and striated; the other oblong, laterally compressed and pro-
duced; ligament external.

Section * With a short, thick, primary tooth. ** Primary tooth
short, compressed, and frequently crested.

Unio pictorum.—THE PaInTER’s Unto. Plate XVI. fig.
3. Oblong-ovate, strong, anterior side rhomboidal and
attenuated; the umbones, somewhat warty; with a dusky-
green epidermis, and concentrically wrinkled. Nearly three
inches broad. Inhabits the rivers of Europe.

TRIBE II.—TRIGONACEA.

With lamelliform, and transversely striated cardinal teeth.
Inhabits the ocean.

Genus 8.—CASTALIA.—Zamarck.

Generic Character.—Equivalve, inequilateral, trigonal;
umbones decorticated, and inflexed behind; hinge with two
lamellar teeth, one of them transversely striated, remote, -
abbreviated, and subtrilamellar tooth; the other elongated
and lateral; ligament external.

The shells of this genus seem to be inhabitants of fresh waters. The
substance of the shell is nacreous: the epidermis is strong, and the
apices corroded.

Castalia ambigua.—Tue AmBicuous CastTaria. Plate
XVI. fig. 4. Ovate, oblique, the umbones truncated; longi-
tudinally ribbed, with distant transverse strie; epidermis
pale chestnut brown; inside pearly. Habitat unknown.

DIMY ARTA. (139

Genus 9.—TRIGONIA.— Lamarck.

Generic Character.—Equivalve, imequilateral, trigonal,
sometimes suborbicular; teeth of the hinge oblong, laterally
compressed, diverging, with transverse furrows; two in the
right valve, grooved on both sides; and four in the left
valve, grooved on one side only ; ligament marginal and ex-
ternal.

Trigonia pectinata.—THE TooTHED TriconrA. Plate
XVI. fig. 5. Suborbicular, with radiated or divergent,
prominent, and somewhat scaly ribs; inside pearly; margin
crenulated. One inch and three-fourths broad. Inhabits
the Australian seas.

TRIBE IlI.—ARCACEA.

Primary teeth small, numerous, and disposed in a line in
each valve, which is either straight or interrupted, the teeth
of one valve fitting into the intermediate spaces of the other
valve.

Genus 10.—NUCULA.—Lamarchk.

Generic Character. —Transverse, oval-trigonal, or oblong,
equivalve, inequilateral; no intermediate area; hinge linear,
with numerous pectinated teeth, interrupted in the middle
by an oblique produced hollow; beaks contiguous, inflected ;
ligament marginal, partly internal.

Section * Shells sublongitudinal. ** Shells transverse.

Nucula margaritacea.—Tue Prarty Nucuta. Plate
XVI. fig. 6. Obliquely ovate, trigonal; striz minute and
almost obsolete; covered with a greenish epidermis; inside
silvery perlaceous; margin crenulated; and having regularly
pectinated teeth. One half inch long. Inhabits the British
seas.

Genus 11.—PECTUNCULUS.—Lamarck.

Generic Character.—Orbicular, nearly lenticular, equi-

140 DIMY ARIA.

valve, subequilateral, and close; hinge arcuated, teeth nu-
merous, oblique, alternately inserted into the opposite valves,
middle teeth obsolete; ligament external.

This differs from the other genera of many toothed shells, in having
the ligament partially inserted internally, and in being destitute of the
angular groove on the exterior of the valves.

Section * No distinct longitudinal furrows. ** With raised longi-
tudinal radiating ribs.

Pectunculus glycimeris:—_TueE De.ictous Pecruncutus.
Plate XVI. fig. 8. Suborbicular; finely striated trans-
versely and longitudinally; covered with a villous skin,
under which it is marked with reddish-chestnut spots or
bands ; inside white, and the margin crenulated. From two
to three inches long. Inhabits the British and Mediter-
ranean seas.

Genus 12,—ARCA.—Linneus.

Generic Character.—Shell transverse, subequivalve, in.
equilateral; beaks remote, separated by the area of the liga-
ment; hinge linear, straight, without ribs at the extremities;
teeth of the hinge numerous, serrated, closely set, alternately
inserted ; ligament external.

Section * Lower margin not crenated. *# Lower margin internally
crenated. |

Arca Noe.—Noau’s Ark. Plate XVI. fig. 9. Oblong,
striated transversely, and longitudinally ribbed; umbones |
remote, and incurvated; margin entire and gaping; cream-
white, with divergent and zigzag chestnut stripes; inside .
white. Two inches broad. Inhabits the American and
British seas.

Genus 18.—CUCULLZA.—Lamarck.

Generic Character.—Shell equivalve, inequilateral, tra-
peziform, ventricose; beaks distant, separated by the area
of the ligament; anterior muscular impression forming a
prominence with the margin angulated, or with an eared
produced border; hinge linear, straight, with very small

DIMYARIA. 14]

transverse teeth, and having at its extremities from two to
five small parallel ribs; ligament entirely external.

Distinguished from the genus Arca, in being more gibbous, the an-
terior side obliquely truncated, and with an ear-shaped testaceous ap-
pendage, placed at the angle of the muscular impression, and forming
a chamber or division.

Cucullea auriculifera.—Tue Earep CucuLtza. Plate
XVI. fig. 10. Obliquely heart-shaped, ventricose, with
decussated strie ; reddish-brown; hinge with two parallel
ribs at each end; white within, and slightly tinged with
violet. Two and a half inches broad. Inhabits the Indian
ocean.

TRIBE IV.—CARDIACEA.

Having the primary teeth irregular, either in form or situ-
ation; and accompanied by one or two lateral teeth for the
most part.

Genus 14._ISOCARDIA.—LZamarck.

Generic Character.—Shell equivalve, heart-shaped, ven-
tricose; beaks very distant, divergent, and spirally turned
to one side; hinge with two primary flattened teeth, situ-
ated under the beak, and with an elongated lateral tooth
under the ligament, which is external.

Isocardia Cor.—THeE Heart Isocarpra. Plate XVI.
fig.11. Globular, and heart-shaped, concentrically wrinkled ;
reddish-chestnut or brown, the umbones paler and promi-
nent; inside white. Four inches long. Inhabits the Medi-
terranean and British seas.

Genus 15.—HIA TELLA.—Daudin.

Generic Character.—Shell equivalve, considerably in-
equilateral and transverse; gaping at the upper margin; a
small cardinal tooth in the right valve, and two oblique
somewhat larger teeth in the left valve; ligament external.

142 DIMYARIA.

Hiatella arctica.—Tue Arctic HiaTetia. Plate XVI.
fig. 12. Transversely oblong; with the anterior end longer
and truncated; the valves with two divergent spiny ridges ;
yellowish-white, with decussated strie; inside perlaceous.
Half an inch Jong, and one inch broad. Inhabits the British
seas.

It appears to be the same as Saxicava rugosa.

Genus 16. _CYPRICARDIA.—Lemarck.

Generic Character.—Shell free, equivalve, inequilateral,
obliquely or transversely elongated; teeth of the hinge three,
situated under the beaks, and one lateral elongated tooth.

Distinguished from Cardita, with which they are closely allied in
form, by having three teeth beneath the apices, like the genus Venus,
in addition to the lateral lengthened tooth or ridge.

Cypricardia Guinaica.— THE GUINEA CyYPRICARDIA.
Plate XVI. fig. 13. Transversely oblong, oblique, angu-
lated, white, and covered with decussated striz ; compressed
before, and the apex rounded; yellowish-white. Two inches
long. Inhabits the coast of Guinea.

Genus 17.—CARDIT A.—Lamarck.

Generic Character.—Shell free, regular, equivalve, in-
equilateral; hinge with two unequal teeth; primary tooth
short, straight, placed under the umbo; the other tooth
oblique, marginal, and elongated.

Some of the species require minute attention to the teeth, to distin-
guish them from the Venericardia.

Cardita sulcata. —THE FurrowEep CarpiTa. Plate
XVI. fig. 15. Subcordate, white, tessellated with brown;
having longitudinal, convex transversely striated ribs; pos-
terior depression heart-shaped. One inch long. Inhabits
the Mediterranean.

Genus 18.—CARDIUM.—Linneus.

Generic Character.—Shell equival ve, subcordiform ; beaks

DIMY ARIA. 143

prominent; the internal margins of the valves denticulated
or plicated; hinge with four teeth in both valves; the two
primary approximate, mutually inserted and crossing each
other; two lateral remote entering teeth.

Section * Shells with no particular angle at the umbones, and the
anterior side at least as large as the posterior. ** With the umbones
earinated or angular, the posterior side often much larger than the
anterior.

Cardium edule—Tue Eprete Carpium. Plate XVI.
fig. 14. With about twenty-six depressed ribs, and trans-
verse obsolete scales; outside yellowish-white, inside white;
beaks protuberant. One to one and a half inch long. In-
habits the European seas, and used as an article of food.

TRIBE V.—CONCHACEA.

With at least three primary teeth in one valve, and the
other generally the same, although sometimes with fewer.

SecTion I.—MaArRIne.

Usually destitute of lateral teeth; epidermis generally
wanting, or caducous.

Genus 19.—_VENERICARDIA.—Zamarck.

Generic Character.—Equivalve, inequilateral, suborbicu-
lar; generally with longitudinal radiated ribs; hinge with
two oblique teeth in each valve, turned in the same direc-
tion.

Venericardia imbricata.—Tuer IMBRicATED VENERICAR-
pia. Plate XVI. fig. 17. Suborbicular, having convex
longitudinal ribs, covered with imbricated, rough scales.
One and a half inch long. Fossil at Grignon.

Genus 20.—ORTYGIA.—Zeach.

Generic Character.—Shell equivalve, transverse, three
primary teeth in each valve, two of which are approximate,
and the other remote; with the ligament subexternal ; um-

er

144 DIMY ARIA.

bones turned much to one side ; beneath which is an elon-
gated cordiform depression; cartilage slope much depressed,
with an elongated groove in the right valve for the recep-
tion of the margin of the left valve.

Ortygia Gallina.—Tue Hen Ortyera. Plate XVI.
fig. 19. Somewhat heart-shaped, with obtuse recurved con-
centric stria, and three or four radiated bands proceeding
from the umbo to the margin, frequently with zigzag mark-
ings throughout; inside white, the margin finely crenated.
One inch long. Inhabits the British seas.

Genus 21.— VENUS. —ZLinneus.

Generic Character.—Equivalve, inequilateral, transverse,
or suborbicular ; hinge with three teeth in both valves, all
approximate, the lateral ones divergent at their summits;
ligament external; a cordiform depression beneath the
| beaks.

Two sections.—* Inner margin of the valves crenulated or denticu-
lated.—** Inner margin of the valves entire.

Venus Casina.—Tue Casina Venus. Plate XVI. fig.
18. Suborbicular, with transverse acute recurved ridges,
crenulated on the hind margin; the depression subcordate.
Two inches long. Inhabits.the British seas.

Genus 22.._-CY THEREA.—Zamarchk.

Generic Character.—Equivalve, inequilateral, suborbi-

| cular, trigonal, or transverse ; right valve with four primary

| teeth, of which three are divergent and approximate at their

base, and one remote; three primary divergent teeth in the

| Opposite valve, and a somewhat remote groove parallel to
the margin; without lateral teeth.

A principal mark of distinction, betwixt the genus Venus and the
Cytherea, is, that all the shells of the latter have four primary teeth
in one valve, and only three united on the other, with an isolated
cavity, which is oval and parallel to the margin, the lateral teeth
divergent to the summit.

——

. DIMYARIA. 145

Cytherea Chione.+- THE CHIoNE CyTHEREA. Plate
XVI. fig. 21. Somewhat heart-shaped, strong; covered
with a chestnut glossy epidermis, faintly wrinkled trans-
versely, longitudinally rayed; with a cordiform depression
under the beak. Two and a half inches long. Inhabits the
British and Mediterranean seas.

This genus is divided into three sections.—* The anterior primary
tooth, with a striated cleft, or the margin dentated.—** Anterior pri-
mary tooth not striated in its cleft, nor dentated in the margin.—
*«** The internal margins crenated or dentated.

Genus 23.—ARTHEMIS.—Poli. EXOLET A.— Brown.

Generic Character.—Shell strong, orbicular, beaks much
turned to one side, beneath which is a short cordiform im-
pression; hinge with three primary teeth, two of which are
contiguous, and the other divergent, which is broad in the
right valve, and cleft in the centre, to receive that of the
opposite valve, which is slender; cartilage situated within
the outer surface of the shell; margins very broad, and
somewhat concave; edges very thick.*

Arthemis orbiculata. —'THE ORBICOLAR ARTHEMIS.
Plate XVI. fig. 23. Orbicular, strong, with regular coarse,
close set transverse strie; generally white or pale brown,
with sometimes three or four brown radiations emanating
from the umbo, and terminating in the margin; inside white.
Two inches long. Inhabits the European seas.

Genus 24.—CYPRIN A.—Zamarch.

Generic Character. — Shell equivalve, inequilateral,
obliquely heart-shaped, beaks obliquely bent; hinge with
three unequal teeth, approximate at the base, and slightly
divergent above; lateral cardinal tooth remote, sometimes
obsolete; ligament external, and partly sunk between the
beaks.

* The name given to this genus by its founder, Poli, is that here em-
ployed. It subsequently received from Captain Brown the name of
Exoleta, which, being an adjective, is inadmissible.

N

a

146 DIMY ARIA.

Distinguished from the genera Venus, Cytherea, and Arthemis, by
having one impressed lateral tooth, on the front side, which is some-
times obsolete; the nymphz or callosities of the hinge large, arched,
and terminated near the apices by a cavity, sometimes very deep.

| Cyprina Islandica. Tur Istanpic Cyprina. Plate
| XVI. fig. 22. Suborbicular, convex, strong, irregularly
striated ; covered with a deep black-brown epidermis; white

| within. Three and three-fourth inches long. Inhabits the
Atlantic ocean and British seas.

Genus 25.. LAS As A.—TLeach.

Generic Character.—Equivalve, inequilateral ; hinge not
quite central; umbo prominent; hinge with two nearly ob-
solete primary teeth, lateral ones very conspicuous; valves
convex; margin plain.

Lasea rubra.—TuHE RED Lasma. Plate XVI. fig. 16.
Convex, smooth, glossy, pellucid, reddish-pink. Fourth of
an inch long. Inhabits the British seas.

Section I].—FLuvIATILeE.

Shells with lateral teeth at the hinge, and covered with
a spurious epidermis.

Genus 26.._GALATHEA.—JZamarck.

Generic Character.—Equivalve, subtrigonal, covered with
| a greenish epidermis; two furrowed primary teeth in the
right valve, joined at their base; and three in the other,
, the intermediate one being separate and protruding; liga-
ment external, short, turgid, and prominent; the elongated
mark protruding in the centre.

Somewhat allied to Cyrena, but distinguished by ‘the divergent form
| ofits primary tooth. They all inhabit fresh waters.
Galathea radiata. Tue RAYED GALATHEA. Plate
| XVI. fig. 20. Somewhat trigonal, gibbous towards the
base; covered with a yellowish-green thin epidermis, be-
neath which it is radiated with pale chestnut. Three and
a half inches long. Inhabits the rivers of Ceylon.

Genus 27.—CY REN A.—ZLamarek.

fea : =
i DIMY ARIA. 147
|

Generic Character. —Shell roundish or trigonal; turgid
and ventricose, inequilateral, solid, with the beaks usually
decorticated; hinge with three teeth in each valve ; lateral
teeth two, one of which is near the primary ones; ligament
external; a great part of which is inserted, and placed on
the largest side.

The apices are always eroded or carious in shells of this genus.
They frequently grow to a large size, and always inhabit rivers.

Cyrena fluminea.—THE River Cyrena. Plate XVII.
fig. 1. Heart-shaped, gibbous, greenish-brown ; transversely
sulcated; variegated with white and violet in the inside.
One inch long. Inhabits the rivers of China.

This genus has two sections.—* With the lateral teeth crenulated or
serrated.—** Having the lateral teeth entire.

Genus 28.—_CYCLAS.—Zamarck.

Generic Character. —Ovate, globular, transverse, and
equivalve, with the beaks tumid; cardinal teeth very small,
sometimes barely perceptible; or with two in each valve, of
which one is complicated ; or only one plicated or lobed tooth
in one valve, and two in the other; lateral teeth trans-
versely elongated, compressed, and lamelliform; ligament
external.

The apices are seldom eroded in shells of this genus, of which all the
species inhabit fresh-water.

Cyclas cornea.—-Tur Horny Cycias. Plate XVII.
fig. 2. Suborbicular, convex, thin, pellucid, with fine con-
centric strie; covered with a horn-coloured epidermis ;
bluish white within. Three-fourths of an inch long. In-
habits rivers of Europe.

Genus 29.—_PISIDIUM.—Pfeiffer.

Generic Character. — Shell equivalve, transverse, with
the sides unequal, completely closing; in the right valve
N 2

ak

148 DIMY ARIA.

one, and in the left valve two opposite, very small primary
teeth ; behind and before, two thin lamellar side teeth ;
those of the latter cleft in the right valve, in order to re-
ceive the opposite ones.

There is sufficient difference betwixt the animals of the Cyclas and
Pisidium to warrant the formation of distinct genera; those of the
former having a shorter and thicker foot in proportion to the size of
the animal, and having a double crested tube at the posterior termi-
nation of the cloak, whereas the latter has only a single tube, which
however is composed of two siphons. The characters, therefore, in
italics, of the genus Cyclas, are inapplicable to that genus, and holdin |
that of Pisidium.

Pisidium obliquum.—THE OBLIQUE “‘Pisiprum. Plate
XV. fig. 23. Nearly oval, with unequal sides, ventricose,

pellucid; striated concentrically, having the appearance of
ribs under a lens; yellowish ash-coloured; inside bluish and

not glossy; beaks somewhat produced, and pointing towards
the anterior slope. Length three lines, breadth nearly five
lines. Inhabits rivers and streams in Britain.

Section II].—TENvIPEDEsS.

The mantle barely united before; foot small, narrow, and
compressed; shell having but a moderate gape.

TRIBE I.—NYMPHACEA.

Having never more than two primary teeth in the same
valve ; shell frequently gaping at the lateral extremities ;
ligament external; umbones usually projecting outwards.
The species are all littoral.

* Tellinaria.
a Without lateral teeth.

Genus 30.—AST ART E.— Sowerby.
CRASSIN A.—Lamarck.t

Generic Character.—Suborbicular, transverse, equivalve,

+ This genus was first instituted by Sowerby, who named it Astarte.
It was afterwards characterized by Lamarck, under the name of

Crassina,

DIMY ARIA. 149

subinequilateral, close; hinge with two strong, diverging,
primary teeth in the right valve, and two very unequal teeth
in the other; ligament external, on the longest side.

Distinguished from Crassatella, by the position of the ligament ; and
from Venus, by having but two teeth in each valve; one of which is,
besides, but slightly projecting.

Astarte Scotica.— THE Scorrish AsTarTE. Plate
XVII. fig. 3. Somewhat heart-shaped, a little compressed,
with regular parallel grooves and ribs; impressions under
the beak lanceolate; covered with a yellow-brown epider-
mis; inside pure white; margin broad and plain. One inch
long. Inhabits the Scottish and Devonshire coasts.

Genus 31.—CAPSA.—Lamarck.

Generic Character. — Transverse, equivalve, valves ap-
proximate and close; hinge with three primary teeth in the
right valve, and a single bifid tooth in the left, inserted into
a cavity in the opposite one; no lateral teeth ; ligament
external.

The ligament is on the short side, as in the genus Donax.

Capsa levigata.—Tue PoxisHeD Capsa. Plate XVII.
fig.4. Triangular, subequilateral, obsoletely striated trans-
versely; covered with a greenish-yellow epidermis; inside
violet towards the umbones. Two inches long. Inhabits
the Indian ocean.

b Shells with one or two lateral teeth.
Genus 32.—DON AX. —JZinneus.

Generic Character.— Transverse, equivalve, inequilateral ;
with the anterior side very short and obtuse; two primary
teeth in one or both valves; and one or two lateral teeth,
more or less apart; ligament external, short, inserted at the
posterior impression.

A well marked characteristic of this genus is, its having at the hinge,
besides the primary teeth, one or two lateral teeth, somewhat distant,

n3

150 DIMYARIA.

and separated from the cardinal teeth, similar to those of Mactra,
Lucina, and Tellina. In the genera Cytherea and Venus, the shortest
side of the shell is always the posterior; and the longest and largest,
having the ligament attached to it, is the anterior ; while in Donax,
this structure is reversed, the ligament being affixed to the shortest
side as in the genus Tellina.

Donax trunculus.—Tue TrouncaTeD Donax. Plate
XVII. fig. 5. Oblong, glossy, finely striated, and radiated
longitudinally ; transversely banded with purple; white and
clouded with purple within; margin crenulated. One inch
and a quarter broad. Inhabits the seas of Europe.

This genus consists of two sections :—* Shells with the margins en-
tire —** Margins crenated.

Genus 33.—LUCIN A.—Zamarck.

Generic Character.—Suborbicular, inequilateral; beaks

small, pointed, and oblique; hinge variable, sometimes with

two divergent teeth, one of which is bifid, but changing with
age; two lateral teeth, sometimes obsolete; the posterior
nearest the primary ones; two distinct muscular impressions
widely separated, the posterior one prolonged.

In the structure of the hinge, Lucina is allied to Tellina, but although
in many instances there is a distinctly marked angular depression on
the shell, it never possesses the irregular plait or fold characteristic of
the Telline.

Lucina undata.—Tur Wavep Lucina. Plate XVII.
fig.7. Orbicular, thin, convex, undulated with fine irregular
strie; pale straw-coloured yellow, and white in the inside ;
margin glossy and plain. Inhabits the British seas.

Genus 34.—MYSIA.—Leach.

Genvric Character.—Suborbicular, inequilateral; beaks
small, pointed, and very slightly turned to one side; hinge
with two primary teeth, joined at their base and divergent,
behind which is an oblique descending cavity; with one
strong muscular impression in each valye; margin thin and
eutire; ligament external.

a

DIMY ARIA. 151

Mysia rotundata.—TuE Rounvep Mysta. Plate XVII.
fig. 6. Orbicular, somewhat convex, thin, sub-pellucid,
and obscurely striated; umbones small and oblique. Three
quarters of an inch long. Inhabits the British seas.

e

Genus 35.—CORBIS.— Cuvier.

Generic Character. — Transverse, equivalve, without
flexuosity at the anterior margin, slightly depressed; beaks
small and incurved ; hinge with two primary teeth, and two
lateral, of which the posterior is nearest the cardinal teeth ;
muscular impressions simple; ligament external.

Corbis fimbriata.—THE FRINGED Corsis. Plate XVII.
fig. 8. Very thick, white, transversely oval, gibbous, longi-
tudinally striated, with transverse undulated furrows; the
margins crenulated ; with depressions somewhat lanceolate.
‘Two inches and a half broad. Inhabits the Indian ocean.

Genus 36.—ARCOPAGIA.—Leach.

Generic Character. —Transverse, equivalve; right valve
sub-depressed; umbones very small, and nearly straight ;
with two primary teeth in each valve, each of the larger
ones being cleft; left valve with two remote lateral teeth,
that on the anterior slope large, with a sinus betwixt it and
the margin for the reception of the lateral tooth in the oppo-
site valve; muscular impression extremely large, and defined
by a deep irregular groove; near its lower centre are several
strong punctiform marks; margin very broad, well defined,
and glossy; ligament subexternal.

Arcopagia crassa.—Tue Tuick Arcopacta. Plate
XVII. fig. 9. Suborbicular, strong, thick; upper valve
flat; with coarse, thick-set, transverse striz; pale yellow,
radiated longitudinally ; inside white, with a large patch of
yellow or pink; muscular impressions very deep. One inch
and a half long. Inhabits the British seas.

152 DIMY ARIA.

Genus 37.—TELLINIDES.—Zamarchk.

Generic Character.—Transverse, inequilateral, flattened,
a little gaping laterally; beaks small, and sub-depressed ;
margin plain, irregular, but not inflected; two divergent
primary teeth in each valve, and two lateral teeth, which are

somewhat obsolete, in one valve.

The want of lateral teeth distinguishes the shells of this genus from
Psammobia, and their not being twisted from Tellina ; the valves being
close, and their interior having fascial muscular impressions, render
them distinct from the Lucina

Tellinides rosea.—THE RosEATE TELLINIDES. Plate
XVII. fig. 10. Ovate, oblique, polished, thin, and of a
beautiful rosy hue; slightly wrinkled transversely. Half an
inch broad. Inhabits the bay of Naples.

Genus 38... TELLIN A.—Linneus.

Generic Character.—Transverse or orbicular; both valves
generally flattened; the anterior side angular, and inflexed
on the margin, or marked with a flexuous irregular plait;
with one or two primary teeth in the same valve, and two
lateral teeth, frequently remote; edge of the front side of
either valve, in some species provided with a row of ser-
rated teeth, extending from the apex to the margin; ligament
external.

There are two sections of this genus :—* Transversely oblong; and,
** Orbicular.

Tellina depressa.—TuHer DEPRESSED TELLINA. Plate
XVIL fig. 11. Oval, flat, pointed at the smaller end, and
slightly reflected; pale yellowish, faintly striated concentri-
cally; covered with a pale brown transparent epidermis.
One inch and three-quarters broad. Inhabits the Mediter-
ranean sea.

** Solenaria.
Genus 39._PSAMMOT 2 A.—Zamarck.

Generic Character.—'Transverse, ovate, or oblong-ovate;

-DIMY ARIA. 153

slightly gaping at the sides; each valve with a single primary
tooth, sometimes in one valve only; ligament external,
attached to callosities at the hinge, and without the irregu-
lar plait of Tellina. They appear like degenerated Psam-
mobiz.

Psammotea violacea.—THE VARIEGATED PsAMMOT@A.
Plate XVIL. fig. 13. Transverse, ovate-oblong, sub-ventri-
cose; radiated with purple; transversely striated. Two
inches broad. Inhabits the Australian seas.

Genus 40.—_PSAMMOBIA.—Zeach.

Generic Character.—Transverse, elliptical, or oblong-
ovate, flattened, slightly gaping at one side; beaks promi-
nent; two primary teeth in the left valve, and one in the
right.

Resembling Tellina in form, but slightly gaping at the sides, and de-
void of the irregular plait on the anterior part.

Psammobia Ferroensis.— THE FaroE Psammosta. Plate
XVII. fig. 12. Oblong-oval; white, radiated with crimson;
finely striated transversely; valves obliquely truncate. One
inch and a half broad. Inhabits the European seas.

Genus 41.—SANGUINOLARIA.—Lamarchk.

Generic Character.— Transverse, somewhat elliptical,
slightly gaping at the lateral extremities; upper margin
arched, and not parallel to the inferior one; hinge with two
approximate teeth in each valve.

At once distinguished from the Solenes, by their never being of a
transverse oblong shape, nor with the edge of the valves parallel to
the base.

Sanguinolaria rosea. —THE RosEATE SANGUINOLARIA.
Plate XVII. fig. 15. Semi-orbicular, smooth, shining, and
convex; of a beautiful rose-colour towards the umbones,
which becomes gradually paler as it descends; with acute
transverse striz. One inch anda half broad Inhabits the
sea at Jamaica.

154 DIMYARIA.

TRIBE II.—LITHOFHAGI.

Shells which bore into clay and other substances, with
accessory plaits, and more or less gaping at their anterior
side; ligament external.

Genus 42.—_VENERUPIS.—Zamarck.

Generic Character.—Transverse, inequilateral; posterior
side short, the anterior slightly gaping; hinge with two
primary teeth in the right valve, three in the left, sometimes
with three in each; teeth small, approximated, parallel, and
slightly divergent ; ligament external.

Nearly allied to Venus, but the teeth are differently disposed, having
three primary teeth in one of the valves at least. Some of the species

of this genus, together with certain oval species of Venus, constitute
the genus Pullastra of Sowerby.

Venerupis perforans.—THE PERFORATING VENERUPIS.
Plate XVII. fig. 16. Sub-rhombic, transversely striated,
wrinkled on the anterior side; brown, with a white inside,
sometimes with a tinge of purple. Three quarters of an
inch broad. Inhabits the British seas, boring into rocks and
clay.

It does not appear to be distinct from Venus Pullastra.

Genus 43.._PETRICOLA.—LZamarch.

Generic Character.—Subtrigonal, transverse, inequilater-
al; posterior side rounded, anterior attenuated, and slightly
gaping; hinge with two teeth in each valve, or in one valve
only.

Petricola pholadiformis.— Tue PHOLAS-SHAPED PETRI-
cota. Plate XVII. fig. 17. Transversely elongated; um-
bones very small; with transverse, rough, prickly striz ;
posterior side extremely short. ‘Three inches long. In-
habits the Australian seas, boring into wood and rocks.

DIMY ARIA. 155

Genus 44.—SAXICAVA.—Lamarck.

Generic Character.—Inequilateral, obtuse, and transverse ;
the anterior upper margin gaping; hinge nearly without teeth ;
ligament external.

Sazicava precisa.—THE ABBREVIATED SAxIcava. Plate
XVII. fig. 18. Oblong, wrinkled, one valve larger than the
other, truncated at the posterior end; of a pale horn colour.
Three quarters of an inch broad. Inhabits the British seas,
in cavities bored in rocks, stones, and wood.

It is probably only a variety of Saxicava rugosa.

TRIBE III.—CORBULACEA.

Inequivalve shells, with an internal ligament; one of the
beaks always projecting beyond the other.

| Genus 45.._PANDORA.—Lamarck.

Generic Character.—Shell regular, inequivalve, inequi-
lateral, transversely oblong; upper valve flattened, lower
convex; hinge with two oblong, diverging cardinal teeth,
in the upper valve, and the other valve with two oblong
grooves; ligament external.

|
| The hinge somewhat like that of Placuna, but more nearly allied to
| Corbula, having two muscular impressions.

Pandora rostrata.—Tur BrEAKED Panpora. Plate
XVII. fig. 19. White, oblong, much produced towards the
beak ; one valve nearly flat, the other convex; rounded at
the anterior end. One inch broad. Inhabits the Mediter-
ranean and British seas.

Genus 46.—CORBULA.—Bruguiere.

Generic Character.—Shell regular, inequivalve, inequi-
lateral, closed or slightly gaping; with a conical, bent,
ascending, primary tooth in each valve; a small pit at its
side; destitute of lateral teeth; ligament external.

156 DIMY ARIA.

Although having some affinity to the genera Crassatella, and Ungu-
lina, they are at once distinguished by the inequality of their valves,
and the strong primary elevated tooth.

Corbula Nucleus.—THE KERNEL CorsuLa. Plate XVII.
fig. 20. Somewhat triangular, strong, with the under valve
much larger than the upper one; transversely striated ;
covered with a thick, brown epidermis. Half an inch long.
Inhabits the British seas.

TRIBE IV.—MACTRACEA.

Equivalve shells, frequently gaping at the lateral ex-
tremities ; with an internal or partly external ligament, and
the animal having a small compressed foot.

* Ligament seen externally or double.
Genus 47.—AMPHIDESMA.—Lamarch.

Generic Character.—Inequilateral, transverse, suboval, or
somewhat rounded; with sides slightly gaping; hinge with
one or two cardinal teeth, and a narrow groove for the inter-
nal ligament; ligament double, the external short, the inter-
nal fixed in the internal grooves.

These possess a peculiar character which distinguishes them from
all other bivalves, namely, the two ligaments.

Amphidesma reticulata. —'THE RETICULATED AMPHI-
DEsMA. Plate XVII. fig. 24. Suborbicular, sub-diaphanous,
compressed, finely reticulated; yellowish-white. One inch
and a quarter long. Inhabits the West Indian seas.

Genus 48.—SOLEMY A.—Lamarckh.

Generic Character.—Inequilateral, equivalve, transversely
elongated, obtuse at the extremities, with the epidermis
smooth, shining, and projecting beyond the margin; beaks
not prominent and hardly distinct; a dilated, compressed,
somewhat oblique cardinal tooth in each valve, slightly con-

| DIMY ARIA. 157

cave above for the reception of the ligament, which is partly
external and partly internal.

These shells bear an affinity to both the Solenes, and the Anatinez.
They also strongly resemble the Modiolz.

Solemya Mediterranea.—T HE MEDITERRANEAN SOLEM-
yA. Plate XVII. fig. 23. Transversely oblong; blackish-
brown; longitudinally ribbed, with imbricated, projecting
foliations; inside white. ~ Inhabits the Mediterranean sea.

Genus 49. TELLIMY A.—Brown.

Generic Character.—Shell equivalve, inequilateral, sub-
orbicular or transverse; left valve without cardinal teeth,
but provided with two projecting lateral teeth with a groove
in their centre, sometimes with one or two teeth on the right
side; right valve with two recurved prominent teeth; mar-
gin entire.

| This genus consists of two sections.—* Shells orbicular. **Shells |
transverse.

Tellimya tenuis.—Tue Tuin Tetiimya. Plate XVII.
fig. 14. Nearly orbicular, white, thin, ventricose, and shin-
ing; one valve, with two teeth locking into a triangular
void in the opposite one, with transverse lamine on each
side. One-third of an inch long. Inhabits the British seas.

Genus 50._UNGULINA.—Daudin.

Generic Character. — Longitudinal or subtransverse,
rounded above, subequilateral, with the valves close; beaks
decorticated; one short primary cleft tooth in each valve,
with an oblong marginal groove divided or narrowed in the
middle; ligament internal, inserted in a pit.

A remarkable feature in this genus is the cavity being divided into
two, the one at the end of the other: the ligament is partially visible.

Ungulina transversa.— THE TRANSVERSE UNGULINA.
Plate XVII. fig. 22. Transversely round, rugose, of a
yellowish-brown colour.

oO

158 DIMY ARIA.

** Shells with an internal ligament, and not gaping at the sides.

Genus 51.—ERYCIN A.—LZamarck.

Generic Character.—Transverse, subinequilateral, equi-
valve, rarely gaping; with two primary teeth, unequal, di-
verging, with a pit interposed; lateral teeth two, oblong,
compressed, short, and inserted; ligament internal, situated
in a pit.

There is much difficulty in judging of the hinges of this genus, owing
to their equivocal character.

Exycina striata. Tue Striated Erycina. Plate
XVII. fig. 21. Yellowish-green, with strong transverse
strie. One inch long. Inhabits the Indian ocean.

Genus 52.—-CRASSATELLA.

Generic Character.—Inequilateral, suborbicular, or trans-
verse, close; primary teeth two, somewhat divergent, with
a hollow at the side; lateral teeth, none or obsolete; liga-
ment internal, inserted into a pit in the hinge.

There is a close affinity betwixt this genus and Mactra and Lutraria ;
like them it has the ligament internal, and attached to the primary
cavities of each valve, but when closed, the shells fit exactly, and do
not gape like these genera. The ligament in some of the species is
partially external, but less visible than in the genus Amphidesma.

Crassatella Kingicola.— Tue Kina’s IsLaAnD CraAssaA-
TELLA. Plate XVIII. fig. 1. Ovate, orbicular, yellowish-
white, with obsolete rays; very minutely striated trans-
versely; the umbones somewhat plicated. ‘Two inches long.
Inhabits the sea at King’s Island, New Holland.

Genus 53.—LIGULA.— Montagu.

Generic Character.—Equivalve, with a broad transverse
tooth in each valve, projecting inwards, furnished with a
pit for the reception of the cartilage, and in some species a
minute tooth.

—S

DIMY ARIA. 159

Ligula pretenuis.—Tue Very Turn Licura. Plate
XVIII. fig. 2. Oval, flat, thin, brittle; a little gaping;
valves with a single, spoon-like tooth in each, projecting
horizontally inwards; white, with a few concentric strie.
One inch broad. Inhabits the British seas.

#*#* Ligament internal; shell gaping at the sides,
Genus 54.—MACTRA.—Linneus.

Generic Character. — Transverse, inequilateral, subtri-
gonal; sides slightly gaping; beaks prominent; one pri-
mary compressed tooth in each valve, and an adjacent heart-
shaped cavity; two lateral compressed teeth, situated near
the hinge, and inserted; ligament internal and placed in the
pit of the hinge. |

In some species where the cavity of the hinge is very large, the pri-

mary tooth is oblique, and always obsolete ; the lateral teeth, however,
always erect.

Mactra truncata.—TuHe TruncaTED Mactra. Plate
XVIII. fig. 3. Strong, opaque, white; truncated on both
sides; with a few concentric wrinkles. One inch and a
half long. Inhabits the British coasts,

Genus 55._MACTRINA.—Brown.

Generic Character.—Subtriangular, inequilateral; umbo
prominent and obtuse; left valve with a strong triangular,
slightly bifid tooth; with triangular transverse pits on each
side, for the reception of two small depressed lateral teeth
in the opposite valve, with a triangular pit between them;
ligament external.

Mactrina triangularis—Tue TriancuLar MAcTRINA.
Plate XVIII. fig. 30. Strong, opaque, white; inside white,
not very glossy; margin strongly crenated. Length, one-
eighth of aninch. Inhabits the sea on the Dorsetshire and
Kentish coasts.

02

160 DIMY ARIA.

Genus 56.—LUTRARIA.—Lamarck.

Generic Character.—Inequilateral, transversely oblong,
or rounded, gaping at the extremities; hinge with one tooth,
which is somewhat complicated, or two teeth, of which one
is simple, with an adjoining deltoid hollow, which is oblique,
and projecting internally; no lateral teeth; ligament inter-
| nal, attached in a pit.

The want of lateral teeth, at once distinguishes the shells of this
genus from those of Mactra.

Lutraria elliptica.—Tue Ovat Lurraria. Plate XVIII.
fig. 4. Oblong-oval, nearly smooth, having a few concen-
tric, nearly obsolete wrinkles; and some diagonal striz at
the ends of the valves; of a fine yellow, or greenish-brown ;
inside white. Five inches broad. Inhabits the seas of
Europe.

There are two sections in this genus.—* Shell transversely oblong.
** Shell orbicular.

Section IV. —CrAssIPEDES. — The mouth united in
front, or partly so; foot thick, posterior; shell gaping when
closed.

TRIBE I.—MYARIA.

Shells having a broad spoon-like tooth in each valve, or
in one only; gaping at both extremities, or only at one end.

Genus 57.—ANATINA.—Lamarck.

Generic Character.—Transverse, subequivalve, gaping at
both sides, or at one only; no cardinal teeth; one broad
| primary tooth in both valves, projecting interiorly; a lateral
plate or rib running obliquely under the primary teeth.

Sometimes there is a fissure or suture extending from the apex,
giving the appearance of a second plate or rib.

These shells form a connecting link between the Mactre and Myz.

DIMYARIA. 16k

Anatina declivis.— THE Stopinc ANATINA. Plate
XVIII. fig. 5. Oval, thin, brittle, a little gaping near the
end, where it is truncated, slightly wrinkled concentrically ;
yellow sand-colour. Two inches broad. Inhabits the
British seas.

Genus 58..MY A.—Linneus.

Generic Character.— Transverse, gaping at both ends,
with one large dilated projecting and nearly vertical primary
tooth in the left valve, and with a hollow in the opposite
valve; ligament internal, short, thick, and inserted in the
hollow of the primary tooth on the one side, and in the pit
of the other valve.

Mya truncata.—Tue Truncated Mya. Plate XVIII.
fig.6. Suboval, truncated, and gaping greatly at the smaller
end; much rounded at the other; covered with a yellowish-
brown epidermis; wrinkled transversely; inside white
Three inches broad. Inhabits the British coasts.

Genus 59.—GALEOMMA.—Daudin.

Generic Character.—Equivalve, inequilateral, transverse,
with a large oval gape at the front margin; hinge without
teeth, ligament internal.

Galeomma Turtoni.—TurtTon’s GALEomMA. Plate XV.
fig. 8. Tumid in the middle, and gradually sloping to the
sides; dull milk-white, covered with short interrupted opaque
lines; beaks prominent and central. Breadth nearly an inch.
Inhabits the English channel.

Genus 60.—MAGDALA.—Leach.

Generic Character.—Transversely oblong-ovate, gaping
at one end; beaks obtuse; hinge without teeth, but pro-
vided with a transverse unconnected plate, attacked to each
valve by a cartilage and an oblique descending groove; car-

tilage internal.
03

162 DIMY ARIA.

Magdala striata.— Tue Str1atTED Macpata. Plate
XVIII. fig. 12. Ovate-oblong, thin, pellucid, white; pos-
terior side rounded and the anterior side truncated and
gaping, with longitudinal striz and concentric wrinkles; in-
side perlaceous. One inch broad. Inhabits the British
seas.

Genus 61.—MY ATELLA.— Brown.

Generic Character. — Sub-parallelogramical, transverse,
anterior end truncated; the valves reflex, forming a hiatus;
umbo small, placed nearest the posterior end; with one
erect, broad, doubly channelled tooth in the left valve,
which locks into a corresponding cavity in the other.

Myatella striataa—Tue StTriateD MyaTe.ua. Plate
XVI. figs. 12 and 30. Subpellucid, white, of a delicate
texture, longitudinally striated; inside white, slightly re-
flecting a nacreous or iridescent hue. Length, half an inch;
breadth, an inch. Inhabits the sea at Tenby in Wales.

Genus 62.—_CRENELLA.—Brown.

Generic Character. — Oblong-ovate, equilateral, ventri-
cose; beaks obtuse, slightly turned to one side; hinge with-
out teeth, but with a flattened, slightly crenated plate in
each valve; the right valve with a triangular, horizontal,
projecting, reflexed plate, and the left one with an oblique
plate, both of which are slightly crenated.

Crenella elliptica. —'THE Ovau CRENELLA. Plate
XVIII. fig. 13. Ovate, ventricose; with decussated striz;
greenish-yellow, inside nacred, the margins crenulated. One-
eighth of an inch long. Inhabits the coasts of Zetland and
Argyle.

Genus 63.—SPHENIA.— Turton.

Generic Character.—Transversely oblong-ovate; slightly
tortuous; hinge without teeth, but with the cardinal margin
flattened.

DIMY ARIA. 163

Sphenia Binghami.—BinecHam’s SpHenta. Plate XVIII.
fig. 14. Upper valve flat, much smaller than the under,
which is convex, and incurved at the extremity, and en-
velopes the smaller valve; covered with a reddish-brown
epidermis; inside bluish-white. Half an inch broad. In-
habits the Devonshire coast.

The Spheniz of Turton are very probably young shells of the genus
Mya.

TRIBE II.—SOLENACEA.

Shells transversely elongated, destitute of accessory pieces,
and gaping at the lateral extremities only; ligament exter-
nal,

Genus 64._GLYCIMERIS.—Zamarck.

Generic Characiter.—Transverse, gaping widely at each
extremity; hinge callous, destitute of teeth; ligament ex-
ternal,

These shells are distinguished from Solen by having teeth at the
hinge, and from Saxicava by the ligament being placed on the shortest
side of the shell.

Glycimeris Siliqua.— Tue Pop Grycimeris. Plate
XVIII. fig. 7. Transversely oblong; covered with a black
epidermis ; umbones decorticated; internal disk of the valves
white, callous, and thick. Two inches and a half broad.
Inhabits the North seas.

Genus 65.—PANOPZ A.—Lamarch.

Generic Character.—Equivalve, transverse, gaping un-
equally at the sides; one conical primary tooth in one valve,
and a compressed, short, ascending callosity on each side;
ligament external, affixed on the elongated side of the shell,
over the callosities.

The more prominent apices of the shells of this genus at once dis.
tinguish them from the Myz.

Panopea Aldrovandi. — AtpRovanpDus’s PANOPEA.

164 DIMY ARIA.

Plate XVIII. figs. 8 and 9. Transversely elongated, un-
dulated; concentrically wrinkled; of a yellow-fawn colour.
Inhabits the Mediterranean.

Genus 66.—SOLEN —Linneus.

Generic Character.—Equivalve, transversely elongated,
gaping at both extremities; beaks very small, always short;
primary teeth small, varying in number, sometimes none,
and rarely a pit between them; ligament external.

There are three sections in this genus :—* Shells with a terminal
hinge; and anteriorly truncated. ** Primary teeth somewhat dis-
tant from the anterior margin. *** Hinge situated nearer the middle
than the anterior end.

Solen Ensis.—Tue Sapre SoLen. Plate XVIII. fig.
1]. Linear, sabre-shaped, somewhat reflected at the end
next the hinge; in each valve a single compressed tooth
without laminz ; olive-brown towards the base of the shell,
and next the apex brownish-purple. From five to seven
inches broad. Inhabits the seas of Europe.

TRIBE III.—PHOLADARIA.

Valves with accessory pieces; or widely gaping ante-
riorly.

Genus 67.—GASTROCHN A.— Spengler.

Generic Character. —Equivalve, somewhat wedge-shaped;
with a very large, oval, oblique, anterior opening betwixt
the valves, the posterior extremity nearly close; hinge linear,
marginal, and without teeth.

Gastrochena modiolina.—THE MopioLirorRM GASsTRO-
cHENA. Plate XVIII. fig. 16. (val, thin, brittle, gaping
at the side; of a light reddish-brown; inside bluish-white.
Three-fourths of an inch long. J ihabits the British coasts;
boring into hard substances.

has

ee
er —~

DIMYARIA. 165

Genus 68.—PHOLAS.—Linneus.

Generic Character.—Animal without a tubular sheath,
projecting anteriorly into two united tubes, frequently sur-
rounded by a common skin, and the posterior extremity pro-
vided with a very short muscular foot, blunt at the end.
Shell bivalve, equivalve, transverse, gaping at both extre-
mities, with various accessory pieces either on the hinge or
below it; inferior margin of the valves inflected.

Pholas crispatus.—THE CurLED Puoxas. Plate XVIII.
fig. 17. Somewhat oval; reticulated on the anterior half,
which separates from the plain wrinkled half by a broad
furrow down the middle. Two inches long and three
broad. Inhabits the British coasts.

TRIBE IV.—TUBICOL&.

Shell contained in a testaceous sheath distinct from its
valves, or incrusted wholly or partly in the wall of this
tube, or projecting outwards.

Genus 69.—TEREDO.—LZinneus.

Generic Character. — Animal much elongated, worm-
shaped, invested by a testaceous tube, and boring into
wood; with two anterior, projectile, short tubes, and two
opercular processes, adhering to the sides of the tubes; with
a posterior short muscle, protected by a bivalve shell. Tube
testaceous, cylindrical, and tortuous, pervious at both ex-
tremities, and covering the animal. Shell bivalve, placed
externally of the tube; each valve provided with a subulate
piece within.

Teredo navalis.—Tue Sure TEREDO, or SHIP-WoRM.
Plate XVIII. figs. 18 to 22. Cylindrical, taper, smooth,
white, somewhat flexuous, finely striated longitudinally.
Inhabits the European seas, in timber.

166 DIMY ARIA.

Genus 70.—TEREDIN A.—Zamarck.

Generic Character.—Tube testaceous, tubular, cylindri-
cal, closed at the posterior extremity, but exhibiting the
two valves of the shell; anterior extremity open.

Teredina personata.—THrE MAskeD TEREDINA. Plate
XVIII. fig. 22. Shell consisting of a straight tube, with a
club-shaped termination, the club consisting of several
sinuses and lobes, and resembling a mask. Fossil from
Courtagnon.

Genus 71.—SEPTARIA.—Zamarck.

Generic Character.—With a very long testaceous tube,
gradually attenuated anteriorly, and appearing as if divided
interiorly by vaulted unfinished partitions; anterior end of
the tube terminated by two other slender tubes, which are
not divided.

There can be no doubt but that the sheath encloses a bivalve, but
as no perfect specimen has hitherto been found, the fact has not been
authenticated.

Septaria arenaria.—THE SAnpD Sepraria. Plate XVIII.
fig. 23. Tubular, tapering, terminating in a slender undi-
vided tube. Feund in sand on the shores of the Indian sea.

Genus 72.—_FISTULANA.—Zamarck.

Generic Character. —With a tubular testaceous sheath,
more tumid and closed behind, and attenuated at the ante-
rior end; open at the summit, and containing an unattached
bivalve shell; valves of the shell equal, and gaping when
shut; animal provided with two tubular appendages in
front.

Lamarck ascertained that the testaceous tubes were not the shells
themselves, and that the attached bivalve was such.

Fistulana gregata.—THE GREGARIOUS FISTULANA. Plate
XVIII. figs. 24 to 26. Sheaths club-shaped, aggregated ;

DIMY ARIA. 167

the shells angularly arcuated, with double, angulated, ser-
rated wings. Minute.

Genus 73.—_CLAVAGELLA.—Zamarck.

Generic Character.—Sheath tubular, testaceous, attenu-
ated and open before; terminating posteriorly in an oval,
subcompressed club, roughened by spiniform tubes; club
showing on one side a valve of the shell, attached to its
walls; the other valve unattached, in the sheath.

Lamarck considers Clavagella as intermediate between Fistulana
and Aspergillum, differing from the latter in having but one external
fixed valve, the other being free and internal, and from the former in
having no perforation at the larger extremity.

Clavagella aperta.—THE OPEN CLAVAGELLA. Plate
XVIII. figs. 27 and 28. An erect tube, adhering to another
body; with a funnel-shaped, expanding, entire, and waved
aperture; provided with an ovate face-valve.

Genus 74.—ASPERGILLUM.—Lamarck.

Generic Character.—Sheath tubular, testaceous, attenu-
ated towards the anterior termination, where it is open, and
thickened posteriorly into a club, with the valve of the
shell incrusted on its walls; club convex, with a terminal
disk, perforated with scattered, somewhat tubular poles,
and having a fissure in the centre.

Aspergillum Javanum.—THE Java ASPERGILLUM. Plate
XVIII. fig. 29. Smooth, club-shaped, the terminal disk
surrounded by fimbriated rays. Five inches long. Inhabits
the Indian seas.

CLASS T1T.—CIRRIPEDA.

The animals are soft, destitute of head or eyes, covered
with a shell, which is fixed to other substances, and in-
capable of locomotion. The body is reversed, inarticulated,

168 PEDUNCULATA.

provided with a mantle, having tentacular, cirrous, many-
jointed arms or feelers above.

The class Cirripeda is divided by Lamarck into two
orders:—I. PepuNcuLaTA. The body supported by a
tubular moveable peduncle, the base of which is attached
to extraneous substances in the ocean, such as stones, wood,
&c.; the mouth is usually placed below.—II. SEssixta.
The body without a peduncle, and attached to extraneous
substances; the mouth usually at the upper and anterior
part of the body.

All the Cirripeda have their shells multivalve, or com-
posed of a number of pieces.

ORDER I—PEDUNCULATA.

Body supported on a tubular fleshy peduncle.

Genus 1.—OTION.—Leach.

Generic Character.—Body pedunculated, enveloped in a
membranous tunic, which is ventricose above; two horn-
like tubes, directed backwards, truncated, open at thei
points, and situated in the apex of the tunic; having a lateral
opening, with many articulated and ciliated arms. Shell
consisting of two small testaceous semilunar valves, attached
near the lateral opening.

Otion Blainvillii_BLaInvILLE’s Orion. Plate XIX.
fig. 1. Ash-coloured; the body and horns spotted with
black.. Inhabits the North seas.

Genus 2._CINERAS.—JLeach.

Generic Character.—Body pedunculated, encased in a
membranous tunic, which is swollen above, with an opening
below the summit, from which protrude many ciliated, ar-
ticulated arms. Shell having five testaceous, oblong, sepa-

PEDUNCULATA. 169

rate valves, two of which are on the sides of the aperture,
and the others dorsal.

Cineras aurita.— Tue Earep Crineras. Plate XIX.
fig. 2. Greenish ash-colour, clouded and streaked with
black ; wrinkled towards the base. Inhabits the coast of
England.

Genus 3.—POLLICIPES.—Leach.

Generic Character.—Body covered by a shell, and sup-
ported on a tubular, tendinous, scaly peduncle; with many
tentacular arms. Shell compressed at the sides, with nu-
merous separated unequal valves, thirteen or more in num-
ber; the lower side ones the smallest.

Pollicipes cornucopia. —THEe Cornucorra PoLticipss.
Plate XIX. fig. 3. Peduncle short, covered with imbri-
cated scales, the base of the scales towards the bottom of
the peduncle rounded, and pointing upwards. Inhabits the |
European seas. |

Genus 4.—SCALPELLUM.—Leach. |

Generic Character.—Body covered by a shell, and sup-
ported by a tubular, scaly peduncle; multivalve, but the
valves never exceeding thirteen in number, concentrically
striated, and frequently with a central pointed inclined
knob. |

Scalpellum vulgare.—THE Common ScALPELLUM. Plate
XIX. fig. 4. Valves rough, the dorsal one compressed ;
covered with short hairs; peduncles short, annulated, and
hairy. Inhabits the British seas.

Genus 5.—ANATIFA.—Bruguiere.

Generic Character. —Body covered with a shell, sup-
ported by a tubular tendinous peduncle ; with long, numer-
ous, and unequal tentacular arms, which are articulated and
ciliated, and emanating from the summit on one side. Shell
compressed on the sides, with five flat valves, the valves

P

a SS Sa a a

170 SESSILIA.

contiguous and unequal ; the lower lateral ones the largest;
| the whole of them united and kept together by means of
| thin membranes.

|| Anatifa levis.—Tue SmMootH ANATIFA. Plate XIX.
| fig. 5. With five smooth valves; the dorsal valve rounded
|

at the sides, and slightly carinated; peduncle very long, of
a scarlet colour. Inhabits the British seas.

This and other species, popularly called Barnacles, were formerly
supposed to give origin to ducks and geese, the filaments having been
taken for feathers.

_—_

ORDER IL—SESSILIA,

|

Body without a peduncle, and enclosed in a multivalve |
shell, seated immediately on marine bodies, or rocks; mouth |
and tentacula placed in the apex, or upper part of the body.

|| * With a bivalve operculum.
Genus 1.—PYRGOMA.—Savigny.

Generic Character.—Sessile, univalve, subglobular, ven-
| tricose, convex above, and open at the apex; opening small,
| elliptical, provided with a bivalve operculum.

Pyrgoma crenata.—TuHeE CRENATED Pyrcoma. Plate
XIX. fig. 6. With radiated ribs, and crenated round the
margins; of a pale violet colour.

Genus 2.—CREUSIA.—Leach.

Generic Character.—Body sessile, subglobular, enclosed
in an operculated shell; having three or four pairs of ten-
tacular arms. Shell sessile, fixed, orbicular, convexo-coni-
cal, consisting of four united unequal valves; operculum
internal and bivalve.

Creusia verruca.—THE WARTED Creusta. Plate XIX.
fig. 7. White, slightly depressed, with interlocked obliquely

el

SESSILIA. | gh

striated valves ; the margin at the base irregularly serrated.
One-fourth of an inch broad. Inhabits the British seas.

** Opercula with four valves,
Genus 3.—ACAST A.—Leach.

Generic Character.—Shell sessile, ovate, subconic, com-
pressed, and consisting of six lateral valves; two of the
valves small, and four large, slightly united; having a cup-
shaped plate, concave internally, at the base.

Acasta Montagui.—Montacu’s Acasta. Plate XIX.
figs. 8and9. Valves erect, triangular, acute, with muricated
ascending spines. Inhabits the British seas

Genus 4.—ADNA.—LZeach.

Generic Character.—Cup-shaped, sessile, shell composed
of one piece; aperture lozenge-shaped; with four valves.

Adna Anglica.—Tue Eneiish Apna. Plate XIX. fig.
28. Shell slightly ribbed; of a fine rose colour; operculum
transversely striated. Inhabits the Devonshire coast, at-
tached to Caryophyllia Anglica.

Genus 5.—BALANUS.—Bruguiere.

Generic Character.—Body sessile, enclosed in an oper-
culated shell; arms numerous, placed in two rows, unequal,
articulated, ciliated, each composed of two cirri, supported
by a peduncle, and exsertile; mouth with four transverse
and dentated jaws, and provided with four hairy palpi-like
appendages. Shell sessile, conical, composed of six valves,
locked together, closed at the base by a testaceous plate;
aperture subtrigonal or elliptical; operculum internal, and
consisting of four moveable valves.

Balanus candidus.—Tur WuiteE Batanus. Plate XIX.
figs. 10 and 11: White; valves nearly smooth; operculum
strongly ridged transversely, with longitudinal, nearly obso-

P2

172 SESSILIA.

lete strie. Two inches broad at the base. Inhabits the
Frith of Forth.

Genus 6.—CORONULA.—Lamarck.

Generic Character.—Body sessile, enveloped in a shell,
with small setaceous and cirrous arms.—Shell sessile, sub-
orbicular, conoid, or conically truncated at the extremities,
with very thick walls, and interiorly hollowed in radiating
cells; aperture regular, of a rounded oval, and interiorly
funnel-shaped ; operculum having four obtuse valves.

Coronula diadema.—'THE Crown CoronuLa. Plate
XIX. fig. 12. Somewhat compressed, with six prominent
longitudinally ribbed valves; alternating with as many de-
pressed transversely striated ones. Found attached to the
skin of whales in the North seas.

Genus 7.—TUBICINELLA.—Zamarck.

Generic Character. — Body enclosed in a shell; with
small setaceous and unequal cirri.—Shell univalve, tubular,
straight, somewhat narrowed towards the base; surrounded
with nearly equidistant transverse ribs; truncated at both
ends, open at the top, and provided with an operculum, con-
sisting of four valves; base closed by a membrane.

Tubicinella balenarum.—THE WHALE TUBICINELLA.
Plate XIX. fig. 13. Tubular, with transverse ribs, and a
ring-shaped margin; operculum bottle-shaped. Found buried
in the fat of the skin of whales in the American seas,—the
operculum, and a portion of the upper part of the tube only
being visible,

The Cirripeda differ so much in structure from the Mollusca, that
they form a perfectly distinct group, intermediate between them and
the Crustacea, or perhaps more nearly allied to the latter. Although
in this arrangement they are not included among the Articulata, it is
obvious that they correspond with them to a great extent, as they have
their arms or filaments jointed. Some testaceous shells occurring in

that great division of the animal kingdom, it has been judged proper
to give some account of them in the following pages.

DIVISION Hl.

wer reouvrAatT sé:

Tue animals of this comprehensive division, have their
bodies, or members, composed of segments or articulated
rings, to which the muscles are attached, on their interior
surface. This division contains five classes, namely, Annu-
losa, Crustacea, Arachnida, Myriapoda, and Insecta. It is
in the first only that testaceous bodies, like those usually
called shells, occur.

CLASS V.—ANNULOSA.

Bodies more or less elongated, soft, naked, or enclosed in
a tube, consisting of a number of segments, and having red
blood. It contains three orders.

ORDER [—SEDENTARIA.

Animals protected by a testaceous tube, from which they
never issue entirely; branchie placed at one extremity of
the body, or near it.

P3

|

174 SEDENTARIA.

TRIBE I.—SERPULACEA.

The branchiz are either separate, or covered by an oper-
culum; tube solid and testaceous.

Genus 1.—MAGILUS.—Zamarck.

Generic Character.—Shell with its base bent into a spiral
form, oval, with four contiguous, convex volutions, the last
of which is the largest, and prolonged into a straight waved
tube, which is convex above, carinated beneath, subdepressed
and plicated on the sides; the plice lamellar, close, waved,
vertical, and thicker on the one side than on the other.

This shell is usually found imbedded in a species of Madrepore. The
animal is unknown. Lamarck supposes that it must, in the first place
occupy the spiral volutions, from which it removes totally, as necessity
requires an extension of the tube ; and that when it quits one part, it
must fill it up with calcareous matter.

Magilus antiquus.—_THE ANTIQUATED Macitus. Plate
XIX. fig. 17. Tubular, distorted, transversely wrinkled ;
of a pale yellowish-brown. Inhabits the sea at the isle of
France.

Genus 2.—GALEOLARIA.—Lamarck.

Generic Character.—Body tubicolar, provided anteriorly
with a testaceous operculum; tubes testaceous, very nu-
merous, cylindrical, subangular, erect, waved, crowded, ad-
hering by their base and open at the summit; aperture or-
bicular, terminating on the side by a spathulate process, with
an orbicular operculum, having from five to nine testaceous
pieces above, and all attached to one side.

Galeolaria recumbens.—THE RECUMBENT GALEOLARIA.
Plate XIX. fig. 16. White, and existing in reclining con-
gregated masses.

Genus 3.—VERMILIA.—Zamarch.

Generic Character.—Body tubicolar, elongated, and atten-

|

SEDENTARIA. 175

uated towards the posterior part, and provided towards the
upper part with a simple, testaceous, orbicular operculum ;
tube testaceous, cylindrical, posteriorly narrowed, more or
less twisted, and adhering by the side to marine substances;
aperture round, and the margin frequently provided with
from one to three denticles.

Shells attached by one side to marine bodies.

Vermilia triquetra. THE TRIANGULAR VERMILIA. Plate
XIX. fig. 18. White or reddish, rugged, variously twisted,
and triangular; carinated along the back. Inhabits the coasts
of Britain.

Genus 4. SERPULA.—Zamarck.

Generic Character.—Body tubicolar, elongated, depressed,
and attenuated behind; segments numerous, and narrow;
small bundles of awl-shaped bristles, in a single row on each
side, and also hooked bristles; branchie terminal, fan-shaped,
and deeply cleft into pinnated, or plumose finger-like divi-
sions; mouth terminal, placed between the branchiz, and
surmounted by a pedicled infundi buliform, or club-shaped
operculum; tube solid, testaceous, irregularly twisted,
either grouped or solitary, fixed, with a rounded and terminal
aperture.

Found solitary, or in groups curiously intertwined.

Serpula vermicularis. — THE VERMICULAR SERPOULA.
Plate XIX. fig. 14. White, cylindrical, tapering, rugged,
variously curved and twisted. Inhabits the coasts of
Britain.

Genus 5.—SPIRORBIS.— Lamarck.

Generic Character.—Body tubular, subcylindrical, pos-
teriorly attenuated; six pinnated retractile branchiz, in
radiated expansions, at the anterior extremity; operculum
placed between the branchie, pedicellate, peltate; tube tes-
taceous, spirally twisted inte an orbicular form or a horizon-

176 SEDENTARIA.

tal plane, depressed and adhering below. ‘The aperture ter —
minal and rounded or angular.

Spirorbis nautiloides. —'THE NAUTILUS-SHAPED Spir- ||
onBis. Plate XIX. fig. 15. White, nautilus-shaped, trans-
versely wrinkled. One-eighth of an inch in diameter. In-
| habits the British coasts, on Alge, &c.

TRIBE I1.—AMPHITRITZA.

Branchie not separate or covered by an operculum, and
disposed anteriorly ; tube membranous, or horny, and more
or less arenaceous.

* With large branchiz on tentacula.

Genus 6.—AMPHIT RITE.—Zamarck.

Generic Character.—Body tubicolar, elongated, cylin-
drical, attenuated behind, with many annulated segments; a
single row of setiferous papille; subulate, fasciculate bristles ||
and hooked sete; branchiz in slender finger-shaped fasciculi,
disposed like a fan, and spreading into a disk; two short
subulate filaments inserted at the internal base of the
branchize, between which is a terminal mouth; tube elon-
gated, cylindrical, tapering towards the base, membranous or
coriaceous, and generally naked.

Amphitrite ventilabrum.— THE Fan AMPHITRITE. Plate
XIX. fig. 19. Tube tapering, incurved, and smooth; of a
cream yellow colour. Inhabits the Mediterranean sea.

Genus 7.—TEREBELLA.—Zamarck.

Generic’ Character.—Body tubicolar, elongated, cylindri-
cal, attenuated posteriorly, segments transverse, and sub-
annulated ; having a row of nodulous and setiferous papill
on each side; with numerous filiform, twisted tentacula sur-
rounding the mouth, and terminating in front of it; two rows
of ramose branchie placed in a single row beneath the ten-

| SEDENTARIA. 177

tacula; tube elonguted, cylindrical, attenuated, and pointed
at the base, membranous, consisting of agglutinated grains
of sand and fragments of shells.

Terebella conchilega.—_THE SHELLY TEREBELLA. Plate
XIX. fig. 21. Tube covered with numerous fragments of
broken shells agglutinated together; with three branchie
on each side. Inhabits the coasts of Holland and Britain.

It is not a shell, properly so called, however, any more than the tube
of the caddis worm.

** With short branchia ; tentacula short or awanting.

Genus 8. _SABELLARIA.—Zamarck.

Generic Character. —Body tubicolar, subcylindrical, atten-
uated behind; with fasciculi of subulate bristles in a single
row on each side, and spathulous bristles and transverse
lamine, bordered with hooked sete; anterior extremity
obliquely truncated, elliptical, surmounted by six rows of
brilliant spangles, three rows on either side; mouth elongat-
ed, cleft, with two lips, situated under the internal spangles;
branchiz small, placed near the mouth; tubes numerous,
congregated in a common mass, composed of grains of sand
and fragments of shells, and having cup-shaped orifices.

Sabellaria crassissima.—TuHEe TuickEsT SABELLARIA.
Plate XIX. fig. 22. Tubes long, thick, somewhat parallel,
and contiguous; the openings nearly obsolete. Inhabits the
coasts of France and England.

Genus 9.—PECTINARIA.—Lamarck.

Generic Character.—Body tubicolar, subcylindrical, at-
tenuated behind, with a row of setiferous papille on either
side; bristles short, fasciculated ; broad, blunt, and oblique
in front, with golden yellow very brilliant pectiniform plates ;
mouth elongated, with two lips, surrounded with numerous
short tentacula; four pectinated exterior branchiz, placed
on the second and third segments of the body. Tube the

178 SEDENT ARIA.

shape of a reversed cone, membranaceous or papyraceous 3;
covered with sandy particles, and not adherent.

Pectinaria Belgica.—TueE BeExteic Pectinaria. Plate
XIX. fig. 23. Tube inversely conical, membranaceous and
covered with particles of sand. Inhabits the European seas.

TRIBE IlI].—MALDANTA.

With intermediate branchie; tube open at both ends.

Genus 10.—DENT ALIUM.—Linneus.

Generic Character.—Body tubicolar, conical, with the
anterior extremity exsertile, and surrounded by a membran-
ous ring; mouth terminal and naked. Tube testaceous,
nearly regular, slightly bent, attenuated towards the pos-
terior extremity, and open at both ends.

* Tubes having longitudinal ribs or strizx.

Dentalhum elephantinum.—Tue ELEPHANTINE DENTA-
Lium. Plate XIX. fig. 27. Green, slightly bent, with ten
longitudinal ribs. Three or four inches long. Inhabits the
Indian and European seas.

** Tubes smooth.

Dentalium Entalis Tue Tootu Dentatium. Plate
XIX. fig. 26. White or yellowish, slightly curved, smooth,
and tapering to a fine point. One and a half inch long. In-
habits the British seas.

Genus 11.—CCKC ALIUM.—Fleming.
BROCHUS.—Brown.

Generic Character.— Animal unknown. Shell tapering,
cylindrical, subarcuated, imperforate at the smaller end;
aperture orbicular, placed at the large end.

Cecalium Trachea.—Tue TRacHEIFORM Ca@caLIuM

SEDENTARIA. 179

Plate XIX. fig. 25. Brown, regularly furrowed transversely.
Fourth of an inch long. Inhabits the British seas.

Genus 12.—_CORNU OIDES.—Brown.

Generic Character. —Animal unknown. Shell cylindrical,
tapering, the smaller end spiral.

Cornuoides major.—THE GREATER CoRNuOIDES. Plate
XIX. fig. 23. White, smooth, and semitransparent. Length
scarcely a line. Inhabits the sea at Sandwich.

Genus 13.—CLYMENE.— Lamarck.

Generic Character.—Body tubicolar, slender, and cylin-
drical, with a series of setiferous papillz on either side; an-
terior extremity retuse, oblique, having a semicircular mar-
gin, protruding beyond the mouth; destitute of tentacula ;
posterior extremity dilated, orbicularly expanded, in a funnel
shape; the margin with equally slit dentations. Tube slen-
der, open at both extremities, and incrusted externally with
grains of sand and fragments of shells.

TRIBE 1V.—DORSALIA.

With branchiz placed on the back, or disposed longitu-
dinally along the body.

Genus 14.—SILIQUARIA.—Zamarck.

Generic Character.—Body tubicolar, but not well known.
Shell tubular, irregularly contorted, posteriorly attenuated,
sometimes spiral at the base, and open at the exterior end,
with a longitudinal, subarticulated slit, which continues its
whole length.

Siliquaria anguina.— THe SNAKE-LIKE SILIQUARIA.
Plate XIX. fig. 24. Shell taper, undulating, with a longi-
tudinal fissure; spiral at the extremity. Inhabits the Indian

seas.

180 ANTENNATA.—APODA.

ORDER IL—ANTENNATA.

An antenniferous head, provided with eyes; and having
a projectile proboscis frequently furnished with jaws; and
setiferous. papille, which are pediform and retractile; the
branchiz are longitudinally disposed.

Section I.—Branchiz arranged in the form of complicat-
ed tufts or leaflets, or ramose, constantly large and apparent;
without spines.

To this section belong the Aphroditew, Nereide, Eunice,
and Amphinomee; none of which are furnished with shells.

ORDER IL—APODA.

No feet, or retractile setiferous, pediform mammilles; no
antenniferous head; branchiz disposed longitudinally in the
interior.

Hirudinea, and Echiurea.

ON THE STRUCTURE OF THE MOLLUSCA.

Tue animal kingdom has been divided into four great
sections, characterized by peculiarities of organization, and
named Vertebrata, Mollusca, Articulata, and Radiata.

The VERTEBRATA are distinguished from the rest by
having an internal skeleton, composed of bones articulated
with each other, a brain and spinal marrow contained within
a skull and vertebre, together with five organs of sense,
and an alimentary canal opening at the two extremities of
the body, and placed below or before the great trunk of the
nervous system. The Mollusca, Articulata, and Radiata,
‘have no internal skeleton, distinctly defined brain, or spinal
marrow. The ArticuLAtTA have the body and limbs
divided into segments, or formed of pieces jointed together.
The Raprata have amore or less evident disposition of
their organs, or of some of them, into a radiating form, so
as to spread out from a common centre.

e Motuusca, so named because generally of soft struc-
ture internally (Animalia mollia, soft animals), may be de-
fined as follows :—Soft, symmetrical, inarticulated animals,
enveloped in a muscular skin, or mantle, which is sometimes
bare, but generally has attached to it, externally or inter-
nally, a calcareous part, or shell, of one or several pieces;
with a complete twofold (or general and pulmonic) circu-
lation of white (or at least not red) blood, contained in
arteries and veins; respiration of water by branchie (or
gills), or sometimes of air by a cavity on the walls of which

Q

182 STRUCTURE OF THE MOLLUSCA.

the pulmonary arteries are distributed; an alimentary canal
with two apertures, and consisting of an cesophagus, one or
several stomachs, and an elongated intestine; a nervous
system composed of a cerebriform ganglion, placed under or
surrounding the cesophagus, and communicating with the
ganglia of the various functions. The organs of sense are
generally little developed, those of touch or general sensa-
tion however being more perfect. In some, generation is
effected by mutual impregnation, each individual of the
species being hermaphrodite; in others, the sexes are sepa-
rate, some individuals being male, others female; in others,
each individual is bisexual, and produces eggs or young
without communicating with another individual. Some are
viviparous, but by far the greater number oviparous.

Those Mollusca which are most highly organized approach
more nearly in structure to the Vertebrata than any other
invertebrate animals. Yet there is a wide separation be-
tween these two great divisions; for the mode of structure
of the most imperfect fish differs essentially from that of the
most perfect molluscous animal.

_ Many systems or methods of arrangement have been pro-
posed by authors for classifying the Mollusca. Although
zoology has made vast progress of late years, it is not yet
so far advanced as to possess general classifications of the
different series of animals admitted to be correct by all or
most of those engaged in the examination of some of the
various groups. The system of Linneus, once generally
adopted, was soon found to be insufficient, it not having
been based upon an extensive and accurate knowledge of
the structure and relations of animals. That of Cuvier, not
many years ago nearly as geueral as that of Linnzus for-
merly was, is also daily undergoing modifications. In each
particular branch, as of birds, for example, or reptiles, every
author has a system of arrangement of his own. This want
of agreement is the necessary result of the imperfect state
of our knowledge, and must continue until natural objects
be completely investigated and understood. Any attempt
to bind the public to any particular system in any depart-

STRUCTURE OF THE MOLLUSCA. 183

ment of natural history must, therefore, be more or less
injurious ; but the adoption of even a very imperfect system
by an individual, is preferable to having no system at all.
It is evident that an arrangement which refers only to some
particular organs or parts of animals cannot afford a correct
idea of their nature, and that a rational system must have
reference to all their organs. Conchological systems, having
reference merely to shells, are of this imperfect kind; for
shells are not animals, but parts, and not even essential
parts, of animals. A slug, which is destitute of a shell, or
at least of an external shell, is most closely related to a
snail, which has a shell; and there are very numerous marine
naked, slug-like Mollusca, which cannot be separated from
similar species furnished with shells. He who would know
the nature of shells, must know first the nature of the ani-
mals of which shells form a part.

According to many modern authors, the Mollusca may be
conveniently arranged into six classes, of which three have
the head distinct, or more or less obvious, while in the other
three it is not apparent, or not well defined.

Mollusca having the head distinct.

I. CepHaLopopa. The body enclosed in a bag formed
by the mantle, from which projects the head, surrounded
by filaments or arms, which are at once organs of prehension
and locomotion. Fig. 1.

II. Preropopa. The body not enclosed ina bag, nor
the head surrounded by filaments; but the sides of the neck
furnished with membranous appendages, like wings or fins.
Fig. 2.

III. GastEeRopopA. None of the characters of the pre-
ceding classes; but at the lower surface ot the body a fleshy
contractile and expansile mass, or foot, enabling the animal
to crawl or swim. Figs. 3 and 4.

Mollusca destitute of a distinct head.

IV. AcepHaLa. Four thin expanded branchie distinct
Q2

184 STRUCTURE OF THE MOLLUSGCA.

from the mantle, and almost always a compressed fleshy
foot. Fig. 5.

V. Bracutoropa. Branchiz not distinct from the mantle;
two ciliated filiaments or arms in place of a foot. Fig. 6.

VI. Tuntcata. The body enclosed in a cartilaginous
bag; branchie not distinct; no special organs of motion.
Fig. 7.

In this arrangement, the general form of the body of these
animals, being in relation with the greater or less complex-
ity of their internal organization, is assumed as a basis.
Thus, some have a distinct head, figs. 1, 2, 3, 4,8; while
in others there is no such part separated or distinguishable
from the rest, figs. 5, 6, 7,9. Among the Mollusca fur-
nished with a head, there are some, the Cephalopoda, fig. 1,
which have around the mouth long appendages subservient
to locomotion; others, the Pteropoda, fig. 2, have wing-like
appendages or fins on the two sides of the body; and in
others, the Gasteropoda, fig. 3, the lower part of the body
forms a kind of muscular foot, by which the animal crawls.
Of the Mollusca of which the head is not distinct, some,
the Acephala, or Acephala Lamellibranchiata, fig. 9, have
the respiratory organs in the form of four thin plates, two
on each side, within the mantle, and not adherent to it;
others, the Brachiopoda, fig. 6, have two twisted and cili-
ated appendages or arms; and others, the T'unicata, fig. 7,
have no organs of motion, but are shut up in a leathery
covering or bag.

The general features or characters of the Mollusca given
above, may now be a little more particularly described.

Their nervous system is composed of nervous filaments
connected with a small number of ganglia, or little nervous
masses, fig. 9, r s, dispersed in different parts of the body.
The principal mass formed by these ganglia, which may be
compared to the brain in the higher animals, fig. 8, p, is
placed transversely over the cesophagus, or gullet, which it
envelopes with a nervous ring or collar. But there is no-
thing in the Mollusca that can be compared to the spinal
marrow, which in the vertebrated animals is cased in an

STRUCTURE OF TILE MOLLUSCA. 185

elongated tube formed by the vertebre, or bones of the
neck, back, loins, and sacrum. The organs of sense are
always less perfect than in the Vertebrata, but differ ex-
tremely in the various groups. Some Mollusca appear to
have only the senses of touch and taste; but in a great
number there are eyes, fig. 1, e; fig. 3, d; of which the
structure varies; in a few only there are organs of hearing ;
but in none of them has a particular organ for smell been
proved to exist, although many of them appear to have the
faculty of smelling, which perhaps is exercised by the whole
surface of the body.

There being neither an internal jointed skeleton, as in
the Vertebrata, nor an external skeleton, composed of hard
jointed pieces or rings, as in the Articulata, the muscles are
attached to different points of the skin, and act only upon
the parts on which they are inserted, so that it is only by the
elongation and contraction of certain parts that they crawl
or swim, and their movements are generally slow, and not
characterized by the precision observed in the higher ani-
mals, or in insects. They never have feet arranged in series
on each side of the body, as in the Vertebrata and Articu-
lata; and it is only in a few of them that there are elongated
and flexile organs intended for locomotion.

Their blood is white, bluish, or limpid, and circulates in
a very complex vascular apparatus, composed of arteries and
veins. The circulation is always double; that is, the blood
passes through two sets of capillary vessels, one set distri-
buted in all parts of the body, the other belonging to the
respiratory apparatus. ‘The heart, fig. 9, /, formed of a
ventricle and one or two auricles, receives the blood which
comes from the respiratory system, and impels it into the
arteries which distribute it to the various parts of the body.
Sometimes there are seen at the base of the pulmonary
arteries bags which receive the venous blood, and which
some have erroneously considered as so many hearts, they
being only receptacles, and not having the power of impel-
ling the blood.

The respiratory organs vary in their form and structure,

Q3

186 STRUCTURE OF THE MOLLUSCA.

being generally adapted for receiving water, but sometimes
air. In the former case they somewhat resemble the gills
of fishes, and are named branchie, fig. 9, g; in the latter,
they are cavities, on the walls of which the blood vessels
are distributed.

Their digestive apparatus consists of a mouth, fig. 9, e,
an cesophagus, a stomach, fig. 9, g, or several stomachs, and
an intestine, fig. 9,7. Sometimes the mouth is furnished
with jaws, or horny teeth, but frequently has no organs of
this nature. In general there are salivary glands, fig. 8, q,
and all the species have a very large liver, fig. 9,7. Several
of these animals secrete variously coloured fluids, such, for
example, as the ink of the cuttle-fish.

Almost all the Mollusca have a development of the skin,
which covers the body, and may be likened to a mantle,
which is the name usually given to it, fig. 1, a 5; fig. 7.
Those of which the mantle is bare and fleshy are called
naked Mollusca. More frequently, however, there is formed
in its substance, or at its surface, a deposition of hard cal-
careous or horny matter, which constitutes a shell; and the
Mollusca which are protected by a covering of this kind are
called testaceous.

Shells increase in size by the deposition of new layers
internally upon those already formed. Each new layer
extends more or less beyond the margins of the layer to
which it is applied, so that as the animal becomes older, its
shell becomes larger and thicker. The outer surface is
generally covered by a thin layer of membranous or horny
matter named the epidermis, and the inner surface is often
covered with a layer of a pearly nature. The form of
shells varies much: sometimes they resemble a shield, which
covers the back of the animal, as in the limpet; at other
times they constitute a tube twisted upon itself, as in snails;
and frequently also they are composed of two plates, united
by a hinge, as in mussels and oysters.

The Mollusca originate from eggs; but sometimes the
eggs are hatched after being laid, and sometimes before, the
young in this case being born alive. In all cases, these

MAMET Case eT oe GTS Tic OT Sek es i ee Ga Oe ee EP aoe ee

STRUCTURE OF THE MOLLUSCA. 187

animals when first produced have nearly the same form as
they are to retain, and are not subject to metamorphoses,
or changes like those undergone by insects.

As the organs are modified in the different classes, it may
now be well to present the principal characters of these
groups.

CLASS IL—CEPHALOPODA.

The class of Cephalopodous Mollusca is composed of ani-

mals of very singular form, fig. 1. Their trunk or body,
generally rounded, is enclosed in the mantle, which has the
form of a bag, sometimes nearly spherical or oval, sometimes
elongated, fig. 1, a 6; their head, fig. 1, d, is large, and
crowned with fleshy arms or appendages, fig. 1, fg ; sub-
servient to locomotion, as well as prehension; so that when |
they crawl, it is with the head below, and the body above.
They are divided into two families: the Dibranchial, and
the Tetrabranchial.
- The DrprancuiaL, or OrDINaARY CEPHALOPODA, have
the most complex organization of all the Mollusca. Their
head is round, and furnished with two large eyes, similar in
structure to those of the vertebrated animals. They have
also a small auditory apparatus. Their mouth is armed
with two strong horny jaws or mandibles, like a parrot’s or
hawk’s bill; and around it are disposed in a circle, long,
tapering, fleshy bodies, fig. 1, fg, capable of being moved
in any direction, muscular and vigorous, and furnished with
cup-like bodies, by which they can be very firmly affixed to
objects on which they lay hold. The rest of their body is
contained in a kind of rounded bag, fig. 1, a b, formed by
the mantle, or fleshy skin.

These animals are all inhabitants of the sea, and respire
by means of branchie placed on each side of the body, at

188 STRUCTURE OF THE MOLLUSCA.

the bottom of the bag formed by the mantle. The water
which issues from this cavity escapes through a funnel
placed at the lower part of the neck, and also serving for
the expulsion of the excrements. There are two branchia,
and at the base of each of these organs is a kind of pulmonic
heart, and at the commencement of the great artery of the
body an aortic heart, which is composed of a ventricle only.
Their stomach is very complex. They secrete a peculiar
fluid, of a very dark colour, called ink, which they can expel
at will, and which they are said to employ to tinge the
water around them, when they wish to conceal themselves.

These Cephalopoda are extremely voracious, and as they
are possessed of activity and great strength, and have nu-
merous means of seizing their prey, they are very destructive
to fishes and crustacea. Several are remarkable for the
manner in which their skin is covered with variously coloured
spots, which alternately appear and disappear. To this group
belong the Cuttle-fishes, Argonauts, and others.

The Octopi have eight nearly equal arms, of great length
and vigour, by means of which they clasp their prey. Some
authors think that china-ink is made of the black fluid of
a species of cuttle-fish, but others are of a different opinion.

The Argonauts are very similar to the cuttle-fishes, but
have two of their arms much widened toward the end, and
live in a large convoluted shell, remarkable for its delicate
texture and beauty. Some naturalists think that they do
not themselves form these shells, but are merely parasites
which take possession of them, after the unknown inhabi-
tants have been destroyed, in the same manner as the hermit
crab lodges in other shells.

The Cuttle-fishes, fig. 1, differ from the octopi and argo-
nauts in having their body more elongated and furnished with
two fins, or, fig. 1, 6 6, fleshy expansions projecting on either
side longitudinally ; and ten arms, of which two are much
longer than the rest. They have also in the interior of their
body a kind of oval shell, composed of a multitude of thin
lamine of calcareous matter, and which is employed in the
arts, under the name of cuttle or cuttle-bone.

STRUCTURE OF THE MOLLUSGA. 189

The Calmaries have the body much elongated and fur-
nished with two terminal fins. Their internal shell is
horny ; but they have ten arms, two of them more elongat-
ed, like the cuttle-fishes, which they otherwise resemble in
structure.

The TETRABRANCHIAL CEPHALOPODA differ from those
spoken of, in having four in place of two branchie, and in
their tentacula or arms being destitute of cups. Their body
is contained in the last cell of a large spirally convolute
shell, divided by transverse partitions into several cavities
or cells. Each of these partitions is perforated by a hole,
and the tube or siphon thus formed extends to the posterior
extremity or apex of the shell, and is lined by a membranous
contractile tube posterior to the body of the animal. The
siphon communicates with an external reservoir, and can be
distended with fluid, or emptied, so that the air which oc-
cupies the cells may be compressed or dilated, and thus in-
crease or diminish the specific gravity of the animal. The
Pearly Nautilus is the type of this group of animals, to which
also belongs the Ammonite family.

CLASS I1.—PTEROPODA.

The Fteropodous Mollusca, fig. 2, are small marine ani-
mals organized for swimming, they having no organ by
means of which they can crawl, or even fix themselves to
objects. Their body is generally contained in part in a small
shell, fig. 2, a, but sometimes it is naked, and their neck is
furnished with two thin expansions resembling wings, fig. 2,
bb. The Hyale, for example, is of this kind. ‘These ani-
mals abound in the seas of warm climates; to which, how-
ever, the species are not restricted; for some of them, as
Clio borealis, are so numerous in the arctic seas, as at certain
seasons to furnish whales with their ordinary food.

190 STRUCTURE OF THE MOLLUSCA.

CLASS IIT—GASTEROPODA.

The Gasteropodous Mollusca, figs. 3, 4, are distinguished
by having a fleshy foot or disk attached to the lower part of
the body, sometimes, as in slugs, to its whole length, but
more frequently only to its anterior part. One may form a
correct enough idea of the general form of all the Gaster-
opoda by examining a slug or a snail. Their body is elon-
gated, and terminated anteriorly by a head, fig. 3, e, which
projects beyond the mantle, and usually bears two or four
retractile tentacula, fig. 3, cc, inserted above the mouth,
and very small eyes, fig. 3, d, of a very simple structure.
Their body is covered beneath by a fleshy mass, fig. 3, f;
fig. 4, gg, which generally presents the form of a broad disk,
and is the instrument by which the animal crawls along the
ground, but which sometimes constitutes a vertical fin.
Their back is furnished with a mantle, which is sometimes
bare, but generally covered by a shell. In most cases, the
shell is large enough to contain the animal entirely, when it
contracts itself, and it generally has the form of a tube
twisted upon itself. In many species a horny or calcareous
plate, called the operculum, is attached to the foot behind,
fig. 4, h; fig. 8, b, and serves to close the aperture of the
shell, when the animal has withdrawn.

The organs of respiration are sometimes adapted for air,
more frequently for water; but in those species which have
a twisted shell, they are always lodged in the last or body
convolution, and receive the ambient element either by a
hole in the mantle, or by a wide opening between the body
and the mantle, which is also sometimes prolonged into a
canal or tube, by means of which the animal can respire
without protruding either its head or its foot. In this latter
case, the shell has a notch or canal, for the respiratory tube,
situated at the fore part of the aperture of the shell, near the
end of the columella.

Hie

STRUCTURE OF THE MOLLUSCA. 191

The heart, fig. 8, 7, is usually composed of an auricle and a
ventricle, and, as in the other Mollusca, receives the arterial
blood coming from the organs of respiration. The mouth is
surrounded by contractile lips, and sometimes armed with
horny teeth fixed to the palate, or with a fleshy proboscis,
fig. 4, e. The stomach, liver, and other viscera, are lodged
beneath the mantle, and generally contained within the
shell. The intestine, fig. 8, m, almost always ends on the
right side of the body.

In this class, the organs of sense are less developed than
in the Cephalopoda. The tentacula are organs of touch,
and perhaps of smell also. They have no special organ of
hearing. Their eyes, sometimes placed on the head, some-
times at the base of the tentacula, on their sides, or at
their tips, are always very small and simple, or sometimes
wanting.

Their food is various; some are terrestrial, others live in
fresh water, but the greater number in the sea. They form
the most numerous class of the Mollusca, and species of them
occur in all countries.

The Gasteropodous Mollusca may be arranged into several
orders, respecting which there is much diversity of opinion,
and, as in every department of zoology, a great difference of
nomenclature. The orders proposed by Cuvier, and adopted
by many, are:—Pulmonata, Pectinibranchiata, Tubuli-
branchiata, Scutibranchiata, Tectibranchiata, Cyclobranchi-
ata, Inferobranchiata, Nudibranchiata, Heteropoda, and
Cirrobranchiata.

ORDER L—GASTEROPODA PULMONATA.

The Gasteropoda which respire air differ from the rest in
having, in place of branchie, a cavity on the back, or a kind
of lung, formed by a membranous bag, furnished internally
with a complex network formed by the pulmonary vessels,
and opening externally by a hole in the edge of the mantle,

192 STRUCTURE OF THE MOLLUSCA.

| over the neck, on the right side. They all live on vegetable
| substances. Some are terrestrial, others aquatic.

The Terrestrial Pulmonated Gasteropodous Mollusca have
the head furnished with four retractile tentacula, of which
| the upper two are longer, and bear the eyes at their tips.
|| ‘The mouth is armed with a palatal tooth, and a small tongue
|| covered with minute prominences. The body varies inform,
and some are naked, or provided only with an internal shell, |
while others have an external spiral shell, of which the apex
'| is obtuse, and the aperture entire before. The naked species
constitute the genera Arion, Limar, Vaginula, Parmacella,
and others. ‘Those having an external shell are, Vitrina,
Bulimus, Pupa, Vertigo, Succinea, Achatina, Helix, and
|| others.

The slugs, Limacina, are terrestrial pulmonated Gaster- |
opoda destitute of external shell. Their body is elongated,
and they have for mantle a fleshy disk, which is hardly sepa-
rated from the rest of the skin, and occupies the forepart of
| the back. They are herbivorous, feeding chiefly on young
plants, fruits, and mushrooms. It is in the evening, or after
rain that they are most active, and during the day they re-
main concealed in holes, under stones or dead leaves, or even
in the ground. During winter they remain torpid, in holes
or crevices, or buried in the earth. |

The snails, Helicina, have a convoluted shell, sometimes
| flattened, sometimes globose, with a roundish or crescent-
| shaped aperture. They differ little in their organization
from the slugs; only the mantle, in place of forming a con-
vex scutum, constitutes a large cone, twisted upon itself,
and covered by the shell. In summer and autumn, they are
very voracious, but toward the end of the latter season they
eat little, and, at the approach of winter, they retire to a
suitable place, withdraw within the shell, close its aperture
with membranous layers, and remain torpid until the warm
weather in spring excites them to activity. 'These Mollusca
have the power not only of repairing their shells when broken
or crushed, but even of reproducing their tentacula and large
portions of the body when removed by accident or for experi-

| eee |
I

STRUCTURE OF THE MOLLUSCA. 193

ment. They are very numerous, and species occur in all
climates. Nearly allied to the Helicina are the Bulimi,
Pupe, Succinee, Clausilig, and other genera, forming seve-
ral natural families.

The Aquatic Pulmonated Gasteropoda, although they live
in the water, respire air, for which they come occasionally
to the surface. They have only two tentacula, the terres-
trial species having four. Among them are the Planorbes,
of which the tentacula are very slender, and the shell pre-
sents the appearance of a flat disk, the turns being rolled up
in the same plane; the Zimnei, which have the shell oval or
oblong, and the tentacula flattened and triangular; the
Physe, similar to the Limnei, but with the lobes of the
mantle capable of covering part of the shell, which is ex-
tremely thin; and the Awricule, of an oval or oblong form,
with the columella strongly plaited or toothed.

ORDER IL—GASTEROPODA PECTINIBRANCHIATA.

This division of the Gasteropoda, the most numerous in
genera and species, is characterized by having a branchial
cavity, in which are disposed one or two branchiz, having
the form of membranous lamine arranged in series. This
cavity is placed on the back, occupies the last or largest turn
of the shell, and opens externally by a large slit situated
between the body and the edge of the mantle. The shell
is almost always spirally twisted, as in the snails; their head
is furnished with two tentacula, and two eyes, supported
sometimes on tubercles; and their mouth is in the form of
a proboscis. In some there is a prolongation of the mantle
in the form of a canal, and named the siphon, by means of
which the animal can respire without emerging from the
shell. In those species which have a siphon, there is a
corresponding canal at the forepart of the aperture of the
shell.

R

194 STRUCTURE OF THE MOLLUSCA.

This order is extremely numerous, and comprehends the
families of the Turbonina, Trochina, Cyclostomina, Neritina,
Buccinina, Fusina, Muricina, Volutina, Cypre@ina, and
others.

The Trochina, which are destitute of respiratory siphon,
have a spiral shell of a conical form, with the aperture entire,
closed by an operculum, and somewhat quadrangular. They
are represented by the genus Jrochus.

The Turbonina, to which belong the genera Turbo, Lit-
torina, and others, have the shell globose, oval, or oblong,
with the aperture completed internally by the penultimate
turn. They have two long tapering tentacula, bearing the
eyes at their base externally. On the sides of the foot
are membranous expansions, sometimes simple, sometimes
fringed. Their operculum is sometimes horny, sometimes
calcareous, or extremely thick.

The Cyclostomina differ from the rest in respiring air, and
in not having branchial organs in their respiratory cavities,
but are otherwise so nearly allied to the families of this
order, that they cannot well be separated from them. The
aperture of the shell is round, margined, and closed by a thin
circular operculum. They are terrestrial, and live in woods,
among moss, or under stones.

The Valvatina have a shell somewhat resembling that of
the Planorbes, but with a circular aperture, furnished with
an operculum.

The Paludinina, which resemble the Cyclostomina, have
the aperture of the shell thin-edged, and are furnished with
branchiz for respiring water.

The Phasianelle, Ampullarie, and Melanie, which live
chiefly in warm climates, are nearly allied to the Turbonina.

The Janthine, of which the shell somewhat resembles
that of a snail, differ from the animals spoken of above, in
having no operculum, and in being furnished with a vesicular
organ under the foot, resembling a water-bubble, and which
prevents the animal from crawling, but enables it to float.
The common species, Janthina fragilis, on being touched,

| STRUCTURE OF THE MOLLUSCA. 195

emits a fluid of a deep purple colour, which tinges the water
around it.

The Neritina have the columella straight, which renders
the aperture of the shell semicircular. To this family may
be referred the Natice, of which the structure of the foot
is peculiar, it being composed of two disks meeting at an
acute angle, and the WVerite.

The families which follow are all furnished with a respi-
ratory siphon.

The Buccinina have an oval or elongated shell, with an
oval aperture, and a notch at its forepart. The foot is
generally of moderate size and rounded before, the mantle
entire on the margin, and prolonged anteriorly into a canal,
the mouth armed with a proboscis. Of this kind is the genus
Buccinum, from which Nassa differs chiefly in having the
columella covered with a thick plate of calcareous matter.
The Dolia belong to the same tribe, and are remarkable for
the length of their proboscis, and the great size of the foot. |
The Harpe have the foot abrupt before, very large, and
tapering to a point behind. The genera Purpura, Cassis,
Terebra, and Cerithium, differing greatly in the form of the
shell, and considerably in the structure of the animal, may
be considered as part of the same series.

The Muricina have the aperture of the shell always pro-
longed into a canal generally of great length. The animals,
however, greatly resemble those of the Buccinina. They
have a proboscis, and the right edge of the mantle furnished
with lobes or filaments. They are all carnivorous, and in-
habit the sea. The Murices are distinguished by their shell,
of which the canal is long and straight, and the turns fur-
nished with transverse ridges or varices, often presenting
spines or lamellz, which are frequently branched or frondose.
The Fusz have the canal also long, but they are destitute of
varices. The Strombi have the outer edge of the aperture
extremely dilated when old. In the Pterocer@ it is divided |
into long processes.

The Volutina have the columella furnished with oblique
plaits. To this tribe belong the Volutes, Mitre, and Olive,
R2 rf

————

196 STRUCTURE OF THE MOLLUSCA.

In the Cypreina, the aperture 1s extremely narrow, and
bordered with plaits or teeth on both sides. The Ovule
are similar, but with teeth only on one side of the aperture.

The Cones have the shell of an obconical form, and the
aperture very narrow, without plaits or teeth.

Many of the Pectinibranchiata have shells in the form of
a shield, cup, or hollow cone, and have been called Cupaloid.
Of this kind are the genera Pileopsis, of a conical form, with
the apex a little spiral; Crepidula, of an oval form, with the
aperture half closed by a horizontal plate, which supports
the abdominal sac, and is covered beneath by the foot;
Calyptrea, having in the hollow of their conical shell, a
small projecting lamina, looking like the commencement of
a columella; Scgaretus, in which the shell is concealed by
the mantle, the aperture very large, and the spire small.

ORDER U1—GASTEROPODA TUBULIBRANCHIATA.

The Tubulibranchiate Gasteropoda have a great resem-
blance to the Pectinibranchiate species, but are distinguished
by very important differences in their organization, as well
as by their shell, which is fixed to submarine bodies, and
has the form of a more or less irregular tube, of which the
commencement only is spirally bent. Vermetus, Mayilus,
and Siliquaria, belong to this order.

ORDER IV.—GASTEROPODA SCUTIBRANCHIATA,

The animals of this order have the shell very widely open,
more or less scutiform, and covering the branchiz, or even
the whole body. In Haliotis, the shell is slightly convoluted,
with the spire very small and flattened, the aperture exces-
sively large. Along the columella is a series of holes by

STRUCTURE OF THE MOLLUSGCA. 197

which the water arrives at a slit in the right side of the
mantle, and penetrates into the branchial cavity. Round the
foot is a double membrane cut into lamine and furnished
with long filaments. Fissurella has a shell like that of a
limpet, but with a hole in the top, which affords passage to
the water necessary for respiration, as well as to the feces.

The Emarginule present in front a notch or slit, for the
same purpose.

ORDER V.—GASTEROPODA CYCLOBRANCHIATA.

The Cyclobranchiata are very nearly allied to the Scuti-
branchiata; but are distinguished by having their branchize
fixed beneath the edges of the mantle. The Patellina are
furnished with a conical shell, which covers the whole body.
They have two pointed tentacula, bearing the eyes at their
base ; a short proboscis, and a circular series of respiratory
lamellz between the mantle and the foot. The Chitonina
differ from all other Mollusca in having an oblong depressed
shell, composed of eight plates, kept together by ligaments,
and cased in a thick margin. A membranous veil over the
mouth answers for tentacula; and the branchiew, composed
of triangular lamellz, are placed under the margin of the
mantle.

ORDER VL—GASTEROPODA INFEROBRANCHIATA,

The Inferobranchiata, which are very few, are naked
Mollusca, having their branchie composed of a long series
of lamine, and placed on the two sides of the body, between
the foot and the edge of the mantle. They differ from the
Cyclobranchiata not only in being destitute of shell, but
also in some points of their internal structure. The Phyl.

R3

198 STRUCTURE OF THE MOLLUSOCA.

lidia, having the head furnished with four tentacula, and
the arms on the hind-part of the mantle; and the Diphyl-
lidia, having on each side of the head a pointed tentaculum
and a slight tubercle, and the anus on the right side; both
having the body oval, or more or less tubercular, belong to
this group.

ORDER VIL—GASTEROPODA TECTIBRANCHIATA,

The Tectibranchiate Gasteropoda are also marine Mol-
lusea, but have the branchie unsymmetrical, and composed
of more or less divided lamine attached along the right side
or on the back, and more or less covered by the mantle,
which almost always contains in its substance a small shell.
To this order belong the Pleurobranchi, of an oval form,
with the branchie fixed on the right side, in a groove be-
tween the mantle and the foot, a proboscidiform mouth, sur-
mounted by a small triangular veil, and two tentacula, four
stomachs, of which the second is sometimes armed with bony
pieces, and the anus behind the branchie; the Aplysia,
which resemble slugs, but with the edges of the foot raised
up in the form of flexible crests, a long neck, four tentacula,
of which the upper are hollowed like the ears of a quadru-
ped, and placed above the eyes; the Dollabelle, which differ
from the Aplysiz only in having the branchie and mantle at
the posterior extremity of the body; and the Acera or Bulle,
which resemble the Aplysize in having the stomach armed
with a bony piece, but are distinguished by their tentacula,
which are short, broad, and disposed so as to form a large
fleshy shield over the eyes, some of them, the Acere, being
naked; others, the Bulle, covered with a shell.

STRUCTURE OF THE MOLLUSCA. 199

ORDER VIII.—GASTEROPODA NUDIBRANCHIATA.

All the Mollusca of this order are destitute of a shell, and
bear branchie seated on some part of the back. They are
all marine, and have a general resemblance to slugs. Of the
families which belong to this order may be mentioned: the
olidina, having the branchiz in the form of shreds, cirri,
or papillz, disposed along the sides, and two pairs of ten-
tacula; the Tritoniina, with the branchize in the form of
arbuscules or papille disposed along the sides, and two re-
tractile tentacula; the Dorina, with four tentacula, the
branchiz tufted, and disposed in a circular form at the hind-
part of the body above.

ORDER IX.—GASTEROPODA HETEROPODA.

The Heteropoda are not formed for crawling, as all the
preceding orders are, but for swimming. Their foot is com-
pressed into a vertical membranous plate, which they use as
afin. Their body is formed of a gelatinous, transparent
substance, and their branchie are placed on the hind-part of
the back. Of this kind are the Carinaria, ef which some
of the organs are covered by a thin, transparent, conical shell,
having the apex curved backwards; and the Firole, which
have no shell, but otherwise resemble the Carinariz.

ORDER X.—GASTEROPODA CIRROBRANCHIATA.

The Cirrobranchiate Gasteropoda have the respiratory
apparatus composed of tufts of tentacular filaments situated
on the sides of the neck. Such is the family of the Den-

200 STRUCTURE OF THE MOLLUSCA.

taliina, in which the animal is much elongated, conical, and
covered with a conico-tubular shell, open at both ends.

CLASS IV.—ACEPHALA, OR LAMELLI-
BRANCHIATA.,

The great class of Mollusca known by the names of La-
mellibranchiata, derived from the form of their respiratory
organs, or Tropiopoda, from the compressed form of the
foot, are readily known by their having a shell formed of
two valves, connected by a hinge, fig. 5. The animals of
this class are of a compressed form, with the head not dis-
tinct; the mouth, fig. 9, e, situated anteriorly, between two
pairs of flattened labial appendages, fig. 9, f; the cesophagus,
fig. 9, e, generally short; the stomach pyriform, fig. 9, g;
the intestine, fig. 9, 7, convoluted within; the liver and
ovary, fig. 9,7; the circulatory apparatus a ventricle and an
arterial system, and a venous system with two auricles; two
pairs of laminiform transversely striated branchia, fig. 9, q,
situated, a pair on each side, between the mantle and the
body. The nervous system, fig. 9, 7s, is very simple; there
being no cerebral mass, or head; nor any organs of sense,
besides those of taste and touch. Continuous with the lower
part of the body is a compressed muscular foot, fig. 9, k, not
capable of being used for crawling. The mantle, fig. 9, bb
is very large, thin, laminiform, induplcate, and enclosing the
body. There are generally two tubes behind, fig. 9, op,
one for allowing a passage to the water, p, the other for the
expulsion of the excrement, 0. These tubes are often united
with a common envelope, fig. 5, 6. The shell consists of
two valves, covering the mantle, and having at its upper
part an elastic ligament, which throws them open, when the
adductor muscles, of which there are two, generally distant

-

STRUCTURE OF THE MOLLUSCA. 201

but sometimes approximated so as to seem single, are re-
laxed. All the species are aquatic, some residing in fresh
water, but the greater number in the sea. They feed on
organic particles carried to the mouth by the water through
the lower siphon. Their generative system consists of an
ovary enveloped in the visceral mass, and the individuals do
not impregnate each other.

This class may be divided into several great families; but
the species are so nearly allied in structure that it has not
been found expedient to arrange them into orders.

The Ostracea have no foot, or a very small one, and for
the most part live fixed to submarine bodies, either by the
shell, or by their byssus; their mantle is open behind as well
as before, and its two lobes nowhere unite to form particular
apertures, as is the case with all the other Lamellibranchiata.
Some of them have a single adductor muscle, while others
have two.

Among the former are the Ostree, or oysters, having a
coarse laminated shell; and the Pectines, or clams, having
a divergently ribbed shell. To the bimuscular series belong
the Meleagrine, or pearl-oysters, and several other genera.

The Mytilina have the mantle open beneath, coherent
behind, forming a single orifice; the foot slender, tongue-
shaped, with a byssus at its base behind; the shell regular,
equivalve, very inequilateral. To this family belong the
genera Mytilus, Modiola, Pinna, and others.

The Unionina have the mantle open beneath, coherent
behind, forming two orifices, the lower incomplete and bar-
bate; the foot large; the shell regular, equivalve, inequi-
lateral, with a strong epidermis. They are fresh water ani-
mals. Unio, Alasmoden, Anodon.

The Arcina have the mantle open in its whole length,
and destitute of tubes; the foot very short, thick, and trun-
cated; the shell equivalve, inequilateral, with numerous
small teeth along the hinge. Arca, Nucula, Pectunculus.

The Chamacea have the mantle closed, with three aper-
tures, one for the foot, the two posterior for respiration and
the passage of the excrement, but without tubes; the valves

202 STRUCTURE OF THE MOLLUSCA.

generally ribbed and laminated. T'ridacna, Chama, Iso-
cardia.

The Cycladina have the mantle-lobes free beneath, united
behind, and forming an internally double tube, the foot
very extensile, cylindrical; the shell very thin and delicate.
They reside in fresh water. Cyrena, Cyclas, Pisidium.

The Venerina have the mantle-lobes free beneath, united
behind to form a tube containing two siphons, the foot com-
pressed, extensile; the shell varying in form, convex, con-
centrically striated, with prominent umbones, and the hinge
with from two to four divergent teeth, and elongated lateral
teeth. Lucina, Cyprina, Astarte, Venus, Cytherea, Vene-
rupis.

The Cardiina have the mantle closed, with an opening
for the foot, and two extensile tubes, the foot large, com-
pressed, tapering; the shell equivalve, entirely closed, gen-
erally very convex, the hinge with central and lateral teeth.
Cardium, Donaz.

The Tellinina have the mantle open anteriorly for the
foot, and bordered with tentacular appendages, closed be-
hind, but with an aperture for the elongated and separated
siphons; the foot much compressed, sharp-edged; the shell
various in form, compressed, inequivalve, inequilateral, the
posterior end shorter and flexuous; the hinge with one or
two small central teeth. Tellina, Cryptodon.

The Solenina have the animal much elongated, the mantle
closed, but with an opening in front for the foot, and form-
ing behind a tube, internally double; the foot conical; the
shell long, equivalve, extremely inequilateral, thin, gaping
at both ends; the hinge with not more than two small pro-
minent teeth in each valve. Solen, Psammobia.

The Mactrina have the animal oval or elliptical, with the
mantle closed, but open in front for the foot, and forming
behind a tube internally double; the foot large, compressed,
bent; the shell equivalve, inequilateral, more or less gaping
at both ends; the hinge with an oblique triangular depres-
sion for the internal ligament, there being also a small
external ligament. Mactra, Lutraria, Amphidesma, Anatina.

STRUCTURE OF THE MOLLUSCA. 203

The Myina have the mantle closed beneath, open in front
for the foot, and forming behind two long, united or sepa-
rated tubes; the foot small, compressed, tapering; the shell
elliptical, oval, or oblong, generally inequivalve, gaping at
both ends; the hinge with a concave prominent tooth in
one valve, and a corresponding depression in the other, for
the ligament. Mya, Lyonsia, Montacuta, Corbula.

The Pholadina, remarkable for boring into stone, clay, or
wood, have the mantle closed and more or less tubular, with
an anterior aperture for the foot, which is small, and two
elongated coherent tubes behind; the branchie elongated,
so as to extend into the siphon; the shell generally bare,
white, brittle, open at both ends, with the hinge toothless, the
ligament external, often with a calcareous plate. Pholas.

The Teredines, which are remarkable for boring into
wood, have their mantle prolonged into a tube much longer
than their small rhomboidal valves, and terminated by two
very short tubes, of which the base is furnished on each
side with a hard and mobile plate. They are very destruc-
tive to the timber of harbours, and the planks of ships.

The Fistulane, Gastrochene, Clavagelle, and Aspergilla,
belong to the same series.

CLASS V.—BRACHIOPODA.

The Brachiopoda, fig. 6, are in some respects very similar
to the Lamellibranchiata, they being equally furnished with
a two-lobed mantle, and a bivalve shell; but they are des-
titute of a foot, and present, in place of that organ, two
fleshy arms, fig. 8, furnished with filaments, and capable of
being extended and drawn within the shell, in a spiral form.
The branchie are not distinct from the mantle, and the
mass formed by their viscera is very small. They have no
organs of locomotion, but live fixed to submarine bodies.
The principal genera are Lingula, Terebratula, and Orbicula.

204 STRUCTURE OF THE MOLLUSCA.

The Lingule have a long fleshy stalk, of which one end
is generally fixed to a rock, and the other bears two oblong,
flattened valves. Their arms, which are attached on the
sides of the mouth, are very long; and the branchial vessels
are dispersed over the inner surface of the mantle, forming
on each side a series of small parallel folds.

The Terebratule have two unequal valves joined by a
hinge; and it is through a hole at the summit of one of
them that the fleshy peduncle passes by means of which the
animal is fixed. Their branchiz are less distinct than those
of the Lingule, and consist of a network of vessels on the
inner surface of the mantle; but their muscular system is
more developed, and there is in the interior of the shell a
small solid apparatus, of which the structure is sometimes
very complex, and of which the principal use is to furnish
points of attachment to the muscles, and to assist in sepa-
rating the valves.

The Orbiculine have a round and conical valve, like that
of the Patellz, while the other is flat, and perforated for the
passage of a very small pedicle. Their arms and branchial
vessels resemble those of the Terebratule.

CLASS VI.—TUNICATA.

The Tunicated or acephalous shell-less Mollusca, fig. 7,
differ much from all the rest in their general form, as well
as in several important peculiarities of their structure. Their
mantle forms a bag, fig. 7, a, or a tube open at both ends.
Their branchie are always small, and never divided into
four lamine. They have neither foot nor arms, and eyi-
dently form a passage to certain lower animals which are
placed among the polypi in the division of the Zoophytes.
Their structure is more simple than that of any other Mol-
lusea, and they live for the most part affixed to submarine
bodies. ;

STRUCTURE OF THE MOLLUSCA. 205

The Salpe have the most complex structure of all the
Tunicata. Their mantle is tubiform, with transverse mus-
cular bands, and enclosed in a transparent cartilaginous
envelope. Both are open at each end, and their posterior
orifice has a valve, so disposed as to allow water to enter,
but not to escape. The mouth is placed in the interior of
the tube formed by the mantle, towards its anterior part;
and the heart, liver, and other viscera are collected into a:
small mass near that aperture; the anus is situated pretty
far behind, and a single branchia, composed of a membrane
transversely plaited, extends obliquely from the upper to
the lower wall of the pallial cavity; the water which tra-
verses this tube consequently bathes the respiratory appa-
ratus, and it is by forcibly expelling it that the animal shifts
its place. When adult, these animals are free, but at first
they are often joined together so as to form a long chain,
and swim about a long time in this manner.

The Simple Ascidie have no locomotory power, but live
affixed to rocks. Their mantle has the form of a bag, fig.
7, a, with two orifices, fig. 7, 6 c, generally near each other ;
and the interior of this cavity is lined by the network of
branchial vessels. ‘The mouth and the mass of viscera are
fixed at the bottom of the branchial sac, and the intestine
ends near one of its apertures. Of this extensive series of
animals there are numerous genera.

Other Tunicata, very nearly allied to the preceding, live
united into a common mass, and are for this reason desig-
nated by the name of Compound Ascidie. A tissue of gel-
atinous or cartilaginous consistence contains a great number
of these little creatures, and presents at its surface a multi-
tude of small six-rayed stars formed by their apertures.

The name of Botrylli is given to small aggregated Tuni-
cata, of an oval form, which differ somewhat from the pre-
ceding, inasmuch as they have their branchial sac open at
both ends, and the anal orifice opening in a central cavity,
around which ten or twelve of these Mollusca are grouped
in a radiating manner.

Lastly, the Pyrosomata are aggregated Mollusca pretty
| 8

206 STRUCTURE OF THE MOLLUSCA,.

much resembling the Botrylli in their internal organization,
but which are united in very great numbers, so as to form
a large hollow cylinder, open at one end only, contractile,
and swimming in the sea.

The above account of the Mollusca, chiefly translated
from the works of M. Milne-Edwards, a French naturalist
remarkable for the extant and accuracy of his investigations,
and the clearness and precision of his style, will serve to
afford a general idea of the structure and arrangement of
these animals. Should one desire to form a more particular
acquaintance with them, he has only to examine with care
the organs of those species which he may easily procure in
any part of the country where he may be placed. A knife,
a needle, a small forceps, and a good lens, together with
some vessels, are all the apparatus necessary for this pur-
pose. The actions of the living animals may also be ob-
served, by placing the marine species in salt water, the
aquatic in fresh water, and the terrestrial in a glass, or on
leaves. The best guides are the works of Cuvier, Blain-
ville, Milne-Edwards, and Deshayes. After commencing
such an investigation, the student will not likely return to
the mere practice of gathering shells, which, however amus-
ing to many, is not a very rational or satisfactory employ-
ment.

EXPLANATION OF THE FIGURES.

Plate XX. fig. 1 SEPIA OFFICINALIS.
a bc, the body enclosed by the mantle.
b b, the longitudinal flaps, or fins.
c ec, the edge of the bag formed by the mantle.
d, the head.
e e, the eyes.

i

4
|
|

————

EXPLANATION OF THE FIGUKES. 207

f g, the arms, or tentacula.

J f, two of the arms longer than the rest, and often called
tentacula, or pedicellate arms.

g 9, the eight ordinary arms, covered internally with little
acetabula, or cups.

Fig. 2. CymBuL1a PERONII.

a, the shell.
b b, the fins, attached to the sides of the head and neck.
c, the head. :

Fig. 3. LIMNZUS STAGNALIs.

a, the spiral shell.

b, the supraoral flap, or veil.
cc, the tentacula.

d, the eyes.

e, the head.

Fig. 4. Fusus cornEvs.

a a, the shell.

b, the head.

cc, the tentacula,

d d, the eyes.

e, the proboscis.

J, the respiratory process, or siphon.
g g, the foot.

h, the operculum.

Fig. 5. Mya TRUNCATA.

a, the shell.
b, the siphon-tube.

Fig. 6. TEREBRATULA, showing the two arms.
Fig. 7. ASCIDIA INTESTINALIS.

a, the cartilaginous sac.
b, the upper orifice, for water.
c, the lower orifice, for excrement.

Plate XXI. fig. 8. ANIMAL oF A TURBO.

aa, the foot.

b, the operculum.

c, the proboscis.

d d, the tentacula.

e, the eyes, at the base of the tentacula externally,
s 2

en

7

208 EXPLANATION OF THE FIGURES.

Sf, the mantle, slit open.
g, the edge of the mantle, over the neck.
h, the branchia.
i, the branchial vein.
j, the heart.
| k, the branchial artery.
l, the extremity of the intestine.
m, the intestine.
n, the stomach and liver, in the convoluted part of the
body.
o, the oviduct.
p; the cerebral ganglion and nerves.
q, the salivary glands.
r, the fringed membrane which borders the left side of
the opening of the respiratory cavity beneath.
Fig. 9. Mactra STULTORUM.
aa, the left valve of the shell, the right having been
removed.
b b, the left lobe of the mantle, lining the valve. -
c, the anterior adductor muscle.
d, the posterior adductor muscle.
e, the mouth, and part of the cesophagus.
J, the two oral appendages, or tentacula.
g, the stomach.
h, the elongated appendage of the stomach.
i, the intestine, convoluted in and around the liver.
j, the liver.
k, the large, bent, tapering, compressed foot.
1, the rectum passing through the heart.
m, the end of the rectum.
n, the anus or termination of the rectum.
o, the upper siphon, for the passage of excrement,
p, the lower siphon, for respiration.
gq, the branchiz of the left side.
r, the anterior ganglion.
s, the posterior ganglion.
t, interganglionary nerve.

DIRECTIONS

FOR

COLLECTING, CLEANING, AND ARRANGING
SHELLS.

SHELLS can only be expected perfect when they are found
with the animal alive in them, or taken by the dredge or
trawling-net from their native beds. Fine specimens, how-
ever, are sometimes found adhering to fishermen’s lines or
nets. After violent storms many shells are often found on
the beach, driven from their beds by the agitation of the
waters; on such occasions perfect specimens are frequently
to be met with. The Conchologist ought, therefore, to
avail himself of every opportunity of walking along the
beach, immediately after the tide begins to recede. Most
of the shells seen in collections, have been picked up dead
on the beach, and are therefore seldom very perfect, as they
have been tossed to and fro by the waves, and either worn
or broken. Should they even be driven beyond the reach
of the tide, in this situation they are exposed to the con- |
tinual heat of the sun, by which their colours become faded.

River and land shells are mostly thinner than those of
the sea: though this is by no means a general rule, as the
Paper Nautilus, some Placune, and Pinne, which are marine
shells, are extremely thin and brittle.

Several of the Lanp Suetus are very beautifully coloured,
and elegant in their form, particularly those found in tropi-
cal climates. In Africa, they grow to an amazing size, and

s3

210 COLLECTING SHELLS.

would be very unwelcome guests in our house gardens, as
they commit great havoc among the esculent plants. The
Achatina Zebra of Africa, is very frequently found seven
inches from the apex to the base. A few of our own land
shells are very beautiful; but from their being familiar to
us, we look on them with the greatest indifference ; for
example, Helices Pomatia, arbustorum, and nemoralis.

MarInE SHELLS are to be met with on almost every
shore in the known world, but those of warm climates have
in general a finer polish, and exceed all others in point of
colouring.

Some authors affirm, that the Cyprea tribe abandon their
shells every year, to form new ones of a larger size; but
this seems rather a doubtful circumstance, and has not yet
been satisfactorily explained.

When shells are found with the animal alive, hot water
should be poured uponthem. The animal may then be easily
taken from bivalve shells; but caution is required in the
univalves; as should part of it be left in the volutions, it
will be almost impossible to extract it; and the shell be-
comes very offensive.

The instruments used in procuring marine shells are three,
namely, the Dredge, the Gangui, and the Rake. The latter
two are, however, not so important as the former, which we
shall first describe.

OF THE DREDGE.

There is no instrument like the dredge, in point of gen-
eral utility. It is much used for fishing oysters, and acts
upon the bottom of the sea almost like the rake. No natu-
ralist, who lives on the sea-coast, should be without a
dredge; and to those travelling in foreign countries, in
search of natural objects, it will be found of the utmost
utility. It is to be much deplored that so few naturalists
think of possessing themselves of this very useful instru-
ment; as by its aid many remarkable animals might be dis-

COLLECTING SHELLS. 244

covered, which inhabit the mighty deep. Indeed we may
be said to know scarcely anything of the marine natural
history of foreign lands, as few or none of them have been
assiduously explored by the dredge. The following is a
representation of that instrument.

To have a clear idea of the dredge, and the parts which
compose it, we must imagine a round bar of iron, forged in
the shape of an almost equilateral triangle, A, B, C, of the
above figure, and having its two extremities joined at A. To
form the summit or point of the triangle, each of the sides
should be above five feet. The two branches, A B, and
A C, are rounded and bent, as they approach the base of the
triangle. The base, B C, is forged into a plate, six inches
in breadth, with a sharp cutting edge in front, turned up-
wards at an angle of about sixty degrees. The back, or that
part opposed to the edge of the plate, is an inch thick. By

212 COLLECTING SHELLS.

means of the curvature, 6 B, c C, figs. 1 and 2, of the two
lateral branches, A B and A C, the edge of the plate, B C,
is brought forward, and a little turned to the side of the
summit, A, as may be seen in the profile of the dredge, fig.
2, AC. This edge makes, with the plane of the triangle,
contained between the straight parts of the two descending
branches, A B, A C, an angle of about sixty degrees.

There is a large iron ring attached to the summit A.
When, by means of a rope passed through this ring, the
dredge is dragged along the bottom of the sea, the edge
BC, which is turned downwards, rakes the bottom strongly,
and detaches from it all the bodies which adhere to it. But
it is not enough that these bodies should be detached from
the bottom of the ocean; they must also be retained, and
raised by means of a net.

This net, attached to the dredge, and which follows it at
the bottom of the sea, in order that it may receive within it
the bodies that are detached, has the form of a bag. The
lower part of this bag, which is intended to drag along the
bottom, should be made of untanned hide, so as to resist
the friction. The side next the plate should consist of straps
of leather, crossing each other like a net, and attached to
eight holes in the back of the plate B C, which may be seen
in fig. 1. This plate is pierced with eleven holes, but three
of them are intended for the reception of three bars, the use
of which will afterwards be explained.

The upper part of the net is attached to a rod 6 ¢, figs. 1
and 2, which crosses the triangle, A B C, parallel to the
plate B C, which is distant from that plate about two feet:
this red is round, and nearly two inches in diameter; the
two extremities terminate in a flattened end, perforated to
receive the two ascending branches A B, A C.

The curvature of this rod removes it from the plane of
the triangle, 6 Ac, in a way contrary to that in which the
base of the plate, B C, is removed from it, by means of the
curvature of the two ascending branches A B, A C, at their
inferior extremities ; and these removals in a contrary way,
keep the bag always open, of which the edges have been

COLLECTING SHELLS. 213

attached, as we have said, one end to the back plate B C,
and the other to the transverse rod or bar be.

This rod must be firmly fixed in its place; for this pur-
pose, it is a little flattened, and pierced in its middle, D,
with a hole. A bar, A D, figs. 1 and 2, which comes from
the summit A, of the dredge, and which is also flattened and
pierced with a hole at its extremity, D, is joined, by means
of that extremity, to the middle of the rod, 6 c, on the con-
cave side. so that the two holes are adapted to each other.
The extremity of a small cross bar of iron, Df, is made to
pass these, which issues by the other side of the rod, bc,
and the bar, AD. The same cross-piece of iron, D f, is
attached, in a similar manner, by its other extremity, f,
which is made to pass, that it may be afterwards bent,
through one of the holes, with which the back of the plate,
B C, is pierced.

This plate, as we before mentioned, is pierced with eleven
holes, of which eight only are employed in giving passage to
the meshes of the net or bag. These holes are arranged two
and two together: an idea of their arrangement, and the use
of the three others, may be learned by inspecting tig. 1. That
in the middle serves to attach the cross-bar Df. The two
others serve to attach in like manner, two similar cross-bars,
d d, d d, fig. 1, which strengthen the whole machine, and of
which the other extremity is attached to the rod, bc, by a
kind of hook which embraces that rod.

The bar, A D, and the cross-bar, Df, are inclined to one
another. By means of this inclination, the bar A D, through
which passes the cross bar Df, is strongly fixed to the rod
6 c, from which it can be removed only by being elongated.
This bar, A D, is a little less thick than the two ascending
branches A B, AC; they are, however, nearly two inches
in diameter. The three branches, A B, A C, A D, unite
again at the summit of the dredge, where they are welded
together so as to make only one, whose extremity is bent to
embrace the ring, as seen at A, figs. 1 and 2. The common
oyster-dredge is smaller than that which we have described,
and of a lighter make.

io ee es re

214 COLLECTING SHELLS.

We have still to describe the manner in which this instru-
ment is used for the fishing of shells. A cord is passed
through the ring attached to the point of the dredge, another
cord is attached to the middle of the rod, bc, by a knot which
embraces the rod, 6 c, the perpendicular branch A D, and
the small cross-bar Df at the point where they unite. When
the boat has reached the place of fishing, the dredge is thrown
out at the stern in the manner in which an anchor is thrown
out. The last-named cord serves to keep the dredge in its
place, the plate being turned below till it arrive at the bot-
tom of the sea, and to prevent it from being overturned by
the way. When the dredge has reached the bottom, it is
hauled along by rowing and sailing. Should the dredge be
stopped by any rock or irregularity at the bottom, the rope
attached to the ring should be pulled. When the bag is sup-
posed to be full, the dredge is drawn on board by the eap-
stan, and the bag is emptied of its contents.

Different species of sea-weed are frequently covered by
minute shells. Weeds should always be carefully examined.
Many of the smaller and microscopic shells are found at high
water-mark among the fine dross and drifted fragments of
shells: this sand should be brought home and examined at
leisure. To facilitate the process, a small wire-cloth sieve
should be made of about six or seven inches square, and all
the sand sifted through it; and the shells left. See Plate
Viste.

OF THE DREDGING-BAG.

This is the most simple apparatus for fishing shells. It is
a large net in the shape of a bag. The mouth of this bag is
kept open while at the bottom of the sea, by means of a
stick placed transversely, keeping the margins apart from
one side to the other. This stick is equal to the diameter
of the aperture of the bag, and as it is placed horizontally, it
divides that aperture into two halves, the one inferior, and
the other superior. The whole circumference of the lower
part is furnished with small pieces of lead, whose weight :

COLLECTING SHELLS. 215

draws itdown. The circumference of the upper part is pro-
vided, on the contrary, with small pieces of cork, which raise
it up; thus the bag remains always open at the bottom of
the sea. The bag is dragged by means of a rope, which
attaches it to a boat, the motions of which it follows. The
lead with which the lower part of the aperture is loaded,
causes is to drag strongly along the bottom of the sea, the
shells and marine plants of which are pulled off, and enter
the bag as it is moved forward.

OF THE RAKE.

In many cases, the bag has not sufficient power to detach
those shells which adhere strongly to rocks, at the bottom

of the ocean; in which case, the rake will be found an effi-
cient instrument.

The rake is composed of a cross-piece of iron, armed with
teeth, and attached toa long handle, of a similar form to the
rake used by gardeners, except that from the two extremities
of the cross-iren proceed two iron branches, which are at- ||
tached to the handle, and which form, with the cross-piece, |
a kind of semicircle. This semicircle serves for attachment
and aperture to a net, in shape of a bag. This rake is fixed
by the end of a handle to a rope, by means of which, fishers,
in a boat, draw it in by the help of a capstan. The teeth
of the rake drag along the bottom of the sea, and detach the
marine bodies which adhere to it; these are received into the
net, by means of which they are brought up to the surface.

Lanp SHELLS inhabit nearly every country of the globe.
They are found in woods, hedges, and gardens, where they
take up their residence in the hollows of trees, crevices of
rocks, holes in old walls, the roots of hedges, under stones,
amongst moss; or adhere to the branches and stumps of
trees, and under the shade of leaves, or amongst nettles, or
other weeds. It is during the day that they retire to those
situations, and in the evening they are met with crawling

216 COLLECTING SHELLS.

abroad; or in the day-time when the weather is moist and
rainy.

FresH WATER SHELLS are to be met with in almost
every lake, pond, river, and ditch, either lurking in the mud
at the bottom, or crawling on leaves, or on the sides of the
_ lakes, &e In ordinary cases, a tin spoon must be used to
| search for them; this is like the head of a dredge-box, of
four inches and a half diameter, perforated with numerous
small holes, not exceeding the sixteenth part of an inch
caliber. To this must be attached a handle for the recep-
tion of a walking-stick or other piece of wood. With this
spoon the Conchologist must rake along the surface of the
' mud and sand at the bottom of ditches, rivulets, or ponds,
and having brought a quantity to the surface, the mud must
be washed entirely away, and the shells, if there are any,
will remain behind.

For Anodonta Cygnea, and other large species, which

burrow deep in the mud, a different sort of net is necessary.
This consists of an iron triangle of twelve inches, by seven
at the base, to which a hollow upright handle is affixed, and
in this is inserted a pole of sufficient length to reach the
bottom. It must be firmly screwed to the handle. A net
of twine or hair-cloth is attached to the triangle. The
point of the triangle should be sharp, so that it may the
more easily penetrate the mud, through which it must be
drawn in situations where shells are likely to exist.
Great deception is practised by some dealers in shells, by
which means they easily impose on those who are unac-
quainted with them. If a shell happens to have the lip
broken, they take a common file, and form it anew; by
which the character of the shell is often completely altered.
Some go so far as even to form a canal, to imitate rare shells,
and also counterfeit striz; when they have accomplished
this, they then imitate the external colouring, and finish the
whole by a coat of varnish. The shells they thus transform
| are, in general, worn specimens; though in some instances
good shells are sacrificed to obtain their object.

Much might be here said on the arts practised’ to alter,

CLEANING SHELLS. 217

patch up, and beautify shells; but this has no connection
with the science, and may therefore be omitted, as a natu-
ralist would prefer a worn, or even a broken specimen, to
one either altered, or coloured and varnished, by which it
can be rendered pleasing to the eye of only the inexperienced
in Natural History. Surely the lover of nature must look
with contempt on all artificial means employed either to
alter or amend the objects of his study. It will be suffi-
cient to point out the means of simply cleaning testaceous
bodies.

When shells are perforated by sea-worms, or when any
other accidental circumstance occurs to deform a good
specimen, it is certainly desirable to use some means to
improve it; and for this purpose a cement may be made of
fine whitening, flour, and gum; the holes or cracks may be
filled up with this composition, and allowed to dry; it should
always be a little above the surface, and cautiously scraped
down with a knife; when ridges or strie can easily be
imitated, if necessary, with a file or engraving instrument.

The parts thus mended may be coloured with common’

water-colours, and then brushed; or if on a smooth shell,
polished with the palm of the hand, and afterwards rubbed
over with Florence oil, which should be well dried off with
a piece of flannel. If this mode is judiciously managed, the
specimen may be examined, and the blemish never dis-
covered.

Many shells, even when obtained alive, are incrusted with
extraneous matter: the best and safest means of removing
this is, first to steep them in warm water, and then to scrape
them with a knife, or start them off with an engraving tool.
A little sand paper may also be used, but care must be
taken not to injure the shell. When as much of the crust
is in this way removed, as can with safety be done, recourse
should be had to muriatic acid, very much diluted with
water; by applying this cautiously with a feather to the
places you wish removed, for a very short period, it will
soon decompose the extraneous matter. Two minutes at
a time is as long as it can with safety be applied, but one
T

OO Souja ((—sss ft.

218 CLEANING SHELLS.

minute’s application often has the desired effect. It should
then be immersed in cold water, and the parts well scrubbed
with a nail-brush and soap. Should the crust not be entirely
removed, this process may be repeated, but the greatest care
is to be used not to allow the acid to touch the inside, as
it will instantly remove the fine enamelled surface. Some
are so cautious as to melt bees’ wax, and coat the parts of
the shell they do not wish touched with the acid.

When water is used too hot in the first process, it often
makes the fine polished surface crack in a thousand direc-
tions.

After the process of corrosion, some make use of flannel or
a brush, and emery or tripoly, to polish the shell. This may
be done in cases where the polished insides happen to be
touched with the corrosive fluid; but in all instances where
the places cleared by the acid are of a white or chalky appear-
ance, they should be washed over with Florence oil, and then
rubbed hard with flannel or a nail-brush. This mode gives
the shell the appearance of nature, and at the same time
stops the action of the acid, should any remain in the shell,
while it is also of great use in preserving it from decay. It
is of great advantage in preserving the epidermis, which
often, when it becomes dry from lying long in a cabinet,
cracks and quits the external surface of the shell. It would
not be amiss to rub shells over with oil once a-year.

This practice of oiling shells I believe I was the first who
thought of. Ihave communicated it to all my friends who
collect shells; and it has been generally approved. Indeed
one friend, who had a very large collection, was so pleased
with the effect it produced, that he washed off the gum
from all his shells, and oiled them. The common practice
of collectors is, when they obtain a specimen which is a
little worn, to coat it over with a solution of gum arabic
which certainly heightens the colours; but the gloss is by
no means natural, and a judge may in a moment discover the
deception. This varnishing system is carried to a great
length by some, who have almost every shell in their cabi-
nets daubed over with gum arabic, so that they all shine with

ARRANGING SHELLS. 219

great lustre, even although many of the shells should be dim

in their natural state.

Oiling shells has a wonderful effect in restoring their
colours, when obscured by the surface being somewhat de-
composed, and of a chalky appearance. If not too much
decomposed, the spots and colours will have all their original
freshness. Shells are composed of animal matter and lime,
and when they are decomposed, it is from the animal matter
being set at liberty by the action of some acid: consequently,
the application of oil is a substitute for the animal mattea
which they had lost.

SIMPLE METHODS OF ARRANGING CABINETS.

The most simple method of arranging shells in a cabinet,
is to place them in boxes or trays made of card-paper. First
cut white cards of the size you wish the boxes (if they may
be so termed); then take a pair of steel dividers which are
fixed with a screw, and set them to the size the depth of the
sides is wished; place the card upon a piece of pasteboard,
and draw the dividers along the surface, one leg being guided
by the edge of the card; press pretty hard so as to make a
deep groove; then cut out the corners, and press up the
sides, which will be found to stand quite stiff; but if great
nicety is wanted, a piece of paper may be pasted on the cor-
ners. On the bottom of every box should be written the
name of the shell it contains, with its country and habitat ;
a reference to some author who describes it; and such other
remarks as may be thought necessary.

My friend Mr. Nichol, Lecturer on Natural Philosophy,
has a remarkably neat method of preserving his shells: it is
by attaching conical or raised pieces of cork to pasteboard ;
they are made to fit as nearly as possible the size of the
apertures of univalve shells, which completely prevents them
from rolling about in the drawers, and then it has this advan-
tage, that the shells can be taken in the hand and examined
on all sides.

Another plan is to attach all the shells to pieces of thick

} T2

220 ARRANGING SHELLS.

pasteboard, covered with white paper, so that two specimens
of each shell are required to show the species to advantage,
one side to be turned up, and another down. They must
be attached by the following composition; which is the same
mentioned at page 217 for mending shells.

Fine Spanish whitening, 2 02.
Gum Arabic, 2 oz.
Finest flour, 4 OZ.

Ox-gall, a tea-spoonful.

This cement may be kept in a pot in a dry state, and a
little warm water poured on it when required. Some prefer
a solution of gum arabic for attaching them. The solution
of gum arabic plain, will not, however, answer the purpose,
as it cracks when the weather becomes hot, and the shells
are disengaged. It should therefore be made in the following
manner.

Gum Paste.
White Sugar-candy, 2 oz.
Common Gum Arabic, 4 oz.

Ox-gall, one tea-spoonful.

When properly dissolved, it should be strained through
fine muslin or gauze, and two table-spoonfuls of starch or
hair-powder added to it, together with half-a-drachm of cor-
rosive sublimate. It may then be put into an earthen-ware
pot or bottle, and allowed to dry. A little warm water
poured on it will render it fit for use in a few minutes.

~

GLOSSARY

OF TERMS USED IN CONCHOLOGY.

A,

ABBREVIATED, Shortened, cut short.

Abdomen, the belly.

Aculeated, furnished with, or end-
ing in, prickles.

Acuminated, ending in a sharp
point, sharp-pointed.

Adnate, adhering or growing to-
gether, adjoining.

Alated, winged, applied to the ex-
panded lip of the Strombus genus,
we.

Ambitus, the circumference or out-
line of the valves.

Annulated, formed of or divided
into distinct rings.

Annulations, rings.

Antiquated, longitudinally furrow-
ed, but interrupted by transverse
furrows, as if the shell had ac-
quired new growth at each fur-
row.

Aperture, the mouth or opening of
the shell.

Apex, the tip or point of the
spire.

Apophysis, an excrescence.

Approximating, approaching near
to, or near together.

Arcuated, bent in the form of an
arch.

Arcuations, bendings, curvings.

Area, the surface contained be-
tween lines or boundaries.

Arenose, sandy.

Areola, a small area or circle.

Articulations, junctures, or join-
ings.

Attenuated, thin, slender.

Auricled, having appendages like
ears.

Auriform, ear-shaped.

Aurited, eared, having ears as in
the scallops. '

B.

Barb, filaments resembling a
beard.

Base, in univalves, that part of
the shell by which it is affixed
to rocks, &c. or the opposite ex-
tremity to the apex.

Beak, the continuation of the body
of univalves in which the canal
is situate.

Beard, the filaments by which some
bivalves adhere to rocks, &c.

Bellying, distended in the middle.

Bi, prefixed to any word, signifies
two.

Biangulated, having two corners
or angles.

Bicuspid, having two points.

Bidentate, having two teeth,

Bitid, opening with a cleft.

Bifarious, parting in opposite di-
rections,

Bilabiate, furnished with two lips,

Bilobate, divided into two lobes.

Bimarginate, furnished with a
double margin as far as the lip.

Biradiate, having two rays.

Bivalve, consisting of two valves
or pieces,

_Blotched, spotted in an irregular

way.
Blunt, obtuse, opposed to acute.
Borer, a piercer.
Brinded, streaked.
Bulging, gibbous, swollen out.
Bullate of a blistered appearance.
Byssus, a beard, or tuft of fila-
ments, common in Mytilus and
Pinna,

C,

Calcareous, relating to lime, of a
limy nature,

222

Canaliculated, made like a pipe or
gutter.

Cancellated, longitudinally and
transversely ribbed.

Carinated, having a longitudinal
prominence like the keel of a
vessel.

Cartilage, a flexible fibrous sub-
stance by which the valves are
united, situated near the beak.

Cauda, the elongated base of the
venter, lip, and columella.

Cicatrix, the glossy impression in
the inside of the valves, to which
the muscles of the animal are
affixed.

Ciliate, edged with parallel hairs,
bristles or appendages, like the
eye-lids.

Cinereous, of the colour of wood
ashes.

Clavate, club-shaped, thicker to-
wards the top, elongated towards
the base.

Columella, the upright pillar in the
centre of most of the univalve
shells.

Commissure, a joint or seam.

Complicated, doubled together.

Compressed,squeezed together per-
pendicularly, in opposition to de-
pressed, which is flattened hori-
zontally.

ie ap aaah arched over, vault-
ed.

Concamerations, divided into com-
partments, as in the Nautili.

Concave, hollowed out like a bowl.

Concentric, surrounding a centre.

Conche, shells consisting of two or
more pieces or yalvyes, bivalves,
or multivalves.

Cone, the form of a sugar-loaf.

Confluent, running together.

Conoid, a figure like a cone, sugar-
loaf-shaped.

Contorted, twisted, or incumbent
on each other, in an oblique di-
rection.

Contracted, shortened, shrunk up.

Convoluted, rolled upon itself,
twisted spirally, like a piece of
paper rolled between the finger
and thumb.

Cordate, heart-shaped.

GLOSSARY.

Callosity, a smooth protuberance.

Callus, a deposition of calcareous
matter.

Campanulate, bell-shaped.

Cochlez, shells of one piece, uni-

valves. Decorticated, worn, divested of epi-
Cochleate, twisted like a screw or dermis or skin.

the shell of a snail. Decussated, generally applied to

Cordiform, resembling the form ot
a heart.

Coriaceous, of a leather-like con-
sistence.

Corneous, of a horn colour, re-
sembling a horn.

Coronal, relating to the crown or
top.

Coronated, crowned, or girt to-
wards the apex.

Costated, ribbed, having large
ribs.

Corpus, the body of the shell, the
last or great wreath in which the
aperture is situate.

Cortex, the anterior skin or epi-
dermis.

Crenulated, notched at the margin,
scalloped.

Crispated, rough with waving lines
or curled.

Cuneiform, shaped like a wedge.

Cylindrical, round like a cylinder
or a roller.

Cymbiform, boat-shaped.

D.

striz, or lines, which are crossed,

or which intersect each other

perpendicularly and _ horizon-
ll

tally.

Defiexed, bent aside.

Dentary, of or belonging to the
teeth.

Denticle, a small tooth, such as the
tooth of a saw.

Denticulated, set with small teeth,
as in Arca.

Depressed, pressed down horizon-
tally, low, shallow, flat.

Dexter valve, the right valve.

Diaphanous, transparent,
that can be seen through.

Digitated, fingered or clawed, as
in the lobes of the outer lip of
the Strombi, &e.

Disk, the middle part of the valves,
or that which lies between the
umbo and the margin.

Divaricated, straddling, spreading
out widely.

Divergent, tending to various parts
or directions from one point.

Dorsum, the back: it generally
means the upper surface of the
body of the shell, when laid upon
the aperture or opening. In the
genera of Patella and Haliotis,

clear,

Ss

GLOSSARY.

the back means the upper convex
surface.
Dotted, punctured like a thimble.
Duplicated, divided into plaits or
folds.
Duplicature,
doubled.

a fold, any thing

E.

Echinated, bristled like a hedge-
hog, set with spines.

Effuse, spread out.

Elliptical, haying the form of an
ellipsis.

Elongated, lengthened, drawn out.

Emarginate, 2 with the margin or

a ieucat edge notched.

Ensiform, sabre-shaped.

Entire, whole, uninterrupted, not
divided.

Epidermis, the outer coating or
scarf skin of the shell.

Equidistant, being at the same dis-
tance.

Equilateral, having all sides alike.

Equivalve, having both valves of
equal dimensions.

Exolete, worn or faded.

Exserted, standing out, protruding.

Extraneous, not essentially or na-
turally forming part of an object.

F,

Falcated, bent or hooked like a
scythe.

Fascia, a coloured band.

Fasciated, filleted, or covered with
bands.

Fascicled, clustered together as in
a bundle.

Fasciculated, consisting of little
bundles.

Fastigiate, flat and even at top.

Faux, what can be seen of the
cavity of the first chamber of
the shell, by looking in the aper-
ture.

Ferruginous, of an iron colour, or
rust coloured.

Filament, a slender thread-like
process.

Filiform, thread-shaped, slender
and of equal thickness.

Fimbriated, fringed.

Fissure, a cleft, a little slit, or nar-
row chasm.

Flexuous, zigzag,with angles gently
winding.

Flexure, a bending.

223

Fluyiatile, of or belonging to rivers,
or to fresh water.

Foliaceous, consisting of laminz
or leaves.

Foliated, bent into lamine or
leaves.

Fornix, the excavated part under
the umbo. It likewise signifies
the upper, or convex shell in the
Ostrea.

Fragile, brittle, easily broken.

Front, in univalves, when the aper-
ture is turned towards the ob-
server.

Furcated, forked.

Furrow, a small trench or hollow,

Fuscated, darkened, obscured.

Fusiform, spindle-shaped, inter-
pk between the conical and
oval.

G.

Gap, or gape, an opening in bi-
valves when the valves are shut,
as in the Pholades, Mye, &c.

Gaping, opening widely.

Geminated, marked with a double
elevated stria connecting the
wreathes.

Geniculate, keeled.

Genus, an assemblage of species
possessing certain characters in
common, by which they are dis-
tinguished from all others.

Genera, the plural of genus.

Gibbous, bulged or bulging.

Glabrous, smooth, having a smooth
surface.

Globose, globular.

Granulated,beaded, in small grains
or beads.

Groove, a hollow channel.

H.

Hemispherical, in the shape of a
half globe.

Hirsute, rough, beset with strong
hairs.

Heteroclitical, synonymous with
heterostrophe.

Heterostrophe, reversed, applied to
shells whose spires turn in a con-
trary direction to the usual way.

Hispid, with stiff hairs.

1& J.

Jagged,denticulated,uneven,tooth-
ed like a saw.

224

Imbricated, placed like the tiles of
a house.

Imperforated, not pierced with a
hole, wanting an umbilicus.

Inequilateral, when the anterior
and posterior sides make differ-
ent angles with the hinge.

Inequivalve, where one valve is
more convex than the other, or
dissimilar in other respects, as
in the common oyster.

Inarticulate, not jointed.

Incumbent, one lying over the
other.

Incurved, g pent inwards, crook-

Incurvated,$ ed.

Indented, unequally marked, hol-
lowed.

Inflated, tumid, swollen, asif blown
out.

Inflected, or inflexed, bent inwards.

Intercostal, placed between the
ribs.

Internode, the space between one
knot or joint and another.

Interrupted, divided, separated.

Interstice, space between one part
and another, a crevice.

Intortion, the turning or twisting
in any particular direction.

Involucre, a covering.

Involution,that part which involves
or inwraps another.

Involute, where the exterior lip is
turned inwards, at the margin,
as in the Cyprea.

Isabella-colour, a brownish-yellow
with a shade of brownish-red.

Juncture, the joining of the whorls
in univalyve shells.

K.

Keel, the longitudinal prominence
in the Argonauta.

Knob, a protuberance, any part
bluntly arising above the rest.

Ge

Labra, the lips.

Laciniate, jagged or cut into irre-
gular segments.

Lacunose, having the surface coy-
ered with pits.

Lamellar, consisting of films or
plates.

Lamellated, divided into distinct
plates or foliations.

Lamine, thin plates, laid one coat
above another.

GLOSSARY.

Lanceolate, oblong, and gradually
tapering like the head of a lance.

Lateral, placed at the side, or ex-
tending to one side, from the
centre.

Latticed, having longitudinal lines
or furrows, decussated by trans-
verse lines.

Lenticulate, doubly convex, of the
form of a lens.

Ligament, a solid body, softer than
a cartilage, but harder than a
membrane, which connects the
valves in bivalves.

Limb, the disk of bivalve shells.

Linear, composed of lines, or slen-
der like a line.

Lineate, marked with lines.

Lip, the outer edge of the aperture
of univalves.

Littoral, of or belonging to the
shore.

Lobated, rounded at the edges.

Longitudinal, in the direction of
the length of the shell from the
apex to the base.

Lubricity, slipperiness, smoothness
of surface.

Lunated, formed like a half moon.

Luniform, in the shape of a cres-
cent.

Lunulated, crescent-shaped.

Lunule, a crescent-like mark or
spot, situated near the anterior
and posterior slopes in bivalve
shells.

M.

Margin, the whole circumference
or outline of the shell in bivalves.

Marginated, having a prominent
margin or border.

Membrane, a thin filmy body.

Membranaceous, consisting of
membranes. :

Mottled, clouded or spotted with
various colours.

Mucronate, ending in a sharp rigid
point.

Multilocular, | many-chambered,
consisting of several divisions.
Muricated, clothed with sharp

spines.

N.

Nacred, pearly, perlaceous. i
Nemoral, of or belonging to a wood.
Nitid, glossy.

Nodose, knotty.
Nucleus, a kernel.

0.

_Ob, prefixed to words, is used for

inversely or inverted ; as obconic,
inversely conic; obcordate, in-
versely heart-shaped.

Oblong, much longer than broad.

Oblong-ovate, between egg-shaped
and oblong.

Obsolete, indistinct, not well de-
fined.

Ocellated, applied to eye-like spots.

Ochreous, of the colour of yellow
ochre.

Offuscated, darkened,
dimmed.

Olivaceous, of a greenish olive
colour.

Operculum, a lid which closes the
aperture of some turbinated uni-
valves ; and also some of the tops
of multivalves.

Orbicular, spherical,
round.

Order, the second division of the
animal kingdom. Orders are
made up of families and genera.

Orifice, an opening or perforation.

Ovate, shaped like the longitudinal
section of an egg.

Ovoid, approaching to the shape of
an egg.

clouded,

circular,

Ee

Palmated, webbed, as in the feet of
some water birds.
Papillz, small dots or pimples.

Papillary,? having the surface
Papillous, covered with dots or
pimples.

Papillose, pimpled, dotted.

Papyraceous, thin as paper.

Parasitical, living on some other
body or animal.

Parietes, the walls of a shell.

Patulous, with a gap or opening.

Partitions, calcareous processes,
dividing the shells of the genus
Nautilus, Serpula, &c.

Pectinated, resembling the teeth of
a comb.

Pedicle, the support of the Lepas
Anatifera and its corresponding
species, by which they are at-
tached to wood, &e.

Peduncele, a foot-stalk or tube on
which any thing is seated.

GLOSSARY.

Pediform, foot-shaped.

Pelagic, belonging to the deep sea.

Pellicle, the skin or film.

Pellucid, transparent, clear.

Peltate, shield-shaped, orbicular
and attached by a central pe-
dicle.

Pentagonal, eben five angles.

Perforated, pierced with holes.

Perlaceous, of or like mother-of-
pearl.

Pervious, admitting passage.

Phosphorescent, emitting light in
the dark.

Pillar, in univalves is the internal
continuation of the columella, or
inner lips, and extends from the
base to the apex.

Pinnated, winged.

Plaited, folded.

Plaits, folds.

Plicated, folded or plaited, as in
the pillar of the volute tribe.

Plumose, having a feathery appear-
ance.

Polythalamous, divided into sever-
al chambers.

Porrected, projecting.

Prismatic, generally applied to the
colours of shells, being like those
of the prism ; iridescent.

Produced, lengthened out.

Protrude, to thrust forward.

Protuberances, parts higher or
more elevated than the parts
adjoining.

Punctulated, with small hollows
like the punctures of a thimble,

Pyriform, pear-shaped.

Q.
Quadrangular, having four right

angles.
Quadriplicated, having four plaits.

R.

Radiated, furnished with rays.

Radicated, is when the shell is
fixed by the base to another body.

Rectangular, having right angles.

Recurvated, turned backwards,

Recuryed, bowed back.

Reflected, thrown backwards, or
bent back.

pr ee d, the same as recurvated.

Refracted, abruptly bent, as if
broken.

Reniform, kidney-shaped.

226

Repand, with a waved margin.

Replicated, folded or plaited, so as
to form a groove or channel.

Reticulated, formed like a piece of
net-work.

Retrofiected, bent backwards.

Retrorse, bent back.

Retroverted, turned back.

Retuse, ending in an obtuse sinus.

Reversed spire, is when the volu-
tions turn the reverse way of a
common cork screw, or to the
sun’s apparent motion.

Revolute, rolled backwards.

Ribbed, having longitudinal, or
transverse ridges.

Ridge, the upper part of a slope.

Rima, a chink or interstice.

Rostrum, the beak; the extension
of the shell, in which the canal]
is situated.

Rotund, round, circular, spherical

Rotundated, blunted, or turned at
the edge.

Rudimentary, small, undeveloped ;
generally applied to the indis-
tinct teeth of shells.

Rufous, of a reddish colour.

Rugose, rugged, full of wrinkles.

S.

Sanguineous, of a blood colour, or
resembling blood.

Scabrous, rough, rugged, harsh, 01
like a file.

Scalloped, indented at the edges.

Scrobiculus, a depression or cavity.

Scrobiculate, pitted, having the

a surface covered with hollows.

Scutellated, .

Scutelliform, shield-shaped.

Seam, the line formed by the union
of the valves.

Semi, is used in composition in the
sense of half.

Semi-cordate, half heart-shaped.

Semi-cylindrical, half cylindrical,
cut through lengthways.

Semi-orbicular, the shape of a half
globe.

Semi-lunar, the shape of a half

moon.

Semi-pellucid, somewhat pellucid,
or shining.

Septiform, in the shape of a parti-
tion.

Serrated, like the teeth of a saw.

Serrulated, very minutely serrated.

Sessile, sitting or seated; without
a stalk.

Seta, a bristle.

GLOSSARY.

Setaceous, bristly, covered with
bristles.

Setiferous, bearing bristles.

Setose, covered with bristles,

Sinister valve, is the left valve.

Sinus, a groove or cavity.

Siphon, a cylindrical tube.

Siphunculus, a cylindrical canal
perforating the partitions in poly-
thalamous shells; for instance,
as in the Nautilus Spirula.

Solitary, generally applied to
single tooth in bivalves.

Spathulate, rounded and broad at
the top, and becoming narrow
like a spatula or battledore.

Species, the division of a family or
genus, containing such as agree
with it in generic characters ; or
such as are derived from one
common parentage.

Spiny, thorny, covered with thorn-
like processes.
Spinous, having

hedge-hog.

Spire, all the whorls of univalve
shells, excepting the onein which
the aperture is situated, which is
termed the body.

Spiral, twisted like a cork-screw.

Squamose, scaly.

Stellated, starred, consisting of
star-like figures.

Striated, scored, or covered with
fine thread-like lines.

Sub, in composition, means almost,
or approaching to; as sub-glo-
bose, somewhat globular.

Sub-arcuated, somewhat arched.

Sub-conic, somewhat conical.

Sub-diaphonous, somewhat trans-
parent or clear.

Subrotund, nearly globular.

Subulate, awl-shaped.

Sulcated, furrowed.

Sulci, furrows or ridges.

Summit, the tip or apex.

Suture, a hollow line of division in
univalve shells, the spiral line of
which separates the wreaths.

spines like a

5 3

Tentacula, the feelers of snails,
which inhabit shells.

Tesselated, chequered like a chess
board.

Testacea, the third order of worms,
including those which are coy-
ered with a testaceous shell.

Testaceous, consisting of carbonate
of lime and animal matter.

GLOSSARY.

Tetragonal, four cornered.

Torose, swelling into knobs or pro-
tuberances.

Tortuosity, wreath, flexure.

Tortuous, twisted, wreathed, wind-

ing.

A aveci: placed across, or cross-
ways. When the breadth of a
shell is greater than its length,
it is called transverse.

Trapezitorm, shaped like a tra-
pezium.

Trigonal, having three angles.

Truncated, stunted, cut short or
abruptly off at the end.

Tubercle, a little knot or pimple.

Tuberculated, knotted, pimpled.

Tuberosities, prominent knots or
excrescences.

Tubicolar, inhabiting a tube.

Tubular, in the shape of a hollow
tube.

Tubulate, tubulous or hollow.

Tunicated, coated.

Turbinated, shaped like a top or

pear.
Turgid, swollen.

U & YV:z

Valve, a distinct piece or part ; the
whole of univalve shells, or shells
in one piece; and the half of bi-
yaives or shells in two divisions,

ce

Varices, longitudinal thick ribs in
univalve shells.

Variety, is when one species differs
some little degree trom that of
another.

Vaulted, arched, like the roof of
one’s mouth.

Venter, the belly, situated in the
body of the shell ; being the most
prominent part, when the aper-
ture is turned to the observer,

Ventral, belonging to the belly.

227

Ventricose, inflated, swollen in the
middle.

Vermiform, worm-shaped.

Vertex, in the Patella the top or
most prominent part, situated in
general nearly in the middle. In
the genus Bulla it is used for the
apex.

Verrucose, warty.

Verticillate, whorled.

Umbilicated, having a depression
in the centre like a navel.

Umbo, in bivalve shells, the promi-
nent part which turns over the
hinge.

Umbonate, bossed, having a raised
knob in the centre.

Undulated, waved, having a waved
surface.

Ungulate, shaped Hke a horse’s
hoof.

Unilocular, with a single chamber
or compartment.

Univalve, shells consisting of one
valve, or piece.

Volutions, the wreaths, or turnings
of the shells of univalves,

Urceolate, swelling in the middle
like a pitcher.
ulva, a mark in several bivalve
shells; formed when the valves
are united on the posterior and
anterior slopes.

W.

Whorl, one of the wreaths or turn.
ings of the spire of univalves,

Z.

Zigzag, having contrary turnings
and windings.

Zoned, surrounded with one or

more girdles,

y
re cally |
' ier “OH

CLASSES, ORDERS, GENERA AND PLATES

TO ILLUSTRATE THE GENERA.

THE CLASSES ARE PRINTED IN CAPITALS, THE ORDERS IN SMALL CAPITALS,
AND THE GENERA IN THE ORDINARY TYPE.

A

Plate Fig.

Acasta,
Acera,
Achatina,
Adna,

Ammonites,
Ammonoceratites,
Amphidesma,
Amphitrite,
Ampullaria,
Anastoma,
Anatifa,
Anatina,
Ancillaria,
Ancylus,
ANNULOSA,
Anodonta,
Anomia,
Anomia,
ANTENNATA,

Arcopagia,
Argonauta,
Argonauta,
Arthemis,
ARTICULATA,
Aspeérgillum,
Astarte,
Auricula,
Avicula,

19 8,9
1 15,16
13° «15
19 28
14 29
16. et
10 «65
17 28
19 19
ae
13 95
19-6
is. 8
11 3
14 18
16 8
1 7
$05 iS
6 2B
16 «9
17". 288
th 18
i
16 23
18 29
re
iss

Page
171

B.

Plate Fig. Page
Baculites, 10 3 67
Balanus, 19) JOSE ii
Belemnites, LO 207, iG
Birostrites, 124
BIVALVE SHELLS, 36
Brochus, 19 25 178
Buccinum, Se 28 51
Buccinum, ll 14 81
Bulimus, 13 «#16 = 105
Bulla, Br 22 50
balla, 14 25 =111

C.

Calceola, 124
Calyptrea, 14 19 114
Cancellaria, 12 4 88
CEPHALOPODA, 66
Capsa, 17 4 149
Cardita, 16 15 142
Cardium, 5 7 38
Cardium, 16 14 142
Carinaria, 10 1 66.
Carocoila, 13 26 106
Cassidaria, il 22 8+
Cassis, ll 21 84
Chama, 2 5 41
Chama, 15 20 135
Cerithium, 12 9 90
Concholepas, 11 17 82

Chiton,

230

Chitonellus,
Cineras,
CIRRIPEDA,
Clausilia,
Clavagella,
Cleodora,
Clymene,
Coeecalium,
Colombella,

CONCHIFERA,

Conilites,
Conus,
Conus,
Corbis.
Corbula,
Cornuoides,
Coronula,
Crania,
Crassatella,
Crassina,
Crenatula,
Crenella,
Crepidula,
Creusia,
Cristellaria,
Cucullea,
Cyelas,
Cyclostoma,
Cymbulia,
Cyrena,
Cyprea,
Cypreea,
Cypricardia,
Cyprina,
Cytherea,

Delphinula,
Dentalium,
Dentalium,
Diaphana,
Diceras,
DimyYARIA,
Discina,
Discorbis,
Dolabella,
Dolium,
Donax,
Donax,

Eburna,
Emarginula,
Etheria,
Exoleta,

Fasciolaria

INDEX.

Fistulana,
Fisurella,
Fusus,

Galathea,
Galeolaria,
Galeomma,

GASTEROPODA,

Gastrochcena,
Glycimeris,
Gryphea,
Gyrogona,

Haliotis,
Haliotis,
Harpa,
Helicina,
Helix,
Helix,
HETEROPODA,
Hiatella,
Hippopus,
Hyalza,
Hyria,

Tanthina,
Tridina,
Isocardia,

Laplysia,
Lasza,
Lenticulites,
LEPAS,
Ligula,
Limacina,

Lingula,
Lituola,
Lucina,
Lutea,
Lutraria,
Lymnea,

Mactra,
Mactra,
Mactrina,

Plate Fig. Page
18 24t026 168
14 20 114
12 5 88

INDEX.

Magdala, ; 1 | Parmophorus,
“gl Patella,
Malleus, Patella,
Marginella, Pecten,
Melania, Pectinaria,
Melanopsis, Pectunculus,
Meleagrina, 30 | Pedum,
Melonia, PEDUNCULATA
Miliola, Perna,
Mitra, Petricola,
Modiola, Phasianella,
MOLLUSCA, Philliroe,
Monoceros, 3 | Pholas,
Monodonta, Pholas,
Monomyanria, Physa,
MULTIVALVE SHELLS, 5 Pileopsis,
8 Pinna,
Pinna,
Pirena,
Pisidium,
Placentula,
Mysia, 0 | Plagiostoma,
Mytilus, Planaria,
Mytilus, Planaxis,
Planorbis,
Pleurobranchus,
Pleurotoma,
Plicatula,
Natica, Podopsis,
Nautilus, Pollicipes,
Nautilus, Polystomella,
Navicella, Psammobia,
Nerita, Psammotea,
Nerita, é Pterocera,
Neritina, PTEROPODA,
Neritoides, : Pterotrachea
Nodosaria, Pupa,
Nucula, Purpura,
Nummulites, Pyramidella,
Pyrgoma,
Pyrula,

>

Oliva,

Onchidium,

Orbicula, Radiolites,
Orbiculina, Ranella,
Orbulites, Renulina,
Orthocera, Retusa,
Ortygia, Ricinula,
Ostrea, 2 Rotulites,
Ostrea,

Otion,

Ovula,

Sabella,

Sabellaria,
Paludina, ‘ 3 Sanguinolaria,
Panopea, Scalaria,
Pandora, Scalpellum,
Parmacella, SEDENTARIA,

232

Siderolites,
Septaria,
Serpula,
Serpula,
SEssILIA,
Sigaretus,
Siliquaria,
Sipho,
Solarium,
Solen,
Solen,
Spherulites,
Spirolina,.
Spirorbis,
Spirula,
Spondylus,
Spondylus,
Stomatella,
Stomatia,
Strombus,
Strombus,
Succinea,
Saxicava,

Terebella,
Terebellum,
Terebra,
Terebratula,
Teredina,

i.

INDEX.

THE

Teredo,
Teredo,
Tornatella,
Tridacna,
Trigonia,
Triton,
Trochus,
Trochus,
Tubicinella,
Turbinella,

Ungulina,
Unio,
Umbrella,

Valvata,
Venericardia,
Venerupis,
Venus,
Venus,
Vermetus,
Vermilia,
Vitrina,
Voluta,
Voluta,
Volvaria,
Vulsella,

END.

EDINBURGH:
FULLARTON AND MACNAB, PRINTERS, LEITH WALK.

Plate.

Fig. Page
30.6

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18 18to22 165
12 (2a
1 21 184
14 5 139
ll 26 86
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12 8 89
9 28 55
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12) A a 90
10 4 68
LT 22 Sato.
16 3 138
14 24 16
13 4 100
16) AT 4a
17 16 154
1 4 40
16 «684
12 24 94
19 48 “2b
13 5 107
2 7 61
il Be ES
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Fullarton&C° Lonim &Edimburgh

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Bivalve.

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GENCTEA.

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Prvalve.

A Fallarton& C° London &Ea inburgh

Univalve.

4 A Fullarton&C*London&Famburgh

CON eCTA

Univalve

AFnllarton&C*Londmé& Sdmburgh

L Fragile Carinaria, 2 Argus Argonauta. 3 Faujas’s Baculites. 4 Ribbed Tur-
rilites. 5 Glossy Ammoceratites. 6 Striated Orbulites. 7 Armed Ammonites.
8 Umbilicated Nautilus. 9 Flat Nummulites. 10 Creased Vorticialis. 11 Wrinkled
Polystomella. 12 Chalk Siderolites. 13 Vesicular Discorbis. 14 Star-shaped
Placentula. 15 Rolled Lenticulina. 16 Trochus-shaped Rotulites. 17 Round
Melionia. 18 Oval Miliola. 19 One-sinused Orbiculina. 20 Scaled Cristellaria.
21 Lid-shaped Renulina. 22 Nautilus-shaped Lituola. 23 Club-shaped Spiro-

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fina. 24 Perons Spirula. 25 Pyramidical Conilites, 26 Bent Hippurites. 27 |
Shining Nodosaria. 28 Radish Root Orthocera. 29 Subconic Lelemnites. |

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1 General Conus. Bloody Oliva. 3 Cinnamon Ancillaria. 4 Awl-shaped
Terebellum. 5 Egg-shaped Ovula. 6 Bluish Marginella. 7 Bat Voluta. 8
Measley Cyprea, 9 Pontifical Mitra. 10 Merchant Columbella. 11 Cylindric
Volvaria. 12 Filleted Terebra. 13 Ceylonese Eburna. 14 Waved Buccinum.
15 Partridge Delium. 16 Roseate Harpa. 17 Peruvian Concholepas. 18 Banded
Monoceros. 19 Persian Purpura. 20 Rugged Ricinulu. 21 Patched Cassis.
22 Thyrrene Cassidaria, 23 Diana’s Ear Strombus. 24 Knosty Plerocera. 25
Pelican's Foot Rostellaria. 26 Variegated Triton. 27 Spiral Murex.

XI

XU

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1 Prickly Ranella. 2 Nodulous Struthiolaria. 3 Fig Prula. 4 Reticulated Can-
cellaria. 5 Horny Fusus. 6 Quadrangular Fasciolaria. 7 Javanese Pleurotoma.
8 Pear Turbinella. 9 Semi-Granulated Cerithium. 10 Thick-lipped Monodonta.
11 Auger Turitella. 12 Childish Phasianella. 13 Monstrous Nerita. 14 Fresh
water Neritina. 15 Canrena Natica, 16 Furrowed Planaxis. 17 Bristly Turbo.
18 Ornamental Rotella. 19 Common Janthina. 20 Precicus Scalaria. 21 Ma
gician Trochus, 22 Fringed Delphinula. 23 Perspective Solarium. 24 Worm
hike Vermetus. 25 Concave Sigarotus. 26 Wimble Pyramidella. 27 Banded Tor
nutella. 28 Asinine Haliotis. 29 Tumoured Stomatia. 30 Imbricated Stomatelle

1 Oval Navicella. 2 Guiana Ampullaria. 3 Viviparous Paludina., 4 Pond Val
vata, 5 Pellucid Vitrina. 6 Fountain Physa. 7 Dark Pirena. 8 Crowned Mela

nia. 9 Pond Lymnea. 10 Ditch Lutea. 11 Keeled Planorbis. 12 Elegant .

Cyclostoma. 13 Judas Auricula. 14 Oblong Succinea. 15 Virgine Achatina. 16
Mountain Bulimus. 17 White Planaria. 18 Pimpled Clausilia. 19 Least
Carychium. 20 Dwarf Vertigo. 21 Moss Pupa. 22 Greater Helicina. 23
Haliotis-shaped Testacella. 24 Shore Neritoides. 25 Globular Anastoma. 26
Stone Carocolla 27 Grove Helix, 28 Polished Melanopsis. 29 Red Limax. 30
Rumphius’s Dolabella. 3) Cup-shaped Parmaceka.

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1 Skuil Terebratula. 2 Waved Anemea. % Placenta Placuna. 4 Latchet Vul-
sella. 5 Masked Crania. 6 Peron'’s Cymbulia. 7 Duck Lingula. 8 Oyster-like
Discina. 9 Pyramidal Cleodora. 10 Striated Chitonellus. 11 Helix-like Lima-
cina. 12 Three-toothed Hyalwa. 13 Fasciculated Chiton. 14 Plumed Pleuro-
branchus. 15 Common Patella. 16 Prickly Crepidula. 17 Slit Emarginula.
18 Oblong Ancylus. 19 Chinese Calyptrea. 20 Greek Fissurella. 21 Rayed
Sipho, 22 Australian Parmophorus. 23 Open Bulla. 24 Indian Umbrella.
25 Radiated Laplysia, 26 Feather-like Lamilaria. 27 Retusa Plicata. 28 Wood-
like Bulla, 29 Flexible Akera. 30 White Diaphana. 31 Hungarian Pileopsis.

- 1 Angulated Grypheea, 2 Long-spined Spondylus. 3 Edible Ostrea. 4 Branched

Plicatula. 5 Speckled. Pecten. 6 Thorny Plagiostoma. 7 Glassy Lima. 8 Tur-
ton's Galeomma. 9 Spondylus-shaped Pedum. 10 Pearl-bearing Meleagrina.
11 English Avicula 12 White Malleus. 13 Saddle Perna. 14 Muscle- shaped
Crenatula. 15 Huge Pinna. 16 Edible Mytilus. 17 Discordant Modiola. 18

_ Spotted Hippopus. 19 Oval Etheria. 20 Lazarus Chama. 21 Giant Tridacna

22 Nile Iridina. 23 Oblique Pisidium.

XV

XVI

1 Swan Anadonta. 2 Little Bird Hyria. 5 Painters’ Unio. 4 Ambiguous Cas-
talia. 5 Toothed Trigonia. 6 Pearly Nucula. 7 Ram-horned Diceras. 8 Deli-
cious Pectunculus. 9 Noah’s Arca. 10 Eared Cucullea. 11 Heart Isocardia.
12 Striated Hiatella. 13 Guinea Cypricardia. 14 Edible Cardium. 15 Fur-
rowed Cardita. 16 Red Lasea. 17 Imbricated Venericardia. 18 Casina Venus.
19 Hen Ortygia. 20 Rayed Galathea. 21 Chione Cytherea. 22 Islandic Cyprina.
28 Orbicular Ezxoleta.

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1 River Cyrena. 2 Horny Cyclas. 3 Scottish Crassina. 4 Polished Capsa. 5
Truncated Donax. 6 Rounded Mysia. 7 Waved Iwina. 8 Fringed Corbis. 9 —
Thick Arcopagia. 10 Roseate Tellinides. 11 Depressed Tellina. 12 Variegated
Psammotceea. 13 Faroe Psammobia. 14 Thin Tellimya. 15 Roseate Sanguino
laria. 16 Perforating Venerupis. 17 Pholas-shaped Petricola. 18 Abbreviated
Saxicava. 19 Beaked Pandora. 20 Kernel Corbula. 21 Striated Hrycina, 22
Transverse Ungulina, 23 Mediterranean Salemya. 24 Reticulated Amphidesma

A Fullarton&C° London &Edmburgh

1 King's Island Crassatella. 2 Very thin Ligula. 3 Truncated Mactra. 4 Oval
Lutraria, 5 Sloping Anatina. 6 Truncated Mya. 7 Pod Glycimeris. 8 Aldro
vandus’s Panop. 9 Hinge of Do. 10 Solen-shaped Trutina. 11 Sabre Solen
12 Striated Magdala. 13 Oval Crenella. 14 Bingham’s Sphenia. 15 Wrinkled
Pholeobia. 16 Modioliform Gastrochena. 17 Curled Pholas. 18 Ship Teredo,
19 A terminating side valve of Do. 20 A bivalve of Do. 21 Section of anierror
part of tube of Do. 22 Masked Teredina. 23 Sand Septaria. °%4 Gregarious
Fistularia. 25 A bivalve of Do. A side valve of Do. 27 Open Cluvagella. 28
Face valve of Do. 29 Java Aspergillum. 30 Triangular Mactrina.

X1X

1 Blainville’s Otion. z Hared Cineras. 3 Cornucopia Poilicipes. 4 Common
Scalpellum. 5 Smooth Anatifa. 6 Crenated Purgoma. 7 Warted Creusia. §&
Montagus Acasta 9 Operculum of Do. 10 White Balanus. 11 Operculum of
Do. 12 Crown Coronula. 13 Whale Tubicineila. 14 Vermicular Serpula 15
Nautilus-shaped Spirorbis. 16 Recumbent Galeolaria. 17 Antiquated Magilus.
18 Triangular Vermilia. 19 Fan Amphitrite. 20 Belgic Pectinaria. 21 Shelly
‘Terebella. 22 Thickest Sabellaria. 23 Large Cornuoides. 24 Snake-like Sili-
quaria, 25 Trochi-formed Brochus. 26 Tooth Dentalium. 27 Hlephantine. 28
English Adna.

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