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•MANUAL OF THE MOLLUSCA;*

» / .

OR, A

RUDIMENTARY TREATISE

RECENT AND FOSSIL SHELLS.

BY

S. P. WOODWARD,

*»

ASSOCIATE OF THE LINNEAN SOCIETY;
ASSISTANT IN THE DEPARTMENT OF MINERALOGY AND GEOLOGY

IN THE BRITISH MUSEUM; AND
MEMBER OF THE COTTESWOLDE NATURALISTS' CLUB.

ILLUSTRATED BY
A. N. WATERHOUSE AND JOSEPH WILSON LOWRY.

LONDON:
JOHN WEALE, 59, HIGH HOLBOEN.

MDCCCLI.

in Lih,

LONDON

PRINTED BY WILLIAM OSTELL,
HART STREET, BLOOMSBURY.

CONTENTS.

PAGE

Table of the Sub-kingdoms and Classes of Animals 2

INTRODUCTION.

CHAPTER I.

ON THE POSITION of THE MOLLTJSCA IN THE ANIMAL KINGDOM.
— Characters of the four primary groups ; — Vertebrata —
Mollusca — Articulata — Radiata. Their equal antiquity ... 3

CHAPTER II.

CLASSES or THE MOLLTJSCA. — 1. Cephalopoda. — 2. Gasteropoda.
— 3. Pteropoda. — 4. Brachiopoda. — 5. Conchifera. — 6.
Tunicata 6

CHAPTER III.

HABITS AND ECONOMY or THE MOLLUSCA. — Sedentary tribes,
their mode of attachment ; locomotive tribes, their means
of progression ; situations frequented by shell -fish. — Food :
vegetable- infusorial- and animal-feeders. — Use of shell-fish
to other animals for food ; use of shells for ornamental and
other purposes ; prices of shells. — Duration of molluscous
animals ; tenacity of life ; fecundity ; oviposition 10

252012

VI CONTENTS.

CHAPTER IV. PAGE

STRUCTURE AND PHYSIOLOGY OF THE MOLLUSCA. — Nervous
system; organs of sense. — Muscular system. — Digestive
system ; lingual teeth ; secretions. — Circulating system ;
aquiferous canals. — Respiratory system. — The shell, its
composition and structure; nacreous, fibrous, and porcel-
laneous shells ; epidermis ; erosion of fresh-water shells.
Formation and growth of the shell ; adult characters ; de-
collated shells ; monstrosities ; colours ; the operculum ;
homologies. — Temperature and hybernation. — Reproduc-
tion : of lost parts ; by gemmation ; viviparous ; alternate ;
oviparous. — Development 21

CHAPTER V.

CLASSIFICATION. — Affinities; analogies; species; genera; fami-
lies ; the quinary system 55

CHAPTER VI.

NOMENCLATURE. — Synonyms; authorities; types 59

ABBREVIATIONS 61

SYNOPSIS OF THE GENERA.
CLASS I. CEPHALOPODA. ORDER I. DIBRANCHIATA 62

SECTION A. OCTOPODA 64

Fam. I. Argonautid<B. — Argonauta 66

Fam. II. Octopodida. — Octopus, Piunoctopus, Eledone,

Cirroteuthis, Philonexis 67

SECTION B. DECAPODA 68

Fam. III. Teuthidce. — Loligo, Gonatus, Sepioteuthis, Belo-
teuthis, Geoteuthis, Leptoteuthis, Cranchia, Sepiola, Lo-
ligopsis, Cheiroteuthis, Onychoteuthis, Enoploteuthis,
Ommastrephes

CONTENTS. Vll

PAGE

Fam. IV. Belemnitidte. — Belemnites, Belemnitella, Acan-
thoteuthis, Belemnites, Belemnoteuthis, Conoteuthis ... 73

Fam. V. Sepiada. — Sepia, Spirulirostra, Beloptera, Be-
lemnosis 76

Fam. VI. %>»#d#.---Spirula .., 77

ORDER II. TETRABRANCHIATA 83

Fam. I. Nautilidce. — Nautilus, Lituites, Trochoceras, Cly-

menia , 83

Fam. II. Orthoceratidte. — Orthoceras, Gomphoceras, On-

coceras, Phragmoceras, Cyrtoceras, Gyroceras, Ascoceras 87
Fam. III. Ammonitida. — Goniatites, Bactrites, Ceratites,

Ammonites, Crioceras, Turrilites, Hamites, Ptychoceras,

Baculites 91

CLASS II. GASTEROPODA , 97

ORDER I. PROSOBRANCHIATA 103

SECTION A. SIPHONOSTOMATA lOi

Fam. I. Strombidce. — Strombus, Pteroceras, Rostellaria,

Seraphs 104

Fam. II. MuricidcB. — Murex, Pisania, Eanella, Triton, Tas-
ciolaria, TurbinelJa, Cancellaria, Trichotropis, Pyrda,

Fusus 106

Fam. III. Buccinida. — Buccinum, Pseudoliva, Anolax,
Halia, Terebra, Eburna, Nassa, Phos, Ringicula ?, Pur-
pura, Purpurina, Monoceros, Pedicularia, Bicinula, Pla-
naxis, Magilus, Cassis, Oniscia, Cithara, Cassidaria, Do-

lium, Harpa, Columbella, Oliva, Aneillaria 110

Fam. IV. Conida. — Conus, Pleurotoma 117

Fam. V. Volutida. — Voluta, Cymba, Mitra, Yolvaria, Mar-

gineUa 118

Fam. VI. Cypraida. — Cypra3a, Erato, 0 vulum 120

Vlll CONTENTS.

PAGE

SECTION B. HOLOSTOMATA 122

Fam. I. Naticida. — Natica, Sigaretus, Lamellaria, Narica,

Yelutina 122

Fam. II. Pyramidellida. — Pyramidella, Odostomia, Chem-

nitzia, Stylina, Loxonema, Macrocheilus . . / .' . . . 125

Fam. Ill, Cerithiadce. — Cerithium, Potamides, Nerinaea,

Fastigiella, Aporrhais, Struthiolaria 127

Fam. IV. Melamadae. — Melania, Paludomus, Melanopsis... 130
Fam. V. TurritelliddB. — Turritella, Aclis, Csecum, Verme-

tus, Siliquaria, Scalaria 132

Fam. VI. Litorinidae. — Litorina, Solarium, Phorus, Lacuna,

Litiopa, Eissoa, Skenea, Truncatella, ? Lithoglyplius .,, 134
Fam. VII. Paludinidte. — Paludina,Ampullaria, Amphibola,

Yalvata 138

Fam. VIII. Neritidae. — Nerita, Pileolus, Neritina., Navicella 140
Fam. IX. Turbinidce. — Turbo, Phasianella, Imperator, Tro-

chus, Eotella, Monodonta, Delphinula, Adeorbis, Euom-

phalus, Stomatella, Broderipia 142

Fam. X. Haliotis. — Haliotis, Stomatia, Scissurella, Pleuro-

tomaria, Murchisonia, Trochotoma, Cirrus, lanthina 146

Fam. XI. Fissurellid(B. — rissurella, Puncturella, Simula,

Emarginula, Parmophorus 149

Fam. XII. Calyptraidce. — Calyptrsea, Crepidula, Pileopsis,

Hipponyx 151

Fam. XIII. PatellidcB. — Patella, Acmsea, Gadinia, Sipho-

uaria 153

Fam. XIV. Dentaliada.— Dentalium 156

n. XV. CUtonida.— Chiton . . 156

NOTICE.

THE second part of this Manual is now in preparation, and
will be published early in the summer. It will contain an ac-
count of the remaining orders of shell-fish: a chapter on the
Geographical Distribution of the MoUusca, with a Map of the
Marine and Terrestrial Provinces ; a chapter on the distribution
Fossil Shells ; another on the methods of collecting and pre-
serving Land, Fresh-water, and Sea-shells ; the Preface ; and an
Index of the genera and technical terms .

The writer desires to acknowledge his obligations to Mr.
Hugh Gumming. Professor Edward Forbes, and other gentlemen
vho have assisted him by advice, and the loan of specimens :
dso to Mr. Tan Voorst, for permission to copy some interesting
igures from the " British MoUusca :?J and his thanks are most
especially due to Mr. John Edward Gray, Keeper of the Zoolo-
gical Department of the British Museum, for access to his library

cabinet, and the use of some of the best engravings which
llustrate these pages.

KINGDOM ANIMALIA.

SUB-KINGDOM I. VEBTEBRATA.

CLASS I. MAMMALIA.

II. AVES.

III. REPTILIA.

IV. PISCES.

SUB-KINGDOM II.
MOLLUSCA.

CLASS I. CEPHALOPODA.
II. GASTEROPODA.

III. PTEROPODA.

IV. BRACHIOPODA.

V. CONCHIFERA.
YI. TUNICATA.

SUB-KINGDOM III,
AKTICULATA.

CLASS I. INSECTA.

II. ARACHNIDA.

III. CRUSTACEA.

IV. CIRRIPEDA.
Y. ANELLATA.

YI. ENTOZOA.

SUB-KINGDOM IY. EADIATA.

CLASS I. ACALEPHA.

II. ECHINODERMATA.

III. ZOOPHYTA.

IY. FORAMINIFERA.

Y. INFUSORIA.

YI. AMORPHOZOA.

MANUAL OF THE MOLLUSCA.

INTRODUCTION.

CHAPTER I.

ON THE POSITION OF THE MOLLUSCA IN THE
ANIMAL KINGDOM.

ALL known animals are constructed upon four different types,
and constitute as many natural divisions or sub-kingdoms.

1. The first of these primary groups is characterized by an
internal skeleton, of which the essential, or ever-present part, is
a backbone, composed of numerous joints, or vertebra. These
are the animals most familiar to us ; beasts, birds, reptiles, and
fishes, are four classes which agree in this one respect, and are
hence collectively termed vertebrate animals, or the vertebrata.

2. Another type is exemplified in the common garden-snail,
the nautilus, and the oyster ; animals whose soft bodies are pro-
tected by an external shell, which is harder than bone, and equally
unlike the skeleton of fishes, and the hard covering of the crab
and lobster. These creatures form the subject of the present
history, and are called mollmca.*

* Mollusca soft (animals), from mollis. The Greeks termed them Ma-
lakia, whence the modern word Malacology, or the study of shell-fish.

B 2

M^TCAL OF TKE

3. The various tribes of insects, spiders, crabs, and worms>
Lave no internal skeleton ; but to compensate for it, their outer
integument is sufficiently hard to serve at once the purposes of
bones, and of a covering and defence. This external armature,
like the bodies and limbs which it covers, is divided into seg-
ments or joints, which well distinguishes the members of this
group from the others. The propriety of arranging worms with
insects will be seen, if it be remembered, that even the butterfly
and bee commence existence in a very worm-like form. This
division of jointed animals bears the name of the articulate.

4. The fourth part of the animal kingdom consists of the
coral-animals, star-fishes, sea-jellies, and those countless micro-
scopic beings which swarm in all waters. Whilst other animals
are bi-lateral, or have a right and left side, and organs arranged
in pairs, — these have their organs placed in a circle around the
mouth or axis of the body, and have hence obtained the appella-
tion of radiata.

These groups illustrate successively the grand problems of
animal economy. The lower divisions exhibit the perfection-
izing of the functions of nutrition and reproduction ; the higher
groups present the most varied and complete development of
the senses, locomotive powers, and instincts. We may also trace
in them an ideal progression from the simplest to the most
complicated structure and conditions. Commencing with the
Infusorial monad, we may ascend in imagination by a succession
of closely allied forms, to the sea-urchin arid holothuria* ; and
thence by the lowest organized worms, upwards to the flying
insect. Or, starting at the same point, we may pass from the
polypes to the tunicaries ; and from the higher kinds of shell-
fish to the true fishes, and so on to those classes whose physical
organization is most nearly identical with our own.

The mollusca are thus related to two of the other primary
groups ; — by the affinity of their simpler forms to the zoophytes,

See the History of British Star-fishes, by Professor E. Forbes.

MOLLUSCA IN THE ANIMAL KINGDOM. 5

and of their highest class to the fishes ; — to the cirripedes and
other articulate animals, they present only superficial and illusive
resemblance.

And further, we shall find that although it is customary to
speak of shell-fish as " less perfect" animals, yet they really
attain the perfection of their own type of structure ; indeed it
would seem to have been impossible to make any further advance,
physical, or psychical, except by adopting a widely different
plan from that on which the molluscous animals have been
constructed.

The evidence afforded by geological researches at present
tends to shew that the four leading types of animal structure
have existed simultaneously from the very beginning of life
upon the globe ;* and though perpetually varying in the form
under which they were manifested, they have never since entirely
ceased to exist.

By adding to the living population of the world, those forms
which peopled it in times long past, we may arrive at some dim
conception of the great scheme of the animal kingdom. And if
at present we see not the limits of the temple of nature, nor
fully comprehend its design, — at least we can feel sure that there
is a boundary to this present order of things ; and that there has
been a plan, such as we, from our mental constitution, are able
to appreciate, and to study with ever-increasing admiration.

* Mr E. Logan, Geological Surveyor of the Canadas, has discovered foot
prints of a tortoise, near Montreal, in the "Lingula Shale," or oldest fossi-
biferous rock at present known.

MANUAL OF THE MOLLUSCA.

CHAPTER II.
CLASSES OP THE MOLLUSCA.

THE mollusca are animals with soft bodies, enveloped in a mus-
cular skin, and usually protected by a univalve or bivalve shell.

That part of their integument which contains the viscera and
secretes the shell, is termed the mantle ; in the univalves it
takes the form of a sac, with an opening in front, from which
the head and locomotive organs project : in the bivalves it is
divided into two lobes.

The univalve mollusca are encephalous, or furnished with E
distinct head ; they have eyes and tentacula, and the mouth is
armed with jaws. Cuvier has divided them into three classes,
founded on the modifications of their feet, or principal locomo-
tive organs.

1. The cuttle-fishes constitute the first-class, and are termed

cephalopoda* because their feet, or more properly arms, are at-
tached to the head, forming a circle round the mouth.

Fig. l.f Oral aspect of a Cephalopod.

* From Cepkale, the head and poda feet. See the frontispiece and pi. I.

f Fig. 1. Loligo mdgaris, Lam. \. From a specimen taken off Tenby, by J.
S. Bowerbank, Esq. The mandibles are seen in the centre, surrounded by the
circular lip, the buccal membrane (with two rows of small cups on its lobes),
the eight sessile arras, and the long pedunculated tentacles (t), with their en-
larged extremities or clubs (c). The dorsal arms are lettered (d), the funnel (f).

CLASSES OF THE MOLLUSCA.

2. Iii the gasteropoda* or snails, the under side of the body
forms a single muscular foot, on which the animals creep or
glide.

Fig. 2. A Gastero^od.\

3. The pterpoda% only inhabit the sea, and swim with a pair
of fins, extending outwards from the sides of the head.

Fig. 3. A Pteropod. §

The other mollusca are acephalous, or destitute of any dis-
tinct head ; they are all aquatic, and most of them are attached,
or have no means of moving from place to place. They are di-
vided into three classes, characterized by modifications in their
breathing-organ and shell.

4. The brackiapoda^ are bivalves, having one shell placed
on the back of the animal, and the other in front ; they have nc

* Gaster, the under side of the body.

f Fig. 2. Helix desertorum. Forskal. From a living specimen in the
British Museum, March, 1850.

\ Pteron, a wing.

§ Fig. 3. Hyaloea tridentata, Lam., from Quoy and Gaimard.

^[ Brachion, an arm ; these organs were supposed to take the place ol
the feet in the preceding classes.

MANUAL OF THE MOLLUSCA.

special breathing organ, but the mantle performs that office ; they
take their name from two long ciliated arms, developed from the
sides of the mouth, with which they create currents that bring
them food.

Fig. 4, 5, 6. Brachiopoda*

5. The conchifera,} or ordinary bivalves, (like the oyster),
breathe by two pairs of gills, in the form of flat membraneous
plates, attached to the mantle ; one valve is applied to the right,
the other to the left side of the body.

6. The tunicata have no shell, but are protected by an elas-
tic, gelatinous tunic, with two orifices ; the breathing-organ
takes the form of an inner tunic, or of a riband stretched across
the internal cavity.

Five of these modifications of the molluscan type of organiza-
tion, were known to Linnaeus, who referred the animals of all
his genera of shell-fish to one or other of them ; % but unfortu-
nately he did not himself adopt the truth which he was the first

* Fig. 4. (3). Rhynchonella psittacea, Chem, sp., dorsal valve, with the
animal (after Owen). 5, 6, Terebratula australis, Q,uoy. From specimens
collected by Mr. Jukes. (2). Ideal side view of both valves, (f, the retractor
muscles, by which the valves are opened). (1). Dorsal valve. These wood-
cuts have been kindly lent by Mr. J. E. Gray.

f Conckifera, Shell-bearers.

J The Linnsean types were — Sepia, Limax, Clio, Anemia, Ascidia. Tere-
Iratula was included with Anomia, its organization being unknown.

CLASSES OF THE MOLLUSCA.

to see ; and here, as in his botany, employed an artificial, in pre-
ference to a natural method.

The systematic arrangement of natural objects ought not,
however, to be guided by convenience, nor " framed merely for
the purposes of easy remembrance and communication." The
true method must be suggested by the objects themselves, by
their qualities and relations ; — it may not be easy to learn, — it
may require perpetual modification and adjustment, — but inas-
much as it represents the existing state of knowledge it will aid
in the UNDERSTANDING of the subject, whereas a " dead and
arbitrary arrangement" is a perpetual bar to advancement, " con-
taining in itself no principle of progression." (Coleridge.)

Fig. 7. A Bivalve.*

Fig. 8. A Tunicavy.^

Mya truncata, L. £. From Forbes and Hanley.

t Ascidia merttula, Mull. Ideal representation; from a specimen dredsred
by Mr. Bowerbank, off Tenby.

B 3

10 MANUAL OF THE MOLLUSCA.

CHAPTER III.
HABITS AND ECONOMY OF THE MOLLUSCA.

EVERY living creature has a history of its own ; each has charac-
teristics by which it may be known from its relatives ; each has
its own territory, its appropriate food, and its duties to perform
in the economy of nature. Our present purpose, however, is to
point out those circumstances and trace the progress of those
changes which are not peculiar to individuals or to species,
but have a wider application, and form the history of a great
class.

In their infancy the molluscous animals are more alike, both
in appearance and habits, than in after life ; and the fry of the
acquatic races are almost as different from their parents as the
caterpillar from the butterfly. The analogy, however, is reversed
in one respect ; for whereas the adult shell-fish are often seden-
tary, or walk with becoming gravity, the young are all swimmers,
and by means of their fins and the ocean-currents, they travel
to long distances, and thus diffuse their race as far as a suitable
climate and conditions are found. Myriads of these little
voyagers drift from the shores into the open sea and there perish ;
their tiny and fragile shells become part of a deposit that is for
ever increasing over the bed of the deep sea, — at depths too
great for any living thing to inhabit. (Forbes.)

Some of these little creatures shelter themselves beneath the
shell of their parent for a time, and many can spin silken threads
with which they moor themselves, and avoid being drifted away.
They all have a protecting shell, and even the young bivalves
have eyes at this period of their lives, to aid them in choosing an
appropriate locality.

After a few days, or even less, of this sportive existence, the

HABITS AND ECONOMY OF THE MOLLUSCA. 11

sedentary tribes settle in the place they intend to occupy during
the remainder of their lives. The tunicary cements itself to rock
or sea-weed ; the shipworm adheres to timber, and the pholas
and UtJiodomus to limestone rocks, in which they soon excavate
a chamber which renders their first means of anchorage unneces-
sary. The mya and razor-fish burrow in sand or mud; the
mussel and pinna spin a byssus ; the oyster and spondylus
attach themselves by spines or leafy expansions of their shell ;
the brachiopoda are all fixed by similar means, and even some
of the gasteropods become voluntary prisoners, as the Upponyx
and vermetus.

Other tribes retain the power of travelling at will, and shift
their quarters periodically, or in search of food ; the river-mussel
drags itself slowly along by protruding and contracting its flexible
foot ; the cockle and trigonia have the foot bent, enabling them
to make short leaps ; the scallop (pector opercularis) swims
rapidly by opening and shutting its tinted valves. Nearly all
the gasteropods creep like the snail, though some are much
more active than others; the pond-snails can glide along the
surface of the water, shell- down wards ; the nucleobranches and
pteropods swim in the open sea. The cuttle-fishes have a
strange mode of walking, head-downwards, on their outspread
arms ; they can also swim with their fins, or with their webbed
.arms, or by expelling the water forcibly from their branchial
chamber ; the calamary can even strike the surface of the sea
with its tail, and dart into the air like the flying-fish. (Owen.)

By these means the mollusca have spread themselves over
every part of the habitable globe ; every region has its tribe ;
every situation its appropriate species ; the land-snails frequent
moist places, or woods, or sunny banks and rocks, climb trees,
or burrow in the ground. The air-breathing limneids live ir
fresh- water, only coming occasionally to the surface; and the
auriculas live on the sea-shore, or in salt-marshes. In the sea,
each zone of depth has its molluscous fauna. The limpet and
periwinkle live between tide-marks, where they are left dry twice

12 MANUAL OF THE MOLLUSCA.

a-day ; the trochi and purpura are found at low water, amongst
the sea-weed ; the mussel affects muddy shores, the cockle re-
joices in extensive sandy flats. Most of the finely-coloured shells
of the tropics are found in shallow water, or amongst the breakers.
Oyster-banks are usually in four or five fathom water ; scallop-
banks at twenty fathoms. Deepest of all, the terebratula are
found, commonly at fifty fathoms, and sometimes at one hundred
fathoms, even in Polar seas. The fairy-like pteropoda, the
oceanic- snail, and multitudes of other floating molluscs, pass
their lives on the open sea, for ever out of sight of land ; whilst
the litiopa and scylltea follow the gulf-weed in its voyages, and
feed upon the green delusive banks.

The food of the mollusca is either vegetable, infusorial, or
animal. All the land-snails are vegetable-feeders, and their de-
predations are but too well known to the gardener and farmer ;
many a crop of winter corn and spring tares has been wasted by
the ravages of the " small grey slug." They have their likings,
too, for particular plants, most of the pea-tribe and cabbage-
tribe are favourites, but they hold white mustard in abhorence,
and fast or shift their quarters while that crop is on the ground.*
Some, like the " cellar-snail," feed on cryptogamic vegetation, or
on decaying leaves ; and the slugs are attracted \^ fungi, or any
odorous substances. The round-mouthed sea-snails are nearly
all vegetarians, and consequently limited to the shore and the.
shallow waters in which sea- weeds grow. Beyond fifteen fathoms,
almost the only vegetable production is the nullipore ; but here
corals and horny zoophytes take the place of algce and afford a
more nutritious diet.

The whole of the bivalves, and other head-less shell-fish, live
on infusoria, or on microscropic vegetables, brought to them by
the current which their ciliary apparatus perpetually excites ;
such, too, must be the sustenance of the magilus, sunk in its

* Dilute lime-water and very weak alkaline solutions are more fatal to
snails than even salt.

HABITS AND ECONOMY OF THE MOLLUSCA. 13

coral bed, and of the calyptrcea9 fettered to its birth-place by its
calcarious foot.

The carnivorous tribes prey chiefly on other shell-fish, or on
zoophytes ; since, with the exception of the cuttle-fishes, their
organization scarcely adapts them for pursuing and destroying
other classes of animals. One remarkable exception is formed by
the stylina, which lives parasitically on the star-fish and sea-
urchin ; and another by the testacelle, which preys on the com-
mon earth-worm, following it in its burrow, and wearing a
buckler, which protects it in the rear.

Most of the siphonated univalves are animal-feeders ; the
carrion-eating stromb and whelk consume the fishes and other
creatures whose remains are always plentiful on rough and
rocky coasts. Many wage war on their own relatives, and take
them by assault ; the bivalve may close, and the operculated
nerite retire into his home, but the enemy, with rasp-like tongue,
armed with silicious teeth, files a hole through the shell, — vain
shield where instinct guides the attack ! Of the myriads of small
shells which the sea heaps up in every sheltered " ness," a large
proportion will be found thus bored by the whelks and purples ;
and in fossil shell-beds, such as that in the Touraine, nearly half
the bivalves and sea-snails are perforated, — the relics of antedi-
luvian banquets.

This is on the shore, or on the bed of the sea; far away
from land the carinaria and firola pursue the floating acalephe ;
and the argonaut, with his relative the spirula, both carnivorous,
are found in the " high seas," in almost every quarter of the
globe. The most active and rapacious of all are the calamaries
and cuttles, who vindicate their high position in the naturalists'
" system," by preying even on fishes.

As the shell-fish are great eaters, so in their turn they afford
food to many other creatures ; fulfilling the universal law of eat-
ing, and being eaten. Civilized man still swallows the oyster,
although snails are no longer reckoned " a dainty dish ;" mussels,
cockles, and periwinkles are in great esteem with children and

MANUAL OF THE MOLLUSCA.

the other unsophisticated classes of society ; and so are scallops
and the kaliotis, where they can be obtained. Two kinds of
whelk are brought to the London market in great quantities ; and
the arms of the cuttle-fish are eaten by the Neapolitans, and also
by the East Indians and Malays. In seasons of scarcity, vast
quantities of shell -fish are consumed by the poor inhabitants of
the Scotch arid Irish coasts.* Still more are regularly collected
for bait ; the calarnary is much used in the cod-fishery, off New-
foundland, and the limpet and whelk on our own coasts.

Many wild animals feed on shell-fish ; the rat and the racoon
seek for them on the sea-shore when pressed by hunger; the
South-American otter, and the crab-eating opossum constantly
resort to " salt-marshes, and the sea, and prey on the mollusca ;
the great whale lives habitually on the small floating pteropods ;
sea-fowl search for the literal species at every ebbing tide;
whilst, in their own element, the marine kinds are perpetually
devoured by fishes. The haddock is a " great conchologist ;"
and some good northern sea-shells have been rescued, unbroken,
from the stomach of the cod ; whilst even the strong valves of
the cyprina are not proof against the teeth of the cat-fish
(anarJiicas) .

They even fall a prey to animals much their inferiors in saga-
city ; the star-fish swallows the small bivalve entire, and dissolves
the animal out of its shell; and the bubble-shell (phyline),
itself predacious, is eaten both by star-fish and sea-anemone
(actinia).

The land-snails afford food to many birds, especially to the
thrush tribe ; and to some insects, for the luminous larva of the
glow-worm lives on them, and some of the large predacious
beetles (e. g. carabus violaceus and goerius olens}, occasionally
kill slugs.

The greatest enemies of the mollusca, however, are those of
their own nation ; scarcely one-half the shelly tribes graze peace-

See Hugh Miller's <c Scenes and Legends of the North of Scotland."

I

HABITS AND ECONOMY OF THE MOLLTJSCA. 15

fully on sea- weed, or subsist on the nutrient particles which the
sea itself brings to their mouths ; the rest browse on living zoo-
phytes, or prey upon the vegetable-feeders.

Yet in no class is the instinct of "self-preservation" stronger,
nor the means of defence more adequate ; their shells seem ex-
pressly given to compensate for the slowness of their movement,
and the dimness of their senses. The cuttle-fish escapes from
attack by swimming backwards and beclouding the water with an
inky discharge ; and the sea-hare (aplysia) pours out, when
irritated, a copious purple fluid, formerly held to be poisonous.
Others rely on passive resistance, or on concealment for their
safety. It has been frequently remarked that molluscs resemble
the hue and appearance of the situation they frequent ; thus, the
limpet is commonly overgrown with balani and sea-weed, and
the ascidian with zoophytes, which form an effectual disguise ;
the lima and modiola spin together a screen of grotto-work.
One ascidian (a. cochligera) coats itself with shell-sand, and the
carrier-trochus cements shells and corals to the margin of its
habitation, or so loads it with pebbles, that it looks but like a
little heap of stones.

It must be confessed that the instincts of the shell-fish are of
a low order, being almost limited to self-preservation, the escape
from danger, and the choice of food. Their history offers none
of those marvels which the entomologist loves to relate. An
instance of something like social feeling has been observed in a
Roman snail (helix pomatia) who, after escaping from a garden,
returned to it in quest of his fellow-prisoner ; — but the accom-
plished naturalist who witnessed the circumstance hesitated to
record a thing so unexampled. The limpet, too, if we may trust
the observations of Mr. Robert, of Lyme Regis, is fond of home,
or at least possesses a knowledge of topography, and returns to
the same roost after an excursion with each tide. Professor
Forbes has immortalized the sagacity of the razor-fish, who sub-
mits to be salted in his hole, rather than expose himself to be
caught, after finding that the enemy is lying in wait for him.

MANUAL OF THE MOLLTJSCA.

On the other hand, Mr. Bowerbank has a curious example of
"instinct at fault," in the fossil spine of a sea-urchin, which
appears to have been drilled by a carnivorous gasteropod !

We have spoken of shell-fish as articles of food, but they have
other uses, even to man ; they are the toys of children, who hear
in them the roaring of the sea; they are the pride of "collectors"
— whose wealth is in a cone or " wen tie-trap ;"* and they are
the ornaments of barbarous tribes. The Friendly-islander wears
the orange-cowry as a mark of chieftanship (Stutchbury), and
the New Zealander polishes the elenckus into an ornament more
brilliant than the " pearl ear-drop" of classical or modern times.
(Clarke.) One of the most beautiful substances in nature is the
shell-opal, formed of the remains of the ammonite. The forms
and colours of shells (as of all other natural objects), answer some
particular purpose, or obey some general law ; but besides this,
there is much that seems specially intended for our study, and
calculated to call forth enlightened admiration. Thus the tints
of many shells are concealed during life by a dull external coat,
and the pearly halls of the nautilus are seen by no other eyes
than ours. Or descending to mere "utility," how many tracts
of coast are destitute of limestone, but abound in shell-banks
which may be burned into lime ; or in shell-sand, for the use of
farmers.f

* The extravagant prices that have been given for rare shells, are less to
be regretted, because they have induced voyagers to collect. Mere shell-col-
lecting, however, is no more scientific than pigeon-fancying, or the study of
old china. For educational purposes the best shells are the types of genera,
or species which illustrate particular points of structure ; and, fortunately for
students, the prices are much diminished of late years. A Carinaria once
" worth 100 guineas" (Sowerby) is now worth Is. only; a Wentle-trap which
fetched 40 guineas in 1 701' (Rump hius) was worth only 20 guineas in 1753,
and may now be had for 5s. I The Conus gloria-mans has fetched £50 more
than once, and Cyprcea umbilicata has been sold for £30 this year, 1850.

f Shell-sand is only beneficial on peaty soils, or heavy clay land. It
sometimes hardens into limestone, as on the coast of Devon ; and at Guada-
loupe, where it contains litoral shells and human skeletons of recent date.

HABITS AND ECONOMY OP THE MOLLTJSCA. 1 7

Not much is known respecting the individual duration of the
shell-fish, though their length of life must be very variable.
Many of the aquatic species are annuals, fulfilling the cycle of
their existence in a single year ; whole races are entombed in
the wintry tide of mud that grows from year to year in the beds
of rivers, and lakes, and seas ; thus, in the Weald en clay we find
layer above layer of small river-snails, alternating with thin
strata of sediment, the index of immeasureably distant years.
Dredgers find that~whilst the adults of some shell-fish can be
taken at all seasons, others can be obtained late in the autumn or
winter only; those caught in spring and summer being young, or
half-grown; and it is a common remark that dead shells (of some
species) can be obtained of a larger size than any that we find
alive, because they attain their full-growth at a season when our
researches are suspended. Some species require part of two
years for their full development; the young of the doris and
eolis are born in the summer time, in the warm shallows near
the shore ; on the approach of winter they retire to deeper water,
and in the following spring return to the tidal rocks, attain their
full-growth early in the summer, and after spawning-time dis-
appear.

The land-snails are mostly biennial ; hatched in the summer
and autumn, they are half-grown by the winter-time, and acquire
their full-growth in the following spring or summer. In confine-
ment, a garden -snail will live for six or eight years ; but in their
natural state it is probable that a great many die in their second
winter, for clusters of empty shells may be found, adhering to one
another, under ivied walls, and in other sheltered situations ; the
animals having perished in their hybernation. Some of the
spiral sea-shells live a great many years, and tell their age in a
very plain and interesting manner, by the number of fringes
(varices) on their whirls ; the contour of the ranella and murex
depends on the regular recurrence of these ornaments, which
occur after the same intervals in well-fed individuals, as in their
less fortunate kindred. The Ammonites appear, by their varices,

18 MANUAL OF THE MOLLUSCA.

or periodic mouths (pi. III., fig. 3), to have lived and continued
growing for many years.

Many of the bivalves, like the mussel and cockle, attain their
full-growth in a year. The oyster continues enlarging his shell
by annual " shoots," for four or five years, and then ceases to
grow outwards ; but very aged specimens may be found, especi-
ally in a fossil state, with shells an inch or two in thickness.
The giant- clarn (tridawia) , which attains so large a size that
poets and sculptors have made it the cradle of the sea-goddess, — •
must enjoy an unusual longevity ; living in the sheltered lagoons
of coral-islands, and not discursive in its habits, the corals grow
up around, until it is often nearly buried by them ; but although
there seems to be no certain limit to its life (though it may live
a century for all that we know), yet the time will probably come
when it will be overgrown by its neighbours, or choked with
sediment.

The fresh-water molluscs of cold climates bury themselves
during winter, in the mud of their ponds and rivers ; and the
land- snails hide themselves in the ground, or beneath moss and
dead leaves. In warm climates they become torpid during the
hottest and driest part of the year.

Those genera and species which are most subject to this
" summer sleep," are remarkable for their tenacity of life ; and
numerous instances have been recorded of their importation from
distant countries, in a living state. In June, 1850, a living
pond-mussel was sent to Mr. Gray, from Australia, which had
been more than a year out of water.* The pond-snails (ampul-
larice] have been found alive in logs of mahogany from Honduras
(Mr. Pickering) ; and M. Caillaud carried some from Egypt to
Paris, packed in saw-dust. Indeed, it is not easy to ascertain
the limit of their endurance ; for Mr. Laidlay having placed a
number in a drawer for this purpose, found them alive after fine

* "It was alive 498 days after it was taken from the pond ; and in the
interim had been only twice for a few hours in water, to see if it was alive."-
Rev. W. 0. Newnham.

HABITS AND ECONOMY OF THE MOLLUSCA. 19

years, although, in the warm climate of Calcutta. The cyclosto-
mas, which are also operculated, are well known to survive impri-
sonments of many months ; but in the ordinary land-snails such
cases are more remarkable. Some of the large tropical bulimi,
brought by Lieutenant Graves from Valparaiso, revived after being
packed, some for thirteen, others for twenty months. In 1849,
Mr. Pickering received from Mr. Wollaston a basket-full of
Madeira snails (of twenty or thirty different species), three-
fourths of which proved to be alive, after several months' confine-
ment, including a sea-voyage. Mr. Wollaston has himself told
us that specimens of two Madeira snails (helix papilio and tecti-
formis) survived a fast and imprisonment in pill-boxes, of two
years and a half, arid that a large number of the small helix
turricula, brought to England at the same time, were all living
after being inclosed in a dry bag for a year and a half.

But the most interesting example of resuscitation occurred to
a specimen of the Desert snail, from Egypt, chronicled by Dr.
Baird.* This individual was fixed to a tablet in the British
Museum, on the 25th of March, 1846 ; and on March 7th, 1850,
it was observed that he must have come out of his shell in the
interval (as the paper had been discoloured, apparently in his
attempt to get away) ; but finding escape impossible, had again
retired, closing his aperture with the usual glistening film ; this
led to his immersion in tepid water, and marvellous recovery.
He is now (March 13th, 1850) alive and flourishing, and has sat
for his portrait. (Fig. 2.)

The permanency of the shell-bearing races is effectually pro-
vided for by their extreme fecundity ; and though exposed to a
hundred dangers in their early life, enough survive to re-people
the land and sea abundantly. The spawn of a single doris may
contain 600,000 eggs (Darwin) ; a river-mussel has been
estimated to produce 300,000 young in one season, and the
oyster cannot be much less prolific. The land-snails have fewer
enemies, and, fortunately, lay fewer eggs.
* An. Nat. Hist. 1850.

20

MANUAL OF THE MOLLUSCA.

Lastly, the mollmca exhibit the same instinctive care with
insects and the higher animals, in placing their eggs in situations
where they will be safe from injury, or open to the influences of
air and heat, or surrounded by the food which the young will
require. The tropical bulimi cement leaves together, to protect
and conceal their large, bird-like, eggs ; the slugs bury theirs in
the ground ; the oceanic-snail attaches them to a floating raft ;

Fig. 9. lanthina with its raft.

and the argonaut carries them in her frail boat. The horny cap-
sules of the whelk are clustered in groups, with spaces pervading
the 'interior, for the free passage of sea- water ; and the nidamental
ribbon of the doris and eolis is attached to a rock, or some
solid surface from which it will not be detached by the waves.
The river-mussel and cyclas carry their parental care still further,
and nurse their young in their own mantle, or in a special mar-
supium, designed, like that of the opossum, to protect them until
they are strong enough to shift for themselves.

If any one imbued with the spirit of Paley or Chate- .briand,
should study these phenomena, he might discover more than the
" barren facts" which alone appear, without significance, to the
unspiritual eye ; he would see at every step fresh proofs of the
wisdom and goodness of God, who thus manifests his greatness
by displaying the same care for the maintenance of his feeblest
creatures, as for the well-being of man, and the stability of the
world.

STRUCTURE AND PHYSIOLOGY OP THE MOLLUSCA. 21

CHAPTER IV.
STEUCTUEE AND PHYSIOLOGY OF THE MOLLUSCA.

MOLLUSCOUS animals possess a distinct nervous system, in-
struments appropriated to the five senses, and muscles by which
they execute a variety of movements. They have organs, by
which food is procured and digested, — a heart, with arteries
and veins, through which their colourless fluids circulate, — a
breathing-organ, — and in most instances, a protecting shell.
They produce eggs ; and the young generally pass through one
preparatory, or larval, stage.

The nervous system, upon which sensation and the exercise
of muscular motion depend, consists of a brain or principal
centre, and of various nerves possessing distinct properties : the
optic nerves are only sensible of light and colours ; the auditory
nerves convey impressions of sound ; the olfactory, of odours ;
the gustatory, of flavours ; whilst the nerves of touch or feeling
are widely diffused, and indicate in a more general way the pre-
sence of external objects. The nerves by which motion is pro-
duced, are distinct from these, but so accompany them as to ap-
pear like parts of the same cords. Both kinds of nerves cease
to act when their connection with the centre is interrupted or
destroyed. There is reason to believe, that most of the move-
ments of the lower animals result from the reflection of external
stimulants (like the process of breathing in man), without the
intervention of the will.*

In the mollusca, the principal part of the nervous system is
a ring surrounding the throat (oesophagus), and giving off nerves
to different parts of the body. The points from which the nerves
radiate, are enlargements, termed centres (ganglia), those on the

* See Miiller's Elements of Philosophy, edited by Dr. Baly.

22 MANUAL OF THE MOLLUSCA.

sides and upper part of the ring represent the brain, and supply
nerves to the eyes, tentacles, and mouth; other centres, con-
nected with the lower side of the cesophageal ring, send nerves
to the foot, viscera, and respiratory organ. In the bivalves, the
branchial centre is the most conspicuous, and is situated on the
posterior adductor muscle. In the tunicaries, the corresponding
nervous centre may be seen between the two orifices in tjie
muscular tunic. This scattered condition of the nervous centres
is eminently characteristic of the entire sub-kingdom.

Organs of special sense. — Sight. The eyes are two in num-
ber, placed on the front or sides of the head ; sometimes they
are sessile, in others stalked, or placed on long pedicels (om-
matopJwra). The eyes of the cuttle-fishes resemble those of
fishes in their large size and complicated structure. Each con-
sists of a strong fibrous globe (slerotic), transparent in front
(cornea), with the opposite internal surface (retina) covered by
a dark pigment which receives the rays of light. This chamber
is occupied by an aqueous humour, a crystalline lens, and a vi-
treous humour, as in the human eye. In the strombidce, the
eye is not less highly organised, but in most of the gasteropoda
it has a more simple structure, and perhaps only possesses sen-
sibility of light without the power of distinct vision. The
larval bivalves have also a pair of eyes in the normal position
(fig. 30) near the mouth ; but their development is not con-
tinued, and the adults are either eyeless, or possess merely ru-
dimentary organs of vision, in the form of black dots (ocelli)
along the margin of the mantle.* These supposed eyes have
been detected in a great many bivalves, but they are most con-
spicuous in the scallop, which has received the name of argus
from Poli, on this account (fig. 10).

In the tunicaries similar ocelli are placed between the ten-
tacles which surround the orifices.

* " Each possesses a cornea, lens, choroid and nerve ; they are, without
doubt, organs of vision." — Garner.

STRUCTURE AND PHYSIOLOGY OP THE MOLLUSCA. 23

Pig. 10. Pecten varius.*

Sense of Hearing. In the highest cephalopods, this organ
consists of two cavities in the rudimentary cranium which pro-
tects the brain ; a small calcarious body or otolithe is suspended
in each, as in the vestibular cavities of fishes. f Similar auditory
capsules occur near the base of the tentacles in the gasteropoda,
and they have been detected, by the vibration of the otolithes,
in many bivalves and brachiopods. With the exception of
tritonia and eolis, none of mollusca have been observed to emit
sounds. (Grant).

Sense of Smell, This faculty is evidently possessed by the
cuttle-fishes and gasteropods ; snails discriminate their food by
it, slugs are attracted by offensive odours, and many of the ma-
rine zoopliaga, may be taken with animal baits. In the pearly
nautilus, there is a hollow plicated process beneath each eye,

Fig. 11. Tentacle of a Nudibranch.%

* Pecten varius, L., from a specimen dredged by Mr. Bowerbank, off
Tenby ; mt the pallial curtains ; 5r, the branchice.

f In the Octopods, there is a foramen near the eye, and in some of the
Calamaries a plicated organ, which M. D'Orbigny regards as an external
ear.

$ Fig. 11. Tentacle of Eolis eoronata> Forbes, from Alder and Haneock.

MANUAL OP THE MOLLTJSCA.

which M. Valenciennes regards as the organ of smell*. Messrs
Hancock and Erableton attribute the same function to the la-
mellatecl tentacles of the nudibranchs, and compare them withi
the olfactory organs of fishes.

The labial tentacles of the bivalves are considered to be or-
gans for discriminating food, but in what way is unknown (fig.
18. I. £.)% The sense of taste, is also indicated rather by the
habits of the animals, and their choice of food, than by the
structure of a special organ. The acephala appear to exercise
little discrimination in selecting food, and swallow anything that
is small enough to enter their mouths, including living animal-
cules, and even the sharp spicula of sponges. In some instances,
however, the oral orifice is well guarded, as in pecten (fig. 10.)
In the Enceplmla, the tongue is armed with spines, employed
in the comminution of the food, and cannot possess a very de-
licate sense. The more ordinary
and diffused sense of touch is pos-
sessed by all the mollusca ; it is
exercised by the skin, which is
everywhere soft and lubricous,

and in a higher degree by the

/.. P-T i • i AC -i 0\ Fig- 12. Lenton Squamosum.-\

fringes of the bivalves (fig. 12),

and by the filaments and tentacles (vibraculd) of the gasteropods ;
the eye-pedicels of the snail are evidently endowed with great
sensitiveness in this respect. That shell-fish are not very sensi-
ble of pain, we may well believe, on account of their tenacity of
life, and the extent to which they have the power of reproducing
lost parts.

Muscular System. The muscles of the moUusca are prin-
cipally connected with the skin, which is exceedingly contractile
in every part. The snail affords a remarkable, though familiar

* Mr. Owen regards the membraneous lamella between the oral tentacles
and in front of the mouth, as the seat of the olfactory sense. See Fig. 44.

f Fig. 12. Lepton sqaumosum Mont., from a drawing by Mr. Alder, ia
the British Mollusca ; copied by permission of Mr. Van Voorst.

STRUCTURE AND PHYSIOLOGY OF THE MOLLTJSCA. 25

instance, when it draws in its eye-stalks, by a process like the
inversion of a glove-finger ; the branching gills of some of the
sea-slugs, and the tentacles of the cuttle-fishes, are also emi-
nently contractile.*

The inner tunic of the ascidians (fig. 8, t.) presents a beau-
tiful example of muscular tissue, the crossing fibres having much
the appearance of basket-work ; in the transparent salpians,
these fibres are grouped in flat bands, and arranged in charac-
teristic patterns. In this class (tunicatd) they act only as
sphincters (or circular muscles), and by their sudden contraction
expel the water from the branchial cavity. The muscular foot of
the bivalves is extremely flexible, having layers of circular fibres
for its protrusion, (fig. 18./) and longitudinal bands for its re-
traction (fig. 30 k) ; its structure and mobility has been com-
pared to that of the human tongue. In the burrowing shell-fish
(such as solen\ it is very large and powerful, and in the boring
species, its surface is studded with silicious particles (spicula),
which render it a very efficient instrument for the enlargement
of their cells. (Hancock.} In the attached bivalves it is not
developed, or exists only in a rudimen-
tary state, and is subsidiary to a gland
which secretes the material of those threads
with which the mussel and pinna attach
themselves. (Fig. 13.) These threads
are termed the byssus ; the plug of the

anomia, and the pedicel of terebratula

TP .. Fig. 13. Dreissena.\

are modifications 01 the byssus.

In the cuttle-fishes alone, we find muscles attached to in-
ternal cartilages which represent the bones of vertebrate animals ;
the muscles of the arms are inserted in a cranial cartilage, and
those of the fins in the lateral cartilages, the equivalents of the
pectoral fins of fishes.

* The muscular fibres of shell-fish do not exhibit the transverse stripes
which characterize voluntary muscles in the higher animals.

f Fig. 13. Dreissena potymorpha (Pallas sp.) from the Surrey timber-
docks. /, foot, b, byssus.

C

*o MANUAL OF THE MOLLUSCA.

Muscles of a third kind are attached to the shell. The valves
of the oyster (and other mono-myaries) are connected by a single
muscle ; those of the cytherea (and other di-myaries\ by two ;
the contraction of which brings the valves together. They are
hence named adductors ; and the part of the shell to which they
are attached is always indicated by scars. (Tig. 14, a. a').

A

i place of

Pig. 14. Left valve of Cytherea chione*

The border of the mantle is also muscular, and the pL
its attachment is marked in the shell by a line called the pallial
impression (p ) ; the presence of a bay, or sinus ( s ), in this line,
shews that the animal had retractile siphons ; the foot of the
animal is withdrawn by retractor muscles also attached to the
shell, and leaving small scars near those of the adductors
(Fig. 30*).

The gasteropods withdraw into their shells when alarmed,
by a shell-muscle, which passes into the foot, or is attached to
the operculum ; its impression is horse- shoe-shaped in the lim-
pet, as also in navicella, concholepas, and the nautilus ; it be-

* Fig. 14. Cytherea chione, L., coast of Devon, (original) ; h, the hinge
ligament ; u, the umbo ; I, the lunule ; c, cardinal tooth ; 1 1', lateral teeth ;
a, anterior adductor ; « ', posterior adductor ; p, pallial impression ; s, sinus,
occupied by retractor of the siphons.

STRUCTURE AND PHYSIOLOGY OF THE MOLLUSCA. 27

comes deeper with age. In the spiral univalves, the scar is
less conspicuous, being situated on the columella, and sometimes
divided, forming two spots. It corresponds to the posterior
retractors in the bivalves.

Digestive system. This part of the animal economy is all-
important in the radiate classes, and scarcely of less consequence
in the mollusca. In the ascidians (fig. 8, i\ the alimentary
canal is a convoluted tube, in part answering to the oesophagus,
and in part to the intestine ; the stomach is distinguished by
longitudinal folds, which increase its extent of surface ; it receives
the secretion of the liver by one or more apertures. In those
bivalves, which have a large foot, the digestive organs are con-
cealed in the upper part of that organ ; the mouth is unarmed,
except by two pairs of soft membranous palpi, which look like
accessory gills (fig. 18. I. t.) The ciliated arms of the brachi-
pods, occupy a similar position (figs. 4, 5, 6), and are regarded
as their equivalents*. The encephalous mollusca are frequently
armed with horny jaws, working vertically like the mandibles of
a bird ; in the land-snails, the upper jaw is opposed only by the
denticulated tongue, whilst the limneids have two additional
horny jaws, acting laterally. The tongue is muscular, and armed
with recurved spines (or lingual teeth), arranged in a great va-
riety of patterns, which are eminently characteristic of the
genera.* Their teeth are amber-coloured, glossy, and trans-
lucent ; and being silicious (they are insoluble in acid), they can
be used like a file, for the abrasion of very hard substances.
With them the limpet rasps the stony nullipore, the whelk bores
holes in other shells, and the cuttle-fish doubtless uses its tongue
in the same manner as the cat. The tongue, or lingual ribbon,
usually forms a triple band, of which the central part is called
the rachis, and the lateral tracts pleura, the rachidiari teeth

* The preparation of tlie lingual ribbon as a permanent microscopic object,
requires some nicety of manipulation, but the arrangement of the teeth may
be seen by merely compressing part of the animal between two pieces of
glass.

C 2

MANUAL OP THE MOLLUSCA.

sometimes form a single series, overlapping each other, or there
are lateral teeth on each side of a median series. The teeth on
the pleurse are termed uncini ; they are extremely numerous in
the plant-eating gasteropods. (Fig. 15. A.)*

Fig. 15. Lingual Teeth of Mollusca.

Sometimes the tongue forms a short semi-circular ridge/
contained between the jaws ; at others, it is extremely elongated,
and when withdrawn, its folds extend backwards to the stomach.
The lingual ribbon of the limpet is longer than the whole ani-
mal; the tongue of the whelk has 300 rows of teeth ; and
the great slug has 160 rows, with 180 teeth in each row.

Fig. 16. Tongue of the

The front of the tongue is frequently curved, or bent quite

over ; it is the part of the instrument in use, and its teeth are

* Fig. 15. A. Lingual teeth of trochus cinerarius (after Loven). Only
the median tooth, and the (5) lateral teeth, and (90) uncini of one side of a
single row are represented. B. One row of the lingual teeth of cyprcea
europaa; consisting of a median tooth, and three uncini on each side of it.

t Fig. 16. Lingual ribbon of buccinum undatum (original), from a pre-
paration communicated by \Vm. Thomson, Esq., of King's College.

STRUCTURE AND PHYSIOLOGY OF THE MOLLUSCA. 29

often broken or blunted. The posterior part of the lingual rib-
bon usually has its margins rolled together, and united, forming
a tube, which is presumed to open gradually. The new teeth
are developed from behind forwards, and are brought successively
into use, as in the sharks and rays amongst fishes. In the
bullada the rachis of the tongue is unarmed, and the business of
communicating the food is transferred to an organ which re-
sembles the gizzard of a fowl, and is often paved with calcarious
plates, so large and strong as to crush the small shell-fish
which are swallowed entire. In the
aplysia, which is a vegetable-feeder,
the gizzard is armed with numerous
small plates and spines. The stomach
of some bivalves contains an instru-

ment called the « crystalline stylet," Kg 1? Gizsar^f Bulla,
which is conjectured to have a si-
milar use. In the cephalopods there is a crop in which the
food may accumulate, as well as a gizzard for its trituration.

The liver is always large in the mollusca (fig. 10) ; its se-
cretion is derived from arterial blood, and is poured either into
the stomach, or the commencement of the intestine. In the
nudibranehs, whose stomachs are often remarkably branched,
the liver accompanies all the gastric ramifications, and even
enters the respiratory papillas on the backs of the eolids. The
existence of a renal organ has been ascertained in most classes ;
in the bivalves it was detected by the presence of uric acid. The
intestine is more convoluted in the herbivorous than in the car-
nivorous tribes : in the bivalves and in Jialiotis it passes through
the ventricle of the heart ; its termination is always near the
respiratory aperture (or excurrent orifice, when there are

* Fig. 17. Gizzard of bulla lignaria (original). Front and side view of a
half-grown specimen, with the part nearest the head of the animal down,
wards ; in the front view the plates are in contact. The cardiac orifice is in
the centre, in front ; the pyloric orifice is on the posterior dorsal side, near
the small transverse plate.

30 MANUAL OP THE MOLLUSC A.

two*), and the excrements are carried away by the water which
has already passed over the gills.

Besides the organs already mentioned, the eiicephalous mol-
lusks are always furnished with well- developed salivary glands,
and some have a rudimentary pancreas ; many have also special
glands for the secretion of coloured fluids, such as the purple of
the murex, the violet liquid of ianthina and aplysiat the yellow
of the bulladce, the milky fluid of eolis, and the inky secretion of
the cuttle-fishes. A few exhale peculiar odours, like the garlic-
snail (helix alliaria) and eledone moschata. Many are phos-
phorescent, especially the floating tunicaries (salpa and pyrosoma),
and bivalves which inhabit holes ( plwladidce). Some of the cuttle-
fishes are slightly luminous ; and one land-slug, the phosphorax,
takes its name from the same property.

Circulating system. The mollusca have no distinct absorbent
system, but the product of digestion (chyle) passes into the ge-
neral abdominal cavity, and thence into the larger veins, which
are perforated with numerous round apertures. The circulating
organs are the heart, arteries, and veins ; the blood is colourless,
or pale bluish white. The heart consists of an auricle (sometimes
divided into two), which receives the blood from the gills ; and
a muscular ventricle which propels it into the arteries of the
body. Prom the capillary extremities of the arteries it collects
again into the veins, circulates a second time through the respi-
ratory organ, and returns to the heart as arterial blood. Besides
this systemic heart, the circulation is aided by two additional
branchial hearts in the cuttle-fishes ; and by four in the brachio-
poda. Mr. Alder has counted from 60 to 80 pulsations per
minute in the nudibranchs, and 120 per minute in a vitrina.
Both the arteries and veins form occasionally wide spaces, or

* In most of the gasteropods the intestine returns upon itself, and ter-
minates on the right side, near the head. Occasionally it ends in a perfo-
ration more or less removed from the margin of the aperture, as in trocho-
toma, fissurella, macrochisma, and dentalium. In chiton the intestine is
straight, and terminates posteriorly.

STRUCTURE AND PHYSIOLOGY OP THE MOLLUSCA. 31

sinuses ; in the cuttle-fishes the oesophagus is partly or entirely
surrounded by a venous sinus ; and in the acephala the viceral
cavity itself forms part of the circulating system.

The circulation in the tunicaries presents a most remarkable
exception to the general rule, for their blood ebbs and flows in
the same vessels, as it was supposed to do in the human veins
before the time of Harvey. In the transparent salpce it may be
seen passing from the heart into vessels connected with the
viscera and tunics, and thence into the branchial vessels ; but
when this has continued for a time, the movement ceases, and
recommences in the opposite direction, passing from the heart
to the gill and thence to the system. (Lister.} In the compound
tunicaries, there is a common circulation through the connecting
medium, in addition to the individual currents.

Aquiferous canals. Sea-water is admitted to the visceral
cavity of many of the mollusks (as it is also in radiate animals),
by minute canals, opening externally in the form of pores.
These aquiferous pores are situated either in the centre of the
creeping disc, as in cyprtea, conus, and ancillaria ; or at its mar-
gin, as in haliotis, doris, and aplysia. In the cuttle-fishes, they
are variously placed, on the sides of the head, or at the bases of
the arms; some of them conduct to the large sub-orbital
pouches, into which the tentacles are retracted.

Respiratory system. The respiratory process consists in the
exposure of the blood to the influence of air, or water con-
taining air ; during which oxygen is absorbed and carbonic acid
liberated. It is a process essential to animal life, and is never
entirely suspended, even during hybernation. Those air-
breathers that inhabit water are obliged to visit the surface fre-
quently ; and stale water is so inimical to the water-breathers,
that they soon attempt to escape from the confinement of a glass
or basin, unless the water is frequently renewed.* In general,

* When aquatic plants are kept in the same glass with water-breathing
snails, a balance is produced ; which enables both to live without change of
water.

32 MANUAL OF THE MOLLUSCA.

fresh-water is immediately fatal to marine species, and salt-water
to those which properly inhabit fresh ; but there are some which
affect brackish water, and many which endure it to a limited ex-
tent. The depth at which shell-fish live, is influenced by the
quantity of oxygen which they require ; the most active and
energetic races live only in shallow water, or near the surface ;
those found in very deep water are the lowest in their instincts,
and are specially organized for their situation. Some water-
breathers require only moist sea-air, and a bi-diurnal visit from
the tide, — like the periwinkle, limpet, and Jcellia ; whilst many
air-breathers live entirely in the water or in damp places by the
water-side. In fact, the nature of the respiratory process is the
same, whether it be aquatic or aerial, and it is essential in each
case that the surface of the breathing-organ should be preserved
moist. The process is more complete in proportion to the ex-
tent and minute sub -division of the vessels, in which the circu-
lating fluid is exposed to the revivifying influence.

The land-snails (pulmonifera), have a lung, or air-chamber,
formed by the folding of the mantle, over the interior of which
the pulmonary vessels are distributed ; this chamber has a round
orifice, on the right side of the animal, which opens and closes
at irregular intervals. The air in this cavity seems to renew
itself with sufficient rapidity (by the law of diffusion), without
any special mechanism.

In the aquatic shell-fish, respiration is performed by the
mantle, or by a portion of it specialized, and forming a gill
(brancJiia). It is effected by the mantle alone in one family of
tunicaries (pelonaiadce), in all the brachiopoda> and in one family
of gasteropods (actceonidte).

In most of the tunicata, the breathing organ forms a distinct
sac lining the muscular tunic, or mantle (fig. 8. #.) ; this sac has
only one external aperture, and conducts to the mouth, which is
situated at its base. It is a sieve-like structure, and its inner
surface is clothed with vibratile cilia* which create a perpetual

* From cilium, an eyelash ; they are only visible under favourable circum-

STRUCTURE AND PHYSIOLOGY OF THE MOLLUSCA. 33

current, setting in through the (branchial) orifice, escaping through
the meshes of the net, and passing out by the anal orifice of the
outer tunics. The regularity of this current is interrupted only
by spasmodic contractions of the mantle, occurring at irregular
intervals, by which the creature spirts out water from both orifices,
and thus clears its cavity of such accumulated particles as are
rejected by the mouth ; and too large to escape through the
branchial pores. In the salpians, these contractions are ryth-
mical, and have the effect of propelling them backwards. In the
ordinary bivalves, the gills form two membranous plates on each
side of the body ; the muscu-
lar mantle is still sometimes
united, forming a chamber
with two orifices, into one
of which the water flows,
whilst it escapes from the
other ; there is a third open-
ing in front, for the foot, but
this in no wise influences the
branchial circulation. Some- ^ 18- Trigonia pectinata*
times the orifices are drawn out into long tubes, or siphons, es-
pecially in those shell-fish which burrow in sand. (Figs. 19
and 7.)

Fig. 19. Bivalve wth long siphons.^

stances, with the aid of a microscope ; but the currents they cause are easily
made perceptible by dropping fine sand into the water over them.

* Trigonia pectinata, Lam. (original). Brought from Australia by the
late Captain Owen Stanley. The gills are seen in the centre through the
transparent mantle, o, mouth j / 1, labial tentacles ; ft foot ; v, vent.

f Fig. 19. Psammobia vespertina, Chemn. after Poli, reduced one half.
The arrows indicate the direction of the current, r $, respiratory siphon.
t *, excurrent siphon.

C 3

34 MANUAL OF THE MOLLUSCA.

Those bivalves which have no siphons, and even those in
which the mantle is divided into two lobes, are provided with
valves or folds which render the respiratory channels just as
complete in effect. These currents are not in any way connected
with the opening and closing of the valves, which is only done
in moving ; or in efforts to expel irritating particles.*

In some of the gasteropoda the respiratory organs form tufts,
exposed on the back and sides (as in the nudibranches), or pro-
tected by a fold of the mantle (as in the infer obranclies and
tectibranches of Cuvier). But in most the mantle is inflected,
and forms a vaulted chamber over the back of the neck, in which
are contained the pectinated or plume-like gills (fig. 61). In the
carnivorous gasteropods (siphon ostomata) the water passes into
this chamber through a siphon, formed by a prolongation of the
upper margin of the mantle, and protected by the canal of the
shell ; after traversing the length of the gill, it returns and es-
capes through a posterior siphon, generally less developed, but
very long in ovulum volva, and forming a tubular spine in typhis.

In the plant-eating sea-snails (liolostomata), there is no true
siphon, but one of the " neck-lappets" is sometimes curled up
and performs the same office, as in paludina and ampullaria (fig.
84). The in-coming and out-going currents in the branchial
chamber, are kept apart by a valve-like fringe, continued from
the neck -lappet. The out-current is still more effectually isolated
mfasurella, kaliotis, and dentalium, where it escapes by a hole in
the shell, far removed from the point at which it entered. Near
this outlet are the anal, renal, arid generative orifices.

The cephalopods have two or four plume-like gills, symme-
trically placed in a branchial chamber, situated on the under-side

* If a river-mussel be placed in a glass of water, and fine sand let fall
gently over its respiratory orifices, the particles will be seen to rebound from
the vicinity of the upper aperture, whilst they enter the lower one rapidly.
But as this kind of food is not palatable, the creature will soon give a plunge
with its foot, and closing its valves, spirt the water (and with it the sand)
from both orifices ; the motion of the foot is, of course, intended to change
its position.

STRUCTURE AND PHYSIOLOGY OF THE MOLLI3SCA. 35

of the body ; the opening is in front, and occupied by a funnel,
which, in the nautilus, closely resembles the siphon of the palti-
dina, but has its edges united in the cuttle-fishes. The free
edge of the mantle is so adapted that it allows the water to enter
the branchial chamber on each side of the funnel ; its muscular
walls then contract and force the water through the funnel, an
arrangement chiefly subservient to locomotion.* Mr. Bower-
bank has observed, that the eledone makes twenty respirations
per minute, when resting quietly in a basin of water.

In most instances, the water on the surface of the gills is
changed by ciliary action alone ; in the cephalopods and salpians,
it is renewed by the alternate expansion arid contraction of the
respiratory chamber, as in the vertebrate animals.

The respiratory system is of the highest importance in the
economy of the mollusca, and its modifications afford most va-
luable characters in classification. It will be observed that the
Cuvierian classes are based on a variety of particulars, and are
very unequal in importance ; but the orders are characterized by
their respiratory conditions, and are of much more nearly equal
value.

Orders. Classes.

Dibranchiata. Owen.

Tetrabranchiata. Owen.

Nucleobranchiata. Bl.
ENCEPHALA Prosobranchiata. M. Edw.

Pulmonifera. Cuv.

Opisthobranchiata. M. Edw. -

Aporobranchiata. Bl.
( Palliobranchiata. Bl.
ACEPHALA j Lamellibranchiata. BL
( Heterobranchiata. Bl.
The Shell. The relation of the shell to the breathing-organ
is very intimate ; indeed, it may be regarded as a pneumo-skeleton,

* A very efficient means of locomotion in the slender pointed calamaries,
which dart backwards with the recoil, like rockets.

v CEPHALOPODA.

GASTEROPODA.

i

PTEROPODA.
BRACHIOPODA.
CONCHIFERA.
TUNICATA.

36 MANUAL OF THE MOLLUSC A.

being essentially a calcified portion of the mantle, of which the
brea thing- organ is at most a specialised part.*

The shell is so characteristic of the mollusca that they have
been commonly called "testacea" (from testa "a shell"), in
scientific books ; and the popular name of "shell-fish," though
not quite accurate, cannot be replaced by any other epithet in
common use. In one whole class, however, and in several
families, there is nothing that would be popularly recognised as
a shell.

Shells are said to be external when the animal is contained in
them, and internal when they are concealed in the mantle ; the
latter, as well as the shell-less species, being called naked mollusks.

Three-fourths of the mollusca are univalve., or have but one
shell; the others are mostly bivalve, or have two shells; the
pJiolads have accessory plates, and the shell of chiton consists of
eight pieces. Most of the multivalves of old authors were arti-
culate animals (cirripedes), erroneously included with the mollusca,
which they resemble only in outward appearance.

All, except the argonaut* acquire a rudimental shell before
they are hatched, which becomes the nucleus of the adult shell ;
it is often differently shaped and coloured from the rest of the
shell, and hence the fry are apt to be mistaken for distinct species
from their parents.

In cymba (fig. 20) the nucleus is large and irregular; mfusus
antiquus it is cylindrical ; in the pyramidellidce it is oblique ; and
it is spiral in carinaria, atlanta, and many limpets, which are
symmetrical when adult.

The rudimentary shell of the nudibranchs is shed at an early

* In its most reduced form the shell is only a hollow cone, or plate, pro-
tecting the breathing organ and heart, as in Umax, testacella, carinaria. Its
peculiar features always relate to the condition of the breathing-organ ; and in
terebratula and pelonaia it becomes identified with the gill. In the nudi-
branchs the vascular mantle performs wholly or in part the respiratory office.
In the cephalopods the shell becomes complicated by the addition of a distinct,
internal, chambered portion (phragmocone), which is properly a visceral
skeleton ; in spirula the shell is reduced to this part.

STRUCTURE AND PHYSIOLOGY OF THE MOLLTJSCA. 37

age, and never replaced. In this respect the
molluscan shell differs entirely from the shell
of the crab and other articulate animals,
which is periodically cast oif and renewed.

In the bivalves the embryonic shell forms
the umbo of each valve ; it is often very unlike
the after-growth, as in unio pictorum, cyclas
henslowiana and pecten pusio. In attached
shells like the oyster and anomia the umbo fre-
quently presents an exact imitation of the sur-
face to which the young shell originally adhered.

Shells are composed of carbonate of lime,
with a small proportion of animal matter.
The source of this lime is to be looked Fig. -20. Cymba*
for in their food. Modern inquiries into organic chemistry have
shown that vegetables derive their elements from the mineral
kingdom (air, water, and the soil), and animals theirs from the
vegetable. The sea-weed filters the salt-water, and separates
lime as well as organic elements ; and lime is one of the most
abundant mineral matters in land plants. From this source the
mollusca obtain lime in abundance, and, indeed, we find frequent
instances of shells becoming unnaturally thickened through the
superabundance of this earth in their systems. On the other
hand, instances occur of thin and delicate-shelled varieties, in
still, deep water, or on clay bottoms ; whilst in those districts
which are wholly destitute of lime, like the lizard in Cornwall,
and similar tracts of magnesian- silicate in Asia Minor, there are
no mollusca. (Forbes?)

The texture of shells is various and characteristic. Some,
when broken, present a dull lustre like marble or china, and are
termed porcellanous ; others are pearly or nacreous ; some have
& fibrous structure; some are horny, and others glassy and trans-
lucent.

* Fig. 20. Cymba .proboscidalis, Lam., from a very young specimen in
the cabinet of Hugh Cmning, Esq., from Western Africa.

38

MANUAL OF THE MOLLTJSCA.

Fig. 21. Pinna. Fig. 22. Terebratula. Fig. 23. Pearl*

The nacreous shells are formed by alternate layers of very
thin membrane and carbonate of lime, but this alone does not give
the pearly lustre which appears to depend on minute undulations
of the layers, represented in fig. 23. This lustre has been suc-
cessfully imitated on engraved steel buttons. Nacreous shells,
when polished, form "mother of pearl ;" when digested in weak
acid, they leave a membraneous residue which retains the original
form of the shell. This is the most easily destructible of shell-
textures, and in some geological formations we find only casts of
the nacreous shells, whilst those of fibrous texture are completely
preserved.

Pearls are produced by many bivalves, especially by the
Oriental pearl-mussel (avicula margaritifera), and one of the
British river-mussels (wiio margaritiferus). They are caused by
particles of sand, or other foreign substances, getting between
the animal and its shell ; the irritation causes a deposit of nacre,
forming a projection on the interior, and generally more brilliant
than the rest of the shell. Completely spherical pearls can only
be formed loose in the muscles, or other soft parts of the animal.
The Chinese obtain them artificially, by introducing into the
living mussel foreign substances, such as pieces of mother-of-pearl
fixed to wires, which thus become coated with a more brilliant
material.

* Tigs. 21, 22, 23. Magnified sections of shells, from Dr. Carpenter.
Fragments of shell ground very thin, and cemented to glass slides with Canada
balsam, are easily prepared, and form curious microscopic objects. A great
variety of them may be procured of Mr. C. M. Topping, of Pentonville.

STRUCTURE AND PHYSIOLOGY OF THE MOLLUSC A. 39

Similar prominences and concretions — pearls which are not
pearly — are formed inside porcellanous shells ; these are as
variable in colour as the surfaces on which they are formed.*

The fibrous shells consist of successive layers of prismatic cells
containing translucent carbonate of lime ; and the cells of each
successive layer correspond, so that the shell, especially when
very thick (as in the fossil inoceramus and trichites), will break
up vertically, into fragments, exhibiting on their edges a structure
like arragonite, or satin- spar. Horizontal sections exhibit a
cellular net- work, with here and there a dark cell, which is empty.

(fig. 21.)

The oyster has a laminated structure, owing to the irregular
accumulation of the cells in its successive layers, and breaks up
into horizontal plates.

In the boring-shells (pJioladidte) the carbonate of lime has an
atomic arrangement like arragonite, which is considerably harder
than calcarious spar; in other cases the difference in hardness
depends on the proportion of animal matter, and the manner in
which the layers are aggregated.!

In many bivalve shells there occurs a minute tubular structure,
which is very conspicuous in some sections of pinna and oyster-
shell.

The brachiopoda exhibit a characteristic structure by which
the smallest fragment of their shells may be determined; it
consists of elongated and curved cells, matted together, and
often perforated by circular holes, arranged in quincunx order
(fig. 22).

But the most complex shell-structure is presented by the
porcellanous gasteropoda. These consist of three strata which
readily separate in fossil shells, on account of the removal of their

* They are pink in turbinellus and strombus ; white in ostrea ; white or
glassy, purple or black in mytilus ; rose-coloured and translucent in pinna.
(Gray.}

f The specific gravity of floating shells (such as argonanta and ianthind)
is lower than that of any others. (De la Beche.)

40

MANUAL OF THE MOLLUSC A.

B

animal cement. In fis;. 24. a represents the outer, b the middle,
and c the inner stratum ; they
may be seen, also, in fig. 25.

Each of these three strata
is composed of very nume-
rous vertical plates, like cards
placed on edge ; and the di-
rection of the plates is some-
times transverse in the central
stratum, and lengthwise in ri&- 24« Sections of a cone.*
the outer and inner (as in cyprcea, cassis, ampullaria, and bull-
mm\ or longitudinal in the middle layer, and transverse in the
others (e. g. conus, pyrula, oliva, and valuta).

Each plate, too, is composed of a series of prismatic cells,
arranged obliquely (45°), and their direction being changed in
the successive plates, they cross each other at right angles.
Tertiary fossils best exhibit this structure, either at their broken
edge, or in polished sections. f (Bowerbank) .

The argonaut-shell, and the bone of the cuttle-fish, have a
peculiar structure ; and the Hippurite is distinguished by a can-
cellated texture, unlike any other shell, except, perhaps, some of
the cardiacece and chamacete.

Epidermis. All shells have an outer coat of animal matter
called the " epidermis" (or periostracum), sometimes thin and
transparent, at others thick and opaque. It is thick and olive-
coloured in all fresh-water shells, and in many arctic sea-shells
(e. g. cyprina and astarte) ; the colours of the land-shells often

* Sections of conus pondwosus, Brug., from the Miocene of the Tonraine.
A, longitudinal section of a fragment, B, complete horizontal section; a, outer
layer; b, middle; c, inner layer; d, e,f, lines of growth.

f It is necessary to bear in mind that fossil shells are often pseudomor-
pJums, or mere casts, in. spar or chalcedony, of cavities once occupied by shells ;
such are the fossils found at Blackdown, and many of the London clay fossils
at Barton. The Palseozoic fossils are often metamorphic, or have undergo]
a re-arrangement of their particles, like the rocks in which they occur.

one

STRUCTURE AND PHYSIOLOGY OF THE MOLLUSCA. 41

depend on it ; sometimes it is silky as in helix sericea, or fringed
with hairs, as in trichotropis ; in the whelk and some species of
triton and conus it is thick and rough like coarse cloth, arid in
some modiolas it is drawn out into long beard-like filaments.

In the cowry and other shell-fish with large mantle lobes, the
epidermis is more or less covered up by an additional layer of
shell deposited externally.

The epidermis has life, but not sensation, like the human
scarf-skin ; and it protects the shell against the influence of the
weather, and chemical agents ; it soon fades, or is destroyed,
after the death of the animal, in situations where, whilst living,
it would have undergone no change. In the bivalves it is organ-
ically connected with the margin of the mantle.

It is most developed in shells which frequent damp situations,
amongst decaying leaves, and in fresh -water shells. All fresh-
waters are more or less saturated with carbonic-acid gas, and in
limestone countries hold so much lime in solution as to deposit it
in the form of tufa on the mussels and other shells.* But in the
absence of lime to neutralise the acid, the water acts on the shells,
and would dissolve them entirely if it were not for their protecting
epidermis. As it is we can often recognise fresh-water shells by
the erosion of those parts where the epidermis was thinnest,
namely, the points of the spiral shells and the umbones of the
bivalves, those being also the parts longest exposed. Specimens
of melanopsis and bithinia become truncated again and again in
the course of their growth, until the adults are sometimes only
half the length they should be, and the discoidal planorbis some-
times becomes perforated by the removal of its inner whirls ; in
these cases the animal closes the break in its shell with new
layers. Some of the unios thicken their umbones enormously,
and form a layer of animal matter with each new layer of shell,
so that the river-action is arrested at a succession of steps.

* As at Tisbury, in Wiltshire, where remarkable specimens of anodons
were obtained by the late Miss Benett.

MANUAL OF THE MOLLUSCA.

FORMATION AND GROWTH OF THE SHELL.

The shell, as before stated, is formed by the mantle of the
shell-fish, indeed, each layer of it was once a portion of the man-
tle, either in the form of a simple membrane, or as a layer of
cells ; and each layer was successively calcified (or hardened with
carbonate of lime) and thrown off by the mantle to unite with
those previously formed. Being extra- vascular it has no inherent
power of repair. (Carpenter.)

The epidermis and cellular structures are formed by the mar-
gin (or collar) of the mantle; the membranous and nacreous
layers, by the thin and transparent portion which contains the
viscera; hence we find the pearly texture only as a lining
inside the shell, as in the nautilus, and all the aviculida and

If the margin of a shell is fractured during the life-time of the
animal, the injury will be completely repaired by the reproduction
both of the epidermis and of the outer layer of shell with its pro-
per colour. But if the apex is destroyed, or a hole made at a
distance from the aperture, it will merely be closed with the
material secreted by the visceral mantle. Such inroads are often
made by boring worms and shells, and even by a sponge (cliond)
which completely mines the most solid shells. In Mr. Gray's
cabinet is the section of a cone, in whose apex a colony of UtJwdomi

Fig. 25. Section of a cone perforated by lithodomi.

STRUCTURE AND PHYSIOLOGY OF THE MOLLUSCA. 43

had settled, compelling the animal to contract itself, faster even
than it could form shell to fill up the void.

Lines of growth. So long as the animal continues growing,
each new layer of shell extends beyond the one formed before it ;
and, in consequence, the external surface becomes marked with
lines of growth. During winter, or the season of rest which cor-
responds to it, shells cease to grow ; and these periodic resting-
places are often indicated by interruptions of the otherwise regu-
lar lines of growth and colour, or by still more obvious signs. It
is probable that this pause, or cessation from growth, extends
into the breeding season ; otherwise there would be two periods
of growth, and two of rest in each year. In many shells the
growth is uniform ; but in others each stage is finished by the
development of a fringe, or ridge (varix\ or of a row of spines,
as in tridacna and murex. (Owen, Grant.)

Adult characters. The attain-
mpnt of the full-growth proper to
each species is usually marked by
ihanges in the shell.

Some bivalves, like the oyster,
and gryphcea (fig. 26), continue to
.ncrease in thickness long after
;heyhave ceased to grow outwards; KS- 26' Section of gryphcea*
the greatest addition is made to the lower valve, especially near
,he umbo ; and in the spondylus some parts of the mantle secrete
more than others, so that cavities, filled with fluid, are left in the
substance of the shell.

The adult teredo smdfatulana close the end of their burrows ;
the pholadidea fills up the great pedal opening of its valves ; and
the aspergillum forms the porous disk from which it takes its
name. Sculptured shells, particularly ammonites, and species of
rostellaria mdfusus, often become plain in the last part of their

* Fig. 26. Section of gryphoea incurva, Sby. Lias, Dorset, (original ; dimi-
nished one half), the upper valve is not much thickened ; the interior is filled
with lias.

44 MANUAL OF THE MOLLTJSCA.

growth. But the most characteristic change is
the thickening and contraction of the aperture
in the univalves. The young cowry (fig. 27)
has a thin, sharp lip, which becomes curled in-
wards, and enormously thickened and toothed in
the adult ; the pteroceras (pi. 4, fig. 3) deve-
lopes its scorpion-like claws, only when full-
grown ; and the land-snails form a thickened lip,
or narrow their aperture with projecting pro-
cesses, so that it is a marvel how they pass in
and out, and how they can exclude their eggs, -^
(e. g. pi. 12, fig. 4, anastoma; and fig. 5, helix
hirsuta).

Yet at this time they would seem to require more space and
accommodation in their houses than before, and there are several
curious ways in which this is obtained. The neritida and auri-
culiddB dissolve all the internal spiral columnf of their sheljs ;
the cone (fig. 24, B,) removes all but a paper-like portion of its
inner whirls ; the cowry goes still further, and continues removing
the internal layers of its shell-wall, and depositing new layers
externally with its overlapping mantle (fig. 76), until, in some
cases, all resemblance to the young shell is lost in the adult.

The power which mollusks possess of dissolving portions of
their own shells, is also exhibited by the murices, in removing
those spines from their whirls which interfere with their growth ;
and by the purpurce and others in wearing away the wall of their
aperture. The agency in these cases is supposed to be chemical.

Decollated shells. It frequently happens that as spiral shells
become adult they cease to occupy the upper part of their cavity ;
the space thus vacated is sometimes filled with solid shell, as in
magilus ; or it is partitioned off, as in vermetus, euomphalus,
turritella and triton (fig. 62). The deserted apex is sometimes
very thin, and becoming dead and brittle, it breaks away, leaving

* Cypraa testudinaria, L., young.

f This is sometimes done by the hermit-crab to the shells it occupies.

STRUCTURE AND PHYSIOLOGY OF THE MOLLUSCA. 45

the shell truncated, or decollated. This happens constantly with
the truncatellce, cylindrella, and bulimus decollates ; amongst the
fresh-water shells it depends upon local circumstances, but is very
common vrithpirena and cerithidea.

Forms of shells. These will be described particularly under
each class ; enough has been said to show that in the molluscan
shell (as in the vertebrate skeleton) indications are afforded o
many of the leading affinities and structural peculiarities of the
animal. It may sometimes be difficult to determine the genus of
a shell, especially when its form is very simple ; but this results
more from the imperfection of our technicalities and systems,
than from any want of co-ordination in the animal and its shell.

Monstrosities. The whirls of spiral shells are sometimes
separated by the interference of foreign substances, which adhere
to them when young ; the garden-snail has been found in this
condition, and less complete instances are common amongst sea-
shells. Discoidal shells occasionally become spiral (as in speci-
mens of planorbis found at Rochdale), or irregular in their
growth, owing to an unhealthy condition. The discoidal ammo-
nites sometimes show a slight tendency to become spiral, and
more rarely become un symmetrical, and have the keel on one
side, instead of in the middle.

All attached shells are liable to interference in their growth,
and malformations consequent on their situation in cavities, or
Tom coming in contact with rocks. The dreissena polymorpha
distorts the other fresh-water mussels by fastening their valves
h its byssus ; and balani sometimes produce strange protube-
rances on the back of the cowry, to which they have attached
themselves when young.*

In the miocene tertiaries of Asia Minor, Professor Forbes

* In the British Museum there is a helix terrestris (cheinn.) with a small
stick passing through it, and projecting from the apex and umbilicus. Mr.
Pickering has, in his collection, a helix hortensis which got entangled in a nut-
shell when young, and growing too large to escape, had to endure the incubus
to the end of its days.

46 MANUAL OF THE MOLLUSCA.

discovered whole races of netitina, paludina, and melanopsis, wit;
whirls ribbed or keeled, as if through the unhealthy influence o
brackish water. The fossil periwinkles of the Norwich Crag ar
similarly distorted, probably by the access of fresh-water ; paralle
cases occur at the present day in the Baltic.

Reversed shells. Left-handed, or reversed varieties of spira
shells have been met with in some of the very common species
like the whelk and garden-snail. Bulimus citrinus is as often
sinistral as dextral ; and a reversed variety of/usus antiqum wa
more common than the normal form in the pliocene sea. Othe
shells are constantly reversed, as pyrula perversa, many species o
pupa, and the entire genera, clausilia, cylindrella, physa, and tn
pJioris. Bivalves less distinctly exhibit variations of this kind
but the attached valve of chama has its umbo turned to the righ
or left indifferently ; and of two specimens of lucina childreni in
the British Museum, one has the right, the other the left valv
flat.

The colours of shells are usually confined to the surface beneat
the epidermis, and are secreted by the border of the mantle
which often exhibits similar tints and patterns (e. g. voluta undu
lata, fig. 73). Occasionally the inner strata of porcellanous shell
are differently coloured from the exterior, and the makers of shell
cameos avail themselves of this difference to produce white o
rose-coloured figures on a dark ground.*

The secretion of colour by the mantle depends greatly on th
action of light ; shallow- water shells are, as a class, warmer am
brighter coloured than those from deep water ; and bivalve
which are habitually fixed or stationary (like spondylus and pecten
pleuronectes) have the upper valve richly tinted, whilst the lowe
one is colourless. The backs of most spiral shells are darke

* Cameos in the British Museum, carved on the shell of cassis cornuta
are white on an orange ground ; on c. tuberosa, and madagascariensis, whit
upon dark claret-colour ; on c. rufa, pale salmon-colour on orange ; and on
strombus gig as, yellow on pink. By filing some of the olives (e. g. oliva utri
culus] they may be made into very different coloured shells.

STRUCTURE AND PHYSIOLOGY OF THE MOLLUSCA. 47

than the under sides ; but in ianthina the base of the shell is
habitually turned upwards, and is deeply dyed with violet. Some
colours are more permanent than others ; the red spots on the
naticas and nerites are commonly preserved in tertiary and oolitic
fossils, and even in one example (of n. subcostata schl.) from
Devonian limestone. Terebratula hast at a, and some pectens of
the carboniferous period, retain their markings ; the orthoceras
anguliferm of the Devonian beds has, zig-zag bands of colour ;
and a terebratula of the same age, from arctic North America,*
is ornamented with several rows of dark red spots.

The operculum. Most spiral
shells have an operculum, or lid,
with which to close the aperture
when they withdraw for shelter
(see gasteropoda). It is deve-
loped on a particular lobe at the

posterior part of the foot, and

• , PI i Fig, 28. Trochus ziziphinus.^

consists of horny layers, some

times hardened with shelly matter (fig. 28).

It has been considered by Adanson, and more recently by
Mr. Gray, as the equivalent of the dextral valve of the conchifera ;
but however similar in appearance, its anatomical relations are
altogether different. In position it represents the byssus of the
bivalves (Loven) ; and in function it is like the plug with which
unattached specimens of bysso-arca close their aperture. (Forbes.)

Homologies of the shell. J The shell is so simple a structure
that its modifications present few points for comparison; but
even these are not wholly understood, or free from doubt. The

* Presented to tlie British Museum by Sir John Richardson.

f Trochus ziziphinus, from the original, taken in Pegwell Bay abundantly.
Phis species exhibits small tentacular processes, neck-lappets, side-lappets,
;entacular filaments, and an operculigerous lobe.

£ Parts which correspond in their real nature — (their origin and develop-
ment)— are termed homologous ; those which agree merely in appearance, or
)ffice, are said to be analogous.

48 MANUAL OF THE MOLLUSCA.

bivalve shell may be compared to the outer tunic of the ascidian,
cut open and converted into separable valves. In the concJiifera
this division of the mantle is vertical, and the valves are right
and left. In the brachiopoda the separation is horizontal, and
the valves are dorsal and ventral. The monomyarian bivalves lie
habitually on one side (like the pleuronectidce among fishes) ; and
their shells, though really right and left, are termed " upper"
and " lower" valves. The univalve shell is the equivalent of
loth valves of the bivalve. In the pteropoda it consists of dorsal
and ventral plates, comparable with the valves of terebratula. In
the gasteropoda it is equivalent to both valves of the concJiifera
united above.* The nautilus shell corresponds to that of the
gasteropod ; biit whilst its chambers are shadowed forth in many
spiral shells, the siphuncle is something additional ;rand the entire
shell of the cuttle-fish and argonautf have no known equivalent
or parallel in the other molluscous classes. The student might
imagine a resemblance in the shell of the ortkoceras to a lack-bone ;
but the true homologue of the vertebrate skeleton is found in the
neural and muscular cartilages of the cephalopod; whilst its
phragmocone is but the representative of the calcarious axis (or
splanchno-skeleton) of a coral, such as amplexus or siphonophyllia.

Temperature and hybernation. Observations on the tempera-
ture of the mollmca are still wanted ; it is known, however, to
vary with the medium in which they live, and to be sometimes a
degree or two higher or lower than the external temperature; with
snails (in cool weather), it is generally a degree or two higher.

The mollusca of temperate and cold climates are subject to
hybernation ; during which state the heart ceases to beat, respira-

* Compare fssurella or trochus (fig. 28) with lepton squamosum (fig. 12).
The disk of hipponyx is analogous to the ventral plate of hyalsea and tere-
bratula.

f The argonaut shell is compared by Mr. Adams to the nidamental cap-
sules of the whelk ; a better analogue would have been found in the raft of
the ianthina, which is secreted by the foot of the animal, and serves iv float
the egg -capsules.

STRUCTURE AND PHYSIOLOGY OF THE MOLLUSCA. 49

tion is nearly suspended, and injuries are not healed. They also
(Bstivate, or fall into a summer sleep when the heat is great ; but
in this the animal functions are much less interrupted. (Midler.)

Reproduction of lost parts. It appears from the experiments
of Spallanzani, that snails, whose ocular tentacles have been de-
stroyed, reproduce them completely in a few weeks ; others have
repeated the trial with a like result. But there is some doubt
whether the renewal takes place if the brain of the animal be
removed as well as its horns. Madame Power has made similar
observations upon various marine snails, and has found that por-
tions of the foot, mantle, and tentacles, were renewed. Mr.
Hancock states that the species of eolis are apt to make a meal
off each other's bronchia, and that, if confined in stale water,
they become sickly and lose those organs ; in both cases they are
quickly renewed under favourable circumstances.

Reproduction by gemmation. The social and compound tu-
nicaries resemble zoophytes, in the power they possess of bud-
ding out new individuals, and thus of multiplying their commu-
nities indefinitely, as the leaves on a tree. This gemmation takes
place only at particular points, so that the whole assemblages
are aggregated in characteristic patterns. The buds of the social
tunicaries are supported at first by their parents, those of the
compound families by the general circulation, until they are in a
state to contribute to the common weal.

Viviparous reproduction. This happens in a few species of
gastropods, through the retention of the eggs in the oviduct,
until the young have attained a considerable growth. It also
appears to take place in the acephalans, because their eggs gene-
rally remain within some part of the shell of the parent until
hatched.

Alternate generation. Amongst the tunicaries an example
is found of regulated diversity in the mode of reproduction. The
salpians produce long chains of embryos, which, unless broken
by accident, remain connected during life ; — each individual of
these compound specimens produces solitary young} often so im-

D

50

MANUAL OP THE MOLLUSCA.

like the parent as to have been described and named by natural-
ists as distinct species; — these solitary salpians again produce
chains of embryos, like their grand-parents. (C/iamisso.)

Oviparous reproduction. The sexes are distinct in the most
highly organised (or dioecious) mollusca ; they are united in the
(iiionwcious) land-snails, pteropods, brachiopods, tuiiicaries, and
in part of the conchifers. The prosobranchs pair; but in the
dioecious acephalans and cuttle-fishes, the spermatozoa are merely
discharged into the water, and are inhaled with the respiratory
currents by the other sex. The monoecious land-snails require
reciprocal union ; the limneids unite in succession, forming float-
ing chains.

The eggs of the land-snails are separate, and protected by a
shell, which is sometimes albuminous and flexible, at others cal-
carious and brittle; those of the fresh-water species are soft,
mucous, and transparent. The spawn of the sea-snails consists
of large numbers of eggs, adhering together in masses, or spread
out in the shape of a strap or ribbon, in which the eggs are ar-
ranged in rows ; this nidamentat ribbon is sometimes coiled up
spirally, like a watch-spring, and attached by one of its edges.

The eggs of the carnivo-
rous gasteropods are in-
closed in tough albuminous
capsules, each containing
numerous germs ; these
are deposited singly, or in
rows, or agglutinated in
groups, equalling thepareiji
animal in bulk (fig. 70).
The nidamental capsulu
of the cuttle-fish are clus-
tered like grapes, each
containing but one embryo ; those of the calamary are gron

Fig. 29. Spaivn of Doris*

Nidamental ribbon of Doris Johnstoni. (Alder and Hancock.}

nipec

I

STRUCTURE AND PHYSIOLOGY OF THE MOLLUSCA. 51

in radiating masses, each elongated capsule containing 30 or
40 ova. The material with which the eggs are thus cemented
together, or enveloped, is secreted by the nidamental gland, an
organ largely developed in the female gasteropods and cepha-
lopods (fig. 43, n).

Development. The molluscan ovum consists of a coloured
yolk (vitellus), surrounded by albumen. On one side of the yolk
is a pellucid spot, termed the germinal vesicle, having a spot or
nucleus on its surface. This germinal vesicle is a nucleated cell,
capable of producing other cells like itself; it is the essential part
of the egg, from which the embryo is formed ; but it undergoes
no change without the influence of the spermatozoa.* After im-
pregnation, the germinal vesicle, which then subsides into the
centre of the yolk, divides spontaneously into two ; and these
again divide and subdivide into smaller and still smaller globules,
each with its pellucid centre or nucleus, until the whole presents
a uniform granular appearance. The next step is the formation
of a ciliated epithelium on the surface of the embryonic mass ;
movements in the albumen become perceptible in the vicinity of
the cilia, and they increase in strength, until the embryo begins
to revolve in the surrounding fluid. f

* No instance of " partheno-genesis" is known among the moUusca ; the
most " equivocal " case on record is that related by Mr. Gaskoin. A speci-
men of helix lactea, Mull., from the South of Europe, after being two years
in his cabinet, was discovered to be still living ; and on being removed to a
plant-case it revived, and six weeks afterwards had produced twenty young
ones!

f According to the observations of Professor Loven (on certain bivalve
mollusca), the ova are excluded immediately after the inhalation of the sper-
matozoa, and apparently from their influence; but impregnation does not
take place within the ovary itself. The spermatozoa of cardium pygmaum
were distinctly seen to penetrate, in succession, the outer envelopes of the ova,
and arrive at the vitellus, when they disappeared. With respect to the " ger-
minal vesicle ;" according to Barry, it first approaches the inner surface of
the vitelline membrane, in order to receive the influence of the spermatozoa ;
it then retires to the centre of the yolk, and undergoes a series of sponta-
neous subdivisions. In M. Loven's account, it is said to "burst" and par-

D 2

f

52 MANUAL OF THE MOLLUSCA.

Up to this point nearly the same appearances are presented
by the eggs of all classes of animals, — they manifest, so far, a
complete " unity of organization." In the next stage, the de-
velopment of an organ, fringed with stronger cilia, and serving
both for locomotion and respiration, shews that the embryo is
a molluscous animal; and the changes which follow soon point
out the particular class to which it belongs. The rudimentary
head is early distinguishable, by the black eye-specks ; and the
heart, by its pulsations. The digestive and other organs are first
" sketched out," then become more distinct, and are seen to be
covered with a transparent shell. By this time the embryo is
able to move by its own muscular contractions, and to swallow
food; is is therefore " hatched," or escapes from the egg.

The embryo tunicary quits the egg in the cloacal cavity of its
parent, and is at this time provided with a swimming instrument,
like the tail of the tadpole, and with processes by which it attaches
itself as soon as it finds a suitable situation.

The young bivalves also are hatched before they leave their
parent, either in the gill cavity or in a special sac
attached to the gills (as in cyclas), or in the in-
terspaces of the external branchial laminae (as in
unio). At first they have a swimming disk, fringed
with long cilia, and armed with a slender ten-
tacular filament (Jlagellum). At a later period this
disk disappears progressively, as the labial palpi
are developed ; and they acquire a foot, and with
it the power of spinning a byssus. They now

tially dissolve, whilst the egg remains in the ovary, and before impregnation ;
it then passes to the centre of the yolk, and undergoes the changes described
by Barry, along with the yolk, whilst the nucleus of the germinal vesicle, or
some body exactly resembling it, is seen occupying a small prominence on
the surface of the vitelline membrane, until the metamorphosis of the yolk
is completed, when it disappears, in some unobserved manner, without ful-
filling any recognized purpose.

* Fig. 30. Very young fry of crenella marmorata, Forbes, highly magni-
fied ; el, disk, bordered with cilia if, fiagellum ; v v3 valves ; m, ciliated mantle.

STRUCTURE AND PHYSIOLOGY OF THE MOLLUSCA. 53

have a pair of eyes, situated near the labial tentacles (fig. 30*, e)}
which are lost at a further stage, or replaced by numerous ru-
dimentary organs placed more favourably for vision, on the bor-
der of the mantle.

Most of the aquatic gasteropoda are very minute when
hatched, and they enter life under the same form, — that which

Fig. 30 *. Try of the Mussel*

has been already referred to as permanently characteristic of the
pteropoda. (Tig. 60.)

The Pulmonifera and Cephalopoda produce large eggs, con-

* Fig. 30*. Fry of mytilus edulis, after Loven. <?, eye; <?', auditory
capsule ; 1 1, labial tentacles ; s sf, the stomach ; 6, branchiae ; h, heart ; v,
vent ; /, liver ; r, renal organ ; a, anterior adductor ; «', posterior adductor ;
/, foot. The arrows indicate the incurrent and excurrent openings ; between
which the margins of the mantle are united in the fry.

MANUAL OF THE MOLLTJSCA.

taining sufficient nutriment to support the embryo until it has
attained considerable size and development ;
thus, the newly-born cuttle-fish has a shell
half an inch long, consisting of several
layers, and the bulimus ovatus has a shell
an inch in length when hatched. (Fig. 31.)
These are said to undergo no transforma-
tion, because their larval stage is concealed
in the egg. The embryonic development
of the cuttle-fishes has not been observed ;
it is probable that they would reveal more
curious changes than occur in any other class.

The researches of John Hunter f into the embryonic condi-
tion of animals, led him to the conclusion that each stage in the
development of the highest animals corresponded to the perma-
nent form of some one of the inferior orders. This grand gene-
ralisation has since been more exactly defined and established by
a larger induction of facts, some of which we have already de-
scribed, and may now be stated thus : —

In the earliest period of existence all animals display one
uniform condition ; but after the first appearance of special de-
velopment, uniformity is only met with amongst the members of
the same primary division, and with each succeeding step it is
more and more restricted. From that first step, the members
of each primary group assume forms and pass through phases
which have no parallels, except in the division to which each
belongs. The mammal exhibits no likeness, at any period, to
the adult mollusk, the insect, or the star- fish ; but only to the

* Egg and young of bulimus ovatus, Mull, sp., Brazil, from specimens in
the collection of Hugh Cuming, Esq.

f " In his printed works the finest elements of system seem evermore to
flit before him, twice or thrice only to have been seized, and after a momentary
detention to have been again suffered to escape. At length, in the astonishing
preparations for his museum, he constructed it, for the scientific apprehension,
out of the unspoken alphabet of nature." (Coleridge?}

CLASSIFICATION. oo

ovarian stage of the invertebrata, and to more advanced stages
of the classes formed upon its own type. And so also with the
highest organized mollmca ; after their first stage they resemble
the simpler orders of their own sub- kingdom, but not those of
any other group.

These are the views of Professor Owen — the successor of
Hunter — by whom it has been most clearly shewn and stead-
fastly maintained, that the "unity of organization" manifested
by the animal world results from the design of a Supreme
Intelligence, and cannot be ascribed to the operation of a me-
chanical " law."

CHAPTER Y.
CLASSIFICATION.

THE objects of classification are, first, the convenient and intel-
ligible arrangement of the species ; * and, secondly, to afford a
summary, or condensed exposition, of all that is known respect-
ing their structure and relations.

In studying the shell -fish, we find resemblances of two
kinds. First, agreements of structure, form, and habits ; and,
secondly, resemblances of form and habits without agreement of
structure. The first are termed relations of affinity; the second
of analogy.

Affinities may be near, or remote. There is some amount of
affinity common to all animals ; but, like relationships amongst
men, they are recognized only when tolerably close. Besem-
blances of structure which subsist from a very early age are pre-
sumed to imply original relationship; they have been termed

* At least 12,000 recent, and 15,000 fossil species of molluscous animals
are known.

36 MANUAL Of1 THE MOLLUSCA.

genetic (or histological), and are of the highest importance.
Those which are superinduced at a later period, are of less con-
sequence.

Analogies. Modifications relating only to peculiar habits
are called adaptive; or teleological> from their relation to final
causes.* A second class of analogical resemblances are purely
external and illusive ; they have been termed mimetic (Strick-
land}, and, by their frequency, almost justify the notion that a
certain set of forms and colours are repeated, or represented in
every class and family. In all artificial arrangements, these mi-
metic resemblances have led to the association of widely dif-
ferent animals in the same groups. f Particular forms are also
represented geographically J and geologically, § as well as sys-
tematically.

In all attempts to characterise groups of animals, we find,
that in advancing from the smaller to the larger combinations,
many of the most obvious external features become of less avail,
and we are compelled to seek for more constant and comprehen-
sive signs in the phases of embryonic development, and the con-
dition of the circulating, respiratory, and nervous systems.

Species. All the specimens, or individuals, which are so much
alike that we may reasonably believe them to have descended
from a common stock, constitute a species. It is a particular
provision for preventing the blending of species, that hybrids are
always barren; and it is certain, in the case of shells, that a
great many kinds have not changed in form, from the tertiary

* For example, the paper nautilus, from its resemblance to carinaria, was
long supposed to be the shell of a nucleobranche, parasitically occupied by the
" ocythoe."

f E. g. Aporrhais with strombus, and ancylus with patella.

J Monoceros imbricatum and buccinum antarcticum take the place, in
South America, of our common whelk and purple, and solen gladiolus and
solen americanus of our solen siliqua and ensis.

§ The frequent recurrence of similar species in successive strata may lead
beginners to attribute too much to the influence of time and external circum-
stances ; but such impressions disappear with further experience.

CLASSIFICATION. 57

period to the present day, — a lapse of many thousand years, —
and through countless generations. When individuals of the
same brood differ in any respect, they are termed varieties ; for
example, one may be more exposed to the light, and become
brighter coloured ; or it may find more abundant food, and grow
larger than the rest. Should these peculiarities become perma-
nent at any place, or period, — should all the specimens on a
particular island or mountain, or in one sea, or geological forma-
tion, differ from those found elsewhere, — such permanent variety
is termed a race ; just as, in the human species, there are white
and coloured races. The species of some genera are less subject
to variation than others ; the nuculcE, for example, although very
numerous, are always distinguishable by good characters. Other
genera, like ammonites, terebratula, and tellina, present a most
perplexing amount of variation, resulting from age, sex, supply
of food, variety of depth, and of saltness in the water. And
further, whilst in some genera every possible variety of form
seems to have been called into existence, in others only a few,
strikingly distinct forms, are known.

Genera are groups of species, related by community of struc-
ture in all essential respects. The genera of bivalves have been
characterised by the number and position of their hinge-teeth ;
those of the spiral univalves, by the form of their apertures;
but these technical characters are only valuable so far as they
indicate differences in the animals themselves.

Families are groups of genera, which agree in some more
general characters than those which unite species into genera.
Those which we have employed are mostly modifications of the
artificial families framed ^by Lamarck, a plan which seemed more
desirable, in the present state of our knowledge, than a subdi-
vision into very numerous families, without assignable characters.

The orders and classes of mollusca have already been referred
to ; those now in use are all extremely natural.

It has been sometimes asserted that these groups are only
scientific contrivances, and do not really exist in nature ; but

D 3

MANUAL OF THE MOLLUSCA.

this is a false as well as a degrading view of the matter. The
labours of the most eminent systematists have been directed to
the discovery of the subordinate value of the characters deriv-
able from every part of the animal organization ; and, as far as
their information enabled them, they have made their systems
expressive " of all the highest facts, or generalisations, in natural
history.55 (Owen.)

M. Milne Edwards has remarked, that the actual appearance
of the animal kingdom is not like a well-regulated army, but
like the starry heavens, over which constellations of various mag-
nitude are scattered, with here and there a solitary star which
cannot be included in any neighbouring group.

This is exceedingly true ; we cannot expect our systematic
groups to have equal numerical values,* but they ought to be of
equal structural importance ; and they will thus possess a sym-
metry of order, which is superior to mere numerical regularity.

All the most philosophic naturalists have entertained a belief
that the development of animal forms has proceeded upon some
regular plan, and have directed their researches to the discovery
of that " reflection of the divine mind.55 Some have fancied
that they have discovered it in a mystic number, and have ac-
cordingly converted all the groups mi® fives. -\ We do not under-
value these speculations, yet we think it better to describe things
so far only as we know them.

Greafr difficulty has always been found in placing groups
according to their affinities. This cannot be effected in — the
way in which we are compelled to describe them — a single series ;
for each group is related to all the rest ; and if we extend the
representation of the affinities to very small groups, any arrange-

* The numerical development of groups is inversely proportional to the
bulk of the individuals composing them. ( Waterhouse.}

f The quinarians make out five molluscous classes, by excluding the tnni-
cata ; the same end would be attained in a more satisfactory manner by re-
ducing the pteropods to the rank of an order, which might be placed next to
the opistho • branches.

NOMENCLATURE. 59

merit ou a plane surface would fail, for the affinities radiate in
all directions, and the " net-work" to which Fabricius likened
them, is as insufficient a comparison as the " chain" of older
writers.*

CHAPTER VI.
NOMENCLATIVE.

THE practice of using two names — generic and specific — for
each animal, or plant, originated with Linnaeus ; therefore no
scientific names date further back than his works. In the con-
struction of these names, the Greek and Latin languages are
preferred, by the common consent of all countries.

Synonyms. It often happens that a species is named, or a
genus established, by more than one person, at different times,
and in ignorance of each other's labours. Such duplicate names
are called synonyms ; they have multiplied amazingly of late,
and are a stumbling-block and an opprobium in all branches of
natural history. f

* The quinary arrangement of the molluscous classes reminds us of the
eastern emblem of eternity — the serpent holding its tail in its mouth.
The following diagram is offered as an improved circular system : —

[FISHES.]

Di-brauchiata.

Nucleo- Tetra-

Opistho- Proso-

Aporo- ^~\1 Pulmo-

Pallio- Lamelli-

Hetero-branchiata.

[ZOOPHYTES.]

f In Pfeiffer's Monograph of the Helicidte, a family containing seventeen
genera, no less than 330 generic synonyms are enumerated; to this list, Dr.
Albers, of Berlin, has lately added another hundred of his own invention !

0 MANUAL OF THE MOLLUSCA.

One very common estuary shell rejoices in the following
variety of titles: —

Scrobicularia piperata (Gmelin sp).

Trigonella plana (Da Costa).

Mactra Listeri (Aucf).

My a Hispanica (Chemnitz).

Venus borealis (Pennant).

Lutraria compressa (Lamarck).

Arenaria plana (Megerle).

As regards specific names, the earliest ought certainly to be
adopted, — with, however, the following exceptions : —

1. MS. names; which are only admitted by courtesy.

2. Names given by writers antecedent to Linnaeus.

3. Names unaccompanied by a description or figure.

4. Barbarisms; or names involving error or absurdity, *

It is also very desirable that names having a general (Eu-
ropean) acceptation, should not be changed, on the discovery of
earlier names in obscure publications.

With respect to genera, — those who believe in their real ex-
istence, as " ideas of the creating mind," will be disposed to set
aside many random appellations, given to particular shells with-
out any clear enunciation of their characters ; and to adopt later
names, if bestowed with an accurate perception of the grounds
which entitle them to generic distinction.f

Authority for specific names. The multiplication of syno-
nyms having made it desirable to place the authority after each

* This subject was investigated, and reported upon, by a committee of the
British Association, in 1842 ; but the report was not sufficiently circulated.

f Several bad practices — against which there is, unhappily, no law —
should be strongly discountenanced. First, the employment of names already
in familiar use for other objects ; such as cidaris (the title of a well-known
genus of sea-urchins), for a group of spiral shells ; and arenaria (a property of
the botanists), for a bivalve. Secondly, the conversion of specific into generic
titles, a process which has caused endless confusion ; it has arisen out of the
vain desire of giving new designations to old and familiar objects, and thus
obtaining a questionable sort of fame.

NOMENCLATURE. 61

name, another source of evil has arisen; for several naturalists
(fancying that the genus-maker, and not the species-maker ', should
enjoy this privilege) have altered or divided almost every genus,
and placed their signatures as the authorities for names given
half a century or a century before, by LINNAEUS or BRUGUIERE.*
British naturalists have disowned this practice, and agreed to
distinguish, by the addition of " sp.," the authorities for those
specific names whose generic appellations have been changed.

Types. The type of each genus should be that species in
which the characters of its group are best exhibited, and most
evenly balanced. (Waterliouse^ It has, however, been cus-
tomary to take as the type, that species which the genus-maker
placed first on his list ; although by so doing there is risk of
adopting an aberrant form, or one which very feebly represents
the group, of which it is an obscure member.

* The authorities appended to specific names, are supposed to indicate an
amount of work done in the determination and description of the species ;
when, therefore, the real author's name is suppressed, and a spurious one
substituted, the case looks very like an attempt to obtain credit under false
pretences.

ABBREVIATIONS.

Etym., etymology. Syn., synonym. Distr., distribution.

M.S., manuscript, i. e., unpublished.

Sp., species. Brit. M., (in the) British Museum.

Distr., Norway — New Zealand ; including all intermediate seas.

Fossil, lias — chalk ; implies that the genus existed in these, and all inter-
vening strata. Chalk — • means that the genus commenced in the
chalk, and has existed ever since.

Depth ; — 50 fms. ; genus found at all depths between low-water and 50
fathoms. A fathom is six feet.

^ one-fourth the real size ; ^ magnified four times.
Lat., breadth. Long., length. Alt., height or thickness.
line., (uncia) an inch. Lin., (linea) a line, the -^ of an inch.
Mill., millimetre, the twenty-fifth part of an inch.

MANUAL OP THE MOLLUSCA.

CLASS I. CEPHALOPODA.

THE cuttle-fishes, though excluded by dealers from the list of shell-fish, are
the most remarkable, and, rightly considered, the most interesting of any ;
whilst their relatives, the nautili and ammonites, are unmatched for the sym-
metry and wondrous architecture of their pearly shells.

The principal locomotive organs of the cephalopoda, are attached to the
head, in the form of muscular arms or tentacles ;* in addition to which, many
have fins ; and all can propel themselves by the forcible expulsion of water
from their respiratory chamber.

Unlike most of the mollusca, they are symmetrical animals, having their
right and left sides equally developed ; and their shell is usually straight, or
coiled in a vertical plane. The nautilus and argonaut alone (of the living
tribes) have external shells ; the rest are termed " naked cephalopods," be-
cause the shell is internal. They have powerful jaws, acting vertically, like
the mandibles of birds ; the tongue is large and fleshy, and part of its surface
is sentient, whilst the rest is armed with recurved spines ; their eyes are large,
and placed on the sides of the head ; their senses appear to be very acute.
All are marine ; and predatory, living on shell-fish, crabs, and fishes.

The nervous system is more concentrated than in the other mollusca ;
and the brain is protected by a cartilage. The respiratory organs consist of
two or four plume-like gills, placed symmetrically on the sides of the body,
in a large branchial cavity, opening forwards on the underf side of the head ;
in the middle of this opening is placed the siphon or funnel. The sexes are
always distinct ; but the males are much less numerous than the females, and
in many species, at present unknown. They are divided into two orders, the
names of which are derived from the number of the branchitz.

ORDER I. DlBRANCHIATA, Owen.

Animal swimming ; naked. Head distinct. Eyes sessile, prominent.
Mandibles horny (PI. I., fig. 2). Arms 8 or 10, provided with suckers.
Body round or elongated, usually with a pair of fins ; branchia two, fur-

* M. Schultze compares the arms of the cephalopods" to the oral filaments of
myxine.

\ According to the established usage, we designate that the under or ventral side
of the body, on which the funnel is placed. But if the cuttle fishes are compared
with the nucleobranch.es, or the nautilus with the holostomatous gasteropods, their
external analogies seem to favour an opposite condusion.

CEPHALOPODA. 63

nished with muscular ventricles ; ink-gland always present ; parietes of the
funnel entire.

Shell internal (except in argonauta), horny or shelly, with or without
air-chambers.

The typical forms of the cuttle-fishes were well described by Aristotle, and
have been repeatedly examined by modern naturalists ; yet, until Professor
Owen demonstrated the existence of a second order of cephalopods, departing
from all the abovementioned characters, it was not clearly understood how
inseparably the organisation of the cuttle-fishes was connected with their con-
dition as swimming mollusca, breathing by two gills.

The characters which co-exist with the two gills, are the internal ru-
dimentary shell, and the substitution of other means of escape and defence,
than those which an external shell would have afforded ; viz. : powerful arms,
furnished with suckers ; the secretion of an inky fluid, with which to cloud
the water and conceal retreat ; more perfect organs of vision ; and super-
added branchial hearts, which render the circulation more vigorous.*

The suckers (antlia or acetabula), form a single or double series, on the
inner surface of the arms. Prom the margin of each cup, the muscular fibres
converge to the centre, where they leave a circular cavity, occupied by a soft
caruncle, rising from it like the piston of a syringe, and capable of retraction
when the sucker is applied to any surface. So perfect is this mechanism for
effecting adhesion, that while the muscular fibres continue retracted, it is
easier to tear away the limb than to detach it from its hold.f In the decapods,
the base of the piston is surrounded by a horny dentated hoop ; which in the
uncinated calamaries, is folded, and produced into a long sharp claw.

The ink-bag (fig. 33), is tough and fibrous, with a thin silvery outer
coat ; it discharges its contents through a duct which opens near the base of
the funnel. The ink was formerly used for writing (Cicero), and in the pre-
paration of sepia ;% and from its indestructible nature, is often found in a
fossil state.

* In a few species, which have no fins, the arms are webbed. In the only kind
which has an external shell, it is confined to the female sex, and is secreted by the
membranes of the arms. It is now quite certain that such shells as those of the fossil
ammonites and orthocerata. would be incompatible with dibranchiate organization.

t " The complex, irritable mechanism, of all these suckers, is under the complete
control of the animal. Mr. Eroderip informs me that he has attempted, with a hand-
net, to catch an octopus that was floating by, with its long and flexible arms entwined
round a fish, which it was tearing with its sharp hawk's bill ; it allowed the net to ap-
proach within a short distance before it relinquished its prey, when, in an instant, it
relaxed its thousand suckers, exploded its inky ammunition, and rapidly retreated
under cover of the cloud which it had occasioned, by rapid and vigorous strokes of its
circular web." (Owen.)

J Indian ink and sepia are now made of lam :-smoke, or of prepared charcoal.

64 MANUAL OF THE MOLLUSCA.

The skin of the naked cephalopods is remarkable for its variously coloured
vesicles, or pigment-cells. In sepia they are black and brown ; in the calamary,
yellow, red, and brown ; and in the argonaut, and some octopods, there are
blue cells besides. These cells alternately contract and expand, by which the
colouring matter is condensed or dispersed, or perhaps driven into the deeper
part of the skin. The colour accumulates, like a blush, when the skin is irri-
tated, even several hours after separation from the body. During life, these
changes are under the control of the animal, and give it the power of chang-
ing its hue, like the chameleon. In fresh specimens, the sclerotic plates of
the eyes have a pearly lustre ; they are sometimes preserved in a fossil state.

The aquiferous pores are situated on the back and sides of the head, on
the arms (drackial), or at their bases (buccal pores).

The mantle is usually connected with the back of the head by a broad
("nuchal") muscular band; but its margin is sometimes free all round, and
it is supported only by cartilaginous ridges, fitting into corresponding grooves,*
and allowing considerable freedom of motion.

The cuttle-fishes are nocturnal, or crepuscular animals, concealing them-
selves during the day, or retiring to a lower region of the water. They in-
habit every zone, and are met with equally near the shore, and in the open
sea, hundreds of miles from land. They attain occasionally a much greater
size than any other mollusca. MM. Q,uoy and Gaimard found a dead cuttle-
fish in the Atlantic, under the equator, which must have weighed 2 cwt. when
perfect ; it was floating on the surface, and was partly devoured by birds.
Banks and Solander, also met with one under similar circumstances, in the
Pacific, which was estimated to have measured six feet in length. (Owen.)
The arms of the octopods are sometimes two feet long.f From their habits,
it is difficult to capture some species alive, but they are frequently obtained,
uninjured, from the stomachs of dolphins, and other fishes which prey upon
them.

SECTION A. OCTOPODA.

Arms 8 ; suckers sessile. Eyes fixed, incapable of rotation. Body
united to the head by a broad cervical band. Branchial chamber divided
longitudinally by a muscular] partition. Oviduct double ; no distinct nida-
mental gland. Shell external and one-celled (mono-thalamous)> or internal
and rudimentary.

The Octopods differ from the typical cuttle-fishes in having only eight
arms, without the addition of tentacles ; their bodies are round, and they sel-

* Termed the "apparatus of resistance," by D'Orbigny.

t Denys Montfort, having represented a " kraken octopod," in the act of scuttling
a three-master, told M. Defrance, that if this were " swallowed," he would in his next
edition represent the monster embracing the Straits of Gibraltar, or capsizing a whole
squadron of ships. (D'Orbigny.)

CEPHALOPODA. 65

clora have fins. They are the most eccentric or " aberrant" mollusks, supe-
rior in organization to all the rest, but manifesting some remarkable and
unexpected analogies with the lowest classes of animals.

The males of some species of octopus and eledone, are similar to the fe-
males, but are comparatively scarce. Only the females of many others are
known, and every specimen of the argonaut hitherto examined (amounting to
many hundreds), has been of that sex. Dr. Albert Kolliker has suggested
that the real males of the argonaut, and also of octopus granulatus and
tremoctopus viol-acmes are the hectocotyles, previously mistaken for parasitic
worms.

The hectocotyle of octopus granulatus was described by Cuvier,* who ob-
tained several specimens from octopods captured in the Mediterranean. It is
five inches in length, and resembles a detached arm of the octopus, its under
surface being bordered with 40 or 50 pairs of alternate suckers.

The hectocotyle of tremoctopus was discovered by Dr. Kolliker, at Messina,
in 1842, adhering to the interior of the gill-chamber and funnel of the
poulpe ; it is represented in PL I., fig. 3. The body is worm-like, with two
rows of suckers on the ventral surface, and an oval appendage at the posterior
end. The anterior part of the back is fringed with a double series of bran-
chial filaments (250 on each side). Between the branchiae are two rows of
brown or violet spots, like the pigment cells of the tremoctopus. The suckers
(40 on each side) closely resemble those of the tremoctopus, in miniature.
Between the suckers are four or five series of pores, the openings of minute
canals, passing into the abdominal cavity. The mouth is at the anterior
extremity, and is minute and simple; the alimentary canal runs straight
through the body, nearly filling it. The heart is in the middle of the back,
between the branchiae ; it consists of an auricle and a ventricle, arid gives
origin to two large vessels. There is also an artery and vein on each side,
giving branches to the branchial filaments. A nerve extends along the in-
testine, and one ganglion has been observed. The oval sac incloses a small
but very long convoluted tube, ending in a muscular vas deferens ; it contains
innumerable spermatozoa.

The hectocotyle of the argonaut was discovered by Chiaje, who considered
it a parasitic worm, and described it under the name of trichocephalus aceta-
bularis ; it was again described by Costa,^ who regarded it as " a spermato-
phore of singular shape ;" and lastly by Dr. Kolliker 4

Tt is similar in form to the others, but is only seven lines in length, and
has a filiform appendage in front, six lines long. It has two rows of alternate

* An. Sc. Nat. 1 Series, t. 18. p. 147. 1829.
t An. Sc. Nat. 2 Series, 7. p. 173.

t Lin. Trans. Vol. 20, pt. 1, p. 9; and in his own zootoraical berichte, where it is
figured.

66 MANUAL OF THE MOLLUSCA.

slickers, 45 on each side ; but no branchia ; the skin contains numerous
changeable spots of red or violet, like that of the argonaut.*

According to the observations of Madame Power, " the newly hatched
argonaut has no shell, and is quite unlike what it afterwards becomes ; it is a
sort of little worm, having two rows of suckers along its length, with a fili-
form appendage at one extremity, and a small swelling at the other. It might
be supposed to represent an extremely small bmchial appendage, from which
the other parts were afterwards to be developed."! (Kolliker.)
FAMILY I. AllGONAUTID^E.

Dorsal arms (of the fern ale> webbed at the extremity, secreting a symme-
trical involuted shell. Mantle supported in front by a single ridge on the
funnel.

Genus AKGONAUTA, Lin. Argonaut or paper sailor.

Etymology., argonautai, sailors of the ship Argo.

Synonyms, ocythoe (Rafinesque). Nautilus (Aristotle and Pliny).

Example, A. hians, Soland, pi. II., fig. 1. China.

Fig. 32. Arg^naufa argo L. swimming .t
The shell of the argonaut is thin and translucent ; it is not moulded on
the body of the animal, nor is it attached by shell-muscles ; and the unoccu-
pied hollow of the spire serves as a receptacle for the minute clustered eggs.
The argonaut sits in its boat with its siphon turned towards the keel, § and its
sail-shaped (dorsal) arms closely applied to the sides of the shell, as in fig. 32,
where, however, they are represented as partially withdrawn, in order to show
the margin of the aperture. It swims only by ejecting water from its fun-

* Similar instances of a permanently rudimentary condition of the male sex, oc-
cur amongst the lowest organized parasitic crustaceans; the males of achtheres, ler-
nceopoda, tracheliaster, fyc., are frequently a thousand times smaller than the female,
upon whom they live, and from whom they differ both in form and structure.
Gosse has described a similar disparity of the sexes in asplanchna.

t An. Sc. Nat. 2 Series, vol. 16, p. 185.

t From a copy of Rang's figure, in Charlesworth's Magazine; one-fourth the na-
tural size ; the small arrow indicates the current from the funnel, the large arrow th ;
direction in which the " sailor" is driven by the recoil.

§ Poli has represented it sitting the opposite way ; the writer had once an argonaut
shell with the nucleus reversed, implying that the animal had turned quite round in it>
shell, and remained in that position. The specimen is now in the York Museum.

.V

CEPHALOPODA. 67

nel, and crawls in a reversed position, carrying its shell over its back like a
snail. (Madame Power and M. Jiang.)

It was the nautilus (primus) of Aristotle, who described it as floating on
the surface of the sea, in fine weather, and holding out its sail- shaped arms to
the breeze ; a pretty fable, which poets have repeated ever since.

Distribution : 4 species of argonaut are known ; they inhabit the open sea
throughout the warmer parts of the world. Captain King took several from
the stomach of a dolphin, caught upwards of 600 leagues from any land.

Fossil : A. hians is found in the sub-apennine tertiaries of Piedmont. This
species is still living in the Chinese seas, but not in the Mediterranean.

FAMILY II. OCTOPODHXE.

Arms similar, elongated, united at the base by a web. Shell represented
by two short styles, encysted in the substance of the mantle. (Owen.)

OCTOPUS, Cuvier. Poulpe.

Etym., octo, eight, pous (poda) feet.

Syn., cistofjus. (Gray.)

Ex., 0. tuberculatus Bl., pi. I., figs. 1 and 2 (mandibles).

Body oval, warty or cirrose, without fins ; arms long, unequal ; suckers
in two rows ; mantle supported in front by the branchial septum.

The octopods are the "polypi" of Homer and Aristotle; they are solitary
animals, frequenting rocky shores, and are very active and voracious ; the
females oviposit on sea-weeds, or in the cavities of empty shells. In the
markets of Smyrna and Naples, and the bazaars of India, they are regularly
exposed for sale. "Although common (at St. Jago) in the pools of water left
by the retiring tide, they are not very easily caught. By means of their long
arms and suckers they can drag their bodies into very narrow crevices, and
when thus fixed it requires great force to remove them. At other times they
dart tail first, with the rapidity of an arrow, from one side of the pool to the
other, at the same instant discolouring the water with a dark chesnut-brown
ink. They also escape detection by varying their tints, according to the nature
of the ground over which they pass. In the dark they are slightly phospho-
rescent." (Darwin)*

Professor E. Forbes has observed that the octopus, when resting, coils its
dorsal arms over its back, and seems to shadow forth the argonaut's shell.

Distr., universally found on the coasts of the temperate and tropical zones ;
46 species are known ; when adult they vary in length from 1 inch to 2 feet,
according to the species.

PINNOCTOPUS, D'Orb. Finned octopus.
Body with lateral fins, united behind.

* Journal of a Voyage round the "World. The most fascinating volume of travels
published since Defoe's fiction.

MANUAL OF THE MOLLUSCA.

The only known species, P. cordiformis, was discovered by MM. Quoy
and Gaimard, on the coast of New Zealand; it exceeds 3 feet in length.

ELEDONE. (Aristotle.) Leach.
Type, E. octopodia, L.

Suckers forming a single series on each arm ; length 6 to 18 inches. E.
moschata emits a musky smell.

Distr., 2 sp. Coasts of Norway, Britain, and the Mediterranean.

CIRROTEUTHIS, Eschricht. 1836.

Etym., cirrus, a filament, and teuthis a cuttle-fish.

Body with two transverse fins ; arms united by a web, nearly to their
tips; suckers in a single row, alternating with cirri. Length 10 inches.
Colour violet. The only species (C. Mullen Esch.} inhabits the coast of
Greenland.

PHILONEXIS, D'Orb.

Etym., philos, an adept in nexis, swimming.

Type, P. atlanticus, D'Orb.

Arms free ; suckers in two rows ; mantle supported by two ridges on the
funnel. Total length, 1 to 3 inches.

Distr., 6 sp. Atlantic and Medit. Gregarious in the open sea ; feeding
on floating mollusca.

Sub-genus. Tremoctopus (Chiaje), pi. I., fig. 3.

Name from two large aquiferous pores (tremata) on the back of the head.
Arms partly, or all webbed half-way up.
Distr., 2 sp. T. quoyanus and violaceus. Atlantic and Medit.

SECTION B. DECAPODA.

Arms 8. Tentacles 2, elongated, cylindrical, with expanded ends. Suckers
pedun culated, armed with a horny ring. Mouth surrounded by a buccal
membrane, sometimes lobed and funished with suckers. Eyes moveable in
their orbits. Body oblong or elongated, always provided with a pair of fins.
Funnel usually furnished with an internal valve. Oviduct single. Nidamental
gland largely developed. Shell internal ; lodged loosely in the middle of the
dorsal aspect of the mantle.

The arms of the decapods are comparatively shorter than those of the
octopods ; the dorsal pair is usually shortest, the ventral longest. The tenta-
cles originate within the circle of the arms, between the third and fourth pairs;
they are usually much longer than the arms, and in cheiroteuthis are six times
as long as the animal itself. They are completely retractile into large sub-
ocular pouches in sepia, sepiola, and rossia ; partly retractile in loligo and
sepioteuth'is ; non -retractile in cheiroteuthis. They serve to seize prey which
may be beyond the reach of the ordinary arms, or to moor the animal in
safety during the agitation of a stormy sea.

CEPHALOPODA. 69

The shell of the living decapods is either a horny "pen" (gladius) or a
calcarious "bone" (sepion)-, not attached to the animal by muscles, but so
loose as to fall out when the cyst which contains it is opened. In the genus
spirula, it is a delicate spiral tube, divided into air-chambers by a series of
partitions (septa}. In the fossil genus spirulirostra, a similar shell forms the
apex of a cuttle-bone ; in the fossil conoleuthis a chambered shell is combined
with a pen ; and the belemnite unites all these modifications.

The decapods chiefly frequent the open sea, appearing periodically like
fishes, in great shoals, on the coasts and banks. (Owen, D'Orb.)

FAMILY III. TEUTHID2E. CALAMAKIES, OR SQUIDS.
Body, elongated ; fins short, broad, and mostly terminal.
Shell, (gladius or pen) horny, consisting of three parts, — a shaft, and two
lateral expansions or wings.

Sub-family A. Myopsida, D'Orb. Eyes covered by the skin.

LOLIGO. (Pliny) Lamarck. Calamary.

Syn., teuthis (Aristotle) Gray.

Type, L. vulgaris (sepia loligo L.) Fig. 1. PI. I., fig. 6 (pen).

fen, lanceolate, with the shaft produced in front ; it is multiplied by age,
several being found packed closely, one behind another, in old specimens.
(Owen. )

Body tapering behind, much elongated in the males. Tins terminal,
united, rhombic. Mantle supported by a cervical ridge, and by two grooves
in the base of the funnel. Suckers in two rows, with horny, dentated hoops.
Tentacular club with four rows of suckers. Length (excluding tentacles)
from 3 inches to 2| feet.

The calamaries are good swimmers ; they also crawl, head-downwards, on
their oral disk. The common species is used for bait, by fishermen, on the
Cornish coast (Couch). Shells have been found in its stomach, and more
rarely sea-weed (Dr. Johnston). Their egg-clusters have been estimated to
contain nearly 40,000 eggs (Bohadsch).

Distr., 21 sp. in all seas. Norway — New Zealand.

Sub-genus. Teudopsis, Deslongchamps, ]835.
Etym., teuthis, a calamary and opsis like.
Type, T. Bunellii, Desl.

Pen, like loligo, but dilated and spatulate behind.
Fossil, 5 sp. Upper Lias, France, and Wurtemberg.

GONATUS, Gray.

Animal an&pen like loligo in most respects. Arms with 4 series of cups,,
tentacular club with numerous small cups, and a single large sessile cup
armed with a hook ; funnel valveless.

70 MANUAL OF THE MOLLUSCA.

Distr., a single species (G. amana, Holier sp.) is found on the coast o
Greenland.

SEPIOTEUTHIS, Blainville.

Type, S. sepio'idea, Bl. Animal like loligo ; fins lateral, as long as th(
body. Length from 4 inches to 3 feet.

Distr. > 13 sp., West Indies, Cape, Ked Sea, Java, Australia.

BELOTEUTHIS, Minister.

Efym.., belos, a dart and teuthis.

Type, B. subcostata, Miinst. PL IT., fig. 8., LT. Lias, Wurtemberg.

Pen, horny, lanceolate ; with a very broad shaft, pointed at each end
and small lateral wings.

Distr., 6 sp. described by Miinster, considered varieties (differing in ag(
and sex), by M. D'Orbigny.

GEOTEUTHIS, Miinster.

Etym., ge, the earth (i. e. fossil) and teuthis.

Syn., belemnosepia (Agassiz.) belopeltis (Yoltz) loligosepia (Quenstedt.)*

Pen broad, pointed behind ; shaft broad, truncated in front ; lateral wing.'
shorter than the shaft.

Fossil, 9 sp. U. Lias, Wurtemberg ; Calvados ; Lyme Regis. Severa
undescribed sp. in the Oxf. clay, Chippenharn.

Besides the pens of this calamary the ink-bag, the muscular mantle, anc
the bases of the arms, are preserved in the Oxford clay. Some of the ink-
bags found in the Lias are nearly a foot in length, and are invested with f.
brilliant nacreous layer ; the ink forms excellent sepia. It is difficult to un-
derstand how these were preserved, as the recent calamaries " spill their ink"
on the slightest alarm. (Buckland}.

LEPTOTEIJTHIS, Meyer.

Etym., Leptos thin, and teuthis.

Type, L. gigas Meyer, Oxford clay, Solenhofen.

Pen very broad and rounded in front, pointed behind; with obscure diverg-
ing ribs.

CRANCHIA, Leach, 1817.

Named in honour of Mr. J. Cranch, naturalist to the Congo expedition.

Type, C. scabra, Leach.

Body large, ventricose ; fins small, terminal ; mantle supported in fronl
by a branchial septum. Length 2 inches. Head very small. Eyes fixed
Buccal membrane large, 8-lobed. Arms short, suckers in two rows. Tenta-
cular clubs finned behind, cups in 4 rows. Funnel valved.

Pen long and narrow.

* These names must be set aside, being incorrect in themselves, and founded or
a total misapprehension of the nature of the fossils.

CEPHALOPODA. 7 1

Distr., 2 sp. W. Africa. In the open sea.

This genus makes the nearest approach to the octopods.

SEPIOLA. (Rondelet) Leach, 181?.

Ex., S. atlantica (D'Orb.) PL I., fig. 4.

Body short, purse-like ; mantle supported by a broad cervical band, and a
ridge fitting a groove in the funnel. Fins dorsal, rounded, contracted at the
base. Suckers in 2 rows, or crowded, on the arms, in 4 rows on the tentacles.
Length 2 to 4 inches.

Pen, half as long as the back. S. stenodactyla (sepioloidea, D'Orb.) has
no pen.

Distr., 6 sp. Coasts of Norway, Britain, Medit., Mauritius, Japan,
Australia.

Sub-genus. Rossia, Owen (Fidenas? Gray). Mantle supported by a
cervical ridge and groove. Suckers in 2 rows on the tentacles. Length 3
to 5 inches.

Distr., 6 sp. Regent Inlet, Britain, Medit., Manilla.

Sub-family B. Oigopsida, D'Orb.
Eyes naked. Fins always terminal, and united, forming a rhomb.

LOLIGOPSIS, Lam. 1811.
Etym., loligo, and opsis, like.
Type, L. pavo (Lesueur).

Body elongated, mantle supported in front by a branchial septum. Arms
short. Cups in 2 rows. Tentacles slender, often mutilated. Funnel valveless.
Pen slender, with a minute conical appendix. Length from 6 to 12 inches.
Distr., pelagic. 8 sp. N. Sea, Atlantic, Medit., India, Japan, S. Sea.

CHEIROTEUTHIS, D'Orb.

Etym., cheir, the hand, and teuthis.

Type, C. veranii, Per.

Mantle supported in front by ridges. Funnel valveless. Ventral arms
very long. Tentacles extremely elongated, slender, with distant sessile cups
on the peduncles, and 4 rows of pedunculated claws on their expanded ends.

Pen slender, slightly winged at each end. Length of the body 2 inches ;
to the tips of the arms 8 inches ; to the ends ot the tentacles 3 feet.

Distr., 2 sp. Atlantic, Medit. On gulf-weed, in the open sea.

HISTIOTEUTHIS, D'Orb.

Etym., histion, a veil ; and teuthis.

Type, H. bonelliana, Fer. Length 16 inches.

Body short. Fins terminal, rounded. Mantle supported in front by
ridges and grooves. Buccal membrane 6-lobed. Arms (except the ventral
pair), webbed high up. Tentacles long, outside the web, with 6 rows of den-
tated cups on their ends.

72 MANUAL OF THE MOLLUSCA.

Pen short and broad.

Distr., 2 sp. Mediterranean ; in the open sea.

ONYCHOTEUTHIS, Lichtenstein. Uncinated calamary.

Etym., onyx, a claw, and teuthis.

Type, 0. banksii, Leach. ( = bartlingii?) PI. I., fig. 7 and fig. 8 i

Syn., ancistroteuthis (Gray). Onychia (Lesueur).

Pen narrow, with hollow, conical apex.

Arms with 2 rows of suckers. Tentacles long and powerful, armed with
a double series of hooks ; and usually having a small group of suckers at the
base of each club, which they are supposed to unite, and thus use their tenta-
cles in conjunction.* Length 4 inches to 2 feet.

The unciuated calamaries are solitary animals, frequenting the open sea,
and especially the banks of gulf- weed (sargasso). O. banksii ranges from
Norway to the Cape and Indian ocean ; the rest are confined to warm seas.
0. dussumieri has been taken swimming in the open sea, 200 leagues north
of the Mauritius.

Distr., 6 sp. Atlantic, Indian ocean, Pacific.

ENOPLOTEUTHIS, D'Orb. Armed calamary.

Etym., enoplos, armed, and teuthis.

Type, E. smithii, Leach.

Syn., ancistrochirus and abralia (Gray), octopodoteuthis (Ruppell), verani;
(Krohn).

Pen lanceolate. Arms provided with a double series of horny hooks, con
cealed by retractile webs. Tentacles long and feeble, with small hooks at th<
end. Length (excluding the tentacles) from 2 inches to 1 foot ; but somi
species attain a larger size. In the museum of the College of Surgeons then
is an arm of the specimen of E. unguiculata, found by Banks and Solander ii
Cook's first voyage (mentioned at p. 64) supposed to have been 6 feet lon<
when perfect. The natives of the Polynesian Islands, who dive for shell-fish
have a well-founded dread of these formidable creatures. {Owen.)

Distr., 10 sp. Medit., Pacific.

OMMASTREPHES, D'Orb. Sagittated calamary.

Etym., omma, the eyes, and strepho, to turn.

Type, 0. sagittatus, Lam.

Body cylindrical ; terminal fins large and rhombic. Arms with 2 rows o
suckers, and sometimes an internal membranous fringe. Tentacles short am
strong, with 4 rows of cups.

Pen, consisting of a shaft with three diverging ribs, and a hollow conies
appendix. Length from 1 inch to nearly 4 feet.

* The obstetric forceps of Professor Simpson were suggested by the suckers of th
calamary.

CEPHALOPODA. 73

The sagittated calamaries are gregarious, and frequent the open sea in all
climates. They are extensively used in the cod-fishery off Newfoundland, and
are the principal food of the dolphins and cachalots, as well as of the albatross
and larger petrels. The sailors call them " sea-arrows" or "flying squids,"
from their habit of leaping out of the water, often to such a height as to fall
on the decks of vessels. They leave their eggs in long clusters floating at the
surface.

Distr., 14 recent sp. ; similar pens (4 sp.) have been found fossil in the
Oxford clay, Solenhofen ; it may, however, be doubted whether they are ge-
nerically identical.

FAMILY IV. BELEMNITID^.

Shell consisting of a pen, terminating posteriorly in a chambered cone,
sometimes invested with a fibrous guard. The air-cells of the phragmo-cone
are connected by a tiphuncle, close to the ventral side.

BELEMNITES, Lamarck. 1801.

Etym., belemnon> a dart.*

Ex., B. puzosianus, pi. II., fig. 5.

Phragmocone horny, slightly nacreous, with a minute globular nucleus at
its apex ; divided internally by numerous concave septa. Pen represented by
two nacreous bands on the dorsal side of the phragmocone, and produced be-
yond its rim, in the form of sword-shaped processes (pi. II., fig. 5).f Guard,
fibrous, often elongated and cylindrical ; becoming very thin in front, where
it invests the phragmocone. J

Nearly 100 species of belemnites have been found in a fossil state, ranging
from the lias to the gault, and distributed over all Europe. The phragmocone
of the belemnite, which represents the terminal appendix of the calamaries, is

* The termination lies (from lithos, a stone) was formerly given to all fossil genera.
t The most perfect specimens known are in the cabinet of Dr. Mantell, and the
British Museum ; they were obtained by William Buy in the Oxford clay of Christian
Malford, Wilts. The last chamber of a lias belemnite in the British Museum is 6
ncheslong, and 2£ inches across at the smaller end; a fracture near the siphuncle
shows the ink-bag. The phragmocone of a specimen corresponding to this in size,
measures 7^ inches in length.

t The specific gravity of the guard is identical with that of the shell of the recent
sinna, and its structure is the same. Parkinson and others have supposed that it was
jriginally a light and porous structure, like the cuttle bone; but the inucro of the
iepiostaire, with which alone it is homologous, is quite as dense as the belemnite. We
ire indebted to Mr. Alex. Williams, M.R.C.S., for the following specific gravities of
recent and fossil shells, compared with water as 1,000 :—

Belernnites puzosianus, Oxford clay 2,674

Belemnitella mucronata, chalk 2,677

Pinna, recent, from the Mediterranean 2,607

Trichites plottii, from the inferior oolite 2,670

Conus monile, recent 2,910

Conus ponderosus, Miocene, Touraine 2,713

E

74 MANUAL OP THE MOLLUSCA.

divided into air-chambers, connected by a small tube (siphuncle), like the shel
of the pearly nautilus. It is exceedingly delicate, and usually owes its preser
tioii to the infiltration of calc. spar ; specimens frequently occur in the lias
with the meniscus-shaped casts of the air-chambers loose, like a pile of watch,
arlasses. It is usually eccentric, its apex being nearest to the ventral side o:
the guard. The guard is very variable in its proportions, being sometimes
only half an inch longer than the phragmocone, at others one or two feet ii
length. These variations probably depend to some extent on age and sex
M. D'Orbigny believes that the shells of the males are always (comparatively)
long and slender ; those of the females are at first short, but afterwards grow-
ing only at the points, they become as long in proportion as the others. Thjt
guard always exhibits (internally) concentric lines of growth; in B. irregularu.
its apex is hollow. The belemnites have been divided into groups by the pre-
sence aud position of furrows in the surface of the guard.

SECTION I. ACCELI (Bronn.) without dorsal or ventral grooves.
Sub-section 1. Acuarii, without lateral furrows, but often channelled at
the extreme point.

Type., b. acuarius. 20 sp. Lias — Neocomian.
Sub-section 2. Clavati, with lateral furrows.
Type, b. clavatus. 3 sp. Lias.

SECTION II. GASTJIOCCELI (D'Orb.) Ventral groove distinct.
Sub-section 1. Canaliculati, no lateral furrows.
Type, b. canaliculatus. 5 sp. Inf. oolite — Gt. oolite.
Sub-section 2. Hastati, lateral furrows distinct.
Type, b. hastatus. 19 sp. U. lias — Gault.

SECTION III. NOTOCCELI (D'Orb.) with a dorsal groove, and fir
each side.

Type, b. dilatatus. 9 sp. Neocomian.

The belemnites appear to have been gregarious, from the exceeding abuiul-
ance of their remains in many localities, as in some of the marlstone quarrie-
of the central counties, and the lias cliffs of Dorsetshire. It is also probabL
that they lived in a moderate depth of water, and preferred a muddy bottom
to rocks or coral-reefs, with which they would be apt to come in perilous col-
lision. Belemnites injured in the life-time of the animal have been frequently
noticed.

BELEMNITELLA, D'Orb.

Syn., actinocamax, Miller (founded on a mistake.)

Type, B. mucronata, Sby. PL II., fig. 6.

Distr., Europe; N. America. 5 sp. U. greensand and chalk.

The guard of the belemnitella has a straight fissure on the ventral side < I
its alveolar border ; its surface exhibits distinct vascular impressions. The

CEPHALOPODA.

75

phragmocone is never preserved, but casts of the alveolus show that it was
chambered, that it had a single dorsal ridge, a ventral process passing into the
fissure of the guard, and an apical nucleus.

ACANTHOTEUTHIS (Wagner), Munster.

Etym., acantha, a spine, and teuthis.

Syn., Keleeno (Munster.) Belemnoteuthis?

Type, A. prisca, Ruppell.

Founded on the fossil hooks of a calamary, preserved in the Oxford clay
of Solenhofen. These show that the animal had 10, nearly equal arms, all
furnished with a double series of horny claws, throughout their length. A
pen like that of the ommastrephes has been hypothetical^ ascribed to these
arms, which may, however, have belonged to the belemnite or the belemno-
teathis.

BELEMNOTEUTHIS (Miller), Pearce, 1842.

Type, B. antiquus (Ounuington), fig. 33.

Shell consisting of a phragmocone, like
that of the belemnite ; a horny dorsal pen
with obscure lateral bands ; and a thin
fibrous guard, with two diverging ridges on
the dorsal side.

Animal provided with arms and tenta-
cles of nearly equal length, furnished with
a double alternating series of horny hooks,
from. 20 to 40 pairs on each arm ; mantle
free all round ; fins large, medio- dorsal
(much larger than in fig. 33).

Fossil in the Oxford clay of Chippen-
ham. Similar horny claws have been found
in the lias of Watchett; and a guard equally
thin is figured in Buckland's Bridgewater
Treatise, t. 44, fig. 14.

In the fossil calamary of Chippenham,
the shell is preserved along with the mus-
cular mantle, fins, ink-bag, 'funnel, eyes,
and tentacles with their horny hooks ; all
the specimens were discovered, and deve-
loped with, unexampled skill, by William

Buy, of Sutton, near Chippenham.

Fig. 33. BelKmnoteuthis*

* Fig. 33. Belemnoteuthis antiquus, £, ventral side, from a specimen in the cabinet
of William Cunnington, Esq., of Devizes. .The last chamber of 'the phragmocone is
preserved in this specimen, a, represents the dorsal side of an uncompressed phrag-
mocone from the Kelloway rock, in the cabinet of J. G. Lowe, Esq. ; c, is an ideal sec-
tion of the same. Since this woodcut was executed, a more complete specimen has

fO MANUAL OF THE MOLLUSCA.

CONOTEIJTHIS, D'Orb.

Type, C. Dupinianus, D'Orb. PI. II., fig. 9. Neocomian, France.
Phragmocone slightly curved. Pen elongated, very slender.
This shell, which is like the pen of an ommastrephe, with a chambered
cone, connects the ordinary calamaries with the belenmites.

FAMILY V. SEPIADJS.

Shell (cuttle-bone or seplostaire) calcarious ; consisting of a broad lami-
nated plate, terminating behind in a hollow, imperfectly chambered apex
{mucro). Animal with elongated tentacles, expanded at their ends.

SEPIA (Pliny), Linnseus.

Type, S. officinalis, L. PL I., fig. 5.

Syn., belosepia, Voltz. (B. sepio'idea, pi. II., fig. 3, mucro only.)

Body oblong, with lateral fins as long as itself. Arms with 4 rows oi
suckers. Mantle supported by tubercles fitting into sockets on the neck and
funnel. Length 3 to 28 inches.

Shell as wide and long as the body; very thick in front, concave internally
behind ; terminating in a prominent mucro. The thickened part is composed
of numerous plates, separated by vertical fibres, which render it very light and
porous. T. Orbignyana, pi. II., fig. 2.

The cuttle-bone was formerly employed as an antacid by apothecaries ; it
is now only used as "pounce," or in casting counterfeits. The bone of *
Chinese species attains the length of 1| feet. (Adams.)

The cuttle-fishes live near shore, and the mucro of their shell seems in-
tended to protect them in the frequent collisions they are exposed to in swim-
ming backwards. (D'Orb.}

Distr., 30 sp. World-wide.

Fossil, 5 sp. Oxf. clay, Solenhofen. Several species have been foun
on mucrones from the Eocene of London and Paris. PI. II., fig. 3.

SFIRULIROSTRA, D'Orb.

Type, S. BeUardii (D'Orb.) PL II., fig. 4. Miocene, Turin.

Shell, mucro only known ; chambered internally ; chambers connected
by a ventral siphuncle ; external spathose layer produced beyond the phrag •
mocone into a long pointed beak.

BELOPTERA (Blainville) Deshayes.
Etym., belos, a dart, and pteron, a wing.
Type, B. belemnitoides, Bl. PL II., fig. 7.

been obtained for the British Museum ; the tentacles are not longer than the ordinar /
arms, owing, perhaps, to their partial retraction ; this specimen will be figured in D)
Mantell's "Petrifactions and their Teachings." d, is a single hook, natural size; tha
specimens belonging to Mr. Cunnington and the late Mr. C. Pearce, show the largs
acetabular bases of the hooks.

CEPHALOPODA. 77

Shell, mucro (only known) chambered and siplmncled; winged externally.
Fossil, 2 sp. Eocene. Paris ; Bracklesham

BELEMNOSIS, Edwards.

Type, B. anomalus, Sby. sp. Eocene. Highgate (unique.)
Shell, mucro, chambered and siphuncled ; without lateral wings or elon-
gated beak.

FAMILY VI. SPIRULHLE.

Shell entirely nacreous ; discoidal ; whirls separate, chambered (potytkala-
mous^) with a ventral siphuncle.

SPIRULA, Lam., 1801.

Syn., h'tuus, Gray.

Ex., S. leevis (Gray.) PI. I., fig. 9.

Body oblong, with minute terminal fins. Mantle supported by a cervical
and 2 ventral ridges and grooves. Arms with 6 rows of very minute cups
Tentacles elongated. Funnel valved.

Shell placed vertically in the posterior part of the body, with the involute
spire towards the ventral side. The last chamber is not larger in proportion
than the rest ; its margin is organically connected ; it contains the ink-bag.

The delicate shell of the spirula is scattered by thousands on the shores of
New Zealand ; it abounds on the Atlantic coasts, and a few specimens are
yearly brought by the Gulf- stream, and strewed upon the shores of Devon and
Cornwall. But the animal is only known by a few fragments, and one perfect
specimen, obtained by Mr. Percy Earl on the coast of New Zealand.

Distr., 3 sp. All the warmer seas.

ORDER II. TETRABRANCHIATA.

Animal creeping ; protected by an external shell.

Head retractile within the mantle. Eyes pedunculated. Mandibles cal-
carious. Arms very numerous. Body attached to the shell by adductor mus-
cles, and by a continuous horny girdle. Branchiae four. Funnel formed by
the folding of a muscular lobe.

Shell external, camerated (poly-thalamous) and siphuncled; the inner
layers and septa nacreous ; outer layers porcellanous.*

It was long ago remarked by Dillwynn, that shells of the carnivorous gas-
teropods were almost, or altogether, wanting in the palseozoic and secondary
strata ; and that the office of these animals appeared to have been performed,
in the ancient seas, by an order of cephalopods, now nearly extinct. Above
1,400 fossil species belonging to this order are now known by their
shells ; whilst their only living representative is the nautilus pompilius,

* The Chinese carve a variety of patterns in the outer opaque layer of the nautilus
shell, relieved by the pearly ground beneath.

78

MANUAL OP THE MOLLT7SCA.

of which several specimens have been brought to Europe within the last few
years.*

The shell of the tetrabranchiate cephalopods is an extremely elongated
cone, and is either straight, or variously folded, or coiled.

It is straight in orthoceras . baculites.

bent on itself in ascoceras . ptychoceras.

curved in cyrtoceras . toxoceras.

spiral in trochoceras . turrilites.

discoidal in gyroceras . crioceras.

discoidal and produced in . lituites . . ancyloceras.

involute in nautilus . 9 ammonites.

Internally, the shell is divided into cells or chambers, by a series of parti-
tions (septa], connected by a tube or siphuncle. The last chamber is occupied
by the animal, the rest are empty during life, but in fossil specimens they are
often filled with spar. When the outer shell is removed (as often happens to
fossils,) the edges of the septa are seen (as in PL III., figs. 1, 2.) Sometimes
they form curved lines, as in nautilus and orthoceras, or they are zig-zag, as
in goniatites (fig. 53,) or foliaceous, as in the ammonite, fig. 34.

Fig. 34. Suture of an ammonite.^

The outlines of the septa are termed sutures ;J when they are folded the
elevations are called saddles, and the intervening depressions lobes. In
ceratites (fig. 54) the saddles are round, the lobes dentated; in ammonites
both lobes and saddles are extremely complicated. Broken fossils show that
the septa are nearly flat in the middle, and folded round the edge (like a shirt -
frill), where they abut against the outer shell- wall (fig. 37).

The siphuncle of the recent nautilus is a membranous tube, with a very
thin nacreous investment ; in most of the fossils it consists of a succession oi
funnel shaped, or bead-like tubes. In some of the oldest fossil genera, act I"
noceras, gyroceras, and phragmoceras, the siphuncle is large, and contains in

* The frontispiece, copied from Professor Osven's Memoir, represents the animal oi
the first nautilus, captured off the New Hebrides, and brought to England by Mr. Ben-
nett; it is drawn as if lying in the section of a shell, without concealing any%part of it.
The woodcut, fig. 43, is taken from a more perfect specimen, lately acquired by the
British Museum, in which the relation of the animal to its shell is accurately shown.

t A. heterophyllus, Sby., from the lias, Lyme Regis. British Museum. Only
side is represented ; the arrow indicates the dorsal saddle.

J From their resemblance to the sutures of the skull,

,.

CEPHALOPODA.

79

its centre a smaller tube, tlie space between the two being filled up with radiat-
ing plates, like the lamellaj of a coral. The position of the siphuncle is very
variable ; in the ammonitida it is external, or close to the outer margin of
the shell (fig. 37). In the nautilidae it is usually central (fig. 35), or internal
(% 36).

Fig. 35. Nautilus. Fig. 36. ' Clymenia. Fig. 37. Hamites*

The air-chambers of the recent nautilus are lined by a very thin, living
membrane ; those of the fossil orthocerata retain indications of a thick vascu-
lar lining, connected with the animal by spaces between the beads of the
siphuncle. f

The body-chamber is always very capacious ; in the recent nautilus its
cavity is twice as large as the whole series of air-cells ; in the goniatite (fig.
39), it occupies a whole whirl, and has a considerable lateral extension ; and
in ammonites communis it occupies more than a whirl.

Fig. 38. Ammonites. Fig. 39. Goniatites.%

* Fig. 35. Nautilus pompilius, L. Fig. 36. Clymenia striata, Miinst., see pi. II.,
fig. 16. Fig. 37. Hamites cylindraceus Defr., see fig. 58.

t The apocryphal genus spongarium, was founded on detached septa of an ortho-
ceras, from the Upper Ludlow rock, in which the vascular markings distinctly radiate
from the siphuncle. Mr. Jones, warden of Chin Hospital, has several of these in
apposition.

I Fig. 38. Section of ammonites obtusus, Sby. lias, Lyme Regis ; from a very young
specimen. Fig. 39. Section of goniatites sphtericus, Shy. carb. limestone, Bolland (in
the cabinet of Mr. Tennant.) The dotted lines indicate the lateral extent of the body-
chamber.

80

MANUAL OF THE MOLLUSCA.

The margin nf the aperture is quite simple in the recent nautilus, and
affords no clue to the many curious modifications observable in the fossil
forms. In the ammonites we frequently find a dorsal process, or lateral pro-
jections, developed periodically, or only in the adult (fig. 55, and pi. III., fig. 5),

In phragmoceras and gomphoceras (figs. 40, 41) the aperture is so
much contracted that it is obvious the animal could not have withdrawn its
head into the shell like the nautilus.

Fig. 40. Gomphoceras. Fig. 41. Phragmoceras.*

M. Barrande, from whose great work on the Silurian Formations of
Bohemia these figures are taken, suggests that the lower part of the aperture
(s s) which is almost isolated, may have served for the passage of the funnel,
whilst the upper and larger space (c c) was occupied by the neck ; the lobes
probably indicate the position of the external arms.

The aperture of the pearly nautilus is closed by a disk or hood (fig. 43, k),
formed by the union of the two dorsal arms, which correspond to the shell-
secreting sails of the argonaut.

In the extinct ammonites we have evidence that
the aperture was guarded still more effectively by a
horny, or shelly operculum, secreted, in all probabi-
lity, by these dorsal arms. In one group (arietes,)
the operculum consists of a single piece, and is horny
and flexible.f In the round-backed ammonites the
operculum is shelly, and divided into two plates by a
straight median suture (fig. 42). They were de-
scribed in 1811, by Parkinson, who called them tri-
gonellites, and pointed out the resemblance of their Fig. 42.1

* Fig. 40. Gomphoceras Bohemicum (Barrande), reduced view of the aperture ; *,
the siphonal opening. Fig. 41. phragmoceras callistoma (Barr.) both from the U.
Silurian, Bohemia.

t This form was discovered by the late Miss Mary Anning, the indefatigable col-
rector of the lias fossils of Lyme Regis, and described by Mr. Strickland, Geol. Journal,
vol. I., p. 232. Also by M. Voltz, Mem. de 1'Institute, 1837, p. 48.

% Trigonellites lamellosus, Park. Oxford clay, Solenhofen (and Chippenham;) as-
sociated with ammonites lingulatus, Quenstedt. (= A. Brightii, Pratt). From a speci-
men in the cabinet of Charles Stokes, Esq.

CEPHALOPODA. 81

internal structure to the cancellated tissue of bones. Their external surface is
smooth or sculptured ; the inner side is marked by lines of growth. Forty-
five kinds are enumerated by Bronn ; they occur in all the strata in which
ammonites are found, and a single specimen has been figured by M. D'Archiac,
from the Devonian rocks of the Eifel, where it was associated with goniatites*

Calcarious mandibles or rhyncholites (F. Biguet) have been obtained from
all the strata in which nautili occur ; and from their rarity, their large size
and close resemblance to the mandibles of the recent nautilus, it is probable
that they belonged only to that genus.f In the Muschelkalk of Bavaria one
nautilus (N. arietis, JReinecke, = N. bidorsatus, Schlotheim,) is found, and two
kinds of rhyncholite ; one sort, corresponding with the upper mandible of the
recent nautilus, has been called " rhyncholites hirundo" (pi. II., fig. 11), the
other, which appears to be only the lower mandible of the same species, has
been described under the name of " conchorhynchus avirostris."^:

In studying the fossil tetrabranchiata, it is necessary to take into consi-
deration the varying circumstances under which they have been preserved.
In some strata (as the lias of Watchett) the outer layer of the shell has dis-
appeared, whilst the inner nacreous layer is preserved. More frequently only
the outer layer remains ; and in the chalk formation the whole shell has
perished. ' In the calcarious grit of Berkshire and Wiltshire the ammonites
have lost their shells ; but perfect casts of the chambers, formed of calcarious
spar, remain. §

Fossil orthocerata and ammonites are evidently in many instances dead
shells, being overgrown with corals, serpulse, or oysters ; every cabinet affords
such examples. In others the animal has apparently occupied its shell, and
prevented the ingress of mud, which has hardened all around il ; after this it has
decomposed, and -contributed to form those phosphates and sulphurets commonly
present in the body-chamber of fossil shells, and by which the sediment around
them is so often formed into a hard concretion. || In this state they are

* The trlgonellites have been described by Meyer as bivalve shells, under the
generic name of aptychus; by Deslongchamps under the name of Munsteria. M.
D'Orbigny regards them as cirripedes ! M. Deshayes believes them to be gizzards of
the ammonites. M. Coquand compares them with teudopsis; an analogy evidently
suggested by some of the membranous and elongated forms, such as T. sanguinolarius,
found with am. deprcssus, in the lias of Boll. Ruppell, Voltz, Quenstedt, and Zieten,
regard the trigonellites as the opercula of ammonites, an opinion also entertained by
many of the most experienced fossil collectors in England.

t M. D'Orbigny has manufactured two genera of calamari.es out of these nautilus
beaks! (rhynchoteufhis and. paltzoteuthis). In the innumerable sections of ammonite&
which have been made, no traces of the mandibles have ever been discovered.

1 Lepas avirostris (Schlotheim), described by Blainville as the beak of a
brachiopod !

§ Called spnndylolites by old writers.

|| In the alum-shale of Whitby, innumerable concretions are found, which, when
struck with the hammer, split open, and disclose an ammonite. See Dr. Mantell's.
''Thoughts on a Pebble," p. 21.

^ E a

M MANUAL OF THE MOLLUSCA.

permeated by mineral water, which slowly deposits calcarious spar, in crys-
tals, on their walls ; or by acidulous water, which removes every trace of the
shell, leaving a cavity, which at some future time may again become filled
ar, having the form of the shell, but not its structure. In some sec-
tions of orthocerata, it is evidenf that the mud has gained access to the air-
cells, along the course of the blood-vessels ; but the chambers are not entirely
filled, because their lining membrane has contracted, leaving a space between
itself and certain portions of the walls, which correspond in each chamber.

With respect to the purpose of the air-chambers, much ingenuity has
been exercised in devising an explanation of their assumed hydrostatic func-
tion, whereby the nautilus can rise at will to the surface, or sink, on the
approach of storms to the quiet recesses of the deep. Unfortunately for such
poetical speculations, the nautilus appears on the surface, only when driven
up by storms, and its sphere of action is on the bed of the sea, where it
creeps like a snail, or perhaps lies in wait for unwary crabs and shell-fish,
like some gigantic " sea-anemone." with outspread tentacles.

The tetrabranchs could undoubtedly swim, by their respiratory jets
the discoidal nautili and ammonites are not well calculated, by their forms,
for swimming ; and the straight -shelled orthocerata and baculites must have
held a nearly vertical position, head-downwards, on account of the bu-
of their shells. The use of the air-chambers, is to render the whole animal
(and shell) of nearly the same specific gravity with the water.* The object
of the numerous partitions is not so much to sustain the pressure of the water,
as to guard against the collisions to which the shell is exposed. They are most
complicated in the ammonites, whose general form possesses least strength.f
The purpose of the siphuncle (as suggested by Mr. Searles \Vood) is to main-
tain the vitality of the shell, during the long life which these animals cer-
tainly enjoyed. Mr. Forbes has suggested that the inner courses of the
hamites, broke off, as the outer ones were formed. But this was not the case
with the orthocerata, whose long straight shells were particularly exposed to
danger ; in these the preservation of the shell was provided for by the in-
creased size and strength of the siphuncle, and its increased vascularity.
endoceras we find the siphuncle thickened by internal deposits, until (in s
of the very cylindrical species) it forms an almost solid axis.

The nucleus of the shell is rather large in the nautili, and causes

* A nautilus pompiUus (in the cabinet of Mr. Morris) weighs lib., and when t
siphuncle is secured, it floats with a |lb weight in its aperture. The animal \
have displaced^ pints (= 2|lbs ) of water, and therefore, if it weighed 31bs., the spe<
gravity of the animal and shell would scarcely exceed that of salt water.

t The siphuncle and lobed septa did not hold the animal in its shell, as Von B-
imagined: that was secured by the shell-mu&cles. The complicated sutures perh
indicate lobed ovaries ; they occur in genera, which must have produced very sir
eggs.

CEPHALOPODA.

opening to remain through the shell, until the umbilicus is filled up with a
callous deposit : several fossil species have always a hole through the centre.

In the ammonites, the nucleus is exceedingly small, and the whirls com-
pact from the first.

It has been stated that the septa are formed periodically ; but it must not
be supposed that the shell-muscles ever become detached, or that the animal
moves the distance of a chamber all at once. It is most likely that the
adductors grow only in front, and that a constant waste takes place behind, so
that they are always moving onward, except when a new septum is to be
fanned ; the septa indicate periodic rests.

The consideration of this fact, that the nautilus must so frequently have
an air-cavity between it and its shell, is alone sufficient to convince us, that the
chambered cephalopoda could not exist in very deep water. They were pro-
bably limited to a depth of 20 or 30 fathoms at the utmost.*

It is certain that the sexes were distinct in the tetrabrancJuata, but since
only the female of the living nautilus is known, we are left to conjecture how
ar the differences observable in the shells, are dependant on sex. At. D'Orbigny,
having noticed that there are two varieties of almost every kind of ammonite.
— one compressed, the other inflated — naturally assumed that the first were
the shells of male individuals ( $ ), the second of females ( $ ). Dr. Melville
has made a similar suggestion with respect to the nautili ; namely, that the
umbilicated specimens are the males, the iniperforated shells, females. This
is rendered probable by the circumstance, that all the known specimens of

• uiii's were female, and that the supposed male (2V. macromph<

very rare, as we have noticed amongst the male dibranchiata. Of the other
recent species, both the presumed sexes (N. umbilical us <J and N. stenom-
pk'ilus ^ ) are comparatively rare.

FAMILY I. XAVTILIP.E.
Shell. Body-chamber capacious. Aperture simple. Sutures simple.

• •le central, or internal. (Figs. 35, 36.)

NAUTILUS, Breynius, 1?3;2.

7 involute or discoidal, few-whirled. Siphuncle central.
In the recent nautili, the shell is smooth, but in many fossil species it is
corrugated, like the patent iron-roofing, so remarkable for its strength and
ctfandj See pi. II., fig. 10.

* By deep icater. naturalists and dredgers seldom mean more than 25 fathoms, a
comparatively small depth, only found near coasts and islands. At 100 fathoms the
pressuv ~>lbs. to the square inch. Empty bottles, securely corked, and

sunk with we-.iihts be, end 100 fathoms, are always crushed, If filled with liquid, the
cork is driven in. and the liquid replaced by salt water; and in drawing the bottle
np nsrain. the cork is returned to the neck of the bottle, generally in a reversed posi-
tion. v£j> F. Beaufort.)

84

Fig. 43. Namtilu* pompiliiu in its shell.*

The umbilicus is small or obsolete in the typical nautili, and the whirls
enlarge rapidly. In the palaeozoic species, the whirls increase slowly, and
are sometimes scarcely in contact. The last air-cell is frequently shallower
in proportion than the rest.

Animal. In the recent nautilus, the mandibles are horny, but calcified to
a considerable extent ; they are surrounded by a circular fleshy lip, external
to which are four groups of labial tentacles, 12 or 13 in each group, they
appear to answer to the buccal membrane of the calamary (fig. 1). Beyond
these, on each side of the head, is a double series of arms, or brachial ten-
tacles, 36 in number ; the dorsal pair are expanded and united to form the
hood, which closes the aperture of the shell, except for a small space on each
side, which is filled by the second pair of arms. The tentacles are lamellated

* This woodcut and 18 others illustrating the tetrabranchiata, are the property of
Mr. Gray, to whom we are indebted for their use. Fig. 43 represents the recent
nautilus, as it appears on the removal of part of the outer shell-wall (from the specimen
in the British Museum). The eye is seen in the centre, covered by the hood (h) ; t,
tentacles, nearly concealed in their sheaths ; /, funnel ; m, margin of the mantle, very
much contracted ; n, nidamental gland ; a, c, air-cells and siphuncle; s, portion of the
shell ; a, shell-muscle. The internal organs are indicated by dotted lines ; b, bran-
chiae; h, heart and renal glands ; c. crop; g, gizzard; /, liver; o, ovary.

CEPHALOPODA. 85

on their inner surface, and are retractile within sheaths, or " digitations,"
which correspond to the eight ordinary arms of the cuttle-fishes ; their supe-
riority in number being indicative of a lower grade of organization. Besides
these there are four ocular tentacles, one behind and one in front of each eye ;
they seem to be instruments of sensation, and resemble the tentacles of doris
and aplysia (Owen}. On the side of each eye is a hollow plicated process,
which is not tentaculiferous. The respiratory funnel is formed by the folding
of a very thick muscular lobe, which is prolonged laterally on each side of the
head, with its free edge directed backwards, into the branchial cavity ; behind
the hood it is directed forwards, forming a lobe which lies against the black-
stained spire of the shell (fig. 43 *.)* Inside the funnel is a valve-like fold
(fig. 44 s). The margin of the mantle is entire, and extends as far as the
edge of the shell ; its substance is firm and muscular, as far back as the line
of the shell-muscles and horny girdle, beyond which it is thin and transparent.
The shell-muscles are united by a narrow tract, across the hollow occupied by
the involute spire of the shell ; and are thus rendered horse-shoe shaped.
The siphuncle is vascular ; it opens into the cavity containing the heart ( pe-
ricardium}, and is most probably filled with fluid from that cavity. (Owen.)

Respecting the habits of the nautilus, very little is known, the specimen
dissected by Professor Owen had it crop filled with fragments of a small crab,
and its mandibles seem well adapted for breaking shells. The statement that
it visits the surface of the sea of its own accord, is at present unconfirmed
by ob servation, although the air cells would doubtless enable the animal to
rise by a very small amount of muscular exertion.

Professor Owen gives the following passage, from the old Dutch naturalist,
Rumphius, who wrote in 1705, an account of the rarities of Amboina.
" When the nautilus floats on the water, he puts out his head and all his tenta-
cles, and spreads them upon the water, with the poop of the shell above water ;
but at the bottom he creeps in the reverse position, with his boat above him,
and with his head and tentacles upon the ground, making a tolerably quick
progress. He keeps himself chiefly upon the ground, creeping also sometimes
into the nets of the fishermen ; but after a storm, as the weather becomes
calm, they are seen in troops, floating on the water, being driven up ly the
agitation of the waves. This sailing, however, is not of long continuance ;

* The funnel is considered the homologue of the foot of the gasteropods, by Loven,
a conclusion to which we cannot agree. The cephalopoda ought to be compared with
the larval gasteropods, in which the foot only serves to support an operculum; — or
with the floating tribes in which the foot is obsolete, or serves only to secrete a nida-
mental raft (ianthina). However, on examining the nautilus preserved in the British
Museum, and finding that the funnel was only part of a muscular collar, which ex-
tends all round the neck of the animal, we could not avoid noticing its resemblance
to the siphonal lappets of paludina, and to that series of lappets (including the oper-
culigerous lobe) which surrounds the trochus (fig. 87).

86

MANUAL OF THE MOLLUSCA.

for having taking in all their tentacles, they upset their boat, and so return to
the bottom." •

Fig. 44. Nautilus expanded.*

Distr., 2 or 4 sp. Chinese seas, Indian ocean, Persian gulf.

Fossil, about 100 sp. In all strata, S. and N. America (Chile). Europe,
India (Pondicherry).

Sub-genus. Aturia (Bronn), = Megasiphonia D'Orb.

Type, N. zic-zac Sby. PL II., fig. 12, London clay, Highgate.

Shell, sutures, with a deep lateral lobe ; siphuncle nearly internal, large,
continuous, resembling a succession of funnels.

Fossil, 4 sp. Eocene, N. America, Europe, India.

Sul-genus ? Discites, McCoy. Whirls all exposed ; the last chamber
sometimes produced. L. silurian. — Garb : limestone.

Temnocheilus, McCoy. Founded on the carinated sp. of the Carb. lime-
stone.

Cryptoceras, D'Orb. Founded on N. dorsaMs Phil, and one other spe
in which the siphuncle is nearly external.

* Ideal representation of the nautilus, when expanded, by Professor Loven, „ —
appears to have taken the details from M. Valenciennes memoir in the Archives dn
Museum, vol. 2, p. 257. //,, hood, s, s:phon. It is just possible, that when the
nautilus issues from its shell, the gas contained in the last, incomplete, air-chamber,
may expand ; but this could not happen under any great pressure of water.

CEPHALOPODA.

87

LITUITES, Breynius.
Etym., lituus, a trumpet.

Syn., Hortolus, Moutf. (whirls separate.) Trocholites, Conrad.
Ex., L. convolvans, Schl. L. lituus, Hisinger.

Shell, discoidal ; whirls close, or separate ; last chamber produced in a
straight line ; siphuncle central.

Fossil, 15 sp. Silurian, N. America, Europe.

TROCHOCERAS, Barrande, 1848.
Ex., T. trochoides, Bar,
Shettt nautiloid, spiral, depressed.
Fossil, 16 sp. U. Silurian, Bohemia.

Some of the species are nearly flat, and having the last chamber pro-
duced would formerly have been considered Lituites.

Fig. 45. Clymenia striata, Munst.* Fig. 46. C. linearis, Munst.

OLYMENIA, Munster, 1832.
Etym., clymene, a sea-nymph.
Syn. Endosiphonites, Ansted. Sub-clymenia, D'Orb.
Ex., C. striata, pi. II., fig. 16 (Mus. Tennant).
Shell, discoidal ; septa simple or slightly lobed ; siphuncle internal.
Fossil, 43 sp. Devonian, N. America, Europe.

FAMILY II. ORTHOCERATIDJE.

Shell, straight, curved, or discoidal ; body chamber small ; aperture con-
tracted, sometimes extremely narrow (figs. 40, 41) ; siphuncle complicated.

It seems probable that the cephalopods of this family were not able to
withdraw themselves completely into their shells, like the pearly nautilus ;
this was certainly the case with some of them, as M. Barrande has stated,
for the siphonal aperture is almost isolated from the cephalic opening. The
shell appears to have been often less calcified, but connected with more vas-
cular parts than in the nautilus ; and the siphuncle often attains an enor-
mous development. In all this, there is nothing to suggest a doubt of their
being tetrabranchiate ; and the chevron-shaped coloured bands preserved on
the orthoceras anguliferus,\ sufficiently prove that the shell was essentially
external.

* Fig. 45. Sutures of two species of Clymenia from Phillips' Pal. Fos., Devon-
shire.

\ Figured by D'Archiac and Verneuil, Geol. Trans.

MANUAL OF THE MOLLUSCA.

OKTHOCERAS, Breyn.

Etym., orthos, straight, and ceras, a horn.

Syn., cycloceras, McCoy. Gonioceras, Hall.*

Ex. 0. giganteiun (diagram of a longitudinal section), pi. II, fig. 14.

Shell, straight ; siphuncle central ; aperture sometimes contracted.

Fossil, 125 typical sp. (D'Orb).f L. Silurian — Trias; N.America, Aus-
tralia, and Europe.

The orthocerata are the most abundant and wide spread shells of the
old rocks, and attained a larger size than any other fossil shell. A fragment
of 0, giganteum, in the collection of Mr. Tate of Alnwick, is a yard long, and

1 foot in diameter, its original length must have been 6 feet. Other species,

2 feet in length, are only 1 inch in diameter, at the aperture.

Sub-genus I. Cameroceras, Conrad (= melia and thoracoceras, Fischer?).
Siphuncle lateral, sometimes very large (simple ?} .
Casts of these large siphuncles were called hyalites by Eichwald.
27 sp. L. Silurian — Trias ? N. America and Europe.

xl

Fig. 47. Actinoceras.l Fig. 48. Ormoceras.

2. Actinoceras (Bromij, Stokes. Siphuncle very large, inflated between
the chambers, and connected with a slender central tube by radiating plates.
6 sp. L. Silurian — Garb, N. America, Baltic, and Brit.

3. Ormoceras, Stokes. Siphuncular beads constricted in the middle (making
the septa appear as if united to the centre of each). 3 sp. L. Silurian, N.
America.

.4. Huronia, Stokes. Shell extremely thin, membraneous or horny ?
Siphuncle very large, central, the upper part of each joint inflated, connected

* Theca and Tentaculites are provisionally placed with the Pteropoda, they proba-
bly belong here.

t M Barrande has discovered 100 new species in the Upper Silurian rocks of
Bohemia.

I Fig. 47. Actinoceras Richardsoni, Stokes. Lake Winipeg (diagram, reduced |).
Fig. 48. Ormoceras, Bayfieldi, Stokes. Drummond Island, (from Mr. Stokes' paper,
Geol. Trans.)

CEPHALOPODA.

with a small central tube by radiating plates. 3 sp. L. Silurian. Drummond
Island, Lake Huron,

l\

Fig. 49. Huronia verfebralis.*

Numerous examples of this curious fossil were collected by Dr. Bigsby
(in 1822), and by the officers of the regiments formerly stationed on Drum-
mond Island. Specimens have also been brought home by the officers of
many of the Artie expeditions. But with the exception of one formerly in
the possession of Lieut. Gibson, 68., and another in the cabinet of Mr.
Stokes, the siphuncle only is preserved, and not a trace remains of septa or
shell wall. Some of those seen by Dr. Bigsby in the limestone cliff's, were 6
feet in length.

5. Endoceras, Hall (Cono-tubularia Troost}. Shell extremely elongated,
drical. Siphuncle very large, cylindrical, lateral ; thickened internally by re-
peated layers of shell, or partitioned off by funnel-shaped diaphragms. 12 sp.
Lower Silurian, New York.

6. Shell perforated by two distinct siphuncles? 0. bisiphonatum Sby,
Caradoc saridstone, Brit.

" Orthocerata with two siphuncles have been observed, but there has
always appeared something doubtful about them. In the present instance,
however, this structure cannot be questioned." (J. Sowerby.)

Small orthocerata of various species, are frequenlly found in the body
chamber and open siphuncle of large specimens.! The endoceras gemelli-
parum and proleiforme of Hall, appear to be examples of this kind.
GOMPHOCERAS, J. Sby, 1839.

Etym., gomphos, a club, and ceras, a horn.

* Fig. 49. Huronia vertebralis, Stokes, a, from a specimen in the Brit. M., presented
by Dr. Bigsby. The septa are added from Dr. Bigsby's drawing ; they were only in-
dicated in the specimen by "colourless lines on the brown limestone," b. represents
a weathered section, presented to the Brit. Mus. by Captain Kellett and Lieutenant
Wood of H.M.S. Pandora. The figures are reduced £.

t Shells of Seller ophon and Ai urchisonia are found under the same circumstances.

90

MANL'AL OF THE 310LLUSCA.

ty>?.. Apioceras (Fisclier). Poterioceras (McCoy).

Type, G. pyriforme, Sby., fig. 51, and G. Bohemicum, Bar. fig. 40.

!> eoc

Fig. 50. Endoceras.*

Fig. 51. Gomphoceras.i

Shell, fusiform or globular, with a tapering apex ; aperture contracted
the middle ; siphuncle moniliforni, sub-central.

Di$tr.t 10 sp. Silurian — Garb ; N. America, Europe.

ONCOCERAS, Hall.

Eti/m.y oncos, a protuberance.
Type, O. constrictum, Hall. Trenton limestone.
Shell, like a curved goinphoceras ; siphuncle external.
Distr., 3 sp. Silurian, New York.

PHKAGMOCEEAS, Broderip.

Etym., phragmos?* partition, and ceras, a horn.
Type, P. ventricosum (Steininger sp.), pi. II., fig. 15.
Shell curved, laterally compressed : aperture contracted in the mid
sipJi uncle, ventral, radiated. Ex., P. callistoma, Bar., fig. 41.
Distr., 8 sp. U. Silurian — Devonian, Brit., Germany.

* Fig. 50. Diagram of an endoceras (after Hall), a, shell-wall 6. Wall of s
huncle. c c c. Diaphragms (" embryo-tubes " of Hall).

t Fig. 51. Gomphoceras pyriforme. L. Ludlow rock, Mochtre hill, Herefords]
(from Murch, Silur, syst., reduced ^). *. Beaded siphuncle.

CEPHALOPODA.

91

CYRTOCERAS, Goldf. 1533.
Etym., cv.rtos, curved, ceras, horn.

Syn., Campulites, Desh. 1832 (including gyroceras). Aploceras, I>'Orb.
Cainpyloceras and trigonoceras, McCoy.

Ex., C. hybridum, volborthi and beaumonti (Barrande).
Shell, curved ; siphuncle small, internal, or sub-central.
Distr., 36 sp. L. Silurian, Carb— X. America, and Europe.

Fig. 52.*

GTROCERAS, Meyer, 1829.
Etym., gyros, a circle, and ceras.
Sy/i., Nautiloceras, D'Orb.

Ex., G. eifeliense, D'Arch., pi. II., fig. 13. Devonian, Eifel.
Shell, natitiloid ; whirls separate ; siphnncle excentrie, radiated.
Fossil, 17 sp. U. Silurian — Trias? X. America, and Europe,

ASCOCERAS, Barrande, 1848.f

Etym., ascos, a leather bottle,

Shell, bent upon itself, like ptychoceras.

Di&tr.t 7 sp. U. Silurian, Bohemia.

FAMILY III. AinioxiTiDJC.

Shell. Body-chamber elongated; aperture guarded by processes, and
closed by an operculum ; sutures angulated, or lobed and foliated ; siphuncle
external (dorsal, as regards the shell).

The shell of the ammonitida has essentially the same structure with the
nautilus. It consists of an external porcellanous^ layer, formed by the collar

* Fig. 52. Gyroceras goldfussii (= ornatum Goldf). 6. Siphuncle of G. depress**,
Goldf. sp. Devonian. Eifel. From M.M. D'Archiac and Verneuil.

t In Haidinger's Berichte. *

J Its microscopic structure has not been satisfactorily examined : Prof. Forbes
detected a punctate structure in one species.

92 MANUAL OF THE MOLLUSCA.

of the mantle only ; and of an internal nacreous lining, deposited by the whole
extent of its visceral surface. There is an ammonite in the British Museum,
evidently broken and repaired during the life of the animal,* which shews
that the shell was depositedy>0#i within. In some species of ammonites the
collar of the mantle forms prominent spines on the shell, which are too deep
for the visceral mantle to enter ; they are therefore partitioned off (as in A.
armatus, Lias) from the body whirl and air cells, and not exhibited in casts.

The baculites, and ammonites of the section cristati, acquire when adult
a process projecting from the outer margin of their shell. Certain other
ammonites (the ornati, coronati, &c.) form two lateral processes before they
cease to grow (pi. III., fig. 5). As these processes are often developed in
very small specimens, it has been supposed that they are formed repeatedly
in the life of the animal (at each periodic rest), and are again removed when
growth recommences. These small specimens, however, may be only dwarfs.
In one ammonite, from the inferior oolite of Normandy, the ends of these
lateral processes meet, "forming an arch over the aperture, and dividing
it into two outlets, one corresponding with that above the hood of the nautilus,
which gives passage to the dorsal fold of the mantle ; the other with that
below the hood, whence issue the tentacles, mouth, and funnel ; such a modi-
fication, we may presume, could not take place before the termination of the
growth of the individual."t (Owen.)

M. D'Orbigny has figured several examples of deformed ammonites., in
which one side of the shell is scarcely developed, and the keel is consequently
lateral. Such specimens probably indicate the partial atrophy of the branchiae
on one side. In the British Museum there are deformed specimens of Am.
obtusus, amaltheus, find tuberculatus.

Fig. 53.J

* A serpentinus Schloth, U. Lias, Wellingboro. Rev. A. W. Griesbach.

t This unique and abnormal specimen is in the cabinet of S. P. Pratt, Esq.

J Fig. 53. Goniatiies sphericus, Sby. Front and side views of a specimen from the
carb limestone of Derbyshire, in the cabinet of Mr. J. Tennant; the body-chamber
and shell-wall have been removed artificially.

CEPHALOPODA.

93

GONIATITES, De Haan.

Etym., gonia, angles (should be written gonialites ?).
Syn., aganides, Montf.

Examples, G. Henslowi, pi. III., fig. 1., G. sphericus, fig. 53, and 39.
Shell, discoidal ; sutures lobed ; siphuncle dorsal,
Distr. 150 sp. Devonian — Trias, Europe.

BACTRITES, Sandberger (= stenoceras, D'Orb ?).
Shell, straight ; sutures lobed. Type, B. subconicus, Sbger.
Distr., 2 sp. Devonian — Germany.

ifOhA Ay^ y1^ hnS **&

Fig. 54.*

CEEATITES, De Haan.
Type, C. nodosus, pi. III., fig. 2.

Shell, discoidal ; sutures lobed, the lobes crenulated. Fig. 54.
Distr., muschelkalk, 8 sp. Germany, France, Russia, Siberia.
Salt-marls (Keuper). 17 sp. S. Cassian, Tyrol.

M. D'Orbigny describes 5 shells from the gault and U. greensand as
ceratites; but many ammonites have equally simple sutures, when young.

Fig. 55. t
AMMONITES, Bruguiere.

Etym,, ammon, a name of Jupiter, worshipped in Libya under the form
of a ram. The ammonite is the cornu ammonis of old authors.

* Fig. 54. Suture of ceratites nodosus (Brug). The arrow in the dorsal lobe
points towards the aperture.

t Fig. 55. Ammonites rostratus, SLy. From the U. green-sand of Devizes, in the
cabinet of W. Cunnington, Esq. b, front view of one of its partitions.

94

MANUAL OF THE MOLLUSCA.

SyH.f orbulites Lam. planulites, Montf.

Shell, discoidal ; inner whirls more or less concealed ; septa undulated ;
sutures lobed and foliated ; siphuncle dorsal.

Distr., 530 sp. Trias— chalk. Coast of Chili (D'Orb.) Santa Fe de
Bogota (Hopkins), New Jersey, Europe, and S. India.

Capt. Alexander Gerard discovered ammonites similar to our L. oolitic-
species, in the high passes of the Himalaya, 16,200 feet above the sea.
Section A. Bac/c, with an entire Jceel.

1. Arietes, L. oolites, A. bifrons (pi. III., fig. 6), bisulcatus (pi.

Ill, fig. 7).

2. Falciferi, L. oolites, A. serpentinus, radians, hecticus.

3. Cristati, cretaceous, A. cristatus, rostratus (fig. 55), varians.

B. Back crenated.

4. Amalthel, ool. A. amaltheus, cordatus, excavatus.

A. rhothornagensis (pi. Ill, fig. 4).

5. Rhothomagenses, cret.
C.

6. Disci.,

oolitic,

D. .

7. Dentati,

/ cret.
tool.

E.

8. Armati,

L. ool.

9. Capricorni,
10. Ornati,

L. ool.
ool.

A. discus, clypeiformis.
Back channelled.

A. dentatus, lautus.
A. Parkinsoni, anguliferus.
Back squared.

A. armatus, athletus, perarmatus.

A. capricornus, planicostatus.

A. Duncaiii, Jason (pi. III., fig. 5).

Fig. 56. Ammonites coronatus.*
F. Back round., convex.

11. Heterophylli, L. ool. A. heterophyUus (fig. 34).

12. Ligaii, cret. A. planulatus (pi. Ill, fig. 3).

13. Annulati, ool. A. annulatus, biplex, giganteus.

14. Coronati, ool. A. coronatus (fig. 56), sublsevis.

15. Fimbriati, ool. A. fimbriatus, lineatus, hircinus.

* Fig. 56. Profile of ammonites coronatus, Brug. (reduced ^ from D'Orbigny)
Kelloway rock, France, d 1. dorsal lobe ; ss, dorsal saddles ; V V . lateral lobes ; s's'.
lateral saddles; accessory and ventral lobes. The number of accessory lobes increases
with age.

CEPHALOPODA. 05

16. Cassiani, 36 sp. of very variable form, and remarkable for the number
and complexity of their lobes. Trias, Austrian Alps.

T^ nl

A 3

Fig. 57.*

Ex., A. Maximiliani (fig. 57), A, Metternichii.
CRIOCERAS, Leveille.

Etym., krios, a ram, and ceras, a horn.

Syn., tropseum, Sby.

Ex., C. cristatum, D'Orb. (pi. III., fig. 8).

Shell, discoidal ; whirls separate,

Distr., 9 sp. Neocomian — Gault ; Brit., France.
TOXOCERAS, D'Orb.

Etym., toxon, a bow, ceras, a horn.

Ex., T. annulare, D'Orb. (pi. III., fig. 12.)

Shell, bow-shaped ; like an ammonite uncoiled.

Distr., 19 sp. Neocomian. Between this and crioceras and ancylo ceras
there are numerous intermediate forms.

ANCYLOCERAS, D'Orb.

Etym., anculos, incurved.

Ex.* A. spinigerum (pi. III., fig. 10).

Shell, at first discoidal, with separate whirls ; afterwards produced at a
tangent and bent back again, like a hook or crosier.

Distr., 38 sp. Inf. oolite — chalk. S. America (Chile and Bogota), Europe.
SCAPHITES, Parkinson.

Etym., scaphe, a boat.

Ex., S. equalis (pi. III., fig. 9).

Shell, at first discoidal, with close whirls ; last chamber detached and
recurved.

Distr., 17 sp. Neocomian —chalk. Europe.
HELICOCERAS, D'Oub.

Etym., helix (helicos), a spiral, and ceras, horn.

Ex., H. rotundum, Sby, sp. pi. III., fig. 11 (diagram).

» Fig. 57. Am. Maximiliani Klipstein. (= A. bicarinatus Miinst). Trias, Hall-
stadt (copied from Quenstedt). A, Profile shewing the numerous lobes and saddles.
B, suture of one side; v, dorsal saddle.

96 MANUAL OF THE MOLLUSCA.

Shell, spiral, sinistral ; whirls separate .

Distr. > 11 sp. Inf. oolite? — chalk. Europe.
TURRILITES, Lam.

Etym., turns, a tower, and lithos, a stone.

Shell, spiral, sinistral ; aperture often irregular.

Distr., 27 sp. (Bronn). Gault — chalk. Europe.

The turrilite was perhaps di-branchiate, by the atrophy of the respiratory
organs of one side. M. ;D'Orbigny includes in this genus particular specimens
of certain Lias ammonites which are very slightly unsymmetrical ; the same
species occur with both sides alike. He also makes a genus (heteroceras) of
two turrilites, in which the last chamber is somewhat produced and recurved.
T. reflexus (Quenstedt, T. 20, fig. 16) has its apex inflected and concealed.

Fig. 58. Sutures of hamites cylindraceus, Defr.*

HAMITES, Parkinson.

Etym., hamus, a hook.

Ex., H. attenuates, pi. III., fig. 15.

Shell, hook-shaped, or bent upon itself more than once, the courses sepa-
rate.

Distr. , 58 sp. Neocomian — chalk. S. America (Tierra del Fuego) —
Europe.

The inner courses of this shell probably break away or are '* decollated"
in the progress of its growth (Forbes). M. D'Orbigny has proposed a new
genus, hamulina, for the 20 neocomian species.

PTYCHOCEHAS, D'Orb.
Etym., ptyche, a fold.
Ex., P. emericianum, D'Orb., pi. III., fig. 14.

* Fig. 58. Space between two consecutive sutures of the right side, from a speci-
men in the Brit. Mus. a. dorsal line. b. ventral. Baculite limestone, Fresville.

GASTEROPODA.

97

Shell, bent once upon itself; the two straight portions in contact.
Distr., 7 sp. Neocomian — chalk. Brit. France.

BACULITES, Lamarck.
Etym., baculus, a staff.
Ex., B. anceps. PI. III., fig. 13.

Shell, straight, elongated ; aperture guarded by a dorsal process.
Dlstr., 11 sp. Neocomian — chalk. Europe, S. America (Chile).

Baculina, D'Orb. B. Rouyana. Neoc., France. Sutures not foliated.

The chalk of Normandy has received the name of baculite limestone, from
lie abundance of this fossil.

CLASS II. GASTEROPODA.

The gasteropods, including land-snails, sea-snails, whelks, limpets, and the
ke, are the types of the mollusca ; that is to say, they present all the leading
;atures of molluscous organization in the most prominent degree, and make
ss approach to the appearance and condition of fishes than the cephalopods,
id less to the crustaceans and zoophytes than the bivalves.

Their ordinary and characteristic mode of locomotion is exemplified by the
)mmon garden-snail, which creeps by the successive expansion and contraction
• its broad muscular foot. These muscular movements may be seen following
ich other in rapid waves when a snail is climbing a pane of glass.

The nucleobranches are "aberrant" gasteropods, having the foot thin and
irtical ; they swim near the surface of the sea, in a reversed position, or
ihere to floating sea-weed.

Fig. 59. A nucleobranche.*

The gasteropods are nearly all unsymmetrical, the body being coiled up
irally, and the respiratory organs of the left side being usually atrophied,
i chiton and dentalium the branchite and reproductive organs are repeated
i each side.

* Fig. 59. Carinarla cymbium, L. sp. (after Blainville), Mediterranean ; p, pro
scis; t, tentacles; b, branchiae; s, shell; /, foot; d, disk.

93

MANUAL OF THE MOLLUSCA.

A few species of cymba, litorina, paludina, and helix, are viviparous ; the
rest are oviparous.

"When first hatched the young are always provided with a shell, though in
many families it becomes concealed by a fold of the mantle, or it is speedily
and wholly lost.*

The gasteropods form two natural groups; one breathing air (pulmonifera) t
the other water (brancMfera). The air-breathers undergo no apparent meta-
morphosis ; when born, they differ from their parents in size only. The
water-breathers have at first a small nautiloid shell, capable of concealing
them entirely, and closed by an operculum. Instead of creeping, they swim
with a pair of ciliated fins springing from the sides of the
head ; and by this means are often more widely dispersed
than we should be led to expect from their adult habits ;
thus some sedentary species of calyptraa and chiton have
a greater range than the " paper-sailor," or the ever-drifting (
oceanic-snail.

At this stage, which may fairly be compared with the
larval condition of insects, there is scarcely any difference
between the young of eolis and aplysia, or buccinum and
vermetus. (M. Edw.)

The development of the branchiferous gasteropods may be observed with
much facility in the common river-snails (paludina] ; which are viviparous,
and whose oviducts in early summer contain young in all stages of growth
some being a quarter of an inch in diameter.

Fig. GO.t

Fig. 61. Paludina vivipara.%

Embryos scarcely visible to the naked eye have a well-formed shell, orna-
mented with epidermal fringes ; a foot and operculum ; and the head has long
delicate tentacula, and very distinct black eyes.

* M. Loven believes that the embryo shell of the nudibranches falls off at the time
they acquire a locomotive foot.

t Fig. 60. Fry of Eolis (from Alder and Hancock) ; o, the opeiculum ; the origins"
s not larger than the letter o.

I Fig. 61. Paludina vivipara L. (original); the internal organs are represented at
if seen through the shell. The ovary, distended with eggs and embryos, occupies the
right side of the body whirl ; the gill is seen on the left ; and between them the termi
nation of the alimentary canal. Surrey Docks, June, 1850.

GASTEROPODA. 99

The development of the pulmoniferous embryo is best seen in the trans-
parent eggs of the fresh-water limneids ; these are not hatched until the young
have passed the larval condition, and their ciliated head-lobes (or veil), are
superseded by the creeping disk, or foot.

The shell of the gasteropods is usually spiral, and univalve ; more rarely
tubular, or conical,, and in one genus it is multivalve. The following are its
principal modifications :

A. Regularly spiral,

a. elongated or turreted ; terebra, turritella.

b. cylindrical; meyaspira, pupa.

c. short ; buccinum.

d. globular; natica, helix.

e. depressed ; solarium.
f. discoidal; planorbis.

y. convolute; aperture as long as the shell ; cyprtea, bulla.

h. fusiform; tapering to each end, likefusus.

i. trochi-form ; conical, with a flat base, like trochus.

k. turbinated ; conical, with a round base, like turlto.

1. few- whirled; helix hcemastoma. PI. XII., fig. 1.

m. many-whirled; helix polygyrata. PI. XII., fig. 2.

n. ear-shaped ; haliot'is.

B. Irregularly spiral ; siliquaria, vermetus.

C. Tubular; dentalium.

D. Shield-shaped; umbrella, parmophorus.

E. Boat-shaped; navicella.

F. Conical or limpet-shaped • patella.

G. Multivalve and imbricated ; chiton.

The only symmetrical shells are those of carinaria, atlanta, dentalium,
and the limpets. *

Nearly all the spiral shells are dextral, or right-handed ; a few are con-
stantly sinistral, like clausilia ; reversed varieties of many shells, both dex-
tral and sinistral, have been met with.

The cavity of the shell is a single conical or spiral chamber ; no gastero-
pod has a multilocular shell like the nautilus, but spurious chambers are
formed by particular species, such as triton corrugatus (fig. 62), and euomphalus
pentangulatus ; or under special circumstances, as* when the upper part of the
spire is destroyed.

Some spiral shells are complete tubes, with the whirls separate, or scarcely

* The curve of the spiral shells and their opercula, and also of the Nautilus, is a
logarithmic spiral; so that to each particular species may be annexed a number, indi-
cating the ratio of the geometrical progression of the dimensions of its whirls. Rev.
H. Moseley, " On geometrical forms of turbinated and discoid shells." Phil. Trans.
towd. 1838. Pt.2,p.351.

TOO

MANUAL OF THE MOLLUSCA.

in contact, as scalaria, cyclostoma, and valvata ; but more commonly the
inner side of the spiral tube is formed by the pre-existing whirls (fig. 62).

The axis of the shell, around which the whirls are coiled, is sometimes
open or hollow ; in which case the shell is said to be perforated, or umbili-
cated (e, g. solarium). The perforation may be a mere chink, or fissure (riant),
as in lacuna ; or it may be filled up by a shelly deposit, as in many nalicas.
In other shells, like the triton, the whirls are closely coiled, leaving only a pillar
of shell, or columella, in the centre ; such shells are said to be imperf orate.

apex.

anterior canal.
Fig. 62. Section of a spiral univalve*

The apex of the shell presents important characters, as it was the nucleus
or part formed in the egg ; it is sinistral in the pyramidellidte, oblique and
spiral in the nucleobranches and emarginula, and mammillated in turbinella
pi/rum andfusus antiquus.

The apex is directed backwards in all except some of the patellida, in which
it is turned forwards, over the animal's head. In the adult condition of some
shells the apex is always truncated (or decollated), as in cylindrella and bull-
mus decollatus ; in others it is only truncated when the animals have lived

* Fig. 62. Longitudinal section of triton corrugatus, Lam., from a specimen in the
cabinet of Mr. Gray. The upper part of the spire has been partitioned off many times
successively.

GASTEROPODA. 101

fn acidulous waters (e. g. cerithidea wcA.pirena}, and specimens may be ob-
tained from more favorable situations with the points perfect.

The line or channel formed by the junction of the whirls is termed the
suture.

The last turn of the shell, or body -whirl, is usually very capacious ; in
the females of some species the whirls enlarge more rapidly than in the males
(e. g. buccinum undatum). The "base" of the shell is the opposite end to
the apex, and is usually the front of the aperture.

The aperture is entire in most of the vegetable feeders (holostomata], but
notched or produced into a canal, in the carnivorous families (siphonostomata};
this canal, or siphon, is respiratory in its office, and does not necessarily indicate
the nature of the food. Sometimes there is a posterior channel or canal,
which is excurrent, or anal, in its function (e. g. strombida and ovulum volva] ;
it is represented by the slit in scissurella, the tube of typhis, the perforation
infissurella, and the series of holes in haliotis.

The margin of the aperture is termed the peristome ; sometimes it is con-
tinuous (cyclostoma), or becomes continuous in the adult (carocolla) ; very
frequently it is " interrupted," the left side of the aperture being formed only
by the body-whirl. The right side of the aperture is formed by the outer
lip (labrum), the left side by the inner or columellar lip (labium), or partly
by the body- whirl (termed the "wall of the aperture" by Pfeiffer).

The outer lip is usually thin and sharp in immature shells, and in some
adults (e. g. helicella and bulimulus] ; but more frequently it is thickened ;
or reflected ; or curled inwards (inflected*), as in cypraa; or expanded as in
pteroceras ; or fringed with spines as in murex. When these fringes or ex-
pansions of the outer lip are formed periodically they are termed varices.

Lines of colour, or sculpture, running from the apex to the aperture are
spiral or longitudinal, and others which coincide with the lines of growth are
" transverse," as regards the whirls ; but stripes of colour extending from
the apex across the whirls are often described as "longitudinal" or "radia-
ting," with respect to the entire shell.

Shells which are always concealed by the mantle are colourless, like Umax
and parmophorus ; and those which are covered by the mantle-lobes when
the animal expands, acquire a glazed or enamelled surface, like the cowries ;
when the shell is deeply immersed in the foot of the animal it becomes partly
glazed, as in cymba. In all other shells there is an epidermis, although it is
sometimes very thin and transparent.

In the interior of the shell the muscular impression is horse-shoe shaped,
or divided into two scars ; the horns of the crescent are turned towards the
head of the animal.

The operculum with which many of the gasteropods close the aperture of
their shell, presents modifications of structure which are so characteristic of
the sub-genera, as to be worthy of particular notice. It consists of a horny
layer, sometimes strengthened by the addition of calcarious matter on its ex-

102 MANUAL 'OF 'THE ' ftOLLTTSCA.

terior, and in its mode of growth it presents some resemblance to the sheH
itself. Its inner surface is marked by a muscular scar, whose lines bear no
relation to the external lines of growth, and its form is unlike the muscular
scar in the shell. It is developed in the embyro, within the egg, and the
point from which it commences is termed the nucleus ; many of the spiral
and concentric forms fit the aperture of the shell with accuracy, the others
only close the entrance partially, and in many genera, especially those with
large apertures (e. g. dolium, cassidaria, harpa, navicella), it is quite rudi-
mentary or obsolete.

Fig. 63. Fig. 64. Fig. 65. Fig. 06. Fig. 67.

The operculum is described as —

Concentric, when it increases equally all round, and the nucleus is central
or sub-central, as in paludina and atnpullaria (pi. IX., fig. 26) .

Imbricated or lamellar (fig. 64), when it grows only on one side, and the
nucleus is marginal, as in purpura, phorus, and paludomus.

Claw-shaped, or unguiculate, (fig. 63, with the nucleus apical or in front),
as in turbinellus and fusus ; it is claw-shaped and serrated in strombus
(fig. 69).

Spiral, when it grows only on one edge, and revolves as it grows ; it is
always sinistral in dextral shells.

Paucispiral, or few- whirled (fig. 66), as in litorina.

Sub-spiral, or scarcely spiral, in melania. PI. VIII., fig. 25*.

Multispiral or many-whirled (fig. 65) as in trochus, where they some-
times amount to 20 ; the number of turns which the opereulum makes is not
determined by the number of whirls in the shell, but by the curvature of the
opening, and the necessity that the operculum should revolve fast enough to
fit it constantly (Moseley).

It is said to be articulated when it has a projection, as in nerita
(fig. 67).

Too much importance, however, must not be attached to this very va-
riable plate, as an aid to classification ; it is present in some species of vvluta,
olwa, conus, mitra, and cancellaria, but absent in others ; it is (indifferently)
horny or shelly in the species of ampullaria and natica ; in paludina it is
concentric, in paludomus lamellar, in valvata spiral ; in solarium and ceri-
thium, it is multispiral or paucispiral.

Some of the gasteropoda can suspend themselves by glutinous thready

GASTEROPODA.

103

like litiopa and rissoa parva, which anchor themselves
to sea-weeds (Gray), and cerithidea (fig. 68), which
frequently leaves its proper element, and is found
hanging in the air (Adams). A West India land-
snail (cyclostoma suspensum) also suspends itself (Guild-
ing). The origin of these threads has not been ex-
plained ; but some of the limaces lower themselves to
the ground by a thread which is not secreted by any
particular gland, but derived from the exudation over
the general surface of the body (Lister; D'Orbigny).

The division of this extensive class into orders and
families, has engaged the attention of many naturalists,
and a variety of methods have been proposed. Cu-
vier's classification was the first that possessed much
merit, and several of his orders have since been united
with advantage.

Fig. 68.

System of Cuvier.
Class. GASTEROPODA.

Order 1. Pectinibranchiata

2. Scutibranchiata

3. Cyclobranchiata

4. Tubulibranchiata

5. Pulmonata

6. Tectibranchiata

7. Inferobranchiata

8. Nudibranchiata
Class. HETEROPODA.

System now adopted.

Ord. Prosobranchiata, M. Edw.

Ord. Pulmonifera.

Ord. Opisthobranchiata, M. Edw.

Ord. Nucleobranchiata. Bl.

ORDER I. PROSOBRANCHTATA.

Abdomen well developed, and protected by a shell, into which the whole
animal can usually retire. Mantle forming a vaulted chamber^ over the back
of the head, in which are placed the excretory orifices, and in which the
branchiae are almost always lodged. Branchiae pectinated, or plume-like,
situated (proson) in advance of the heart. Sexes distinct. (M. Edwards.)

SECTION A. SIPHONOSTOMATA. Carnivorous Gasteropoda.

Shell spiral, usually imperforate ; aperture notched or produced into a
canal in front. Operculum horny, lamellar.

Animal provided with a retractile proboscis ; eye-pedicels connate with the
tentacles ; margin of the mantle prolonged into a siphon, by which water is
conveyed into the branchial chamber ; gills 1 or 2, comb -like, placed obliquely
o\er the back. Species all marine.

104 MANUAL OF THE MOLLTJSCA.

FAMILY I. STROMBID^. Wing-shells.

Shell with an expanded lip, deeply notched near the canal. Operculum
claw-shaped, serrated on the outer edge.

Animal furnished with Jarge eyes, placed on thick pedicels ; tentacles
slender, rising from the middle of the eye-pedicels. Foot narrow, ill adapted
for creeping. Lingual teeth single ; uncini, three on each side.

The strombs are carrion feeders, and, for molluscous animals, very active ;
they progress hy a sort of leaping movement, turning their heavy shell from
side to side. Their eyes are more perfect than those of the other gasteropods,
or of many fishes.

Fig. 69.*

STROMBUS, L. Stromb.

JStym., stromlos, a top.

Type, S. pugilis. PL IV., fig. 1.

Shell rather ventricose, tubercular or spiny ; spire short ; aperture long,
with a short canal above, and truncated below ; outer lip expanded, lobed
above, and sinuated near the notch of the anterior canal. Lingual teeth
(S. fioridus) 1 cusped ; uncini, 1 tri-dentate, 2, 3 claw-shaped, simple.f

Distr., 60 species. West Indies, Mediterranean, Red Sea, India, Mau-

* Fig. 69. Strombus aims -Dianas, L. (after QuoyandGaimard), Amboina. p, pro-
boscis, between the eye-pedicels ; /, foot, folded up ; o, operculum ; m, border of
the mantle ; s, respiratory siphon.

t The lingual dentition of strombus resembles that of aporrhais, and is unlike that
of the whelks; but it is more probable that aporrhais is the representative of strom-
bus, than that it is very closely allied.

GASTEROPODA. 105

ritius, China, New Zealand, Pacific, West America. On reefs, at low water,
and ranging to 1 0 fathoms.

Fossil, 5 cretaceous species ; 3 sp. Miocene — . South Europe. There is a
group of small shells in the eocene tertiary strata of England and France,
nearly related to the living S. fissurellus L., some of which have been placed
with rostettaria, because the notch in the outer lip is small, or obsolete. They
probably constitute a sub -genus, to which Swainson's name strombidia, might
be applied. Example, S. Bartonensis. PL IV., fig. 2.

The fountain-shell of the West Indies, S. gigas, L., is one of the largest
living shells, weighing sometimes four or five pounds ; its apex and spines are
filled up with solid shell as it becomes old. Immense quantities are annually
imported from the Bahamas for the manufacture of cameos, and for the
porcelain works ; 300,000 were brought to Liverpool alone in the last year,
1850 (Mr. Archer).

PTEROCERAS, Lam. Scorpion-shell.

Etym., pteron, a wing, and ceras, a horn.

Type, P. lambis. PL IV., fig. 3.

Shell like strombus when young ; outer lip, of the adult, produced into
several long claws, one. of them close to the spire, and forming a posterior
canal.

Distr., 10 sp. India, China.

Fossil, nearly 100 sp. are enumerated by D'Orbigny, ranging from the
lias to the upper chalk ; many of them are more nearly related to aporrhais
(certthiadue).

ROSTELLARIA, Lam.

Etym., rostellum, a little beak.

Syn., fusus, Humphreys.

Example, R. curta. PL IV., fig. 4.

Shell with an elongated spire ; whirls numerous, flat ; canals long, the
posterior one running up the spire ; outer lip more or less expanded, with
only one sinus, and that close to the beak.

Distr., 5 sp. Red Sea, India, Borneo, China. Range, 30 fathoms.

Fossil, 70 sp. Neocomian — chalk (=aporrhais ?). 6 sp. Eocene — .
Britain, France, &c.

The older tertiary species have the outer lip enormously expanded, and
smooth-edged ; they constitute the section hippochrenes of Montfort (e. g.
Rost. ampla, Solander. London clay).

Sub-genus;" Spinigera, D'Orb. 184?. Shell like rostellaria ; whirls
keeled ; keel developed into a slender spine on the outer lip, and two on each
whirl, forming lateral fringes, as in ranella. Fossil, 5 sp. Inf. oolite-
chalk. Britain, France.

F 3

106 MANUAL OP THE MOLLUSCA.

SERAPHS, Montfort. (Terebellum, Lam.)

Etym., diminutive of terebra, an auger.

Type, S. terebellum (Linnaeus sp.)=T. snbulatum, Lam. PL IV., fig. 5.

Shell smooth, sub-cylindrical; spire short or none; aperture long and
narrow, truncated below ; outer lip thin.

Distr.y 1 sp. China. Philippines, 8 fms. (Cuming.)

Fossil, 5 sp. Eocene — . London, Paris.

The animal of terebeUum has an operculum like strombus ; its eye-pedicel's
are simple, without tentacles (Adams). In one fossil species, T. fusiforme,
there is a short posterior canal, as in rostellaria.

FAMILY II.

Shell with a straight anterior canal ; aperture entire behind.

Animal with a broad foot ; eyes sessile on the tentacles, or at their base ;
branchial plumes 2. Lingual ribbon long, linear ; rachis armed with a sin-
gle series of dentated teeth ; uncini, single. Predatory, on other mollusca.

MUREX (Pliny) L.

Types, M. palma-rosa?, PL IV., fig. 10. M. tenuispina, PL IV., fig. 9. M,
haustellum, PL IV., fig. 8. M. radix, pinnatus. ^

Shell ornamented with three or more continuous longitudinal varices ;
aperture rounded ; beak often very long ; canal partly closed ; operculum
concentric, nucleus sub-apical (PL IV., fig. 10) ; lingual dentition (M. erinaceus),
teeth single, 3 crested ; uncini single, curved.

Distr., 180 sp. "World- wide; most abundant on the W. coast of tropical
America, in the Chinese Sea, West coast of Africa, West Indies ; ranging
from low water to 25 fathoms, rarely at 60 fathoms.

Fossil, 160 sp. Eocene — . Britain, France, &c.

A few of the species usually referred to this genus, belong to pisania
and trophon.

The murices appear to form only one-third of a whirl annually, ending in
a varix ; some species form intermediate varices of less extent. M. erinaceus
a very abundant species on the coasts of the channel, is called "sting-winkle"
by fishermen, who say it makes round holes in the other shell-fish with its
beak. See p. 27. The ancients obtained their purple dye from species of
murex ; the small shells were bruised in mortars, the animals of the larger
ones taken out. (F. Col.) Heaps of broken shells of the M. trunculus and
caldron- shaped holes in the rocks may still be seen on the Tyrian shore.
(Wilde.) On the coast of the Morea, there is similar evidence of the
employment of M. brandaris for the same purpose. (M. Boblaye.)

TYPHIS, Montfort.
Etym., typhos, smoke.

GASTEROPODA. 107

Type, T. pungens. PL IV.. fig. 11.

Shell like murex ; but having tubular spines between the varfces, of which
the last is open, and occupied by the excurrent canal.

D-istr., 8 sp. Medit., W. Africa, Cape, India, W. America. — 50 fms.
Fossil, 8 sp. Eocene — . London, Paris.

PISANIA, Bivon, 1832.

Etym., a native of (the coast near) Pisa, in Tuscany.

Syn., Pollia, Enzina, and Euthria (Gray).

Types, P. maculosa. PL IV., fig. 14 (Enzina) zonata. PL IV., fig. 15.

Shell with numerous indistinct varices, or smooth and spirally striated ;
canal short ; inner lip wrinkled ; outer lip crenulated.

Operculum ovate, acute ; nucleus apical.

The pisanice have been usually confounded with buccinum, murex, and
ricinula,

Distr., about 120 sp. W. Indies, Africa, India, Philippines, S. Seas, W
America.

Fossil, ? sp. Eocene — . Brii,, France, &c.

RANELLA, LAM. Frog-shell.

Syn., Apollon, Montfort and Gray.

Types, R. grauifera. PL IV., fig. 12. R. spinosa.
• Shell with two rows of continuous varices, one on each side.

Operculum ovate, nucleus lateral.

Distr., 50 sp. Medit., Cape, India, China, Australia, Pacific, W. America.
Range, low-water to 20 fms.

Fossil, 23 sp. Eocene — .

TRITON. Lam.

Etym. Triton, a sea-deity. Syn., persona (Montf. Gray).

Type, T. tritonis, L. sp. PL IV., fig. 13.

Shell with disconnected varices ; canal prominent ; lips denticulated.

Operculum ovate, sub-concentric.

Distr., 100 sp. W. Indies, Medit,, Africa, India, China, Pacific, W.
America. Ranging from low-water to 10 or 20 fathoms ; one minute species
has been dredged at 50 fathoms.

Fossil, 45 sp. Eocene—. Brit., 'France, &c. Chile.

The great triton (T. tritonis) is the conch blown by the Australian and
Polynesian Islanders. A very similar sp. (T. nodiferus) is found in the
Medit., and a third in the W. Indies.

FASCIOLARIA, Lam.
Elym., fasciola, a band.
Type, F. tulipa. PL V., fig. 1.

108 MANUAL OF THE MOLLTJSCA.

Shell fusiform, elongated ; whirls round or angular ; canal open ; co-
lumellar lip tortuous, with several oblique folds. Operc. claw-shaped. F.
gigantea of the S. Seas, attains a length of nearly two feet.

Distr., 16 sp. W. Indies, Medit., W. Africa, India, Australia, S. Pacific,
W. America.

Fossil, 28 sp., U. chalk—. Prance.

TUEBINELLA, Lam.

Etym., diminutive of turbo, a top.

Type, T. pyrum. PL V., fig. 2.

Shell thick ; spire short ; columella with several transverse folds. Oper-
culum claw-shaped. Fig. 63. The shank-shell (T. pyrum} is carved by the
Cingalese, and reversed varieties of it, from which the priests administer
medicine, are held sacred.

Distr., 70 sp. W. Indies, S. America, Africa, Ceylon, Philippines,
Pacific, W. America.

Fossi^ 20 sp. Miocene — .

Sub-genera. Cynodonla (Schum.) T. cornigera. PI. V., fig. 3.

Latirus (Montf.) T. gilbula. PL V., fig. 4.

Cuma (Humphr.) T. angulifera, inner lip with a single prominent fold
operculum like purpura.

Lagena (Schum.) T. Smaragdula, L. sp. N. Australia.

CANCELLARIA, Lam.

Etym., cancellatus, cross-barred.

Type, C. reticulata. PL V., fig. 5.

Shell cancellated ; aperture channelled in front : columella with several
strong oblique folds ; no operculum. The animals are vegetable feeders.
(Desh.)*

Distr., 70 sp. W. Indies, Medit., W. Africa, India, China, California.

Fossil, 60 sp. Eocene — . Britain, France, &c.

TRICHOTROPIS, Broderip, 1829.

Etym., Thrix, (trichos) hair, and tropis, keel.

Type, T. borealis, PL VI., fig. 8. (= ? Admete, Phil., no operculum.)

Shell thin, umbilicated; spirally furrowed; the ridges with epidermal
fringes ; columella obliquely truncated ; operc. lamellar, nucleus external.

Animal with a short broad head ; tentacles distant, with eyes on the
middle ; proboscis long, retractile.

Lingual dentition similar to strombus ; teeth single, hamate, denticulated ;
uncini 3 : 1 denticulate 2 and 3 simple.

* Cancellaria and trichotropis form a small natural family connected with ceri*
thiadae and strombidce.

GASTEROPODA . 109

Listr., 8 sp. Northern seas. U. States, Greenland, Melville Island, Beh-
ring's Straits, N. Brit. 15 — 80 fms.

Fossil, 1 sp. Miocene — . Brit.

PYRULA, Lam. Tig-shell.

Etym., diminutive of pyrus, a pear.

•Syn., Ficula, Sw. Sycotypus, Br.,Cassidula, Humph. Cochlidium, Gray.

Type, P. ficus. (PI. V., fig. 6.)

Shell pear-shaped ; spire short ; outer lip thin ; columella smooth : canal
long, open. No operculum in the typical species.

Distr., 39 sp. W. Indies, Ceylon, Australia, China, W. America.

Fossil, 30 sp. Neocomian — . Europe, India. Chile.

Pyrula ficus has a broad foot, truncated and horned in front ; the mantle
forms lohes on the sides, which nearly meet over the hack of the shell.
Chinese seas, in 17 — 35 fms. water. (Adams.)

Sub-genera. Fulgur, Montf. P. perversa. (= Pyrella, Sw. P. spirillus.)

Rapana, Schum. P. bezoar, shell perforated. Operc. lamellar, nu-
cleus external.

Myristica. Sw. P. melongena. PI. V., fig. 7. Operc. pointed, curved.
Fusus, Lam. Spindle-shell.

Syn., Colus, Humph. Leiotomus, Sw. Strepsidura, Sw.

Type, F. colus. PI. V., fig. 8.

Shell fusiform ; spire many-whirled ; canal straight, long ; operculum
ovate, curved, nucleus apical. PI. V., fig. 9*.

Distr., 100 sp. World-wide. The typical sp. are sub-tropical. Aus-
tralia, New Zealand, China, Senegal, U. States, W. America, Pacific.

Fossil, 320 sp. Bath oolite ? Gault— Eocene— . Brit. &c.

Sub-genera, Trophon, Montf. F. magellanicus, PI. IV., fig. 16. 14 sp.
Antarctic and Northern seas. Brit, coast. 5 — 70 fathoms. Fossil, Chile,
Brit.

Clavella, Sw. (cyrtulus, Hinds) body- whirl ventricose, suddenly con-
tracted in front ; canal long and straight. Resembling a turbinella, without
plaits. 2 sp. Marquesas, Panama. Fossil, Eocene. F. longsevus (Solander),
Barton, &c.

Chrysodomus, Sw. F. antiquus (var.) PI. V., fig. 9. Canal short ; apex
papillary; lingual dentition like buccinum, 12 sp. Spitzbergen, Davis's
Straits, Brit., Medit., Kamschatka, Oregon. Low water to 100 fms. Fossil,
pliocene. Brit., Sicily.

Pusionella, Gray. F. pusio, L. sp. (=F. nifat, Lam.), columella keeled.
Operc., nucleus internal, 7 sp. Africa, India. Fossil, tertiary. France,

Fusus colosseus and proboscidalis, Lam., are two of the largest living
gasteropoda. Fusus (chrysodomus] antiquus, called the red-whelk on the
coasts of the channel, and " Buckie" in Scotland, is extensively dredged for

110

MANUAL OP THE MOLLUSCA.

the markets, being more esteemed than the buccinum. It is the " roaring
buckle," in which the sound of the sea may always be heard. In the Zetland
cottages it is suspended horizontally, and used for a lamp ; the cavity con-
taining the oil, and the canal the wick. (Fleming.) The reversed variety
(F. contrarius, Sby) is found in the Medit., and on the coast of Spain ; it
abounds in the pliocene tertiary (crag) of Essex. The fusus deformis, a
similar sp., found oif Spitzbergen, is always reversed.

FAMILY III. BUCCINID^.

Shell notched in front ; or with the canal abruptly reflected, producing a
kind of varix on the front of the shell.

Animal similar to murex ; lingual ribbon long and linear, (fig. 16) ra-
chidian teeth single, transverse, dentated in front ; uncini single. Carnivorous.

BUCCINUM, L. "Whelk.

Etym., buccina, a trumpet, or triton's-shell.

Type, B. undatum. PI. V., fig. 10.

Shell few whirled ; whirls ventricose ; aperture large ; canal very short,
reflected; operculum lamellar, nucleus external. (See pisania.)

Distr., 20 typical species. Northern and Antarctic seas. Low water to
100 fins. (Forbes). (B ? clathratum, 136 fins., off Cape.)

Fossil, 130 sp., including pisania, &c. Gault ? — Miocene — . Brit., France.

Fig. 70. Nidamental capsu'es of the Whelk.*

The whelk is dredged for the market, or used asx bait by fishermen ; it
may be taken in baskets, baited with dead fish. Its nidamental capsules are
aggregated in roundish masses, which, when thrown ashore, and drifted by
the wind resemble corallines. Each capsule contains five or six young, which,
when hatched, are like fig. 70, b : a, represents the inner side of a single
capsule, shewing the round hole, from which the fry have escaped.

* Fig. 70. From a small specimen, on an oyster-sjiell, in the cabinet of Albany
Hancock, Esq. The line at b, represents the length of the young shell.

GASTEROPODA. HI

Submenus. Cominella, Gray. Ex. B. limbosum, purpura maculosa, &c.
Operculutti as mfusus. About 12 sp.

PSEUDOLIVA, Swainson.

Etym., named from its resemblance to oliva, in form.

Syn., sulco-buccinum, D'Orb. Gastridium (Gray), G. Sowerby.

Type, P. plumbea. PL V., fig. 12.

Shell globular, thick ; with a deep spiral furrow near the front of the
body-whirl, forming, as in monoceros, a small tooth on the outer lip ; spire
short, acute ; suture channelled ; inner lip callous aperture notched in front ;
operculum ? Animal unknown.

Distr., 6 sp. ? W. America.

Fossil, 5 sp. Eocene. Brit., France, Chile.

? ANOLAX (Roissy), Conrad. Lea.

Etym., an aulax, without furrow.

Syn., buccinanops, D'Orb. Leiodomus, Sw. Bullia, Gray.

Types, A. gigantea, Lea- Buc. Isevigatum. B. semiplicata, PI. V., fig. 14.

Shell variable ; like buccinum, pseudoliva, or terebra ; sutures enamelled ;
inner lip callous.

Animal without eyes ; foot very broad ; tentacles long and slender ;
operculum pointed, nucleus apical.

Distr., 26 sp. Brazil, W. Africa, Ceylon, Pacific, W. America.

Fossil, 3 sp. Eocene — . N. America, France.

I? HALIA, Eisso.
Etym., halios, marine. Syn., priamus, Beck.
Types, bulla helicoides (Brocchi). Miocene, Italy. Helix priamus (Meus-
chen). Coast of Guinea ?

Shell like achatina ; ventricose, smooth ; apex regular, obtuse ; operc. ?
The fossil species occurs with marine shells, and sometimes coated by a coral
(lepralia).

TEREBRA, Lamarck. Auger-shell.
Syn., acus, Humph. Subula, Bl. Dorsanum, Gray.
Type, T. maculata. PI. V., fig. 13.

Shell long, pointed, many-whirled ; aperture small ; canal short ; operc.
pointed, nucleus apical.

Animal blind, or with eyes near the summit of minute tentacles.

Distr., 109 sp., mostly tropical. Medit. (1 sp.) India, China, W. America.

Fossil, 24 sp. Eocene — . Brit., France, Chile.

EBURNA, Lamarck. Ivory-shell.
Etym., elur, ivory. Syn., latrunculus, Gray.

12 MANUAL OF THE MOLLUSCA.

Type, E. spirata. PL V., fig. 11.

Shell umbilicated when young ; inner lip callous, spreading and covering
the umbilicus of the adult ; operculum pointed, nucleus apical.

Distr., 9 sp. Red Sea, India, Cape, Japan, China, Australia. Solid,
smooth shells, which have usually lost their epidermis, and are pure white,
spotted with dark red ; the animal is spotted like the shell. 14 fois. (Adams.)

NASSA, Lam. Dog-whelk.

Etym., nassa, a basket used for catching fish.

Syn., desmoulinsia and northia, Gray.

Type, N. arcularia. PL V., fig. 15.

Shell like buccinum ; columellar lip callous, expanded, forming a tooth-
like projection near the anterior canal. Operc. ovate, nucleus apical. Lingual
teeth arched, pectinated ; uncini, with a basal tooth.

The animal has a broad foot, with diverging horns in front, and two little
tails behind. N. obsoleta (Say) lives within the influence of fresh water and
becomes eroded. N. reticulata, L., is common on the English shores, at
low-water, and is called the dog-whelk by fishermen.

Distr., 68 sp. Low-water — 50 fms. World-wide. Arctic, Tropical and
Antarctic Seas.

Fossil, 19 sp. Eocene — . Brit., &c., N. America.

Sub-genus, cyllene, Gray. C. Oweni, PL V., fig. 17. Outer lip with a
slight sinus near the canal ; sutures channelled. W. Africa, Sooloo Islands,
Borneo. Fossil, Miocene, Touraine.

Cyclonassa, Swainson. C. neritea, PL V., fig. 16.

PHOS, Montfort.

Etym., pkos, light, Syn., rhinodomus, Sw.

Type, P. senticosus, PL V., fig. 18.

Shell like nassa ; cancellated ; outer lip striated internally, with a slight
sinus near the canal ; columella obliquely grooved.

The animal has slender tentacles, with the eyes near their tips.

Distr., 30 sp. (Cuming.) Red Sea, Ceylon, Philippines, Australia,
W. America.

? RINGICULA, Deshayes.

Etym., diminutive of ringens, from ringo, to grin.
Type, R. riugens, PL V,, fig. 21.

Shell minute, ventricose, with a small spire ; aperture notched, columella
callous, deeply plaited ; outer lip thickened and reflected.
Distr., 4 sp. ? Medit., India, Philippines, Gallapagos.
Fossil, 9 sp., Miocene — . Brit., Trance. Rinyicula is placed with nassa

GASTEROPODA. 113

by Mr. Gray, and Mr. S. Wood ; it appears to us very nearly allied to cinulia
(=avettana, D'Orb.) in tornatellidce.

PURPURA (Adans), Lam. Purple.

Type, P. persica, PL VI., fig. 1.

Shell striated, imbricated or tuberculated ; spire short ; aperture large,
slightly notched in front ; inner lip much worn and flattened. Operc.
lamellar, nucleus external. PL VI., fig. 2. Lingual dentition like murex
erinaceus ; teeth transverse, 3 crested ; uncini small, simple.

Many of the purpurce produce a fluid which gives a dull crimson dye ; it
may be obtained by pressing on the operculum. P. lapillus abounds on the
British coast at low-water, amongst sea-weed ; it is very destructive to
.mussel-beds (Fleming).

Distr., 140 sp. W. Indies, Brit., Africa, India, New Zealand, Pacific,
Chile, California, Kamschatka. From low-water — 25 fathoms.

Fossil, 30 sp. Miocene — . Brit., France, &c.

Sub-genus. Concholepas, Favan. C: lepas (Gmelin sp.) PL VI., fig. 3.
Peru. The only sp. diifers from purpura in the size of its aperture, and
smallness of the spire.

?PURPURINA (Lycett, 1847). D'Orb.

Shell, ventricose, coronated ; spire, short ; aperture, large, scarcely notched
in front.

Fossil, 9 sp., Bath-oolite. Brit. France. The type, P. rugosa, some-
what resembles purpura chocolatum (Duclos), but the genus probably belongs
to an extinct group.

MONOCEROS, Lam.

Etym., monos, one ; ceras, horn.

Syn., acanthina, Fischer. Chorus, Gray.

Type, M. imbricatum. PL VI., fig. 4 (Buc. monoceros, Chemn).

Shell, like purpura ; with a spiral groove on the whirls, ending in a pro-
minent spine on the outer lip. This genus is retained on account of its geo-
graphical curiosity ; it consists of sp. of purpura, lagena, turbinella, pseudo-
liva, &c.

Distr., 18 sp. W. coast of America.

Fossil, tertiary. Chile.

M. gigantens (chorus) has the canal produced like fusus. M. cingulatum
is a turbinella, and several sp. belong more properly to lagena.

PEDICULARIA, Swainson.

Type, P. sicula. PL VI., fig. 5 (thyreus, Phil.}.

Shell very small, limpet-like ; with a large aperture, channelled in front,
and a minute, lateral spire. Lingual dentition peculiar ; teeth single, hooked,
denticulated ; uncini., 3 ; 1, four-cusped, 2, 3, elongated, three-spined.

114 MANUAL OF THE MOLLUSCA.

Distr., 1 sp. Sicily, adhering to corals. Closely allied to purpura
madreporarum, Sby. Chinese Sea.

RICINULA, Lam.

Etym., dimunitive of ricinus, the (fruit of the) castor-oil plant.
Ex., R. arachnoides. PL VI., fig. 9 (=murex ricinus L.).
Shellt thick, tubereulated. or spiny ; aperture contracted by callous pro-
jections on the lips. Operc. as in purpura.

Distr. 25 sp. India, China, Philippines, Australia, Pacific.
Fossil, 3 sp. Miocene — . France.

PLANAXIS, Lam.

Type, P. sulcata. PI. VI., fig. 6. Syn., quoyia and leucostoma.
Shell, turbinated ; aperture notched in front ; inner lip callous, channel-
led behind ; operculum subspiral (quoyia) or semi-ovate. PI. VI., fig. 7.
Distr., 11 sp. W. Indies, Red Sea, Bourbon, India, Pacific, and Peru.
Fossil, miocene ?

Small coast shells, resembling periwinkles, with which Lamarck placed
them.

MAGILUS, Montf., 1810.

Syn., campulote, Guettard, 1759. Leptoconchus, Riippell.

Type, M. antiquus. PI. V., figs. 19, 20.

Shell, when young, spiral, thin ; aperture channelled in front ; adult,
prolonged into an irregular tube, solid behind ; operculum lamellar.

Distr., 1 sp. ? Red Sea. Mauritius. H

The magilus lives fixed amongst corals, and grows upwards with the
growth of the zoophytes in which it becomes immersed ; it fills the cavity of
its tube with solid shell, as it advances.

CASSIS, Lam. Helmet-shell.

Syn., bezoardica, Schum. Levenia, Gray. Cyprsecassis, Stutch.

Type, C. flammea. PL VI., fig. 14.

Shell, ventricose, with irregular varices ; spire, short ; aperture lo
outer lip reflected, denticulated ; inner lip spread over the body-whirl ; ca
sharply recurved. Operculum small, elongated ; nucleus in the middle of the
straight inner edge.

Distr., 34 sp. Tropical seas; in shallow water. W. Indies, Medit.,
Africa, China, Japan, Australia, New Zealand, Pacific, Mexico.

Fossil, 36 sp. Eocene — . Chile, France.

The queen. conch (C. madagascariensis) and other large species, are used
in the manufacture of shell cameos, p. 46. The periodic mouths (varices]
which are very prominent, are not absorbed internally as the animal grows.
ONISCIA, Sowerby.

Etym., oniscus, a wood louse. Syn,, morum, Bolten.

•

GASTEROPODA.

115

Type, 0. oniscus ; 0. cancellata, pi. VI., fig. 15.

Shell, with a short spire, and a long narrow aperture, slightly truncated
in front ; outer lip thickened, denticulated ; inner lip granulated.

Distr., 6 sp. W. Indies, China, Gallapagos. (20 fras.)

Fossil, 3 sp. Miocene.

CITHARA, Schumacher.

Etym., cithara, a guitar. Syn., mangelia, Reeve (not Leach).

Type, cancellaria citharella, Lam. (cithara striata, Schum.)

Shell, fusiform, polished, ornamented with regular longitudinal rihs;
aperture linear, truncated in front, slightly notched behind ; outer lip mar-
gined, denticulated within ; inner lip finely striated. Operc.

Distr., above 50 sp. of this pretty little genus were discovered by Mr.
Cuming, in the Philippine Islands.

CASSIDAEIA, Lam.

Etym., cassida, a helmet.

Syn., morio, Montf. Sconsia, Gray.

Type, C. echinophora. PI. VI., fig. 13.

Shell, ventricose ; canal produced, rather bent. No operculum.

Distr., 5 sp. Medit.

Fossil, 10 sp. Eocene — . Brit., France, &c.

Fig. 71.*

DOLIUM, Lam. Tne tun.
Type, D. galea. PI. VI., fig. 12.

Shell, ventricose, spirally furrowed ; spire small ; aperture very large ;
outer lip crenated. No operc.

Distr., 14 sp. Medit., Ceylon, China, Australia, Pacific.

* D. perdix, L. sp. £ nat. size (after Quoy). Vanicoro, Pacific. The proboscis
is exserted, and the siphon recurved over the front of the shell.

116 MANUAL OF THE MOLLUSCA.

Fossil, 1 sp. (? Chalk. Brit.) Miocene—. S. Em-ope.
Sub-genus, malea, Valenc. (D. personation) outer lip thickened and denti-
culated ; inner lip with callous prominences.

HARPA, Lani. Harp-shell.

Type, H. ventricosa. PL VI., fig. 11. (=Buc. harpa, L.)

Shell, ventricose ; with numerous ribs, at regular intervals; spire small ;
aperture large, notched in front. No operc.

The animal has a very large foot, with the front crescent- shaped, and
divided by deep lateral fissures from the posterior part, which is said to sepa-
rate spontaneously when the animal is irritated. Mostly obtained from deep-
water, and soft bottoms.

Distr., 9 sp. Mauritius, Ceylon, Philippines, Pacific.

Fossil, 4 sp. Eocene — . France.

COLUMBELLA, Lam.

Eti/m., diminutive of columba, a dove.

Type, C. mercatoria. PL VI., fig. 1 0.

Shell, small ; with a long narrow aperture ; outer lip thickened (especi-
ally in the middle), dentated ; inner lip crenulated. Operculum very small
lamellar.

Distr., 200 sp. Sub-tropical. W. Indies, Medit., India, Gallapagos,
California. Small, prettily-marked shells ; living in shallow water, on sandy
flats, or congregating about stones. (Adams.)

Fossil, 8 sp. Miocene — . (The Brit. sp.

Sub-genus. Columbellina, D'Orb. 4 sp. Cretaceous. France, India.

aper-

GASTEROPODA. 117

Sub-genera. Olivella, Sw. 0. jaspidea, pi. VI., fig. 19.

Animal with small, acute frontal lobes. Operc. nucleus sub-apical.

Scaphula, Sw. O utriculus, pi. VL, fig. 18.
Frontal lobes large, rounded, operculate.

Agaronia, Gray. 0. hiatula, pi. VI., fig. 17.
No eyes or tentacles. Frontal lobes moderate, acute.

ANCILLARIA, Lam.

Etyrn., ancilla, a maiden.

Types, A. subulata, pi. VI., fig. 20. A. glabrata, pi. VI. fig. 21.

Shell like oliva ; spire produced, and entirely covered with shining
enamel. Operc. minute, thin, pointed. Lingual teeth pectinated. Uncini
simple, hooked.

Animal like oli va ; said to use its mantle-lobes for swimming. (D'Orb.)
In A. glabrata, a space resembling an umbilicus, is left between the callous
inner lip and the body whirl.

Distr., 23 sp. Red Sea, India, Madagascar, Australia, Pacific.

Fossil, 21 sp. Eocene — . Brit., France, &c.

FAMILY TV. CcfNiDja, Cones.

Shell inversely conical ; aperture long and narrow ; outer
lip notched at or near the suture; operculum minute,
lamellar.

Animal, foot oblong, truncated in front ; with a conspi-
cuous (aquiferous?) pore in the middle. Head produced.
Tentacles far apart. Eyes on the tentacles. Gills 2. Lin-
gual teeth (uncini ?) in pairs, elongate, subulate, or hastate.

CONUS, L. Cone-shell.

Types, C. marmoreus, pi. VII., fig. 1. C. geographicus, antediluvianus, &c.

Shell conical, tapering regularly ; spire short, many-whirled ; columella
smooth, truncated in front ; outer lip notched at the suture ; operculum
pointed, nucleus apical.

Distr., 269 sp. AU tropical seas. Medit., 2 ; Africa, 23 ; Red Sea, 5 ;
Asia, 124 ; Australia, 16 ; Pacific, 25 ; Gallapagos, 3 ; W. America, 20 ;
W. Indies and Brazil, 21.

Fossil, 80 sp. Chalk — . Brit., France, India, &c.

The cones range northward as far as the Mediterranean, and southward to
the Cape ; but are most abundant and varied in equatorial seas. They inhabit
fissures and holes of rocks, and the warm and shallow pools inside coral-reefs,
ranging from low water to 30 and 40 fathoms ; they move slowly, and some-
times (C. aulicus) bite when handled ; they are all predatory. (Adams.)

Sub-genus. Conorbis, Sw. C. dormitor, PL VII., fig. 2. Eocene — .

Brit., France.

* Fig.- 72. Lingual teeth of bela turricula (after Lov6n).

118

MANUAL OF THE MOLLUSCA.

PLEUROTOMA, Lam.

Etym., pleura, the side, and toma, a notch. Syn., turns, Humph.

Types, P. Babylonica, PL VII., fig. 3. P. miteformis, &c.

Shell fusiform, spire elevated ; canal long and straight ; outer lip with a
deep slit near the suture. Operculum pointed, nucleus apical.

Distr., 430 sp. World-wide. Greenland, Brit., 17 ; Medit., 19 ; Africa,
15; Red Sea and India, 6 ; China, 90; Australia, 15; Pacific, 0? W.
America, 52 ; W. Indies and Brazil, 20. The typical sp. about 20 (China,
16 ; W. America, 4.) Low water to 100 fathoms.

Fossil, 300 sp. Chalk—. Brit., France, &c. Chile.

Sub-genera. Drillia, Gray. D. umbilicata, canal short.

Clavatula, Lam., canal short, operc. pointed, nucleus in the middle of the
inner edge. C. mitra, PL VII., fig. 4.

Tomella, Sw., canal long ; inner lip callous near suture. T. lineata.

? Clionella, Gray. C. sinuata, Born sp. (= P. buccinoides) freshwaters,
Africa.

Mangelia, Leach, (not Reeve). Apertural slit at the suture ; no operc.,
M. tamiata, PL VII., fig. 5. Greenland, Brit., Medit.

Bela, Leach. Operc. nucleus apical. B. turricula, PL VII., fig. 6.

Defrancia, Millet,* no operc. D. linearis, PI. VII., fig. 7.

? Lachesis, Risso, L. minima, PL VII., fig. 8, apex mammillated ; operc.
claw-shaped. Medit., S. Brit. In shallow water.

Daphnella, Hinds. D. marmorata. New Guinea. (Buc. junceum. L. clay).

FAMILY V. VOLUTION.

Shell turreted, or convolute ; aperture notched in front ; columella
liquely plaited. No operculum.

Fig. 73. t
Animal with a recurved siphon ; foot very large partly hiding the \

* According to Mr. S. Hanley, Defrancia is synonymous with Mangelia.
t Fig. 73. V. undulata, Lam. £ Australia (from Quoy and Gaiinard),

GASTEROPODA.

119

mantle often lobed and reflected over the shell ; eyes on the tentacles, or near
their base. Lingual ribbon linear ; rachis toothed ; pleura unarmed.

VOLUTA, L. Volute.
Type, V. musica, PL VII., fig. 9.

Syn., cymbiola, harpula, Sw. Volutella, D'Orb. Scapha, &c., Gray.
Shell ventricose, tliick ; spire short, apex mammillated ; aperture large,
deeply notched in front ; columella with several plaits. V. musica and a few
others have a small operculum.

Animal, eyes on lobes at the base of the tentacles ; siphon with a lobe on
each side, at its base ; lingual teeth 3 cusped.

V. vespertilio and hebrcea fill the nuclei of their spires with solid shelL
V. tbrasiliana forms nidamental capsules 3 inches long. (D'Orb.) In V.
angulata the mantle is produced into a lobe on the left side, and overlaps the
shell.

W. Indies, Cape Horn, W. Africa, Australia, Java, Chili.
Chalk — . India, Brit., Trance, &c.
Volutilithes, Sw. Spire pointed, many-whirled, columella
V. spinosus, PI. VII., fig. 10.
(V. abyssicola], dredged at 132 fathoms; off the Cape.

Distr., 70 sp.

Fossil, 80 sp.

Sub -genera.
plaits indistinct.

Living, 1 sp. (
(Adams).

Fossil, Eocene.

Brit., Paris.

Scaphella, Sw. Fusiform, smooth.
Ex., V. magellanica. Fossil, V. Lamberti, Crag, Suffolk.

Melo, Brod. Large, oval ; spire short.
Type, M. diadema, PL VII., fig. 11. New Guinea, 8 sp.

CYMBA, Broderip. Boat-shell.

Syn., Yetus (Adans.) Gray.

Type, C. proboscidalis, PL VII., fig. -12, and fig.
74 (= V. cymbium, L.)

Shell like voluta ; nucleus large and globular ;
whirls few, angular, forming a flat ledge round the
nucleus.

The foot of the animal is very large, and deposits
a thin enamel over the under side of the shell. It is
ovo-viviparous, and the young animal is very large
when born ; the nucleus becomes partly concealed by
the growth of the shell.

Distr., 10 sp. W. Africa, Lisbon.

MITRA, Lam. Mitre -shell.

Syn., turris, Montf. Zierliana, Gray. Tiara,
Sw.

Cymba.

120 MANUAL OF THE MOLLUSCA.

Types, M. episcopalis, PI. VII., fig. 13. M. vulpecula, fig. 14.

Shell fusiform, thick ; spire elevated, acute ; aperture small, notched in
front ; columella obliquely plaited ; operculum very small.

The animal has a very long proboscis ; it emits a purple liquid, having a
nauseous odour, when imitated. The eyes are placed on the tentacles, or at
their base. Range, from low water to 15 fathoms, more rarely in 15 — 80
fathoms.

Distr., 350 sp. Philippines, India, Red Sea, Medit., W. Africa, Green-
land (1 sp.), Pacific, W. America. The extra-tropical species are minute.
M. Greenlandica and M. cornea (Medit. sp.) are found together in the latest
British Tertiaries (Forbes.)

Fossil, 90 sp. Chalk — . India, Brit., France, &c.

Sub-genera. Imbricaria, Schum. (conoelix, Sw.)

Shell, cone-shaped. I. conica, PL VII., fig. 15.

CyUndra, Schum. (Mitrella, Sw.)

Shell, olive-shaped. C. crenulata, PL VII., fig. 16.

VOLVARIA, Lam.
"Etym., volva, a wrapper.
Type, V. buUoides, PL VII., fig. 1?.

Shell cylindrical, convolute ; spire minute ; aperture long and narrow ;
columella with 3 oblique plaits in front.
Fossil, 5 ? sp. Eocene. Brit., France.

MARGINELLA, Lam.

Etym., diminutive of margo, a rim.

Syn., porcellana (Adans.) Gray. Persicula, Schum.

Types, M. nubeculata, PL VII., fig. 18. M. persicula, fig. 19.

Shell, smooth, bright ; spire short or concealed ; aperture trunca
front; columella plaited; outer lip (of adult) with a thickened margin.
Animal similar to cyprsea.

Distr., 90 sp. Tropical, W. Indies, Brazil, Medit. (1 small sp.) W.
Africa, China, Australia.

Fossil, 30 sp. Eocene — . France, &c.

Sub-genus. Hyalina, Schum. Outer lip scarcely thickened.

Type, voluta pallida, Mont., W. Indies.

FAMILY VI. CYPR^IDJE. Cowries.

Shell convolute, enamelled ; spire concealed ; aperture narrow, (
at each end ; outer lip (of adult) thickened, inflected. No operculum.

Animal with a broad foot, truncated in front ; mantle expanded on each
side, forming lobes, which meet over the back of the shell ; these lobes are
usually ornamented with tentacular filaments; eyes on the middle of the ten-
tacles or near their base ; branchial plume single. Lingual ribbon long,

GASTEROPODA.

121

partly contained in the visceral cavity ; rachis I toothed ; uncini 3. The
cowries inhabit shallow water, near shore, feeding on zoophytes.

CYPILEA, L. Cowry.

Etym., Cypris, a name of Venus.

Types, C. tigris, C. mauritiana, PI. VII., fig. 20.

Shell ventricose, convolute, covered with
shining enamel ; spire concealed ; aperture
long and narrow, with a short canal at each
end ; inner lip crenulated ; outer lip inflected
and crenulated. (Lingual uncini similar).

The young shell has a thin and sharp
outer lip, a prominent spire, and is covered
with a thin epidermis, fig. 75. When full-
grown the mantle lobes expand on each side,
and deposit a shining enamel over the whole
shell, by which the spire is entirely concealed.
There is usually a line of paler colour which

indicates where the mantle lobes met. Cu-
Fig. 75. Cyprcea, . . J

young* prtea annulus is used by the Asiatic Islanders

;o adorn their dress, to weight their fishing-nets, and for barter.
Specimens of it were found by Dr. Layard in the ruins of Nimroud.
Dhe money-cowrey (C. moneta] is also a native of the Pacific and Eastern
eas : many tons weight of this little shell are annually imported into this
country, and again exported for barter with the native tribes of Western
Africa ; in the year 1848 sixty tons of the money-cowry were imported into
Jiverpool ; and in 1849 nearly three hundred tons were brought to the same
)lace, according to the statement of Mr. Archer in the Industrial Exhibition.
Mr. Adams observed the pteropodous fry of C. annulus, at Singapore, adhering
in masses to the mantle of the parent, or swimming in rapid gyrations, or
with abrupt jerking movements by means of their cephalic fins.

Distr., 150 sp. In all warm seas (except E. coast S. America?) but
most abundant in those of the old world. On reefs and under rocks at low
water.

Fossil, 78 sp. Chalk — . India, Brit., France, &c.

Sub -genera. Cyprovula, Gray. C. capensis, PI. VII., fig. 21. Aper-
tural plaits continued regularly over the margin of the canal.

Luponia, Gray. C, algoensis, PI. VII., fig. 22. Inner lip irregularly
plaited in front.

Fig. 76.
Trivial

* Fig. 75. Cyprsea testudinaria, L., young, China.

t Fig. 76. Trivia europaea, Mont. From the "British Mollusca," by Messrs.
Forbes and Hanley.

122 MANUAL OF THE MOLLUSCA.

Trivia, Gray. C. europsea, PL VII., fig. 23 ; fig. 76, and 15, B
Small shells with strise extending over the back. (Uncini ; 1st denticulat
2, 3, simple.)

Distr., 30 sp. Greenland, Brit., W. Indies, Cape, Australia, Pacific, W
America.

ERATO, Risso.

Etym., Erato, the muse of love-songs and mimicry. Type, E. Isevis
PL VII., fig. 24.

Shell minute ; like marginella ; lips minutely crenulated. Animal, liki
trivia.

Distr., 8 sp. Brit., Medit., W. Indies, China.

Fossil, 2 sp. Miocene — . Trance, Brit. (Crag.)

OVULUM, Lam.

Etym., dimunitive of ovum, an egg. Syn., amphiceras, Gronov.

Types, 0. ovum, pi. VII., fig. 25. O. gibbosa and verrucosa.

Shell) like cyprcea; inner lip smooth.

Distr., 36 sp. Warm seas. W. Indies, Brit., Medit. China, W. America

Fossil, 11 sp. Eocene — . France, &c.

Sub-genus, calpurna, Leach. O. volva (" The weaver's shuttle"). Aper.
ture produced into a long canal at each end. Toot narrow, adapted fo]
walking on the round stems of the gorgonice, &c., on which it feeds. C
patula inhabits the S. coast of Britain, it is very thin, and has a sharp oute]
lip.

SECTION B. HOLOSTOMATA. Sea-Snails.

Shell, spiral or limpet shaped ; rarely tubular or multivalve : margin ol
the aperture entire. Operculum, horny or shelly, usually spiral.

Animal with a short non-retractile muzzle ; respiratory siphon wanting,
or formed by a lobe developed from the neck (fig. 61), gills pectinated o:t
plume- like, placed obliquely across the back, or attached to the right side ol
the neck ; neck and sides frequently ornamented with lappets and tentaculai
filaments, Marine or fresh-water. Mostly phytophagous.*

FAMILY I. NATICIDJD.

Shell, globular, few-whirled ; spire small, obtuse ; aperture, semi-lunar :
lip, acute ; pillar often callous.

Animal, with a long retractile proboscis ; lingual ribbon linear ; rachw, I
toothed; uncini, 3 (similar to trivia, fig. 15, B.) ; foot very large ; mantle-lobe s
largely developed, hiding more or less of the shell. Species all marine.

* These " sections" are not very satisfactory, but they are better than any othei:
yet proposed, and they are convenient, on account of the great extent of the ordn
proso-branchiata. Natica and scalaria have a retractile proboscis. Pirena has
notched aperture, and aporrhais, a canal.

GASTEROPODA.

NATICA (Adans.), Lamarck.

Syn.t mammilla, Schm. Cepatia, Gray. Nacca, Risso.
><?, N. canrena, PI. VIII., fig. 1.

Shell, thick, smooth ; inner lip callous ; umbilicus large, with a spiral
callus ; epidermis thin, polished ; operculum sub-spiral.

Animal blind ; tentacles connate with a head veil ; front of the large foot
provided with a fold (mentmri), reflected upon and protecting the head ; operc.
lobe large, covering part of the shell ; jaws horny ; lingual ribbon short ;
branchial plume single.

The coloured markings of the naticse are very indestructible ; they are
frequently preserved on fossils. The naticce frequent sandy and gravelly bot-
toms, ranging from low water to 90 fathoms (Forbes). They are carnivorous,
feeding on the smaller bivalves (Gould), and are themselves devoured by the
cod and haddock. Their eggs are agglutinated into a broad and short spiral
band, very slightly attached, and resting free on the sands.

Distr., 90 sp. Arctic seas, Brit., Medit., Caspian, India, Australia,
China, Panama, W. Indies.

Fossil, 260 sp. Devonian — . S. America, N. America, Europe, India.

Sub-genera, naticopsis, M'Coy. N. Phillipsii. Shell imperforate ; inner
lip very thick, spreading. Operc. shelly (Brit. Mus.). Carb. limestone, 7 sp.

Neverita, Risso. N. Alderi. Fig. 77.

Lunatia, Gray. N. Ampullaria. Perforation simple; epidermis dull,
olivaceous. Northern seas.

Globulus, J. Sby. (Deshayesia,f Raulin ; Ampullina, Desh. not Bl.) N.
Sigaretina. PL VIII., fig. 2. Umbilicus narrow (rimate), lined by a thin
callus. Fossil, eocene. Brit., Paris.

Polmices, Montf., (naticella Guild.) N. mammilla. Shell oblong ; callus
very large, filling the umbilicus.

Cernina, Gray. N. fluctuata. PI. VIII., fig. 3. Globular, imperforate ;
inner lip callous, covering part of the body whirl.

Naticella, Muller. 19 sp. Fossil, Trias, S. Cassian.

* Fi#. 77. Natica Alderi, Forbes. From an original drawing, communicated by
Joshua Alder, Esq.

t Deshayesia was founded on a specimen v ith prominences on the pillar.

124 MANUAL OF THE MOLLTJSCA.

SIGARETUS (Adans.), Lamarck.

Syn., cryptostoma, Bl. Stomatia, Browne.

Type, S. haliotoides. PL VIII., tig. 4.

Shell, striated ; ear-shaped ; spire minute ; aperture very wide, oblique
(not pearly). Operculum minute, horny, suh-spiral.

The flat species are entirely concealed by the mantle when living ; the
convex shells only partially, and they have a yellowish epidermis. The ante-
rior foot lobe (mentum) is enormously developed,

Distr., 26 sp. W. Indies, India, China, Peru.

Fossil, 10 sp. Eocene — . Brit., France, S. America.

Sub-genus, naticina, Gray. N. papilla, pi. VIII., fig. j$. Shell ventricose,
thin, perforated. W. Indies, .Red Sea, China, N. Australia, Tasmania.
Eocene, Paris.

LAMELLARIA, Montagu.

Etym., lamella, a thin plate.

Syn., marsenia, Leach. Coriocella, Bl.

Type, L. perspicua. PL VIII., fig. 6.

Shell ear-shaped; thin, pellucid, fragile; spire very small; aperture
large, patulous ; inner lip receding. No operc.

Animal much larger than the shell, which is entirely concealed by the
reflected margins of the mantle ; mantle non-retractile, notched in front ; eyes
, at the outer bases of the tentacles. Lingual uncini 3, similar ; or one very
large.

Distr., 5 sp. Norway, Brit., Medit., New Zealand, Philippines.

Fossil, 2 sp. Miocene — . Brit. (Crag.)
NARICA, Recluz.

Syn., vanicoro, Quoy. Merria, Gray. Leucotis, Sw.

Type, N. cancellata. PL VIII., fig. 8.

Shell thin, white, with a velvety epidermis ; ribbed irregularly, and spi-
rally striated; axis perforated. Operc. very small, thin.

Animal, eyes at the outer base of the tentacles; foot with wing-like lobes.

Distr., 6 sp. W. Indies, Nicobar, Vanikoro, Pacific.

Fossil, 4 sp. Gault— (D'Orb.) Brit., France.
VELUTINA, Fleming.

Etym., velutinus, velvety (from vellus, a fleece).

Type, V. Isevigata. PL VIII., fig. 7-

Shell thin ; with a velvety epidermis ; spire small ; suture deep ; ap
very large, rounded ; peristome continuous, thin. No operc.

Animal with a large oblong foot ; margin of the mantle developed all
round, and more or less reflected over the shell; gills 2; head broad; tentacles
subulate, blunt, far apart ; eyes on prominences at their outer bases,
vorous. Lingual dentition like trivia (fig. 15, B.).

ciii/av/j.^o

-

GASTEROPODA. 125

Distr., 4 sp. Britain, Norway, N. America, Icy sea to Kamtschatka.
Living on stones near low water, and ranging to 30 fms.

Fossil, 3 sp. Miocene — . Brit.

Sub-genus. Otina (Gray). V. otis. Shell minute, ear shaped. Animal
like velutina, but with a simple mantle, and very short tentacles. W. and
S. W. Brit, coast ; inhabiting chinks of rocks, between tide-marks (Forbes).

FAMILY II. PYRAMIDELLID.E.

Shell spiral, turreted ; nucleus minute, sinistral ; aperture small ; columella
sometimes with one or more prominent plaits. Operculum horny, imbricated,
nuclus internal.

Animal with broad ear-shaped tentacles, often connate ; eyes behind the
tentacles, at their bases ; proboscis retractile ; foot truncated in front ; ton-
gue unarmed. Species all marine.

Several genera of fossil shells are provisionally placed in this order, from
their resemblance to eulima and cliemnitzia* Tornatella, usually placed in or
near this family, is opistho-branchiate.

PYRAMID ELLA, Lam.

Etym., dimunitive of pyramid, a pyramid.

Syn., obeliscus, Humph. (P. dolabrata. PI. VIII., fig. 11.)

Type, P. auris-cati. PL VIII., fig. 10.

Shell slender, pointed, with numerous plaited or level whirls ; apex sinis-
tral ; columella with several plaits ; lip sometimes furrowed internally. Operc.
indented on the inner side to adapt it to the columellar plaits. The shell of
the typical pyramidellse bears some resemblance to cancellaria.

Distr., 11 sp. W. Indies, Mauritius, Australia.

Fossil, 12 sp. Chalk ?— . France, Brit.

ODOSTOMIA, Fleming, 1824.

Etym., odous, a tooth, and stoma, mouth.

Type, 0. plicata, PL VIII., fig. 12.

Shell subulate or ovate, smooth ; apex sinistral ; aperture ovate ; peristome
not continuous ; columella with a single tooth-like fold ; lip thin ; operculum
horny, indented on the inner side.

Distr., sp. Brit., Medit., Red Sea, Australia.

Fossil, 15 sp.? Eocene — . Brit., France.

Very minute and smooth shells, having the habit of rissoce, and like them
sometimes found in brackish water. They range from low water to 40 fms.
The animal is undistinguishable from chemnitzia.

* " The Pyramidellidce present subjects of much interest to the student of extinct
mollusca; numerous forms, bearing all the aspect of being members of this family,
occur among the fossils of even the oldest stratified rocks. Many of them are gigantic
compared with existing species, and the group, as a whole, may be regarded, rather
» appertaining to past ages than the present epoch." (Forbes.)

126 MANUAL OF THE MOLLUSCA.

CHEM;NITZIA, D'Orbigny.

Etym., named in honour of Chemnitz, a distinguished conchologist of
Nuremburg, who published seven volumes in continuation of Martini's " Con-
chylien- Cabinet," 1780-95.

Syn., turbonilla, Risso. Parthenia, Lowe. Pyramis and Jaminea, Br.
Monoptigma, Gray. Amoura, Moller.

Type, C. elegantissima. PI. VIII., fig. 13.

Shell slender, elongated, many- whirled ; whirls plaited ; apex sinistral ;
aperture simple ; ovate ; peristome incomplete ; operculum horny, sub-spiraL

Animal, head very short, furnished with a long, retractile proboscis ; ten-
tacles triangular ; eyes immersed at the inner angles of the tentacles ; foot
truncated in front, with a distinct mentum.

Distr.y Brit. (4 sp.), Norway, Medit. Probably world- wide. Range from
low water to 90 fms.

Fossil, 180 sp. Permian — . Brit., Trance, &c.

The " melanias" of the secondary rocks are provisionally referred to this
genus. Those of the palaeozoic strata to loxonema.

Sub-genus. Eulimella, Forbes. E. scillse, Scacchi. 4 Brit. sp. Shell
smooth and polished ; columella simple ; apex sinistral.

EULIMA, Risso, 1826.

Etym., eulimia, ravenous hunger. Syn^ pasithea, Lea.

Type, E. polita. PI. VIII., fig. 14.

Shell small, white, and polished ; slender, elongated, with numerous level
whirls ; obscurely marked on one side by a series of periodic mouths, which
form prominent ribs, internally; apex acute; aperture oval, pointed above;
outex lip thickened internally ; inner lip reflected over the pillar. Operculum
horny, sub-spiral.

Animal, tentacles subulate, close, with the eyes immersed at their poste-
rior bases ; proboscis long, retractile ; foot truncated in front, mentum bi-
lobed ; operc. lobe winged on each side ; branchial plume single ; mantle with
a rudimentary siphonal fold.

The eulima3 creep with the foot much in advance of the head, which is
usually concealed within the aperture, the tentacles only protruding. (Forbes.)

Distr., 15 sp. Brit., Medit., India, Australia, Pacific. In 5 — 90 fms.
water.

Fossil, 40 sp. Garb. ?— . Brit., France, &c.

Sub-genus. Niso, Risso (=Bonellia, Desh.). N. terebellatus, Lam. sp.
Axis perforated.

Fossil, 3 sp. Eocene — . Paris, Distr., 5 sp. China, W. America
(Cumin g).

STYLINA, Fleming.

Ex., S. astericola. PI. VIII., fig. 15. (Syn. stylifer, Brod.)

,,

lerica

I

GASTEROPODA. 127

Shelly hyaline, globular or subulate, apex tapering, styliforra, nucleus
sinistral.

Animal with slender, cylindrical tentacles, and small sessile eyes at theii
outer bases ; mantle thick, reflected over the last whirls of the shell ; foot
large, with a frontal lobe. Branchial plume single. Attached to the spines
of sea-urchins, or immersed in living star fishes and corals.

PDistr., 6 sp. W. Indies, Brit., Philippines, Gallapagos.
.

LOXONEMA, Phillips.

Etym.y loxos, oblique, and nema, thread ; in allusion to the striated sur-
face of many species.

Shell elongated, many-whirled ; aperture simple, attenuated above, effused
below, with a sigmoidal edge to the outer lip.

Fossil, 75 sp. L. siluriaii — Trias. N. America, Europe.

MACROCHEILUS, Phillips.
Etym., macros, long, and cheilos, lip.

Shell, thick, ventricose, buccinoid ; aperture simple, effuse below ; outer
lip thin, inner lip wanting, columella callous, slightly tortuous.
Type, M. arculatus, Schlotheim sp. Devonian. Eifel.
Fossil, 12 sp. Devonian — Carboniferous. Brit., Belgium.

FAMILY III. CERITHIADJS. Cerites.

Shell spiral, elongated, many-whirled, frequently varicose ; aperture chan-
nelled in front, with a less distinct posterior canal ; lip generally expanded
in the adult ; operculum horny and spiral.

Animal with a short muzzle, not retractile ; tentacles distant, slender ;
eyes on short pedicels, connate with the tentacles ; mantle-margin with a
rudimentary siphonal fold ; tongue armed with a single series of median
teeth, and three laterals or uncini ; marine, estuary, or fresh-water.

CERITHIUM (Adans.). Bruguiere.

Etym.y ceration, a small horn.

Type., C. nodulosum. PI. VIII., fig. 16.

Shell turreted, many-whirled, with indistinct varices; aperture small,
with a tortuous canal in front; outer lip expanded; inner lip thickened.
Operculum horny, paucispiral. PI. VIII., fig. 16*.

Distr., above 100 sp. World-wide, the typical species tropical Norway,
Brit., Medit., W. Indies, India, Australia, China, Pacific, Gallapagos.

Fossil. 460 sp. Trias—. Brit., Trance, U. States, &c.

Sub-genera. Rhinoclavis, Sw. C. vertagus. Canal long, bent abruptly
operc., sub- spiral.

Bittium, Leach. C. reticulatum, PI. VIII., fig. 17. Small northern
species, ranging from low-water to 80 fathoms.

MANUAL OF THE MOLLTJSCA.

Triphoris, Deshayes. C. perversum, PI. VIII., fig. 18. 30 sp. Norway
— Australia. Fossil. Eocene — . Brit., France. Shell sinistral; anterior
and posterior canals tubular. The third canal is only accidentally present,
forming part of a varix.

Cerithiopsis, Forbes. C. tuberculare, Brit. Shell like bittium ; proboscis
retractile j operculum pointed, nucleus apical. Range 4 — 40 fms.

POTAMIDES, Brongniart. Fresh-water Cerites.
Etym., potamos, a river, and eidos, species.
Type., P. Lamarckii, Brong. (=*= Cerit. tuberculatum, Brard.)
Ex., P. mixtus. PI. VIII., fig. 19.

Syn., tympanotomus, Klein, C. fuscatum, Africa. Pirenella, Risso, C.
mammillatum, PL VIII., fig. 22.

Shell like cerithium, but without varices, in the very
numerous typical fossil species ; epidermis thick, olive-
brown ; operculum orbicular, many-whirled.

Distr., old world only ? Africa, India. In the mud
of the Indus they are mixed with sp. of ampullaria,
veiius, purpura, vulsella, &c. (Major W. E. Baker.)

Fossil (sp. included with cerithium) Eocene — .
Europe.

Sub-genera. Cerithidea. Sw., C. decollata, PL VIII.,
fig. 24. Aperture rounded : lip expanded, flattened.
Inhabit salt-marshes, mangrove swamps, and the mouths
of rivers ; they are so commonly out of the water as to
have been taken for land-shells. Mr. Adams noticed
them in the fresh-waters of the interior of Borneo,
. creeping on pontederia and sedges ; they often suspend

themselves by glutinous threads, fig. 78.

Distr. India, Ceylon, Singapore, Borneo, Philippines, Port Essington.
Terebralia, Sw. Cerith, Telescopium, PL VIII., fig. 21.
Shell pyramidal ; columella with a prominent fold, more or less continuous
towards the apex ; and a second, less distinct, on the basal front of the whirls
(as in nerinaa, fig. 79). India, N. Australia.

T. telescopium is so abundant near Calcutta, as to be used for burning
into lime ; great heaps of it are first exposed to the sun, to kill the animals.
They have been brought alive to England (Benson).
Pyrazus, Montf. Cerit, palustre, PL VIII., fig. 20.
Shell with numerous indistinct varices ; canal straight, often tubular ;
outer lip expanded. India, N. Australia.

Cerith radulum and granulatum of the W. African rivers approach very
nearly the fossil pot amides, but they have numerous varices.

* C. obtusa, Lam. sp. copied from Adams.

GASTEROPODA.

129

Lampania, Gray (batillaria, Cantor). Cerith, zonale. PI. VIII., fig. 23.

Shell without varices, canal straight. Chusan.

The fossil potamides decussatus, Brug., of the Paris basin, resembles this
section, and retains its spiral red bands.

NERIN^A, Defrance,

Etym., nereis, a sea-nymph,

Ex., N. trachea. Fig. 79.

Shell elongated, many-whirled, nearly cylindrical; aperture
channelled in front ; interior with continuous ridges on the co-
lumella and whirls.

Fossil, 150 sp. Inf. oolite — U. chalk. Brit., Trance, Ger-
many, Spain, and Portugal. They are most abundant, and attain
the largest size to the south; and usually occur in calcarious
strata, associated with shallow- water shells. (Sharpe.)

Sub-genera,. 1. Nerinaa. Folds simple: 2 — 3 on the co
lumella ; 1 — 2 on the outer wall ; columella solid, or perforated.
Above 50 sp.

2. Nerinella (Sharpe), columella solid; folds simple; co-
lumellar, 0 — 1 ; outer wall 1.

3. Trochalia (Sharpe), columella perforated, with one fold ;
outer wall simple, or thickened, or with one fold ; folds simple.

4. Ptygmatis (Sharpe), columella solid or perforated, usually
with 3 folds ; outer wall with 1 — 3 folds, some of them com-
plicated in form.

? FASTIGIELLA, Reeve.
Type., F. carinata, Reeve.

Shell like turritella ; aperture with a short canal in front (Mus., Cumins:,
and Brit. M.).

APORKHAIS, Aldrovandus.

Etym., aporrhais (Aristotle) "spout-shell" from aporrheo, to flow away.

Syn., chenopus Philippi.

Type, A. pes-pelecani. PL IV., fig. 7, and fig. 80.

Shell with an elongated spire ; whirls numerous, tuberculated ; aperture
narrow, with a short canal in front ; outer lip of the adult expanded and lobed
or digitated ; operc. pointed, lamellar.

Animal with a short broad muzzle ; tentacles cylindrical, bearing the eyes
on prominences near their bases, outside; foot short, angular in front;

Fig. 79.*

* Fig. 79. Nerinaea trachea, Desl., partly ground down to shew the form of the
interior. Bath oolite, Ranville. Communicated by John Morris, Esq.

G3

]30

MANUAL OF THE MOLLUSCA.

branchial plume single, long; lingual ribbon linear; teeth single, hooked,
denticulated ; uncini 3, the first transverse, 2 and 3 claw-shaped.

Fig. 80.*

Distr., 3 sp. Labrador, Norway, Brit., Medit. "W. Africa. Range, —
100 fins.

Fossil ; see Pteroceras and Eostellaria ; above 200 species, ranging from
the lias to the chalk, probably belong to this genus, or to genera not yet
constituted.

STRUTHIOLARIA, Lam.

Etym.) struthio, an ostrich (-foot), from the form of its aperture.

Type, S. straminea, PL IV., fig. 6.

Shell turreted ; whirls angular ; aperture truncated in front ; columella
very oblique ; outer lip prominent in the middle, reflected and thickened in
the adult; inner lip callous, expanded; operculum claw -shaped, curved in-
wards, with a projection from the outer, concave edge.

Animal with an elongated muzzle ? tentacles cylindrical ; eye-pedicels
short, adnate with the tentacles, externally ; foot broad and short, (Kiener.)

Distr. , 5 sp. Australia and New Zealand ; where alone it occurs sub-
fossil.

FAMILY IV. MELANIAM.

Shell spiral, turreted; with a thick, dark epidermis; aperture often
channelled, or notched in front; outer lip acute; operculum horny, spiral.
The spire is often extensively eroded by the acidity of the water in which the
animals live.

Animal with a broad non-retractile muzzle ; tentacles distant, subulate ;
eyes on short stalks, united to the outer sides of the tentacles ; foot broad and
short, angulated in front ; mantle-margin fringed ; tongue long and linear,
with a median and 3 lateral series of hooked rnulti-cuspid teeth. Often
viviparous. Inhabiting fresh- water lakes and rivers throughout the warmer
parts of the world. Only fossil in Britain.

the

Fig. 80. Aporrhais pes-pelecani, L., from a drawing by Joshua Alder, Esq
;( British Mollusea."

I

GASTEROPODA. 131

MELANIA, Lam.

Etym., Melania, blackness (from melas).

Type, M. amarula. PL VIII., fig. 25.

Syn. Thiara, Megerle. Pyrgula, Crist.

Shell turreted, apex acute (unless eroded) ; whirls ornamented with striae
or spines ; aperture oval, pointed above ; outer lip sharp, sinuous ; operculum
subspiral. PL VIII., fig. 25*.

Distr., 160 sp. S. Europe, India, Philippines, Pacific Islands. Distinct
groups in the southern states of N. America.

Fossil, 25 sp. Eocene—. Europe (v. chemnitzia).

Sub-genera. Melanatria, Bowdich. M. fluminea* PL VIII., fig. 26.
Aperture somewhat produced in front ; operculum with rather numerous
whirls. This section includes some of the largest sp. of the genus, and is well
typified by the fossil, M. Sowerbii (cerit. melanoides, Sby.) of the Woolwich
sands. Old World, India, Philippines.

Tibex, Oken, V. fuscatus, PL VIII., fig. 29. V. auritus. W. Africa.
Whirls spirally ridged, or muricated ; aperture broadly channelled in front.

Ceriphasia, Sw., C. sulcata. N. America. Aperture like vibex ; slightly
notched near the suture.

Hemisinus, Sw., H. lineolatus. W. Indies. Aperture channelled in
front.

Melafusus, Sw. (Io3 Lea. Glottella, Gray.) M. fluviatilis. PL VIII.,
fig. 27. IT. States. Aperture produced into a spout in front.

Melatoma, Anthony (not Sw.) M. altilis. Shell like anculotus ; with a
deep slit at the suture. U. States.

Anculotus, Say. A. prsemorsus. PL VIII., fig. 28. Shell globular;
spire very short ; outer lip produced. TJ. States.

Amnicola, Anthony. A. isogona. PL IX., fig. 23. U. States.

? Pachystoma, Gray. M. marginata, Eocene. Paris. Peristome thick-
ened externally, all round.

PALUDOMUS, Swainson.

Etym., palus, a marsh, and domus, home.

Syn., tanalia, Gray. Hemimitra, Sw.

Type, P. aculeatus, Gm. sp. PL IX., fig. 34.

Shell, turbinated, smooth or muricated; with wavy stains beneath the
olive epidermis ; spire small, usually eroded ; operc. horny, lamellar, nucleus
external. Animal like melania ; mantle-margin fringed (Eydoux).

Distr., 10 sp. Ceylon (Himalaya?) in the mountain-streams, sometimes
at an elevation of 6,000 feet. The Himalayan sp. (melania conica, Gray,

* This is a good section of melania, but Mr. Gray's type does not well represent it,
being more like a pirena in the form of its aperture.

132 MANUAL OP THE MOLLTJSCA.

hemimitra retusa, Sw., and several others), referred to this genus, have a
concentric operculum, like paludina.

MELANOPSIS, Lam.

Types, M. buccinoides, M. costata. PL VIII., fig. 30.

Shell ; body-whirl elongated ; spire short and pointed ; aperture distinctly
notched in front ; inner lip callous ; operculum sub -spiral.

Distr., 20 sp. Spain, Asia Minor, New Zealand.

Fossil, 25 sp. Eocene — . Europe.

Sub-genus. Pirena, Lam. (faunus, Montf.) P. atra. PL VIII., fig. 31.
Spire elongated, many whirled ; outer lip of the adult produced.

Distr. , 4 sp. ? S. Africa, Madagascar, Ceylon, Philippines.

FAMILY V. TURRITELLID^.

Shell tubular, or spiral ; upper part partitioned off ; aperture simple ;
operculum horny, many-whirled.

Animal with a short muzzle ; eyes immersed, at the outer bases of the
tentacles ; mantle-margin fringed ; foot very short ; branchial plume single ;
tongue armed.

TURRITELLA, Lam.

Etym., diminutive of turris, a tower.

Syn., terebellum, torcula, zaria and eglisia, Gray.

Type, T. imbricata. PI. IX., fig. 1.

Shell elongated, many-whirled, spirally striated ; aperture rounded, mar-
gin thin ; operculum horny, many -whirled ; with a fimbriated margin.

Animal with long, subulate tentacles ; eyes slightly prominent ; foot
truncated in front, rounded behind, grooved beneath ; branchial plume very
long ; lingual ribbon minute ; median teeth hooked, denticulated ; uncini 3,
serrulated. Carnivorous ?

Distr., 50 sp. World- wide. Ranging from the Laminarian Zone to 100
fms. W. Indies, U. States, Brit. (1 sp.), Iceland, Medit., W. Africa, China,
Australia, W. America.

Fossil, 170 sp., Neocomian — . Brit. &c., S. America, Australia.

Sub-genera. Proto, Defr., P. cathedralis, PL IX., fig. 3, aperture trun-
cated below.

Mesalia, Gray, M. sulcata (var.) PI. IX., fig. 2. Greenland— S. Africa.

Fossil, Eocene. Brit., France.

? ACLIS, Loven.

Etym., A, without, Tcleis, a projection.
Syn., alvania, Leach (not Risso).
Type, A. perforates, Mont. PL IX., fig. 4.
Shell minute, like turritella ; spirally striated ; aperture oval ;
prominent ; axis slightly rimate ; operculate.

GASTEROPODA. 133

Animal with a long retractile proboscis ; tentacles close together, slender,
inflated at the tips ; eyes immersed at the bases of the tentacles ; operc. lobe
ample, unsymmetrical ; foot truncated in front. Ranges to 80 fathoms water.
3 Brit. sp. Norway.

Fossil. ? sp., Miocene — . Brit. (Crag).

(LECUM, Fleming.

Syn., corniculina, Minister. Brochus, Bronn. Odontidium, Phil.

Type, C. trachea, PL IX, fig. 5. Young sp., fig. 6.

Shell at first discoidal, becoming decollated when adult ; tubular, cylindri-
cal, arched ; aperture round, entire ; apex closed by a mammillated septum.
Operc. horny, many-whirled. Lingual teeth, 0 ; uncini, 2, the inner broad
and serrulated.

Distr., Brit., 2 sp., 10 fathoms. Medit.

Fossil, 4 sp. Eocene — . Brit., Castelarquato.

VERMETUS, Adanson. Worm- shell.

Syn., siphonium, Gray. Serpuloides, Sassi.

Types, V. lumbricalis, PI. IX., fig. 7.

Shell tubular, attached ; sometimes regularly spiral when young ; always
irregular in its adult growth ; tube repeatedly partitioned off ; aperture round ;
operc. circular, concave externally.

Distr., Portugal, Medit., Africa, India.

Fossil, 12 sp. Neocomian — . Brit., Trance, &c.

? Sub-genus. Spiroglyplms, Daud. S. spirorbis Dillw. sp., irregularly
tubular ; attached to other shells, and half buried in a furrow which it makes
as it grows. Perhaps an annelide ?

SILIQUARIA, Brug.
Etym., siliqua, a pod.
Type, S. anguina, PL IX., fig. 8.

Shell tubular ; spiral at first, irregular afterwards ; tube with a continuous
longitudinal slit.

Distr., 7 sp. Medit., N. Australia. Found in sponges.
Fossil, 10 sp. Eocene — . France, &c.

SCALARIA, Lam. Wentle-trap.

Etym., scalaris, like a ladder. Type, S. pretiosa, PL IX., fig. 9 ( = T.
scalaris, L.)

Shell, mostly pure white and lustrous ; turreted ; many-whirled ; whirls
round, sometimes separate, ornamented with numerous transverse ribs ; aper-
ture round ; peristome continuous. Operc. horny, few- whirled.

Animal with a retractile proboscis -like mouth ; tentacles close together,
long and pointed, with the eyes near their outer bases ; mantle-margin simple,

134

MANUAL OF THE MOLLUSCA.

with a rudimentary siphonal fold ; foot obtusely triangular, with a fold '(men-
tum] in front. Lingual dentition nearly as in bulla ; teeth 0 ; uncini nume-
rous, simple; sexes distinct; predacious? Range from low water to 80
fathoms. The animal exudes a purple fluid when molested.

Distr., nearly 100 sp. Mostly tropical. Greenland, Norway, Brit.,
Medit., W. Indies, China, Australia, Pacific, 'W. America.

Fossil, nearly 100 sp. Coral-rag — . Brit., N. America, Chile, India.

FAMILY VI. LTTORINID.E

Shell spiral, turbinated or depressed, never pearly ; aperture rounded ;
peristome entire ; operculum horny, pauci-spiral.

Animal with a muzzle-shaped head, and eyes sessile at the outer bases of
the tentacles ; tongue long, armed with a median series of broad, hooked teeth,
and 3 oblong, hooked uncini. Branchial plume single. Foot with a linear
duplication in front, and a groove along the sole, Mantle with a rudimentary
siphonal canal ; operc. lobe appendaged.

The species inhabit the sea, or brackish water, and are mostly literal, feed-
ing on algse.

LITORINA, Ferussac. Periwinkle.

Etym.) litus, the sea-shore.

Type, L. litorea, PL IX., fig. 10.

Shell turbiuated, thick, pointed, few-whirled ; aperture
rounded, outer lip acute, columella rather flattened, imperforate,
operculum pauci-spiral, fig. 81. Lingual teeth hooked and tri-
lobed ; uncini hooked and deutated.

Distr., 40 sp. The periwinkles are found on the sea-shore, in
all parts of the world. In the Baltic they live within the in- Fig. 81.
fluence of fresh- water, and frequently become distorted ; similar monstrosities
are found in the Norwich crag.

The common sp. (L. litorea) is oviparous ; it inhabits the lowest zones of
sea-weed between tide-marks. An allied sp. (L. rudis) frequents a higher
region, where it is scarcely reached by the tide ; it is viviparous, and the
young have a hard shell before their birth, in consequence of which the species
is not eaten. The tongue of the periwinkle is two inches long ; its foot is
divided by a longitudinal line, and in walking the sides advance alternately.
The periwinkle and trochus are the food of the thrush, in the Hebrides, during
winter.

Fossil, 10 sp? Miocene — . Brit., &c. It is probable that a large propor-
tion of the oolite and cretaceous shells referred to turbo, belong to this genus,
and especially to the section tectaria.

Sub-genera. Tectaria, Cuvier, 1817 (= Pagodella, Sw.) L. pagodus,
PI. IX., fig. 11. Shell muricated or granulated ; sometimes with an umbilical

GASTEROPODA.

135

W. Indies, Zanzibar,

fissure. Operc. with a broad, membranous border.
Pacific.

Modulus, Gray (and nina, Gray) M. tectiun, PL IX., fig. 13. Shell tro-
chiform or naticoid ; porcellanous ; columella perforated ; inner lip worn or
toothed ; operc. horny, mftey-whirled. Distr., Philippines, W, America.

Fossarus (Adaus.) Philippi. F. sulcatus, PL IX., fig. 12. Syn., pha-
sianema, Wood. Shell perforated ; inner lip thin; operc. not spiral. Distr.,
Medit. Fossil, 3 sp. Miocene — . Brit., Medit.

Risella, Gray. Lit., melanostoma, PL IX., fig. 14. Shell trochiform,
with a flat or concave base ; whirls keeled ; aperture rhombic, dark or varie-
gated, operc. pauci-spiral. Distr., N. Zealand.

SOLARIUM, Lam. Stair-case shell.

Etym., solarium, a dial.

Syn., architectoma, Bolten. Philippia, Gray. Helicocryptus, D'Orb?

Type., S. perspectivum, PL IX., fig. 15.

Shell orbicular, depressed ; umbilicus wide and deep ; aperture rhombic ;
peristome thin ; operculum horny, sub-spiral.

The spiral edges of the whirls, seen in the umbilicus, have been fancifully
compared to a winding stair-case.

Distr., 25 sp. Tropical seas. Medit., E. Africa, India, China, Japan,
Australia, Pacific, W. America.

Fossil, 56 sp. Eocene — . Brit., &c. 26 other sp. (oolites — chalk,) are
provisionally referred to this genus ; the cretaceous sp. are nacreous (v.
trochus).

Sub-genera. Torinia, Gray. T. cylindracea, operc. conical,
multi-spiral, with projecting edges, fig. 82. Living, New Ire-
land. Fossil, Eocene. Brit. Paris.

Omalaxis, Desh. (altered to bifrontia) S. bifrons, discoidal,
the last whirl disengaged. 6 sp. Eocene, Paris, Brit.

? Orbis, Lea. Discoidal, whirls quadrate. Fossil, Eocene,
America.

? PHORUS, Moritf. Carrier-shell.

Fig. 82.*

ihoreus, a carrier.
Syn., onustus, Humph., Xenophorus, Fischer.
Examples, P. conchyliophorus, Born. P. corrugatus, PL X.,
Shell trochiform, concave beneath ; whirls flat, with foliaceous
or stellated margins, to which shells, stones, &c., are usually
affixed ; aperture very oblique, not pearly ; outer lip thin, much
produced above, receding far beneath. Operc. horny, imbricated,
nucleus external (as \i\purpura and paludomus,) with the trans-
verse scar seen through it, fig. 83. (Mus. Cuming.)

* Operculum of S. patulum, Lam. f , from Deshayes.

fig.l.

136 MANUAL OF THE MOLLUSC A.

Animal with an elongated (non-retractile ?) proboscis ; tentacles long and
slender, with sessile eyes at their outer bases ; sides plain j foot narrow,
elongated behind. (Adams.) Related to scahtria ?

Most of the phori attach foreign substances to the margins of their shells,
as they grow ; particular species affecting stones, whilst others prefer shells or
corals. They are called " mineralogists," and " conchologists," by collectors ;
P. Solaris and P. indicus are nearly or quite free from these disguises. They
are said to frequent rough bottoms, and to scramble over the ground, like the
strombs, rather than glide evenly.

Distr., 9 sp. "W. Indies, India, Malacca, Philippines, China, \V. America.

Fossil, 15 sp. Chalk ? — Eocene—. Brit., France. Shells extremely like
the recent phorus, are met with even in the carb. limestone.

LACUNA, Turton.

Etym., lacuna, a fissure.

Type, L. pallidula, PI. IX., fig. 16. Syn., medoria, Gray.

Shell, turbinated, thin ; aperture semi-lunar ; columella flattened, with
an umbilical fissure. Operc. pauci-spiral.

Animal, operculigerous lobe furnished with lateral wings and tentacular
filaments. Teeth, 5 casped ; uncini 1, 2 dentated, 3 simple. Spawn (ootheca}
vermiform, thick, semicircular. Range, low- water — 50 fathoms.

Distr., Northern shores, Norway, Brit., Spain. Fossil, 1 sp. Glacial
beds, Scotland.

? LITIOPA, Rang.

Etym., litos, simple, ope, aperture.

Type, L. bombix. PI. IX., fig. 24.

Shell minute, pointed ; aperture slightly notched in front ; outer lip sim-
ple, thin ; inner lip reflected. Operc. spiral.

Distr., Atlantic, Medit., on floating sea-weed, to which they adhere by
threads. Fossil, 1 sp. Miocene (Crag.).

RISSOA, Fremenville.

Etym., named after Risso,* a French zoologist.

Type, R. labiosa, PI. IX., fig. 17. Syn., cingula, Mem.

Shell minute, white or homy ; conical, pointed, many-whirled ; smooth,
ribbed, or cancellated ; aperture rounded ; peristome entire, continuous ; outer
lip slightly expanded and thickened. Operc. sub-spiral.

The animal has long, slender tentacles, with eyes on small prominences
near their outer bases ; the foot is pointed behind ; the operculigerous lobe
has a wing-like process and a filament (cirrus) on each side. Lingual teeth
single, sub-quadrate, hooked, dentated ; uncini 3 ; 1 dentated, 2, 3, claw-

* It is much to be regretted that some modern naturalists have tried to find out
and bring into use the obscure genera of Risso, and the worthless fabrications of Mont-
fort and Rafinesque, which had better have remained unknown.

GASTEROPODA. 137

shaped. They range from high- water to 100 fathoms, hnt abound most in
shallow water, near shore, on beds vlfucus and zostera.

Distr., about 70 sp. Universally distributed, but most abundant in the
north temperate zone. X. America, W. Indies, Norway, Brit., Medit., Cas-
pian, India, &c. Rissoa parva adheres to sea -weeds, by threads, like litiopa
(Gray).

Fossil, 100 sp. Permian — . Brit., Prance, &c.

Sub-genera. Kzssoina, D'Orb. Aperture channelled in front. Living and
Fossil (10 sp. Bath oolite.— Brit.) =Tuba, Lea? America.

Hydrobia, Hartm. ( =Paludinella, Loven. Paludestrina, D'Orb.) Shett
smooth ; foot rounded behind ; operc. lobe without filament. Type, litorina
ulvffi, PL IX., fig. 18. Fossil, 10 sp. Wealden— . Brit., &c.

Syncera, Gray (Assiminea, Leach). S. hepatica. Shell like Hydrobia;
tentacles connate with the eye pedicels, which equal them in length. Teeth
5—7 cusped; uncini 1, 2, dentated, 3 rounded. Dlstr., brackish water.
Brit., India.

Nemahira, Benson. N. deltse. PI. IX., fig. 21. Aperture contracted;
peristome entire. Operc. pauci-spiral. Fossil, eocene. Isle of 'Wight.

Jeffreysia, Alder (=Rissoella, Gray, MS.), J. diaphana. Shell minute,
translucent. Operc. semilunar, imbricated, with a projection from the straight,
inner side. (PI. IX., fig. 19.) Head elongated, deeply cleft, and produced
into two tentacular processes ; mouth armed with denticulated jaws, and a
spinous tongue ; tentacles linear, eyes far behind, prominent, only visible
through the shell ; foot bi-lobed in front. 2 sp. Brit. On sea- weed, near
low water (Alder).

SKEXEA, Fleming.

Etym., named after Dr. Skene of Aberdeen; a cotemporary of Linnaeus.

Syn., delphino'idea, Brown.

Type, S. planorbis, PI. IX., fig. 20.

Shell minute orbicular, depressed, few- whirled; peristome continuous,
entire, round. Operc. pauci-spiral. Animal like rissoa, foot rounded behind.
Found under stones at low- water, and amongst the roots of corallina qffiri-
nalis.

Distr., r sp. Northern seas. Norway, Brit.

r TRUXCATELLA, Risso. Looping-snail.

Type, T. truncatula. PL IX., fig. 25. (Mus., Hanley.)

Shell minute, cylindrical, truncated ; whirls striated transversely ; aper-
ture oval, entire ; peristome continuous. Operculum sub-spiral !

Animal with short, diverging triangular tentacles ; eyes centrally behind ;
head bi-lobed; foot short, rounded at each end (Forbes).

The truncatellse are found on stones and sea- weeds between tide-marks,
and survive many weeks out of the water (Lowe). They walk by contracting

138 MANUAL OF THE MOLLUSCA.

the space between their lips and foot, like the geometric caterpillars (Gray).
They are found semi-fossil, along with the human skeletons in the modern
limestone of Guadaloupe.

Distr., 15 sp. W. Indies, Brit., Medit., Rio, Cape, Mauritius, Philippines,
Australia, Pacific (Cuming).

? LITHOGLYPHUS, Megerle.

Type, L. fuscus. PI. IX., fig. 22.

Shell naticoid, often eroded ; whirls few, smooth ; aperture large, entire ;
peristome continuous, outer lip sharp, inner lip callous ; umbilicus rimate ;
epidermis olivaceous ; operculum pauci-spiral.

Distr.t sp. Europe, Oregon.

FAMILY VII. PALUDTNID^E.

Shell conical or globular, with a thick, olive-green epidermis ; aperture
rounded ; peristome continuous, entire ; operculum horny or shelly, normally
concentric.

Animal with a broad muzzle ; tentacles long and slender ; eyes on short
pedicels, outside the tentacles. Inhabiting fresh-waters in all parts of the
world.

PALUDINA, Lam. River-snail.

Etym., palm (paludis) a marsh. Syn., viviparus, Gray.

Type, P. Listen. PL IX., fig. 26. (P. vivipara, fig. 61.)

Shell turbinated, with round whirls ; aperture slightly angular behind ;
peristome continuous, entire ; operc. horny, concentric. Animal with a long
muzzle, and very short eye-pedicels; neck with a small lappet on the left side,
and a larger on the right, folded to form a respiratory siphon ; gill comb-like,
single ; tongue short ; teeth single, oval, slightly hooked and denticulated ;
uncini 3, oblong, denticulated. The paludinee are viviparous ; the shells of
the young are ornamented with spiral rows of epidermal cirri.

Distr., 60 sp. Rivers and lakes throughout the N. hemisphere ; Black
sea, Caspian.

Fossil, 50 sp. Weald—. Brit., &c.

Sub-genus. Bithinia (Prideaux), Gray. B. tentaculata, PI. IX., fig. 27.
Shell small ; operc. shelly. Animal oviparous ; with only one neck-lappet,
on the right side. The bithinise oviposit on stones and aquatic plants ; the
female lays from 30 to 70 eggs in a band of three rows, cleaning the surface
as she proceeds ; the young are hatched in three or four weeks, and attain
their full growth in the second year (Bouchard).

AMPULLAIIIA, Lam. Apple-snail, or idol-shell.

Etym., ampulla, a globular flask.

jEr.. A. globosa, PI. IX., fig. 30. Syn., pachylabra, Sw.

Shell globular, with a small spire, and a large ventricose body-v
peristome thickened and slightly reflected. Operc. shelly.

UU.U. autaiii

Ddy-whirl ;

GASTEROPODA. 139

Animal with a long incurrent siphon, formed by the left neck-lappet ;
left gill developed, but much smaller than the right* ; muzzle produced into

Fig. 84.t

two long tentacular processes ; tentacles extremely elongated, slender. Inha-
bits lakes and rivers throughout the warmer parts of the world, retiring deep
into the mud in the dry season, and capable of surviving a drought, or removal
from the water for many years. In the lake Mareotis, and at the mouth of
the Indus, ampullarise are abundant, mixed with marine shells. Their eggs
are large, inclosed in capsules, and aggregated in globular masses.

Distr.., 50 sp. S. America, West Indies, Africa, India.

Sub-genera. Pomus, Humph. A. ampullacea. Operc. horny.

Marisa, Gray (ceratodes, Guilding). A. cornu-arietis PI. IX., fig. 31.
Operc. horny. Shell discoidal.

Asolene, D'Orb. A. platse. Animal without a respiratory siphon ; operc.
shelly. Distr., S. America.

Lanistes, Montf. A. bolteniana, L., PL IX., fig. 32. Shell reversed,
urnbilicated, peristome thin ; operc. horny. Distr., W. Africa, Zanzibar,
Nile.

Meladomus, Sw. Paludina olivacea, Sby. Shell reversed, imperforate ;
peristome thin ; operc. horny.

? AMPHIBOLA, Schumacher.
Syn., ampullacera, Quoy. Thallicera, Sw.

* The ampullaria is said to have a pulmonic sac in addition to its gills (Gray,
Owen), but we have not met with specimens sufficiently well preserved to exhibit it.

would be very desirable to examine the amp. cornu-arietis, in which, probably,
the gills are symmetrical, as in the cephalopods.

t Fig. 84. Ampullaria canaliculata, Lam. (from D'Orb.) South America. The
branchial siphon (s) is seen projecting from the left side ; o, operculum

140 MANUAL OF THE MOLLUSCA.

Type, A. australis, PL IX., fig. 33.

Shell globular, with an uneven, battered, surface ; columella fissured ;
outer lip channelled near the suture ; operc. horny, sub-spiral. Animal with-
out tentacles ; eyes placed on round lobes ; air-breathing ; respiratory cavity
closed, except a small valvular opening on the right side ; a large gland occu-
pies the position of the gill of paludina ; sexes united (Quoy). Mr. Gray
places this genus amongst the true pulmonifera.

Distr., 3 sp. Shores of New Zealand and the Pacific Islands. The living
shells sometimes have serpula attached to them (Cuming). They are eaten
by the New Zealanders.

VALVATA, Miiller. Valve-shell.

Types, V. piscinalis, PI. IX., fig. 28. V. cristata, PI. IX., fig. 29.

Shell turbinated, or discoidal, umbilicated ; whirls round or keeled ; aper-
ture not modified by the last whirl ; peristome entire ; operc. horny, multi-
spiral.

Animal with a produced muzzle ; tentacles long and slender, eyes at their
outer bases ; foot bi-lobed in front ; branchial plume long, pectinated, parti-
ally exserted on the right side, when the animal is walking. Lingual teeth
broad ; uncini 3, lanceolate ; all hooked and denticulated.

Dislr., 6 sp. Brit., N. America.

Fossil, 19 sp. Wealden— . Brit., Belgium, &c.

FAMILY VIII. NERITIDJS.

Shell thick, semi-globose; spire very small; cavity simple, from the
absorption of the internal portions of the whirls ; aperture semi-lunate ; colu-
mellar side expanded and flattened ; outer lip acute. Operculum shelly, sub-
spiral, articulated.

At each end of the columella there is an oblong muscular impression,
connected on the outer side by a ridge, on which the operculum rests ; within
this ridge the inner layers of the shell are absorbed.

Animal with a broad, short muzzle, and long slender tentacles ; eyes on
prominent pedicels, at the outer bases of the tentacles ; foot oblong, triangular.
Lingual dentition similar to the turbinidce. Teeth 7 ; uncini very numerous.

Fig. 85.*
* Fig. 85. Nerita polita, L. (from Quoy and Gaimard) New Ireland.

GASTEROPODA. 4

NERITA, L. Nerite.

Etym. Nerites, a sea-snail, from nereis.

Type, N. ustulata, PL IX., fig. 35.

Shell thick, smooth or spirally grooved ; epidermis horny ; outer lip
thickened and sometimes denticulated within ; columella broad
and flat, with its inner edge straight and toothed; operc.
shelly, fig. 86.

Distr., 116 sp. Nearly all warm seas. W. Indies, Red
Sea, Zanzibar, Philippines, Australia, Pacific, W. America,
(Cuming). Fig. 86.*

Fossil, 60 sp. Lias — . Brit. &c. The palaeozoic nerites are referred by
D'Orbigny to turbo, natica, &c. N. haliotis is a pileopsis.

Sub-genera. Neritoma, Morris, 1849. N. sinuosa, Sby. Portland stone,
Swindon. (Mus., Lowe). Shell ventricose, thick; [apex eroded; aperture
with a notch in the middle of the outer lip. Casts of this shell are common,
and exhibit the condition of the interior characteristic of all the nerites ; it
was probably fresh- water.

Neritopsis, Grateloup. N. radula, PI. VIII., fig. 9. Shell like nerita ;
inner lip with a single notch in the centre.

Distr., 1 sp. Pacific. Fossil, 20 sp. Trias ? Brit., France, &c.

Velates, Montf. N. perversa, Gm. PL IX., fig. 36. Inner lip very
thick and callous ; outer lip prolonged behind, and partially enveloping the
spire.

PILEOLTJS, (Cookson) J. Sowerby.

Etym., pileolus, a little cap.

Type, P. plicatus, PL IX., fig. 37, 38.

Shell limpet-like above, with a sub-central apex ; concave beneath, with a
small semi-lunar aperture, and a columellar disk, surrounded by a broad con-
tinuous peristome.

Distr., marine ; only known as fossils of the Bath oolite, Ancliffe, and
Mmchinhampton, 3 sp. P. neritoides is a neritina.

NERITINA, Lam. Fresh-water nerite.

Examples, N. zebra, PL IX., fig. 39. N. crepidularia, PL IX., fig. 40.

Shell rather thick at the aperture, but extensively absorbed inside ; outer
lip acute ; inner straight denticulated ; operc. shelly, with a flexible border ;
slightly toothed on its straight edge.

Animal like nerita ; lingual teeth ; — median, minute ; laterals 3, 1 large,
sub-triangular, 2, 3, minute ; uncini about 60, first very large, hooked, denti-
culated ; the rest equal, narrow, hooked, denticulated.

The neritinse are small globular shells, ornamented with a great variety
of black or purple bands and spots, covered with a polished horny epidermis

* Fig. 86. Operculum of N. peloronta. W. Indies.

142 MANUAL OF THE MOLLUSCA.

They are mostly confined to the fresh waters of warm regions. One sp. (N
fluviatilis) is found in Brit, rivers, and in the brackish water of the Baltic
Another extends its range into the brackish waters of the N. American rivers
And the West Indian N. viridis and meleagris, are fonnd in the sea.

N. crepidularia has a continuous peristome, and approaches navicella ii
form ; it is found in the brackish waters of India. N. corona (Madagascar
is ornamented with a series of long tubular spines.

Distr., 76 sp. W. Indies, Norway, Brit., Black Sea, Caspian, India
Philippines, Pacific, "W. America.

Fossil, 20 sp. Eocene — . Brit., France. &c.

NAVICELLA, Lam.

Etym.) navicella, a small boat. Type, N. porcellana. PI. IX., fig. 41.

Shell obloug, smooth, limpet-like ; with a posterior, sub-marginal apex
aperture as large as the shell, with a small columellar shelf, and elongate
lateral muscular scars ; operculum very small, shelly.

Distr., 18 sp. India, Mauritius, Moluccas, Australia, Pacific.

FAMILY IX., TURBINID^.

Shell spiral, turbinated or pyramidal, nacreous inside; operculum calca
rious and pauci -spiral, or horny and multi-spiral.

Animal with a short muzzle ; eyes pedunculated at the outer bases of thi
long and slender tentacles ; head and sides ornamented with fringed lobes am
tentacular filaments (cirri) ; branchial plume single ; lingual ribbon long an(
linear, chiefly contained in the visceral cavity ; median teeth broad ; lateral
5, denticulated; uncini very numerous (sometimes nearly 100), slender, witl
hooked points (Fig. 15, A.).

Marine, feeding on sea-weeds (algce).

The shells of nearly all the turbinidse are brilliantly pearly, when tli
epidermis and outer layer of shell are removed ; many of them are used in th
state for ornamental purposes.

TURBO, L. Top-shell.

Etym., turbo, a whipping-top.

Syn., batillus, marmorostoma, callopoma, &c. (Gray).

Type, T. marmoratus. PI. X., fig. 2.

Shell turbinated, solid ; whirls convex, often grooved or tuberculatec
aperture large, rounded, slightly produced in front ; operculum shelly ar
solid, callous outside, and smooth, or variously grooved and mammillate
internally horny and pauei-spiral. In. T. sarmaticus the exterior of the ope:
culum is botryoidal, like some of the tufaceous deposits of petrifying -(

Animal with pectinated head-lobes.

; wells.

GASTEROPODA. 143

Distr., 60 sp. Tropical seas, W. Indies, Medit., Cape, India, China,
Australia, New Zealand, Pacific, Peru.

Fossil, 360 sp. (including litorina) L. Silurian—. Universal.

PHASIANELLA, Lam. Pheasant-shell.

Syn., eutropia (Humphr,) Gray. Tricolea, Risso.

Type, P. australis. PL X., fig. 3.

Shell elongated, polished, richly coloured ; whirls, convex ; aperture oval,
not pearly ; inner lip callous, outer thin ; operc. shelly, callous outside, sub-
spiral inside.

Animal with long ciliated tentacles ; head-lobes pectinated, wanting in the
minute sp. ; neck-lobes fringed ; sides ornamented with 3 cirri ; branchial
plume long, partly free ; foot rounded in front, pointed behind ; its sides
moved alternately in walking ; lingual teeth even-edged ; laterals 5, hooked,
denticulated; uncini about 70, gradually diminishing outwards, hooked and
denticulated.

Distr., 25 sp. Australia, large sp. India, Philippines ; small sp. Medit.,
Brit., W. Indies, very small sp.

Fossil, 70 sp. Devonian ? — . Europe.

The similarity of the existing Australian fauna, to that of the European
oolites, strengthens the probability that some, at least, of these fossil shells
are rightly referred to Phasianella.

IMPERATOR, Montf.

Type, I, imperialis, PI. 10, fig. 4. Syn., calcar.

Shell trochiform, thick, with a flat or concave base; whirls keeled or
stellated ; aperture angulated outside, brilliantly pearly ; operc. shelly.
Distr., 20 sp. ? S. Africa, India, Australia, New Zealand.

Fig. 87.*

TROCHUS, L.
Etym., trochus, a hoop.

Syn., cardinalia, tegula, and livona, Gray. Infundibulum, Montf. Chlo-
rostoma, Sw. Trochiscus, Sby. Monilea, Sw.

Types, T. niloticus. PL X., fig. 5. T. zizyphinus. Fig. 87.

* Fig. 87. Trochus zizyphinus, L., Pegwell Bay, Kent.

144

MANUAL OF THE MOLLTJSCA.

the smaller

Shell pyramidal, with nearly a flat base ; whirls numerous, flat, variously
striated ; aperture oblique, rhombic, pearly inside ; columella
twisted, slightly truncated ; outer lip thin ; operculum horny,
multi-spiral. Fig. 88 (T. pica).

Animal with 2 small or obsolete head-lobes between the
tentacles ; neck lappets large : sides ornamented with lobes,
and 3 — 5 cirri ; gill very long, linear ; lingual teeth 11, den_
ticulated ; uncini — 90, diminishing outwards.

Distr., 150 sp. World-wide. Low- water to 15 fathoms ;
species range nearly to 100 fathoms.

Fossil, 360 sp. Devonian — . Europe, N. America, Chile.

Sub-genera. Pyramis, Chemn., Tr. obeliscus, PI. X., fig. 6, columella
contorted, forming a slight canal.

Gibbula, Leach. Tr. magus, Brit. Shell depressed, widely umbilicated ;
whirls tumid. Head-lobes largely developed; lateral cirri 3.

Margarita, Leach. Tr. helicinus. PL X., fig. 7. Shell thin ; cirri 5 on
each side. Distr., 17 sp. Greenland, Brit., Falkland Islands. Near low-
water, under stones and sea- weed.

Elenchus, Humph. (= Canthiridus, Montf.) E. iris. PI. X., fig. 8.
Smooth, thin, imperforate, with a prominent base. Australia, N. Zealand.
F. iris scarcely differs in form from Tr. zizyphinus ; E. ladius is like a
pearly phasianella ; and E. varians (bankivia, Menke) wrould be called a
chemnitzia, if fossilized. PL X., fig. 9.

ROTELLA, Lamarck.

Etym., diminutive of rota, a wheel, (Syn., Helicina, Gray !)
Type, R. vestiaria. PL X., fig. 10.

Shell, lenticular, polished ; spire depressed ; base callous ; lingual teeth
; uncini numerous, sub-equal.

13

Distr., 10 sp.

, fig. 12.

India, Philippines, China, New Zealand.
MONODONTA, Lam.

Etym., monos, one, and odous, (odontos) a tooth.

Syn., labio, Oken. Clanculus, Montf. Otavia, Risso.

Types, M. labeo. PL X., fig. 11. M. pharaonis. PL X.,

Shell, turbinated, few- whirled ; whirls spirally grooved and granulated :
lip thickened internally, and grooved ; columella toothed, more or less pro-
minently and irregularly ; operc. horny, many- whirled.

Distr., 10 sp ? W. Africa, Red Sea, India, Australia.

Fossil, (included with trochus) Devonian — . Eifel.

DELPHINULA (Roissy), Lam.
Etym., diminutive of delphinus, a dolphin. (= Cyclostoma, Gray !)

GASTEROPODA. 145

Type, D. laciniata. PL X., fig. 13. (= T. delphinus; L.)

Shell orbicular, depressed ; whirls few, angulated, rugose, or spiny ; aper-
ture round, pearly ; peristome continuous ; umbilicus open ; operculum horny,
many-whirled. On reefs, at low-water.

Animal without head-lobes ; sides lobed and cirrated.

Distr., 20 sp. Red Sea, India, Philippines, China, Australia.

Fossil, 30 sp. ? Trias ? — Miocene — . Europe.

Sub-genera. Liotia, Gray. L. gervillii. PI. X., fig. 14. Aperture
pearly, with a regular, expanded border. Operc. multi-spiral, calcarious.
Distr., 6 sp. Cape, India, Philippines, Australia. Fossil., Eocene — . Brit.,
France.

Collonia, Gray, 1850. C. marginata. PL X., fig. 16. Peristome sim-
ple. Operc. calcarious, with a spiral rib on the outer side. Distr.., Africa,
Fossil, Eocene — . Paris.

Cyclostrema, Marryat. C. cancellata, PL X., fig. 15. Shell nearly dis-
coidal, cancellated, not pearly ; aperture round, simple ; umbilicus wide.
Operc. spiral, calcarious. Distr., 12 sp. Cape, India, Philippines, Australia,
Peru. In 5 — 17 fathoms. Serpularia, Roemer, has the whirls smooth and
dis-united. Eocene, Paris.

ADEOKBIS, Searles Wood.

Type, A. sub-carinatus. PL X., fig. 17.

Shell minute, not nacreous, depressed, few- whirled, deeply umbilicated ;
peristome entire, nearly continuous, sinuated in its inner side, and slightly so
externally. Operc. shelly, multi-spiral.

Distr., W. Indies — China. Low-water to 60 fathoms,

Fossil, 5 sp. Miocene — . Brit.

EUOMPHALUS, Sowerby.

Etym., eu, wide, and omphalos, umbilicus.

Syn., schizostoma, Bronn. -Maclurea, Leseuer. Ophileta, Vanuxem.
Platyschisma, McCoy.

Type, E. pentagonalis. PL X., fig. 18.

Shell depressed or discoidal ; whirls angular or coronated ; aperture poly-
gonal; umbilicus very large. Operc. shelly, round, multi-spiral (Salter).

Fossil, 80 sp., L. sil. — Trias. N. America, Europe, Australia.

Sub-genus. Phanerotimis, J. Sby. 1840, E. cristatus, Phil. Carb. lime-
stone. Brit. Shell discoidal ; whirls separate ; outer margin sometimes
foliaceous.

STOMATELLA, Lam.

Etym., diminutive of stoma, the aperture.

Type, S. imbricata. PL X., fig. 19.

Shell ear-shaped, regular j spire small ; aperture oblong, very large and

H

146 MANUAL OF THE MOLLUSCA.

oblique, nacreous ; lip thin, even-edged ; operc. circular, horny, multi-spiral.
On reefs and under stones at low-water.

Distr., 20 sp. Cape, India, N. Australia, China, Japan, Philippines.

Sub-genus? Gena, Gray. Spire minute, marginal ; no operc ulum. 16
sp. Red Sea, India, Seychelles, Swan River, Philippines (Adams).

BRODERIPIA, Gray.

Etym., named in honour of W. J. Broderip, Esq., the distinguished con-
(•hologist.

Type, B. rosea. PI. X., fig. 20.

Shell minute, limpet-shaped, with a posterior sub-marginal apex ; aper-
ture oval, as large as the shell, brilliantly nacreous.

Distr., 8 sp. Philippines ; Grimwood's Island, S. Seas (Cuming).

FAMILY X. HALIOTID^E.

Shell spiral, ear-shaped or trochiform ; aperture large, nacreous ; outer
lip notched or perforated. No operculum.

Animal with a short muzzle and subulate tentacles ; eyes on pedicels at
the outer bases of the tentacles ; branchial plumes 2 : mantle-margin with a
posterior (anal) fold or siphon, occupying the slit or perforation in the shell ;
operc. lobe rudimentary ; lingual dentition similar to trochus.

In addition to the true haliotids, we have retained in this group such of
the trochi-forin shells as have a notched or perforated aperture.

HALIOTIS, L. Ear-shell.

Etym., hallos, marine, and ous (otos) an ear.

Type, H. tuberculata, PL X., fig. 21.

Shell ear-shaped, with a small flat spire ; aperture very wide, iridescent ;
exterior striated, dull ; outer angle perforated by a series of holes, those of the
spire progressively closed. Muscular impresssion horse-shoe shaped, the left
branch greatly dilated in front. In H. tricostalis (padollus, Montf.) the
shell is furrowed parallel with the line of perforations.

Animal with fimbriated head-lobes ; side-lobes fimbriated and cirrated ;
foot very large, rounded. Lingual teeth; — median small; laterals single,
beam-like ; uncini about 70, with denticulated hooks, the first 4 very large.

The haliotis abounds on the shores of the Channel Islands, where it is
called the ormer, and is cooked after being well beaten to make it tender.
(Hanley) ; it is also eaten in Japan. It is said to adhere very firmly to the
rocks, with its large foot, like the limpet. The shell is much used for inlay-
ing, and other ornamental purposes.

Distr., 75 sp. Brit., Canaries, Cape, India, China, Australia, New Zealand,
Pacific, California.

Fossil, 4 sp. Miocene — . Malta, &c.

Sub-genus? Deridobranchus, Ehrenberg, D. argus, Red Sea. Shell

p such of

GASTEROPODA. 147

large and thick, like haliotis, but entirely covered by the thick, hard, plaited
mantle of the animal.

STOMATIA (Helblin), Lamarck.

Etym,, stoma, the aperture.

Type, S. phymotis, PL X., fig. 22.

Shell like haliotis, but without perforations, their place being occupied by
a simple furrow ; surface rugose, spirally ridged ; spire small, prominent
aperture large, oblong, outer margin irregular.

Distr., 12 sp. Java, Philippines, Torres Straits, Pacific. Under stones
at low water (Cuming).

Fossil. M. D'Orbigny refers to this genus 18 sp., ranging from the L.
Silurian to the chalk, N. America, Europe.

SCISSURELLA, D'Orb.
Etym., diminutive of scissus, slit.

Type, S. crispata, PI. X., fig. 23. Syn., anatomus, Montf.
Shell minute, thin, not pearly ; body-whirl large ; spire small ; surface
striated ; aperture rounded, with a slit in the margin of the outer lip. Oper-
culate.

Distr., 5 sp. Norway, Brit., Medit. In 7 fathoms water off the Orkneys,
and in deep water east of the Zetland Isles.
Fossil, 4 sp. Miocene — . Brit., Sicily.

PLEUROTOMARIA, Defrance.
Etym., pleura, side, and tome, notch.
Type, P. anglica, PI. X., fig. 24.

SJtett, trochiform, solid, few-whirled, with the surface variously ornamented ;
aperture sub -quadrate, with a deep slit in its outer margin. The part of the
slit which has been progressively filled up, forms a band round the whirls.

Fossil, 400 sp. Lower silurian — chalk. N. America, Europe, Australia.
Specimens from clay strata retain their nacreous inner layers, those from the
chalk and limestones have lost them, or they are replaced by crystalline spar.
Pleurotomariae with wavy bands of colour have been obtained in the carb.
limestone of Lancashire. In this extensive group there are some species
which rival the living turbines in magnitude and solidity, whilst others are as
frail as ianthina.

Sub-genus. Scalites, Conrad (= raphistoma, Hall.) E.g., S. angulatus
and stamineus. L. silurian, New York. Shell thin ; whirls angular, flat
above (tabulated), 8 sp. L. silurian — carb. Poly-tremaria, IV Orb., is
founded on P. catenata, Koninck, in which the margins of the slit are wavy,
converting it into a series of perforations.

MURCHTSONIA, D'Archiac.

Etym., named in honour of Sir Roderick I. Murchison.
Type, M. bilineata. PI. X., fig. 25.

148 MANUAL OF THE MOLLUSCA.

Shell elongated, many- whirled ; whirls variously sculptured, and zoned
like pleurotomaria ; aperture slightly channelled in front ; outer lip deeply
notched.

The murchisonise are characteristic fossils of the palseozoic rocks ; they have
been compared to elongated pleurotomarige, or to cerithia with notched aper-
tures ; the first suggestion is most probably correct.

Fossil, 50 sp. L. silurian -—Permian. N. America, Europe.
TROCHOTOMA, Lycett.

Etym., trochus, and tome, a notch.

Syn., ditremaria, D'Orb.

Type, T. conuloides. PI. X., fig. 26.

Shell trochiform, slightly concave beneath; whirls flat, spirally striated,
rounded at the outer angles ; lip with a single perforation near the margin.

Fossil, 10 sp. Lias — Coral Rag, Brit., Trance, &c.

? CIKRUS, Sowerby.

Etym., cirrus, a curl.

Type, C. nodosus, Sby. Min. Con. t. 141 and 219.

Shell sinistral, trochiform, base level ; last whirl enlarging rather more
rapidly, somewhat irregular.

Fossil, 2 sp. Inf. oolite, Bath oolite. Brit., France.

This genus was founded on a pleurotomaria, a euomphalus, and C. nodosus.
(r. Min. Con.) It is still doubtful what species may be referred to it.

IANTHINA, Lam. Violet-snail.

Etym., ianthina, violet-coloured.

Type, helix ianthina L. (I. fragilis, Lam.) PL X., fig. 27-

Shell thin, translucent, trochiform ; nucleus minute, ;Jstyliform, sinistral ;
whirls few, rather ventricose ; aperture four- sided ; columella tortuous ; lip
thin, notched at the outer angle. Base of the shell deep violet, spire nearl)
white.

Animal: — head large, muzzle-shaped, with a tentacle and eye -pedicel or

* Fig. 89. Ianthina fragilis, Lam. (from Quoy and Gaimard). Atlantic, a raft
b egg capsules, c gills, d tentacles and eye-stalks.

GASTEROPODA. 14J

each, side, but no eyes ; foot small, secreting a float composed of numerou
cartilaginous air- vesicles, to the under surface of which the ovarian capsule
are attached. Lingual ribbon, rachis unarmed ; uncini numerous, simpl
(like scalaria). Branchial plumes 2. Sexes separate.

Distr,., 6 sp. Atlantic, Coral sea.

The ianthinse, or oceanic-snails, are gregarious in the open sea, whei
they are found in myriads, and are said to feed on the small blue acalephi
(velella}. They are frequently drifted to the southern and western Britis
shores, especially when the wind continues long from the S.W. ; in Swanse
bay the animals have been found quite fresh. When handled they exude
violet fluid from beneath the margin of the mantle. In rough weather the
are driven about and their floats broken, or detached, in which state they ai
often met with. The capsules beneath the further end of the raft have bee
observed to be empty, at a time when those in the middle contained youn
with fully formed shells, and those near the animal were filled with egg
They have no power of sinking and rising in the water. The raft, which :
much too large to be withdrawn into the shell, is an extreme modification <
the operculum.

FAMILY XI. FISSURELLID.E.

Shell conical, limpet- shaped; apex recurved ; nucleus spiral, often dii
appearing in the course of growth ; anterior margin notched, or apex perft
rated ; muscular impression horse-shoe shaped, open in front.

Animal with a well-developed head, a short muzzle, subulate tentacle
and eyes on rudimentary pedicels at their outer bases ; sides ornamented wit
short cirri ; branchial plumes 2, symmetrical ; anal siphon occupying the ai
terior notch or perforated summit of the shell. Lingual dentition similar 1
trochus.*

FISSURELLA, Lam. Key-hole limpet.

Etym., diminutive offissura, a slit.

Type, F. Listeri. PL XL, fig. 1.

Shell oval, conical, depressed with the. apex in front of the centre ai
perforated ; surface radiated or cancellated ; muscular impression with tl
points incurved.

In very young shells the apex is entire and sub-spiral ; but as the perfi
ration increases in size it encroaches on the summit and gradually removi
it. The key-hole limpets are locomotive ; they chiefly inhabit the laminaris
zone, but range downwards to 50 fms.

Distr., 120 sp. America, Brit., S. Africa, India, China, Australia. T
California— Cape Horn.

* Fissurella is the best gasteropod for comparison with the bivalves ; its large gill
placed one on each side, and its symmetrical shell, pierced with a median orifice f
the escape of the out-going branchial current, are unmistakeable indications of horn
logic* with the lamelli-branchiata. See p. 48.

150 MANUAL OP THE MOLLUSCA.

Fossil, 25 sp. Carb. ? oolites — . Brit., France.

Sub-genera. Ptipillia, Gray. F. apertura, Born. ( = hiantula, Lam.)
Shell smooth, surrounded by a sharp white edge ; perforation very large.
Distr., S. Africa.

FissureUidcea, D'Orb. F. hiatula, Lam. (=megatrema, D'Orb.) Shell
cancellated ; covered by the mantle of the animal. 3 sp. Cape, Tasmania.

(Macroschisma, Sw.) F. macroschisma. PL XL, fig. 2. Anal aperture
close to the posterior margin of the shell. The animal is so much larger than
its shell, as to be compared to the testacelle by Mr. Cuming. Distr., Philip-
pines, Swan river.

Lucapina, Gray. F. elegans, Gray (=aperta, Shy.). Shell white, can-
cellated, margin crenulated ; covered by the reflected mantle. 3 sp. California.

PUNCTURELLA, Lowe.

Syn., cemoria, Leach. Diadora, Gray.

Type, P. noachina. PI. XL, fig. 3.

Shell conical, elevated, with the apex recurved ; perforation in front of the
apex, with a raised border internally ; surface cancellated.

Distr., 2 sp. Greenland, Boreal America, Norway, N. Brit., Tierra-del-
fuego. In 20 — 100 fathoms water.

Fossil, in the glacial formations of N. Brit.

RIMULA, Defrance.

Etym., diminutive of rima, a fissure. (Syn., Rimularia.)
Recent type, R. Blainvillii. PI. XL, fig. 4.

Shell thin and cancellated, with a perforation near the anterior margin.
Distr. , several sp. found on sandy mud at low- water, or dredged in fron
10 — 25 fms. Philippines (Cuming).

Fossil, 3 sp. Bath oolite — coral-rag. Brit., France.

EMARGINULA, Lam.

Etym., dimunitive of emarginata, notched.

Type, E. reticulata. PI. XL, figs. 5, 6.

Shell oval, conical, elevated, with the apex recurved ; surface cancellated ;
anterior margin notched, Muscular impression with recurved points. The
nucleus (or shell of the fry) is spiral, and resembles scissurella. The anterior
slit is very variable in extent. The animal of Emarginula (and also of punc-
turella; has an isolated cirrus on the back of the foot, perhaps representing
the operculigerous lobe (Forbes). Lingual dentition; median teeth sub-
quadrate ; laterals 4, oblong, imbricated ; uncini about 60, the first large and
thick, with a lobed hook, the rest linear, with serrulated hooks (Loven).

Distr., 26 sp. W. Indies, Brit., Norway, Philippines, Australia. Range
from low- water to 90 fathoms.

Fossil, 40 sp. Trias — . Brit., France.

aargin.
in from

GASTEROPODA. 151

Sub-genus. Hemitoma, Sw. Type, E. octoradiata. (E. rugosa. PI. XL.
figs. 7, 8.) Shell depressed ; anterior margin slightly channelled.

PARMOPHORUS, Blainville. Duek's-bill limpet.

Etym., parme, a shield, and phoreus, a bearer.

Type, P. australis. PL XL, fig. 9. Syn., Scutus, Montf.

Shell lengthened-oblong, depressed ; apex posterior ; front margin arched
Muscular impression horse-shoe shaped, elongated. The shell is smooth anc
white, and permanently covered by the reflected borders of the mantle. Th<
animal is black, and very large compared with the shell ; its sides are fringec
with short cirri, and its eyes sessile on the outer bases of thick tentacles ; i
is found in shallow- water, and walks freely (Cuming).

Distr., 10 sp. New Zealand, Australia, Philippines, Singapore, Red Sea
Cape.

Fossil, 3 sp. Eocene ? — . Paris basin.

FAMILY XII. CALYPTILEID^E. Bonnet-limpets.

Shell limpet-like, with the apex more or less spiral ; interior simple, o
divided by a shelly -process, variously shaped, to which the adductor muscle
are attached.

Animal with a distinct head ; muzzle lengthened ; eyes on the externs
bases of the tentacles ; branchial plume single. Lingual teeth single, uncini 3

The bonnet-limpets are found adhering to stones and shells ; most of then
appear never to quit the spot on which they first settle, as the margins c
their shells become adapted to the surface beneath, whilst some wear awa;
the space beneath their foot, and others secrete a shelly base. Both thei
form and colour depend on the situation in which they grow ; those found i
the cavities of dead shells are nearly flat, or even concave above, and colour
less. They are presumed to feed on the sea-weed growing round them, or o:
animacules ; a calyptrcea, which Professor Forbes kept in a glass, ate a sma^
sea slug (goniodoris) which was confined with it. Both calyptreea and pile
opsis sometimes cover and hatch their spawn in front of their foot (Alder an
Clarke).

Mr. Gray arranges the bonnet-limpets next after the vermetidse ; thei
lingual dentition is like velutina.

CALYPTR^EA, Lam. Cup-and-saucer limpet.

Etym., catyptra, a (lady's) cap.

Syn., lithedaphus, Owen.

Types, C. equestris. PI. XL, fig. 10. C. Dillwynnii, fig. 11.

Shell conical; limpet-shaped; apex posterior, with a minute, spire
nucleus ; margin irregular ; interior with a half-cup shaped process on th
posterior side, attached to the apex, and open in front. Surface rugose o
cancellated.

152 MANUAL OF THE MOLLUSCA.

Animal with a broad muzzle ; tentacles rather short ; lanceolate ; eyes on
bulgings at the outer bases of the tentacles; mantle-margin simple, sides
plain. Found under stones, between tide-marks, and in shallow water
(Cuming).

Distr., 50 sp. W. Indies, Honduras, Brit., Medit., Africa, India, Philip-
pines, China, Japan, New Zealand, Gallapagos, Chili,

Fossil, 30 sp. Garb ? chalk—. Brit., France, &c.

, Sub-genera. Crucibulum, Schum. (Dispotaea, Say., Calypeopsis, Less.)
Ex. C. rudis, PL XL, fig. 12. Shell spinulose ; internal cup entire ; attached
by one of its sides. Distr., W. America, Japan, W. Indies. Found on shells,
with its base worn, or smoothed by a shelly deposit (Gray). Between this
section and the next there are several intermediate forms.

Trochita, Schum. (Infundibulum, J. Sby., Galerus, Humph. Trocha-
tella and Siphopatella, Lesson.) T. radians, PI. XL, figs. 13, 14. (=Patella
trochoides, Dillw.) T. sinensis, PI. XL, fig. 15. Shell circular, more or less
distinctly spiral ; apex central ; interior with a more or less complete sub-
spiral partition. Distr., chiefly tropical, but ranges from Britain to New
Zealand. T. prisca (McCoy) is found in the carb. limestone in Ireland ; and
several large species occur in the London clay and Paris basin. The recent
C. sinensis — the " China-man's hat" of collectors — is found on the southern
shores of England, and in the Mediterranean, in 5 — 10 fins, water (Forbes).
Its lingual dentition is given by Loven ; — median teeth broad, hooked, den-
ticulated ; uncini 3, the first hooked and serrated, 2, 3 claw-shaped, simple.
CREPIDULA, Lam.

Etym., crepidula, a small sandal.

Type, C. fornicata, PL XL, fig. 16. Syn., crypta, Humph.

Shell oval, limpet-like ; with a posterior, oblique marginal apex ; interior
polished, with a shelly partition covering its posterior half.

The crepidulse resemble the fresh -water navicellae in form ; but the inter-
nal ledge which mimics the columella of the nerite, is here the basis of the
adductor muscles.

They are sedentary on stones and shells, in shallow water, and are some-
times found adhering to one another in groups of many successive generations.
The specimens or species which live inside empty spiral shells are very thin,
nearly flat, and colourless.

Distr., 40 sp. W. Indies, Honduras, Medit., W. Africa, Cape,
Australia, W. America.

Fossil, 14 sp. Eocene — . France, N. America, Patagonia.
PILEOPSIS, Lam. Bonnet-limpet.

Etym., pileos, a cap, and opsis, like.

Syn., capulus, Montf. Bronchia, Bronn.

Type, P. hungaricus, P!. XL, fig. 1?. P. militaris, PL XL, fig. 18.

GASTEROPODA. 153

Shell conical ; apex posterior, spirally recurved ; aperture rounded ; mus-
cular impression horse-shoe shaped.

Animal with a fringed mantle-margin ; lingual teeth like catyptrcea.

P. hungaricus (the Hungarian-bonnet) is found on oysters, in 5 to 15
fms. water; more rarely as deep as 80 fms., and then very small. P. mili-
taris is extremely like a velutina.

Distr., 7 sp, W. Indies, Norway, Brit., Medit., India, Australia, Cali-
fornia.

Fossil, 20 sp. Lias — . Europe.

Sub-genus. Amathina, Gray. A. tricarinata, PL XI., fig. 19. Shell
depressed, oblong ; apex posterior, not spiral, with three strong ribs diverging
from it to the anterior margin.

Platyceras, Conrad (acroculia, Phil.). P. vetustus. Garb., limestone.
Brit.

Fossil, 20 sp. Devonian — Trias. America, Europe.

HIPPONYX, Defrance.

Etym., hippos, a horse, and onyx, a hoof.

Type, H. cornucopia, PL XI., figs. 20, 21.

Shell thick, obliquely conical, apex posterior ; base shelly, with a horse-
shoe-shaped impression, corresponding to that of the adductor muscle.

Distr., 10 sp. W. Indies. Persian Gulf, Philippines, Australia, Pacific,
W. America.

Fossil, 10 sp. U. chalk — . Brit., France, N. America.

Sub-genus. Amalthea, Schum. A. conica. Like hipponyx, but forming
no shelly base ; surface of attachment worn and marked with a crescent-
shaped impression. Often occurs on living shells, such as the large turbines,
and turbinellee of the Eastern seas.

FAMILY XIII. PATELLID.E. Limpets.

Shell conical, with the apex turned forwards ; muscular impression horse-
shoe-shaped, open in front.

Animal with a distinct head, furnished with tentacles, bearing eyes at
their outer bases ; foot as large as the margin of the shell ; mantle plain or
fringed. Respiratory organ in the form of one or two branchial plumes,
lodged in a cervical cavity ; or of a series of lamellae surrounding the animal,
between its foot and mantle. Mouth armed with horny jaws, and a long
ribbon-like tongue, furnished with numerous teeth, each consisting of a pel-
lucid base and an opaque hooked apex.

The order cyclo-branchiata of Cuvier included the chitons and the limpets,
and was characterised by the circular arrangement of the brarichise. At a
comparatively recent period it was ascertained that some of the patellse
(acmcea) had a free, cervical gill; whilst the chitons exhibited too many
peculiarities to admit of being associated so closely with them. Professor

154 MANUAL OF THE MOLLUSCA.

Forbes has very happily suggested that the cyclo-branchiate gill of patella is3
in reality, a single, long branchial plume, originating on the left side of the
neck, coiled backwards round the foot, and attached throughout its length.
This view is confirmed by the circumstance that the gill of the sea-weed
limpets (nacellcB) does not form a complete circle, but ends without passing
in front of the animal's head.

PATELLA, L. Rock limpet.

Etym., patella, a dish. Syn.t helcion, Montf.

Ex., P. longicostata, PL XI., fig. 22.

Shell oval, with a sub-central apex ; surface smooth, or ornamented with
radiating striae or ribs ; margin even or spiny ; interior smooth.

Animal with a continuous series of branchial lamellae ; mantle -margin
fringed ; eyes sessile, externally, on the swollen bases of the tentacles ; mouth
notched below. Lingual teeth 6, of which 4 are central, and 2 lateral ;
uuciiii 3.

The tongue of the common British limpet (P. vulgata) is rather longer
than its shell ; it has 160 rows of teeth, with 12 teeth in each row, or 1,920
in all (Forbes.) The limpets live on rocky coasts, between tide-marks, and
are consequently left dry twice every day ; they adhere very firmly, by at-
mospheric pressure (151bs per square inch), and the difficulty of detaching
them is increased by the form of the shell. On soft calcarious rocks, like the
chalk of the coast of Thanet, they live in pits half an inch deep, probably
fonned by the carbonic acid disengaged in respiration ; on hard limestones
only the aged specimens are found to have worn the rock beneath, and the
margin of their shell is often accommodated to the inequalities of the surround-
ing surface. These circumstances would seem to imply that the limpets are
sedentary, and live on the sea-weed within reach of their tongues, or else that
they return to the same spot to roost. On the coast of Northumberland we
have seen them sheltering themselves in the crevices of rocks, whose broad
surfaces, overgrown with nullipores, were covered with irregular tracks,
apparently rasped by the limpets in their nocturnal excursions,*

The limpet is much used by fishermen for bait ; on the coast of Berwick,
shire nearly 12,000,000 have been collected yearly, until their numbers are so
decreased that collecting them has become tedious (Dr. Johnston) . In the
north of Ireland they are used for human food, especially in seasons of
scarcity ; many tons weight are collected annually near the town of Larne
alone (Pattison).

On the western coast of S. America there is a limpet which attains the
diameter of a foot, and is used by the natives as a basin (Cuming).

* If limpets are placed in stale water, or little pools exposed to the hot sun, t
creep out more quickly than one would expect ; the tracks they leave are very peculiar,,
and not likely to be mistaken when once seen.

n, they
jculiar.

GASTEROPODA. 155

Distr., 100 sp. Brit., Norway, &c. World-wide.

Fossil, above 100 sp. of patellidse, including acmaa, L. silurian — . N.
America, Europe.

Sub-genera. Nacella, Schum. (=patina, Leach.) Example, P. pellucida.
PL XI., fig. 23. Shell thin; apex nearly marginal. Animal with the mouth
entire below. Branchiae not continued in front of the head. Found on the
fronds and stalks of sea-weeds. Brit., Cape, Cape Horn.

Scutellina, Gray. S. crenulata. Shell with a broad margin, internaDy.
7 sp. lied Sea — Philippines — Pacific — Panama (Cuming).

Metoptoma, Phillips. M. pileus Ph. Shell limpet-like, side beneath the
apex truncated. Resembling the posterior valve of a chiton. 7 sp. Carb.
limestone. Brit.

ACM.EA, Eschscholtz.

Etym., acme, a point.

Syn., tectura, M. Edw. Lottia and scurria, Gray. Patelloida, Quoy.

Type, A. testudinalis. PI. XI., fig. 24.

Shell like patella. Animal with a single pectinated gill ; lodged in a
cervical cavity, and exserted from the right side of the neck when the crea-
ture walks. Lingual teeth 3 on each side of the median line. Low-water to
30 fms. (Forbes.)

Distr., 20 sp. Norway, Brit., Australia, Pacific, W. America.

Sub -genera. Lepeta, Gray (= pro-pilidium, Forbes). Patella cseca,
Mull. Shell minute, apex posterior. Animal blind. Brit. 30 — 90 fms.

Pilidium, Forbes. P. fulva, Milll. Brit. 20—80 fathoms water. Shell
small, apex anterior. Animal blind ; gills 2, not projecting ; mantle even-
edged. Both lepeta and pilidium have large single median teeth, with trilobed
hooks ; and 2 hooked uncini on each side.

GADINIA (Adanson), Gray.

Type, G. peruviana. Plate XI., fig. 26. Syn., mouretia, Sby.
Shell conical; muscular impression horse-shoe shaped, the right side
shortest, terminating at the siphonal groove.

Animal with a single cervical gill ; tentacles expanded, funnel-shaped.
Distr., 8 sp. Medit., Red Sea, Africa, Peru.
Fossil, 1 sp. Sicily.

? SIPHONARIA, Blainville.

Type, S. sipho. PI. XL, fig. 25.

Shell like patella; apex sub -central, posterior; muscular impression
horse-shoe shaped, divided on the right side by a deep siphonal groove, which
produces a slight projection on the margin.

156 MANUAL OF THE MOLLUSCA.

Animal with, a broad head, destitute of tentacles ; eyes sessile on promi-
nent rounded lobes ; gill ? single. The siphonarise are found between .tide-
marks, like limpets ; Mr. Gray places them with the pulmonifera, between
auriculidre and cyclostoniidse.

Distr., 30 sp. Cape, India, Philippines, Australia, New Zealand, Pacific,
Gallapagos, Peru, Cape Horn (Cuming).

Fossil, 3 sp. Miocene — .

FAMILY XIV., DENTALIAD^. Tooth-shells.
DENTALIUM, L.

Type, D. elephantinum. PL XL, fig. 27.

Shell tubular, symmetrical, curved, open at each end, attenuated pos-
teriorly ; surface smooth or longitudinally striated ; aperture circular, not
constricted.*

Animal attached to its shell near the posterior, anal orifice ; head rudi-
dimentary, eyes 0, tentacles 0 ; oral orifice fringed ; foot pointed, conical,
with symmetrical side- lobes, and an attenuated base, in which is a hollovv
communicating with the stomach. Branchiae 2, symmetrical, posterior to th(
heart ; blood red (Clarke) ; sexes united ? Lingual ribbon wide, ovate ;
rachis 1 -toothed ; uncini single, flanked by single unarmed plates.

The tooth-shells are animal-feeders, devouring foramiiiifera and minute
bivalves ; they are found on sand, or mud, in which they often bury them-
selves. The British sp. range from 10 — 100 fms. (Forbes.)

Distr., 30 sp. W. Indies, Norway, Brit., Medit., India.

Fossil, 70 sp. Devonian—. Europe, Chile.

FAMILY XV., CHITONID^E.

CHITON, L.

Etym., chiton, a coat of mail.

Ex., C. squamosus, spinosus, fascicularis, fasciatus. PI. XL, figs,
Shell composed of 8 transverse imbricating plates, lodged in a coriaceou *
mantle, which forms an expanded margin round the body. The first sevei .
plates have posterior apices; the eighth has its apex nearly in front. The
six middle plates are each divided by lines of sculpturing into a dorsal and
two lateral areas. All are inserted into the mantle of the animal by processe »
(apophyses) from their front margins. The posterior plate is considered ho
mologous with the limpet-shell, by Mr. Gray ; the other plates appear lib :
portions of its anterior slope, successively detached. The border of the mantle
is either bare, or covered with minute plates, hairs, or spines.

D. gadus of Montagu is an annelide, belonging to the genus ditrupa.

GASTEROPODA. 157

Animal with a "broad creeping disk like the limpet ; proboscis armed with
cartilaginous jaws, and a long linear tongue ; lingual teeth 3 ; median small,
laterals large, with dentated hooks ; uncini 5, trapezoidal, one of them erect
and hooked. No eyes, or tentacles. Branchiae forming a series of lamellae
between the foot and the mantle, round the posterior part of the body. The
heart is central, and elongated like the dorsal vessel of the armelidcs ; the
sexes are united ; the re-productive organs are symmetrically repeated on each
side, and have two orifices ; the intestine is straight, and the anal orifice pos-
terior and median.

Distr. More than 200 species are known ; they occur in all climates
throughout the world ; most abundant on rocks at low-water, but frequently
obtained by dredging in 10 — 25 fathoms water. Some of the small British
species range as deep as 100 fms. (Forbes.) W. Indies, Europe, S. Africa,
Australia, and New Zealand, California to Chiloe.
Fossil, 24 sp. Silurian — . Brit., Belgium, &c.

Sub-genera* Chiton, (Syn., lophurus, Poli. Radsia, callo-chiton,
ischno-chiton, and lepto-chiton, Gray).

Ex., C. squamosus. PI. XT., fig. 28. Border tessellated.
Distr. Brazil, W. Indies, Newfoundland, Greenland, Brit., Medit., Cape,
Philippines, Australia, New Zealand, W. America.

Tonicia, Gray. C. elegans. Margin bare. Distr. Greenland, C. Horn,
New Zealand, Valparaiso.

Acanthopleura, Guilding. C. spinosus. PI. XT., fig. 29. Margin covered
with spines, or elongated scales. Syn. Schizo-chiton, corephium, plaxiphora,
onycho-chiton, enoplo-chiton, Gray. Distr. W. Indies, C. Horn, Falklands,
Africa, Philippines, Australia, New Zealand, Valparaiso.

Mopalia, Gray. C. Hindsii. Border hairy. ' Distr., W. America, Talk-
land Islands.

Katharina, Gray, C. tunicatus. Mantle covering all but the centre of the
plates. Distr. New Zealand, W. America.

Cryptochiton, Gray, " Saw-dust chiton.". C. amiculatus. Valves covered
with scaly epidermis. Syn., cryptoconchus, Sw. Amicula, Gray. Distr., Ca-
lifornia, New Zealand.

Acanthochites, Leach. C. fascicularis. PI. XI., fig. 30. Border orna-
mented with tufts of slender spines, opposite the plates. Distr., Brit., Medit.
New Zealand.

Chitonellus, Lam. C. fasciatus, Quoy. PL XI., fig. 31. Border
velvety ; exposed portion of the plates small, distant ; apophyses close to-

* The sub-genera of Mr. Gray are founded on the form of the plates of inser-
tion ; they are described in detail in the proceedings of the Zoological Society. Dr.
Middendorf employs the number of the branchial lamince for distinguishing the
sections.

158 MANUAL OF THE MOLLUSCA.

gether. Distr., 10 sp. W. Indies, W. Africa, Philippines, Australia, Pa
Panama. The chitonellse are found in fissures of coral rock (Cuming).

Grypho-chiton, Gray. C. nervicanus.

Helminthochiton, Salter, 1847. H. Griffithii, Salter Geol. Journ. Plate
sub-quadrate, not covered by the mantle ; apophyses widely separated. Fossil.
Silurian. Ireland.

T, BLOOMSBURY.

ELI.

MANUAL OF THE MOLLUSCA.

EXPLANATION OF THE PLATES.

The principal specimens figured were kindly communicated by Mrs.
J. E. Gray, Mr. Hugh Cuming, Major W. E. Baker, Mr. Laidlay of Cal-
cutta, Mr. Pickering, Sir Chas. Lyell, Mr. Sylvanus Hanley, Mr. James
Tennant, and Mr. Lovell Reeve.

The fractions shew the number of times (or diameters) the figures are
reduced, or magnified,

PLATE I.

Octopodid*. PAGE

1. Octopus tuberculatus, Bl. 3-. Mediterranean 67

2. (mandibles] „ t 62

3. Tremoctopus violaceus, $. Chiaje. Messina 65,68

Teuthida.

4. Sepiola oceanica, Orb. Atlantic , 71

6. Loligo vulgaris, Lam. (gladius). •£. Britain 69

7- Onychoteuthis Bartlingii, Le Sueur. \. Indian Ocean 72

8.- -(gladius). £ 72

Sepiadee,

5. Sepia officinalis, L. £. Britain 76

9. Spirula Isevis, Gray. £. New Zealand 77

MANUAL OF THE MOLLUSCA.

PLATE II.

PAGE

1. Argonauta hians, Solander, ^-. China 66

TeutUdae.

8. Beloteuthis subcostata, Miinst. ^. U. Lias, Wurtemberg 70

Belemnitida.

Belemnites Puzosianus, Orb. •£. Oxford Clay, Chippenham 73

6. Belemnitella mucronata, Sby. -^. U. Chalk, Norwich 74

9 . Conoteuthis Dupiniana, Orb. Neocomian, France 76

Sepiada.

2. Sepia Orbigniana, Fer. -|. Mediterranean 78

3 . (Belosepia) sepioi'des, Bl. ^. Eocene, Sussex 76

4. Spirulirostra Bellardii, Orb. -|. Miocene, Turin 76

7. Beloptera belemnitoides, Bl. f . Eocene, Sussex

Nautilidce.

1 0. Nautilus radiatus, Sby. ^. Neocomian, Kent 83

11. bidorsatus, Schl. (upper »z«^^^=Rhyncholites hirundo,

F. Biguet.) f. Muschelkalk, Bavaria 81

12.- — (Aturia) zic-zac, Sby. Eocene, Highgate 86

1 6 . Clymenia striata, Miinst. Devonian, S . Petherwin 87

Orthoceratidce,

14. Orthoceras gigantum, Sby. (section.) •£%. Carb. limestone, Britain

15. Phragmoceras ventricosuni, Stein. ^. L. Ludlow-rock, Salop 90

1 3 . Gyroceras eifeliense, Arch, (section. ) ^. Devonian, Eifel 91

MANUAL OF THE MOLLUSCA.

PLATE III.

AmmonitidcE.

PAGE

1. Goniatites Henslowi, Sby. ^-. Garb, limestone, Isle of Man 93

2. Ceratites nodosus, Brug. •£. Muschel-kaUf, Wurtemburg 93

3. Ammonites planulatus, Sby. -|. Chalk-marl, Sussex , 94

4. — — rhotomagensis, Brongn. i. Chalk-marl, Sussex 94

5< _ — . Jason, Reinecke. ^. Oxford clay, Chippenham 94

6.- — bifrons, Brug. \. Lias, Whitby , 94

7. — — bisulcatus, Brug. \. Lias, Lyme Regis 94

8. Crioceras cristatum, Orb. §. Gault, S. France 95

9. Scaphites a^qualis, Sby. |. Chalk-marl, Sussex 95

10. Ancyloceras spinigeruin, Sby. § . Gault, Folkstone 95

1 1 . Helicoceras rotundum, Sby. Gault, Folkestone 95

12. Toxoceras annulare, Orb. ^. Neocomian, S. France 95

13. Baculites anceps, Lam. £. Chalk, France 97

14. Ptychoceras Emericianum, Orb. §. Neocomian, S. France 96

1 5 . Hamites attenuatus, Sby. ±. Gault, Folkstone 96

1 6. Turrilites costatus, Lam. i. Chalk-marl, Sussex 96

MANUAL OF THE MOLLUSCA.

PLATE IV.

Strombidce.

PAGE

1. Strombus pugilis, L. |. W. Indies 104

2. Bartonensis, Sby. Eocene, Hants 105

3. Pteroceras lambis, L. •§. CMna 105

4. Rostellaria curta, Sby. ±. Kurachee 105

5. Seraphs terebellum, L. §. China 106

6. Struthiolaria straminea, Gm. j%. New Zealand 130

7. Aporrhais pes-pelecani. L. •§. Britain 129

Muricidce.

8. Murex haustellum, L. ^. China 10

9. — — tenuispina, Lam. •£. Moluccas 1C

10. palma-rosae, Lam. £, Ceylon 1C

10.* erinaceus, L. (operculum). Britain 1C

11 . Typhis pungens, Soland. Eocene, Barton 1C

12. Ranella granifera, Lam. |. N. Australia 10?

13. Triton tritonis, L. £. New Guinea— Pacific 101

14. Pisania striata, Gm. sp. Mediterranean 1C

1 5 . (Enzina] turbinella, Kiener. W. Indies 1C

16. Trophon Magellanicus., Gm. ^. Tierra -del-fuego 109

MANUAL OF THE MOLLUSCA.

PLATE V.

MuricicUe.

1. Fasciolaria tnlipa. L. ^. \V. ladies ......... ........................ Iu7

2, Turbinella pynim, L. £. Ceylon ....................................

3 . — - ( Cynodonta) coraigera, Lam. ^. Moluccas ............ 108

- - (Latirus) gilbula, Gm. sp. ^. Australia .............

5. Caucellaria reticulata, Dillw. sp. -£S35StSB>~

6. Pyrula reticulata, Lam. i. China .................................... 109

— (Jlyristica] melongena, L. £. ^bfU.V.lV^.V^a.... 109

.sus colus, L. ^. Ceylon .................. ............... 109

— (Chrysodomus) antiquos, Mull. (var. contrarius, Sby.) Red

- (operculum). [Crag, TValton, Essex 109

10. Buccinum undatum, L. ^. Britain .................................... 110

11. Eburna spirata, L sp. §. Ceylon .................................... Ill

12. Fseudoliya plumbea, Chemn. sp. §. W.America ..... Ill

13. Terebra maculata, L. sp. £. Moluccas .............................. Ill

14. --- (BuUia) semiplicata, Gray. S.Africa ........................ Ill

15. Xassa arcularia, L. sp. §. Moluccas ................................. 112

16. -- (Cyclonassa] neritea, L. sp. Mediterranean .................. „ 112

— (Cyllene) Oweni, Gray. E.Africa .............................. 112

nticosus, L. sp. §. X.Australia .............................. 112

19. Magilus antiquus, Montf. i. Red Sea .............................. 114

- do. young. (Leptoconchus) .................................... 1 14

21. f Ringicula ringens, Lam. f. Eocene, Paris ..... . .................. 112

MANUAL OF THE MOLLUSCA.

PLATE VI.
Bvccinufae.

PAGE

1. Purpura persica, L. sp. £. India 113

2.- — lapilliis, L. sp. (operculum.) Britain 113

3 _ ( Concliolepas) peruviana, Lam. •£. Peru 113

4. Monoceros imbricatum, Lam. §. Cape Horn 1 A3

5. Pedicularia sicula, Sw. Sicily 113

6. Planaxis sulcata, Brag. sp. India 114

7. _ } (operculum) 114

8. Trichotropis borealis, Brod. N. Britain 108

9. Ricinula arachaoides, Lam. China 114

10. Coluinbella mercatoria, Gmel. sp. W.Indies 116

11. Harpa ventricosa, Lam. ^. Mauritius 116

12. Dolium galea, L. sp. \. Mediten-anean 115

13. Cassidaria echinophora, L. \. Medit 115

14. Cassis flammea, L. China , 114

15. Oniscia cancellata, Sby. China 11-1

16. Oliva porphyria, L. |. Panama 116

17. (Agaronia) hiatula, Gm. sp. f . W. Africa 11?

18. (Scaphula} utriculus, Gm. sp. §. Africa

19. (OHvella) jaspidea, Gm. sp. W. Indies 117

20. Aucillaria buccinoi'des, Lam. §. Eocene, Isle of Wight 11?

21. glabrata, L. sp. i. W.Indies 117

J.W.l.owrv fc.

MANUAL OP THE MOLLUSGA.

PLATE VII.

Conidte.

PAGE

1. Conus marmoreus Gm. §. Cliiria .................................... 117

2. - (Conorbis) dormitor, Solander. Eocene, Barton ........... .- 117

3. Pleurotoma Babylonica, L. sp. | . China ........................... 118

4. Clavatula mitra, Gray. W.Africa .................................... 118

5 . Mangelia taeniata, Desh. -f-. Mediterranean ........................ 118

6. Bela turricula, Mont. sp. Britain .................................... 118

7. Defrancia linearis, Bl. sp. f. Medit .................................. 118

8. Lachesis minima, Mont. sp. -f. Britain .............................. 118

VolutldcB.

9. Voluta musica, L. \. W.Indies ....................................... 119

1 0 . Volutilithes spinosus, L. sp. |. Eocene, Barton .................. 119

11. Melo diadema, Lam. sp. ^. New Guinea ........................... 119

12. Cymba proboscidalis, Lam. sp. i. W. Africa ........................ 119

13. Mitra episcopalis, D'Arg. i. Ceylon ...... ........................ 119

14. - vulpecula, L. §. Singapore ............... •^^••- .............. 120

15. -- (Imbricaria) conica, Schuin. ^ttjlljjpinBs /^rtv-Cu ....... 120

16. -- ( Cylindra) crenulata, Chernn. China ........................ 120

17. Volvaria bullo'ides, Lam'. Eocene, Grignon ........................ 120

18. Marginella nubeculata, Lam. §. W. Africa ........................... 120

1 9. - - (Persicula) lineata, Lam. W. Africa ..................... 120

Cyprasicke.

20. Cyprsea Mauritiana, L. i. India — Pacific ........................... 121

21. -- (Ci/provula) capeusis. Gray. §. S. A'frica ............... 121

22. - — (L?tponia) algoeiisis, Gray. S, Africa ..................... 121

23,23*- — (Trivia] europeea, Mont. Britain ..................... 122

24. Erato Isevis, Donovan. Britain . ...................................... 122

25. Ovulum ovum, L. sp. i. New Guinea .............................. 122

MANUAL OF THE MOLLUSCA.

PLATE VIII.

Naticidce.

PAGE

1. Natica canrena, L. sp. §. China 123

2. (Globulus) sigaretina, Lam. §. Eocene, Paris 123

3. (Cermna) fluctuata. Sby. |-. Pliilippines 123

4. Sigaretus haliotoides, L. sp. § . W. Indies 1 24

5. — — (Naticina) papilla, Chemu. sp. Africa 124

6. Lamellaria perspicua, Mont. Mediterranean 124

7. Velutina Isevigata, L. sp. Britain 124

8. Narica cancellata, Chemn. sp. Pacific 124

9. Neritopsis radula, L. sp. Sandwich Islands 141

Pyramidellidtz.

10. Pyramidella auris-cati, Chemn. sp. Mauritius 125

11. — — • (Obeliscus) dolabrata, Gmel. sp. W.Indies 125

12. Odostomia plicata, Mont. sp. f. Britain 125

13. Chemnitzia elegantissima, Mont. sp. f. Weymouth 126

14. Eulima polita, L. Britain ,, 126

15. Stylifer astericola, Brod. Philippines 12

Cerithidae.

16,16*. Cerithium nodulosum, Brug. -|. Moluccas 127

17. •- (Bittium) reticulatum, Da Costa. Britain 127

18. Triphoris perversus, L. sp. Mediterranean 128

19. Potamides mixtus, Defr. Eocene, Paris 12

20. — •— (Pyrazus) palustris, Brug. -|. India

21 . — — (Terebralia) telescopium, Brug. J. India 12

22. — ~ (Pirenelld) mammillatus, Risso sp. Mediterranean 12

23. (Lampania) zonalis, Gray. Chusan 128

24. — — (Cerithidea) decollatus, L. sp. Cape 12

Melaniadce.

25. 25* Melania amarula, L. sp. f . Madagascar 131

26. — (Melanatria) fluminea, Gm. sp. £. Madagascar 131

27. — (Melafusus) fluviatilis, Say. |. TJ. States 131

28. (Anculotus) prsemorsa, Say. U. States 131

29. - (Vibex) fuscata, Gm. sp. Africa 131

30. Melanopsis costata, Eer. Syria 132

81.- — (Pirena) atra. L. sp. |. Ceylon 132

tote Weate>.185l.

MANUAL OF THE MOLLUSCA.

PLATE IX.

Turritellida.

PAGE

1. Turritella, imbricata, L, W.Indies 132

2. — (Mesalia) sulcata, var. Lam, Eocene, Paris 132

3. _ (Proto) cathedralis, Brongn. f. Miocene, Bordeaux... 132

4. Aclis perforatus, Mont. sp. f . Guernsey 132

5. Caecum trachea, Mont. 4. Britain 133

6. - —(fry, magnified f) 133

7. Vermetus lumbricalis, Gm. sp. (young.) W. Africa 133

8. Siliquaria anguina, L. sp. £. New Guinea 133

9. Scalaria pretiosa, Lam. § China 133

Litorinidte.

10. Litorina litorea, L. Britain 134

11. - - (Tectaria) pagodas, L. £. Zanzibar 133

12. — — - (Fossarus) sulcatus, S. Wood. Mediterranean 135

1 3. - — ( Modulus) tectum, Gm. sp. N. Australia 135

14. — (Risella) nana, Lam. sp. § . Tasmania 135

1 5. Solarium perspectivum, L. sp. f . China 135

16. Lacuna pallidula, Da Costa. Britain 136

17. Rissoa labiosa, Mont. Britain 136

18.-- - (Hydrobia) ulvse, Penn. Britain 137

19, - (Jeffrey sia) diaphana, Alder. (Operculum) Britain 137

20.- - (Skenea) planorbis, O. Fabr. (^ inch). Britain 137

21. Nematura deltee, Bens. f. India 137

22. Lithoglyphus fuscus, Pfr. sp. Danube 138

23. Amnicola isogona, Say. IT. States 131

24. Litiopa bombix, Kiener. Mediterranean 136

25. Truncatella subtruncata, Mont. sp. f . Mediterranean 137

Paludinidce.

26. Faludina Listeri, Hanley. |. Norwich 138

27.- — • (Bithinia) teutaciilata, Mont. Norwich 138

28. Valvata piscinalis, Miill. Norwich 140

29. cristata, Mull. Norwich 140

30. Ampullaria globosa, Sw. \. India 138

31 . — - ( Marisa) cornu-arietis, L. sp. Brazil 139

32. — - (Lanistes) Bolteniana, Chernn. sp. i. Nile 139

33. Amphibola avellana, Chemn. sp. New Zealand 139

54. Paludomus aculeatus, Gm. sp. Ceylon .' 133

Neritidce.

35. Nerita ustulata, L. Scinde 141

36. ( Velates] perversus, Gm. sp. Eocene, Soissons 141

37. 38. Pileolus plicatus, J. Sby. Bath oolite, Ancliff 141

39. Neritina zebra, Brug. Pacific 141

40. — — crepidularia. Less. India 142

41 . Navicella porcellana, Chemn. sp. Mauritius — Pacific 142

10 MANUAL OE THE MOLLTJSCA.

PLATE X.

1 . Phorus corrugatus, Reeve. |. Kurachee, India ..................... 135

Turbinid<z.

2. Turbo marmoratus, L. I . China

3. Phasianella australis, Gm. sp. §. New Zealand

4. Imperator imperialis, Chemn. sp. £. New Zealand

5. Trochus niloticus, L. |. China

6. (Pyramis] obeliscus, Gm. sp. China

7. — — (Margarita] helicinus, 0. Fabr. Britain

8. (Menclius) iris, Chemn. New Zealand

9. — — (BanJcivia] varians, Gray. New Zealand

10. Rotella vestiaria, L. sp. New Zealand

11. Monodonta labio, L. sp. W.Africa

12. . (Clanculus] Pharaonis, L. sp. Red Sea

13. Delphinula laciniata, Lam. China

14. _ (Liotia) Gervillii, Defr. Eocene, Sussex

15. - — (Collonid) marginata, Lam. \\. Eocene, Paris

16. (Cyclostrema] cancellata, Marryatt. Philippines ....

17- Adeorbis sub-carinata, Mont. sp. Britain

18. Euomphalus pentangulatus. Sby. |. Carb : limestone, Ireland .

19. Stomatella imbricata, Lam. India

20. (Broderipia] rosea, Brod. f . S. Seas

Haliotida.

21 . Haliotis tuberculata, L. Guernsey

22. Stomatia phymotis, Helblin. Java

23. Scissurella crispata, Fleming. ^. Britain

24. Pleurotomaria Anglica, Sby. \. Lias, Gloucester ..

25. Murchisonia bilineata, D'Arch. Devonian, Eifel ..

26. Trochotoma conuloides, Desl. Bath Oolite, Stroud

27. lanthina fi'agilis, Lam. f. W.Indies

PI. 10.

J.W1,

MANUAL OF TIIE MOLLTJSCA, 11

PLATE XI.

Fissurellida.

PAGE

1. Fissurella Listeri, Orb. W.Indies '. 149

2. macroschisma, Humphr. Philippines 150

3. Puncturella Noachina, L. sp. N.Britain 150

4. Simula Blainvillii, Defr. Philippines 150

5. 6. Emarginula reticulata, Sby. Britain 150

7, 8. • (Hemitoma) rugosa, Quoy . Tasmania 151

9. Parmophorus australis, Bl. £. New Zealand 151

Catyptr&icfae.

10. Calyptrsea equestris, L. sp. Philippines 151

11. - — Dillwynnii, Gray. W.Indies 151

12. (Crucibulum) rudis, Brod. W. America 152

13, 14. (Trochita) radians, Lam. W. America 152

15,15.*— — Sinensis, L. Britain, 152

16. Crepiftula fornicata, L. sp. W. Indies 152

17. Pileopsis Hungaricus, L. f. Torbay 152

18.- - nulitaris, L. W.Indies 152

19. (Amathina) tricarinata, Gray, f . India 153

20. Hipponyx cornncc/pise, Defr. f . Eocene, Paris , 153

21. (shelly base).

22. Patella longicosta, Lam. f. W.Indies 154

23. - — - (Nacetta) pellucida, L. Britain 155

24. Acmsea testndmalis, Mull. sp. Britain 155

25. Siphonaria sp. Kurachee, India 155

26. Gadinia pernviana, Gray. Peru 155

DentaliadcB.

27. Dentalium elephantinum, L. \. Red Sea 156

Chitonidfs.

28. Chiton squamosus, L. i. W.Indies 156

29. (Acanthopleurd) spinosus, Brug. N. Australia 157

30. (Acanthockites) fascicularis, L. Britain 157

31. (Chitonettus) fasciatus, Quoy. f. Philippines 157

MANUAL OF THE MOLLUSCA.

PLATE XII.

Helicidce.

1. Helix (Acavns) heemastoma, L. §v Ceylon.

2. — — (Poly gyro) polygyrata, Born. ' \. Brazil.

3. (Carocotta) lapicida, L. Britain.

4. (Anastoma] globulosa, Lam. Brazil.

5. (Tridopsis) hirsute, Sby. TJ. States.

6. (Streptaxis] contusa, Per. Brazil.

7. (Sag da) epistylium, Mull. Jamaica.

8. (HeliceHa] cellaria, Miill. Britain.

9. • (Stenopus) laevipes, Mull. Malabar.

10. Bulimus oblongus, Mull. £. Guiana.

11, 12 decollatus, L. S. Europe.

13. (Partula) faba, Martyn. Australian Islands.

14. (Zua) lubricus, Miill. Britain.

15. (Azecd) tridens, Pulteney. Britain.

16. Pupa uva, L. sp. Guadaloupe.

17. • (Vertigo] Venetzii, Charp, f. Pliocene, Essex.

18. Megaspira elatior, Spix sp. §. Brazil.

19. Clausilia plicatula, Drap. . Kent.

20. Cylindrella cylindrus, Chemn. sp. §. • Jamaica.

21. Balaea perversa, L. sp. Britain.

22. Achatina variegata, Fab. Col. \. W. Africa.

23. Succinea putris, L. Britain.

24. (Omalonyx) unguis, Orb. Paraguay,

liimacida.

25. Limax maximus, L. Britain.

26. Testacella haliotoides, Per. f. Britain.

27. Parmacella (Cryptella] cslyculata, Sby. ^Canaries.

28. Vitrina Draparnaldi, Cuv. Britain.

29. (Daudebardia) brevipes, Drap. f . Austria.

30. Limnea stagnalis, L. sp. Britain.

31. (Amphipeplea) glutinosa, Miill. Britain.

32. Physa fontinalis, Mont. sp. Britain.

33. Ancylus fluviatilis, Lister sp. Britain.

34. Planorbis corneus, L. sp. Britain.

Auriculidce.

35. Auricula Judse. L. §. India.

36. scarabseus, Gm. sp. Ceylon.

37. • .(Conowlus) cofFea, L. W. Indies.

38. — - (Alexia) deiticulata, Mont. sp. Britain.

39. Carychium minimum, Drap. sp. f . Britain.

Cyclostomi'da.

40. Cyclostoma elegans, Miill. sp. Britain.

41. Cyclophorus involvulus, Mull. sp. f. India.

42. Pupina bi-canaliculata, Sby. N. Australia,

43. Helicina Brownii, Sby. Philippines.

44. Acicula fusca, "Walker, sp. f . Britain,

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