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COMPARATIVE ZOOLOGY,

AT HARVARD COLLEGE, CAMBRIDGE, MASS.

Pounded by private subscription, in 1861.

DR. L. pE KONINCK’S LIBRARY.
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THE

MOLLUSCA AND RADIATA.

ARRANGED BY THE

BARON CUVIER,

WITH

SUPPLEMENTARY ADDITIONS TO EACH ORDER.

BY

EDWARD GRIFFITH, F.L.S., A.S., §e.

AND

EDWARD PIDGEON, Esa.

LONDON :

PRINTED FOR WHITTAKER AND CO.
AVE-MARIA-LANE.

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SECOND GRAND DIVISION

OF THE

ANIMAL KINGDOM.

ANIMALIA MOLILUSCA.

THE mollusca have neither an articulated skeleton, nor aver-
tebral canal. Their nervous system is not united in a spinal
marrow, but merely in a certain number of medullary masses,
dispersed in different parts of the body, the chief of which,
termed the brain, is situated transversely on the cesophagus,
and envelopes it with a nervous collar. Their organs of
motion and sensation have not the same uniformity of number
and position as in the vertebrata, and the irregularity is still
more striking in the viscera, particularly as respects the posi-
tion of the heart and respiratory organs, and even as regards
the structure of the latter; for some of these respire elastic
air, and others salt or fresh water. ‘Their external organs,
however, and those of locomotion, are generally arranged
symmetrically on the two sides of an axis.

The circulation of the mollusca is always double ; that is,
their pulmonary circulation describes a separate and distinct
circle. This function is at least always aided by a fleshy
ventricle, situated between the veins of the lungs and the
arteries of the body, and not, as in fishes, between the veins of
the body and the arteries of the lungs. It is then an aortic
ventricle. The cephalopoda alone are provided with a pul-
monary ventricle, which is even divided into two. The

VOL. XII. B

2 SECOND GRAND DIVISION.

aortic ventricle is also divided in some genera as in Arca and
Lingula ; at other times, as in other bivalves, its auricle only
is divided. When there is more than one ventricle they are
not united in a single mass, as in warm-blooded animals, but
often sufficiently remote the one from the other, and then one
might say there are many hearts.

The blood of the mollusca is white, or bluish, and it appears
to contain a smaller proportionate quantity of fibrine than that
of the vertebrata. ‘There are reasons for believing that their
veins fulfil the functions of absorbent vessels.

Their muscles are attached to various points of their skin,
forming there tissues, which are more or less complex and
dense. Their motions consist of contractions in different
directions, which produce inflexions and prolongations, or
relaxations, of their various parts, by means of which they
_ creep, swim, and seize upon objects, just as the form of these
parts may permit; but as the limbs are not supported by arti-
culated and solid levers, they cannot proceed rapidly, or by
leaps.

The irritability of most of them is extremely great, and
remains for a long time after they are divided. Their skin is
naked, very sensible, and usually covered with a humour that
oozes from its pores. No particular organ of smell has been
discovered in them, though they enjoy that sense; it may
possibly reside in the entire skin, for it greatly resembles a
pituitary membrane. All the acephala, brachiopoda, cirrho-
poda, and part of the gasteropoda, and pteropoda, are desti-
tute of eyes. The cephalopoda, on the contrary, have them
at least as complicated as those of the warm-blooded animals ;
they are the only ones in which the organ of hearing has been
discovered, and whose brain is enclosed within a particular
cartilaginous box.

Nearly all the mollusca have a development of the skin,
which covers their body, and which bears more or less resem-

ANIMALIA MOLLUSCA. a

blance to a mantle ; itis often, however, narrowed into a sim-
ple disk, formed into a pipe, hollowed into a sac, or extended
and divided in the form of fins.

The naked mollusca are those in which the mantle is simply
membranous or fleshy: most frequently, however, it forms
in its thickness one or several laminz, of a substance more or
less hard, deposited in layers, and increasing in extent, as
well as in thickness, because the recent layers always outedge
the old ones.

When this substance remains concealed in the thickness of
the mantle, it is still customary to call the animals naked
mollusca. Most generally, however, it becomes so much
developed, that the contracted animal finds shelter beneath it.
It is then termed a shell, and the animal is said to be testace-
ous. ‘The epidermis which covers it is thin, and sometimes
desiccated.

Until my labours on the subject were published, the testa-
cea were made a particular order; but there are so many
insensible transitions from the naked mollusca to the testacea,
and their natural divisions form such groups with each other,
that this distinction can no longer be admitted. Besides,
there are several of the testacea which are not mollusca.

The variety in the form, colour, surface, substance, and
brilliancy of shells, is infinite. Most of them are calcareous,
some are horny ; but they always consist of matters deposited
in layers, or exuded from the skin under the epidermis, like
the mucous covering, the nails, horns, scales, and even teeth.
The tissue of shells differs according to the mode of this dis-
position, which is either in parallel laminz, or crowded verti-
cal filaments.

All the modes of mastication and deglutition are found in
the mollusca. Their stomachs are sometimes simple, some-
times multiple, frequently provided with a peculiar armature,
and their intestines are variously prolonged. They most

, B2

4 SECOND GRAND DIVISION.

generally have salivary glands, and always a large liver, but
neither pancreas, nor mesentery ; several have secretions
which are peculiar to them.

They also present examples of all the modes of generation.
Several of them possess the faculty of self-impregnation ;
others, although hermaphrodites, have need of a reciprocal
intercourse. Many have the sexes separated. Some are
viviparous, others oviparous; the eggs of the latter are some-
times enveloped with a shell more or less hard, sometimes with
a simple viscosity. These varieties of the digestive and gene-
rative processes are found in the same order, and sometimes
in the same family. The mollusca in general appear to be
animals that are but slightly developed, possessed of but little
industry, and which are only preserved by their fecundity and
vital tenacity.

DIVISION OF THE MOLLUSCA INTO SIX CLASSES.

The general form of the body of the mollusca being in pro-
portion to the complication of their internal organization,
indicates their natural division.

The body of some resembles a sac, open in front, containing
the branchiz, whence issues a well-developed head, crowned
with long and strong fleshy productions, by means of which
they crawl, and seize various objects. These we term the
CEPHALOPODA.

That of others is closed; the appendages of the head are
either wanting, or are extremely reduced ; the principal organs
of locomotion are two wings or membranous fins, situated
on the sides of the neck, and which frequently support the
branchial tissue. They constitute the PrEROPODA.

Others, again, crawl by means of a fleshy disk on their
belly, sometimes, though rarely, compressed into a fin, and

i

ANIMALIA MOLLUSCA. i)

have almost always a distinct head before. We call these
the GASTEROPODA.

A fourth class is composed of those where the mouth remains
hidden in the bottom of the mantle, which also encloses the
branchiz and viscera, and is open either throughout its
length, at both ends, or at one extremity only. Such are our
ACEPHALA.

A fifth comprises those which, also inclosed in a mantle,
and without an apparent head, have fleshy or membranaceous
arms, furnished with cilia of the same nature. We term these
BRACHIOPODA.

Finally, there are some which, although similar to the other
mollusca in the mantle, branchie, &c., differ from them in
numerous horny and articulated limbs, and in a nervous sys-
tem more nearly allied to that of the Articulata. ‘They will
constitute our last class, or that of the CIRRHOPODA.

FIRST CLASS OF MOLLUSCA.

CEPHALOPODA.

THEIR mantle unites under the body, forming a muscular
sac, which envelopes all the viscera. In several its sides are
extended into fleshy fins. The head projects from the open-
ing of the sac ; it is rounded, furnished with two large eyes,
and crowned with arms or feet, conical, fleshy, more, or less
elongated, capable of being flexed in every direction, and ex-
tremely vigorous, the surface of which is armed with suckers
or cups, by means of which they adhere with great tenacity to
every body they embrace. ‘These feet are their instruments of

6 CLASS CEPHALOPODA.

prehension, swimming, and walking. They swim with the
head backwards, and crawl in all directions with the head
beneath and the body above.

A fleshy funnel, placed at the opening of the sac, before the
neck, affords a passage to the excretions.

The cephalopoda have two branchiz within the sac, one on
each side, resembling a highly complicated fern leaf; the great
vena cava, having arrived between them, divides into two
branches, which pour their contents into two fleshy ventri-
cles, each of which is placed at the base of the gill on its
own side, and propels the blood into it.

The two branchial veins communicate with a third ventri-
cle, situated near the bottom of the sac, which, by means of
various arteries, distributes the blood to every part of the
body. :

Respiration is effected by the water which flows into the
sac, and issues through the funnel. It appears that it can
even penetrate into two cavities of the peritoneum, traversed
by the vena cava in their passage to the branchie, and act
upon the venous blood by means of a glandular apparatus
attached to those veins.

Between the base of the feet we find the mouth, armed with
two stout horny jaws, resembling the beak of a parrot.

Between the jaws is a tongue, bristling with horny points;
the cesophagus swells into a crop, and then communicates
with a gizzard as fleshy as that of a bird, to which succeeds a
third membranous and spiral stomach, which receives the bile
from the two ducts of the very large liver. The intestine is
simple and short ; the rectum terminates in the funnel.

These animals are remarkable for a peculiar and intensely
black excretion, with which they darken the surrounding
water when they wish to conceal themselves. It is produced
by a gland, and held in reserve by a sac, variously situated,
according to the species.

CLASS CEPHALOPODA. if

Their brain, which is contained in a cartilaginous cavity of
the head, gives off a cord on each side, which produces a large
ganglion in each orbit, whence are derived innumerable optic
filaments. The eye consists of several membranes, and is
covered by the skin which becomes diaphanous in that parti-
cular spot, sometimes forming folds, which supply the want of
eye-lids. The ear is merely a slight cavity on each side near
the brain, without semi-circular canals, or an external meatus,
where a membranous sac is suspended, which contains a
little stone.

The skin of these animals, of the octopi particularly,
changes colour in places, by spots, with a rapidity which
greatly surpasses that of the chameleon.

The sexes are separated. The ovary of the female is in the
bottom of the sac; two oviducts take up the ova and pass
them out through large glands which envelope ‘them in a
viscid matter, and collect them into clusters. The testis of
the male, placed like the ovary, communicates with a vas
deferens, which terminates in a fleshy penis, situated on the
left of the anus. A bladder and prostate terminate there like-
wise. ‘There is reason to believe that fecundation is effected
by sprinkling, asis the case with most fishes. In the spawn-
ing season, the bladder contains a multitude of little filiform
bodies, which, by means of a peculiar mechanism, are rup-
tured the moment they reach the water, where they move
about with great rapidity, and diffuse a humour with which
they are filled.

These animals are voracious and cruel; possessed both of
agility and numerous modes of seizing their prey, they destroy
immense quantities of fish and crustacea. Their flesh is eaten;
their ink is employed in painting, and the Indian or China
ink is supposed to be made from it.

The cephalopoda comprise but a single order, which is
divided into genera, according to the nature of the shell.

8 CLASS CEPHALOPODA.

Those which have no external shell, according to Linnezus,
formed but the single genus,

SEPIA, Lin.,

Which is now divided as follows:

Octopus, Lam. Polypus of the ancients.

But two small conical granules, of a horny substance, on
the two sides, of the thickness of the back ; the sac, having no
fins, resembles an oval purse; eight feet, all of which are
about equal, very large in proportion to the body, and united
at base by a membrane ; they are employed by the animal in
swimming, crawling, and seizing its prey. The length and
strength of these limbs render them fearful weapons, which
they twine round animals; in this way it has even destroyed
men while bathing. The eyes are small in proportion, and
the skin contracts over them so as entirely to cover them at
the will of the animal. ‘The receptacle of the ink is sunk in
the liver; the glands of the oviducts are small. Some of
them,

PoLyPus, Aristotle,

Have the suckers alternating in two rows along each foot.
The common species, Sepza octopodia, Lin., with a slightly
rough skin, arms six times the length of its body, and fur-
nished with one hundred and twenty pairs of cups, infests the
coast of Europe in summer, and destroys immense numbers
of fishes and crustacea.

The seas of hot climates produce another, Sepia rugosa,
Bosc., Seb., III. ii. 2, 3, whose body is rougher, arms some-
thing longer than the body, and furnished with ninety pairs
of cups. It is from this species that some authors suppose
the Indian ink is procured. Others, again,

CLASS CEPHALOPODA. 9

ELEDON, Aristotle,

Have but a single row of cups along each foot. One of them,
the Poulpe musqué, Lam., Mém. de la Soc. d’ Hist. Nat., 4to.
pl. ii.; Rondelet, 516; is found in the Mediterranean, and is
remarkable for its musky odour.

ARGONAUTA, Lin.

Octopi with two rows of cups; the pair of feet which are
nearest to the back being dilated at the extremity into a broad
membrane. ‘The two cartilaginous granules of the common
octopus are wanting ; but these mollusca are always found in
a very thin shell, symmetrically fluted and spirally convoluted ;
the last whorl so large that it bears some resemblance to a
galley, of which the spire should be the poop. The animal
makes a consequent use of it, and in calm weather whole
fleets of them may be observed navigating the surface of the
ocean, employing six of their tentacula as oars, and elevating
the two membranous ones by way of a sail. If the sea be-
comes rough, or they perceive any danger, the argonaut with-
draws all its arms, concentrates itself in its shell, and descends
to the bottom. The body of the animal does not penetrate to
the bottom of the spires of the shell, and it appears that it does
not adhere to it, at least there is no muscular attachment, a
circumstance which has induced some authors to believe that
its residence there is that of a parasite, like the Pagurus Bern-
hardus, for instance. As it is always found in the same shell,
however, and as no other animal is ever seen there, although
it is very common, and so formed as to show itself frequently
on the surface, and as the germ of it is visible even in the
ovum of the argonaut, this opinion must be considered as
highly problematical, to say nothing more of it.

The ancients were well acquainted with this singular ani-
mal and its maneuvres. It is their Nautilus and their Pom-
pilus.—Pliny, IX. c: xxix.

10 CLASS CEPHALOPODA.

Several species are known, closely resembling each other,
both in the animal and the shell, which were united by Lin-
neeus under the name of Argonauta argo, or the paper nau-
tilus.

BELLEROPHON, Montf.

Certain fossil shells, so called, the animal of which is sup-
posed to have been analagous to the argonauts. They are
spirally and symmetrically convoluted, without septa, but
thick, and not fluted ; the last whorl proportionably shorter.

Lo1ico, Lam.

An ensiform lamina of horn in the back, in lieu of a shell;
the sac has two fins, and besides the eight feet promiscuously
loaded with little cups on short pedicles, the head is furnished
with two much longer arms, provided with cups near the end
only, which is widened. ‘The animal uses these latter to keep
itself immoveable, as if at anchor. The receptacle of the
colouring matter is lodged in the liver, and the glands of the
oviducts are very large. The eggs are deposited closely
together in narrow garlands, and in two rows.

They are now sub-divided according to the number and
armature of the feet, and the form of the fins.

LoLicopsis, Lam.,

Or the Calmarets, should have but eight feet, as in Octopus.
They are only known, however, by drawings of but little
authority.

In the true loligo the long arms are furnished with cups
like the other tentacula, and the fins are placed near the point
of the sac. ‘Three species are found in the European seas.

LL. vulgaris; Sepia loligo; L. Rondel, 506; Salv. 169.
Fins forming a rhomb at the bottom of the sac.

L. Sagittata, Lam.; Seb. III.iv. Fins forming a triangle

1 Cctopus Cuvieriv. 6 Extremity cf Arm & inner rudiment oF
2 Fortion of Arne ef Eledone meschatus. Onychoteuthts angulata.

+ Argenauta arge.4 Sata ettianalis. 7 Nautilus pompilis.

5 Leligo Brogniart. & Spirida australis.

Londen, Lublished by Whittaker & C! Ave Me

3 ae MCZ LIRRATY
vik HARVARD UNIVERSUY
CAMBRIDGE. MA USA

CLASS CEPHALOPODA. Il

at the bottom of the sac; arms shorter than the body, and
loaded with cups for about half their length.

L. media ; Sep.media; L. Rondel, 508. Fins forming an
ellipsis at the bottom of the sac, which terminates in a sharp
point.

ONnYKIA, Lesueur. ONYCHOTHEUTHIS, Lichtenst.

The long arms furnished with cups, terminating in hooks;
in other respects the form is the same.

SEPIOLA, Cuv.

The rounded fins attached to the sides of the sac, and not
to its point; one species. SS. vulgaris; S. sepiola; L. Ron-
del, 519; inhabits European seas. The sac is short and
obtuse, and the fins small and circular. It seldom exceeds
three inches in length, and its horny lamina is as slender, and
sharp as a stilet.

CHONDROSEPIA, Leukard. SEPIOTHEUTES, Blainv.,

The whole margin of the sac, on each side, bordered with
the fins, as in sepia; but the shell horny, as in loligo.

SEPIA, Lam.

The Sepiz, properly so called, have the two long arms of a
loligo, and a fleshy fin extending along the whole length of
each side of the sac. The shell is oval, thick, convex, and
composed of numerous and parallel calcareous laminz, united
by thousands of little hollow columns, running perpendicularly
from one to the other. This structure, rendering it friable,
causes it to be employed for polishing various kinds of work ;
it is also given to birds in aviaries, for the purpose of whetting
their beaks.

The ink-pouch of the sepiz is detached from the liver, and
situated more deeply in the abdomen. The glands of the

12 CLASS CEPHALOPODA.

oviducts are enormous. The eggs are produced attached to
each other in branching clusters, resembling those of grapes,
and are commonly termed sea grapes.

The species most commonly found in the seas of Europe,
Sepia officinalis, L.; Rondel, 498 ; Seb. III. iii., attains the
length of a foot or more. Its skin is smooth, whitish, and
dotted with red.

The Indian Ocean produces another, Sepia tuberculata,
Lam. Soc. d’Hist. Nat. 4to. pl. i. f. 1.

NAUTILUS, Lin.

In this genus Linnezus united all spiral, symmetrical, and
chambered shells, that is to say, such as are divided by septa
into several cavities; their inhabitants he supposed to be
cephalopoda. One of them really does belong to a cephalopod
that strongly resembles a sepia, but it has shorter arms; it
forms the genus

SPIRULA, Lam.

In the hind part of the body, which is that of a sepia, is an
interior shell, which, although very different from the bone
of that animal as to figure, differs but little in its formation.
A correct idea of the latter may be obtained by imagining the
successive lamine, instead of remaining parallel and approxi-
mated, to be concave towards the body, more distant, increas-
ing little in breadth, and forming an angle between them, thus
producing an elongated cone, spirally convoluted in one plane,
and divided transversely into chambers. Such is the shell of
the spirula, which has additional chambers, consisting of a
single hollow column that occupies the internal side of each
chamber, continuing its tube with those of the other chambers
to the very extremity of the shell. This column is termed the
siphon. 'The turns of the spire do not come into contact.

But a single species, Nautilus spirula, L.; List. 550-2, is
known. The

CLASS CEPHALOPODA. 13.

NAUTILUS, properly so called,

Has a shell which differs from the spirula in the sudden
crossing of the lamin, and in the last turns of the spire, which
not only touch the preceding ones but envelope them. The
siphon occupies the centre of each septum.

N. pompilius, L.; List. 551, the most common species ; it
is very large, formed internally of a beautiful mother-of-pearl,
and covered externally with a white crust, varied with fawn-
coloured streaks or bands.

The animal, according to Rumph, is partly contained within
the last cell, has the sac, eyes, parrot beak, and funnel of the
other cephalopoda; but its mouth, instead of having their
large feet and arms, is surrounded by several circles of nume-
rous small tentacula without cups. A ligament arising from
the back traverses the whole siphon and fastens it there. It
is probable that the epidermis is extended over the outside of
the shell, though we may presume it is very thin over the parts
that are coloured.

Individuals are sometimes found, Naut. pompilius, 3,
Gmel.; List. 552; AMMONIE, Montf. 74.; in which the last
whorl does not envelope and conceal the others, but where all
of them, though in contact, are exposed, a circumstance which
approximates them to the ammonites; they so closely resem-
ble the common species, however, in all the rest of the shell,
that it is scarcely possible to believe them to be any thing
more than a variety of it.

Fossil nautili are found of a large or moderate size, and
much more various, as to form, than those now taken in the
ocean.

Chambered shells are also found among fossils, furnished
with simple septa and a siphon, the body of which, at first
arched, or even spirally convoluted, remains straight in the
more recent parts; they are the Liruus of Breyn, in which

14 CLASS CEPHALOPODA.

the whorls are sometimes contiguous and sometimes distinct.
The HorTo Les of Montfort.

In others, the orthoceratites, it is altogether straight ; it is
not improbable that the animal resembled that of the nautilus,
or of the spirula. 'The

BELEMNITES

Probably belong to this family ; but it is impossible to ascer-
tain the fact, as they are only found among fossils. Every
thing, however, proves them to have been internal shells, thin,
and double; that is, composed of two cones united at base,
the inner one much shorter than the other, and divided into
chambers by parallel septa, which are concave on the side
next to the base. A siphon extends from the summit of the
external cone to that of the internal one, and continues thence,
sometimes along the margin of the septa, and sometimes
through their centre. The interval between the two testace-
ous cones is filled with a solid substance, here composed of
radiating fibres, and there of self-involving conical layers, the
base of each being on the margin of one of the septa of the
inner cone. In one specimen we only find this hard portion,
and in another we also find the nuclei of the chambers of the
inner cone, or what are termed the alveoli. Most commonly
these nuclei and the chambers themselves have left no further
traces than some projecting circles on the inside of the internal
cone. In other specimens, again, we find more or fewer of the
nuclei, and still in piles, but detached from the double conical
sheath that enveloped them.

Of all the fossils the Belemnites are the most abundant,
particularly in chalk and compact limestone.

M. de Blainville divides them according as the interior
cone or chambered part penetrates to a greater or less depth,
as the edges of the exterior cone have or have nota little cleft,
as the external surface is marked on one side by a longitudi-

]

CLASS CEPHALOPODA. 15

nal furrow, or by two or more furrows towards the summit, or,
finally, as that surface is smooth and without furrows.

Bodies very similar to the Belemnites, but without a cavity,
and with rather a prominent base, form the genus ACTINO-
CAMAX of Miller. It is also upon conjecture of a similar
nature that reposes the classification of the

AMMONITES, brug.,

Or the Cornua-ammonis, for they no longer exist, except
among fossils. They are distinguished from the nautili by
their septa, which, instead of being plane or simply concave,
are angular, and sometimes undulated, but most frequently
crimped on the edge like the leaf of an acanthus. The small-
ness of their last cell seems to indicate that, like the spirula,
they were internal shells. They are very abundant in the
strata of secondary mountains, where they are found varying
from the size of a lentil to that of a coach-wheel. ‘Their sub-
divisions are based upon the variation of their volutes and
siphons.

The name of AMMONITES, Zam. (SIMPLEGADES, Montf.,
82), is particularly restricted to those species in which all the
whorls are visible. Their siphon is near the margin.

They have lately been divided into the AMMONITES,
Planites of Haan, where the edge of the septa is foliaceous,
and into the CERATITES of Haan, where it is simply angular
and undulated.

Those in which the last whorl envelopes all the others form
the ORBITULITES, Lam., or the GLOBITES and the GonIA-
LITES of Haan, or the PELAGUSES, Montf. 62, in all of
which the siphon is situated as in the preceding ones.

The. ScAPHITES, Sowerb., are those in which the whorls
are contiguous and in the same plane, the last one excepted,
which is detached, and reflexed on itself.

Some, BACULITES, Lam., are entirely straight, without any

16 CLASS CEPHALOPODA.

spiral portion whatever. Some of them are round, and others
compressed. ‘The last sometimes have a lateral siphon.

There are some with their first cells arched. The Ha-
MITES, Sowerb., are arcuated.

Finally, those which vary most from the usual form of this
family are the TURRILITES, Montf. 118, where the whorls, so
far from running in the same plane, suddenly descend, giving
to the shell that form of an obelisk which is called turreted.

It is also thought, and from similar considerations, that we
should refer to the cephalopoda, and consider as internal
shells the

CAMERINES, Brug. NUMMULITES, Lam.,

Commonly called nwmmulites, lenticular stones, &c., which
are only found among fossils, and present, externally, a lenti-
cular figure, without any apparent opening, and a spiral cavity
internally, divided by septa into numerous small chambers, but
without a siphon. They are amongst the most universally
diffused of all fossils, forming, per se, entire chains of calca-
reous hills and immense bodies of building stone.

The most common, and those which attain the greatest
size, form a complete disk, and have only a single range of
cells in each whorl. Some very small species are also found
in certain seas.

The margin of other small species (the SIDEROLITHES,
Lam.), both fossil and living, are bristled with points, which
give them a stellated appearance.

The labours and researches, conducted with infinite patience
by Bianchi (or Janus Plancus), Soldani, Fichtel, Moll, and
D’Orbigny, have ascertained an astonishing number of these
chambered shells without a siphon, like the nummulites, that
are extremely small and frequently microscopical, both in the
sea, among the sand, fuci, &c., and in a fossil state in the sand
formations of various countries.

CLASS CEPHALOPODA. 17

They vary in a remarkable degree as to their general form,
the number and relative position of the chambers, &c. One
or two species, in which alone the animals have been observed,
appeared to present a small oblong body, crowned by numerous
red tentacula, which, added to the septa of the shell, have
caused them to be placed immediately after the cephalopoda,
like the genera just mentioned. This arrangement, however,
requires to be confirmed by more numerous observations,
before we can consider it as final.

Such of these species as were known in the time of Linneus
and Gmelin, were placed by those naturalists among the nau-
tili. M. D’Orbigny, who has exceeded every other person in
attention to this subject, forms them into an order which he
calls FORAMINIFERA, on account of the only communication
between the cells being by means of holes, and divides them
into families according to the manner in which the cells are
disposed. When the cells are simple and spirally arranged,
they constitute his HELICOSTEGA, which are again sub-
divided. Ifthe whorls are enveloped, as is particularly the
case in the nummulites, they become his HELICOSTEGA
NAUTILOIDA.

If the whorls do not envelope each other, they are the
HELICOSTEGA AMMONOIDA.

If the whorls are elevated, as in most of the univalves, they
are the HLELICOSTEGA TURBINOIDA.

Simple cells may also be strung upon a single straight or
slightly curved axis, constituting the family of the STYCOSTEGA.

Or they may be arranged in two alternate series, when they
become the ENALLOSTEGA.

Or a few of them may be collected and united as in a pel-
let, forming the AGATHISTEGA.

Finally, in the entomostega, the cells are not simple, as in
the other families, but are sub-divided by transverse septa in
such a way that a section of the shell exhibits a sort of trellis.

VOL. XII. c

18 CLASS PTEROPODA.

SECOND CLASS OF MOLLUSCA.

THE PTEROPODA

Swim like the cephalopoda in the waters of the sea, but can-
not fix themselves, nor creep there, for want of feet. Their
organs of locomotion consist only of fins, placed like wings at
the two sides of the mouth. But small species are known,
and few in number, all hermaphrodites.

Cio, Lin. CLione, Pall.,

Have the body oblong, membranaceous, without a mantle; the
head formed of two rounded tubes, from which issue small
tentacula; two small fleshy lips and a ligula on the front of
the mouth ; and the fins provided with a vascular net-work,
which takes the place of gills. ‘The anus and the orifice of
generation are under the right gill. Some authors attribute
eyes to these animals.

The mass of the viscera does not nearly fill the exterior en-
velope; the stomach is broad, the intestine short, the liver
considerable.

The most celebrated species (Clio Borealis, L.) swarms in
the seas of the north, and constitutes, from its abundance,
plenty of food for the whales, though each individual is
scarcely an inch long.

Bruguiéres has observed one larger, and not less abundant,
in the Indian Ocean. It is distinguished by its rose colour,
by its emarginated tail, and its body divided by furrows into
six lobes—Encyc. Meth. pl. des Mollusc. pl. lxxv. f. 1, 2.

CLASS PTEROPODA. 19
It appears that we must likewise place here,

The CyMBULIA of Péron,

Which have a cartilaginous or gelatinous envelope, in the form
of a boat, or rather of a hoof, bristling with some little points
in longitudinal series. ‘The animal has two great wings, with
a vascular tissue, answering as both gills and fins, and be-
tween them, on the open side, a third smaller lobe, with three
points. The mouth, with two small tentacula, is between the
wings, towards the closed side of the shell, and above, two
small eyes, and the orifice of generation, from which issues a
penis, in the form of a small proboscis. From their trans-
parency, the heart, brain, and viscera, can be distinguished
through the integuments.

PNEUMODERMON, Cuv.,

Begins to be somewhat removed from Clio: the body is oval,
without mantle, and without shells, the gills attached to the
surface, and formed of small leaflets, ranged in two or three
lines, disposed like an H on the side opposite to the head.
The fins are small; the mouth, furnished with two small lips
and two bundles of numerous tentacula, terminated each by a
sucker, has a small lobe or fleshy tentaculum underneath.
The known species (Prewmodermon Peronii, Cuv., Ann.
du Mus. IV. pl. lix., and Péron, ib. XV. pl. ii.), has been taken
in the ocean by Péron. It is scarcely more than an inch long.

LIMACINA, Cuv.,

Should, according to the description of Fabricius, have close

relations with pneumodermon ; but their body is terminated

by a spiral tail, and is lodged in a very thin shell, of one whorl

and a half, umbilicated on one side, and flatted at the other.

The animal makes use of its shell as a boat, and of its wings

as Oars, when it wishes to swim at the surface of the water.
G2

20 CLASS PTEROPODA.

The known species (Clio helicina of Phips and Gm.)
Argonauta arctica, Fab., Faun., Groen., 387, is but little less
abundant than the Clio Borealis in the icy sea, and is also
considered as one of the principal aliments of the whale.

HYALEA, Lam. CAvouina, Abild.,

Have two very large wings, no tentacula, a mantle cleft at the
sides, lodging the gills in the bottom of its fissures, and in-
vested with a shell likewise cleft at the sides, whose central
face is very gibbous, the dorsal plate larger than the other, and
the transverse line which unites them behind provided with
three short denticulations. In the living state the animal puts.
out, through the lateral clefts of its shell, some stripes, more or
less long, which are productions of the mantle.

The most known species (Anomia tridentata, Forskahl ;
Cavolina natans, Abildgard ; Hyalea cornea, Lam.), Cuv.,
Aun. du Mus. IV. pl. lix., et Péron, ib. XI. pl. iii., fig. 13, has
a small yellowish shell, semi-transparent, and is found in the
Mediterranean and the ocean.

CLEODORA, Péron,

For which Brown originally created the genus Clio, appear
analogous to hyalea, in the simplicity of their wings and the
absence of tentacula between them. It is probable that their
gills are also concealed in their mantle. Nevertheless, their
conical, or pyramidal shell, is not cleft upon the sides.

M. Rang distinguishes the CLEODORA, proper, with pyra-
midal shell.

CRESEIS with conical elongated shell.

CUVIERIES with cylindrical shell.

PSYCHE with globular shell.

EuRYBIA with hemispheric shell.

It has been thought we may approximate to hyalea,

Mollusca’ FY. 3.

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=
Layo a ee es,

12

Ss

12 6

% Ia
1 Cho berealis 5 Limactna helicina. 9 Cresets virgula.
2 Cymbuiia Feront. 6 tivalea globylosa. 10 Curterta columnedla.
3 Freumoderman diaphanun.7 Hy . respinosa. IW Layche globulesa.

4 Preum. Fereniv. & Cleodera laneclata. 1 Lury bea hemispherica:

14 Pyrge levis.

Londomlublished. by Wlattaker & C0? Ave MariaLane, 1833.

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CLASS GASTEROPODA. 21

PyReGo,

A very small fossil shell, discovered by M. Defrance, globular,
very thin, divided by a transverse cleft, very narrow, except
in front, where it widens a little.

THIRD CLASS OF THE MOLLUSCA.

THE GASTEROPODA

Constitute a very numerous class of mollusca, of which some
notion may be formed from the slug and snail.

They generally crawl upon a fleshy disk placed under the
belly, but which sometimes assumes the form of a furrow, or
that of a vertical lamina. The back is furnished with a man-
tle, which extends more or less, assumes various figures, and
produces a shell in the greater number of genera. ‘Their head,
placed in front, is shown more or less according to the degree
in which it is engaged under the mantle. It has only small
tentacula, which are above the mouth, and do not surround it ;
their number varies from two to six, and they are sometimes
wanting; their use is only for touch, or at most for smell.
The eyes are very small, sometimes adherent to the head,
sometimes to the base, or the side, or the point of the tenta-
cula; they are also sometimes wanting. ‘The position, the
structure, and the nature of the respiratory organs, vary, and
give rise to their division into several families. But they
have only an aortic heart, that is placed between the pulmon-
ary vein and the aorta.

The position of the apertures through which the organs of

4 CLASS GASTEROPODA.

generation come forth, and that of the anus, vary. Neverthe-
less, they are almost always on the right side of the body.

Several are absolutely naked. Others have but a concealed
shell; but the greater number have a shell which can receive
and shelter them. _

These shells are produced in the thickness of the mantle:
some of them are symmetrical, with several pieces; some
symmetrical, with a single piece; and some non-symmetrical,
which, in the species where they are concave, and grow for
a long time, necessarily produce an oblong spiral form.

Let us, in fact, figure to ourselves an oblique cone, in
which other cones are successively placed, always broader in
a certain direction than in others: it will be necessary that the
whole shall be rolled towards the side which is the smallest.
The part on which the cone is rolled is named the columella,
and it is sometimes full, sometimes hollow. When it is hol-
low, its aperture is named wmbilicus.

The whorls of the shell may remain pretty nearly in the
same plane, or tend always towards the base of the colu-
mella.

In this last case, the preceding whorls rise one above the
other, and form what is called a spire, which is so much the
sharper as the whorls descend more rapidly and are less wide.
These shells, with projecting spires, are named turbinated.

When, on the contrary, the whorls remain pretty nearly in
the same plane, and do not envelope each other, the spire is
flat, or even concave. These shells are called discoid.

When the top of each whorl envelopes the preceding, the
spire is concealed.

The part from which the animal appears to come forth is
named the aperture.

When the whorls remain pretty nearly in the same plane
when the animal creeps, it has its shell placed vertically, the
columella crosswise over the hinder part of the back, and the

CLASS GASTEROPODA. 23

head passes under the edge of the aperture opposite to the
columella.

When the spire is projecting, it is directed obliquely from
the right side in almost all the species. A small number only
have their spire projecting at the left side when they walk,
and are named reversed.

It is remarked that the heart is always on the side opposite
to that on which the spire is directed. ‘Thus it is usually on
the left, but in the reversed it is on the right. ‘The contrary
is the case with the organs of generation.

The organs of respiration, which are always in the last whorl
of the shell, receive the ambient element from under its edge,
sometimes because the mantle is entirely detached from the
body along that edge, sometimes because it is pierced there
with a hole.

Sometimes the edge of the mantle is prolonged into a canal,
that the animal may be able to seek the ambient element
without putting forth its head and foot from the shell. Then
the shell has also in its edge, near the end of the columella,
opposite to that towards which the spire tends, a notch, or a
canal, to lodge that of the mantle. Consequently, the canal is
on the left in the ordinary species, on the right in the
reversed. |

For the rest, the animal, being very flexible, causes the
direction of the shell to vary, and most frequently, when there
is anotch or a canal, it directs the canal forward, which causes
the spire to be behind, the columella towards the left, and the
opposite edge towards the right. ‘The contrary takes place in
the reversed. ‘This is the reason why it is said that their shell
turns to the left.

The aperture of the shell, and consequently, also, the last
whorl, are more or less large, in relation to the other whorls,
according as the head or foot of the animal, which are con-
stantly to pass out and in there, are more or less large in rela-

24. CLASS GASTEROPODA.

tion to the mass of viscera that remains fixed in the shell. This
aperture is so much broader or narrower as those same parts
are more or less thick. ‘There are some shells whose aperture
is narrow and long. ‘This is when the foot is thin, and folds
in two to enter. ;

Most of the aquatic gasteropoda with spiral shells have an
operculum or a piece, sometimes horny, sometimes calcareous,
attached on the hinder part of the foot, which closes the shell
when the animal has entered and is folded up in it.

There are gasteropoda with the sexes separated, and others
hermaphrodite, of which some can generate of themselves,
while others have need of reciprocal coition. Their organs of
digestion do not differ less than those of respiration.

This class is too numerous not to be divided into a certain
number of orders, which we have derived from the position
and form of the gills.

The PULMONARIA

Respire the atmospheric air in a cavity whose narrow orifice
they open and close at will. They are hermaphrodites, but
require reciprocal copulation. Some have no shell, others
have, and often even completely turbinated ; but they have no
operculum.

The NUDIBRANCHIATA

Have no shell, and have naked gills of divers forms, on some
portion of the back.

The INFEROBRANCHIATA

In other respects similar to the preceding, carry their gills
under the reflected edges of their mantle.

The TECTIBRANCHIATA

Have gills on the back or side, covered by a lamina of the

CLASS GASTEROPODA. 95

mantle, which contains almost always a shell more or less
developed. Sometimes they are merely enveloped by the
folded-back edge of the foot.

These four orders are hermaphrodites, with reciprocal copu-
Jation.

The HETEROPODA

Have the gills on the back, where they form a transverse range
of little plumes, and in some are protected, as well as a part of
the viscera, by a symmetrical shell. What distinguishes them
best is a foot compressed into a thin and vertical fin, at the
edge of which is often seen a small cupper, the only vestige
of the horizontal foot of the rest of the class.

The PECTINIBRANCHIATA

Have the sexes separate. Their respiratory organs consist
almost always of gills, composed of small plates, united in the
form of combs, and are concealed in a dorsal cavity, widely
open above the head.

Pretty nearly all of them have turbinated shells, with the
mouth sometimes entire, sometimes emarginated, sometimes
provided with a siphon, and most frequently capable of being
more or less completely closed, with an operculum attached
to the foot of the animal behind.

The SCUTIBRANCHIATA ?

Have gills analogous to those of the pectinibranchiata ; but the
sexes are united, so that they fecundate themselves without
mutual co-operation, like the class of the acephala. Their
shells are very open, and in several in the form of a shield, not
turbinated. They never have an operculum.

The CYCLOBRANCHIATA

Hermaphrodites, like the scutibranchiata, have a shell of one

26 CLASS GASTEROPODA.

or several pieces, but never turbinated or operculated. Their
gills are attached under the reflected edges of their mantle, as
in the inferobranchiata.

THE FIRST ORDER OF GASTEROPODA.

THE PULMONARIA

Are distinguished from the other mollusca in respiring the
elastic air through an open hole under the reflected edge of °
the mantle, which they dilate or contract at pleasure. Accord-
ingly, they have no gills, but merely a net-work of pulmonary
vessels, which spread over the parietes, and principally over
the roof of their respiratory cavity.

Some are terrestrial, others live in the water, but are obliged
from time to time to come to the surface to open the orifice
of their pectoral cavity to respire.

All these animals are hermaphrodites.

The TERRESTRIAL PULMONARIA

Have almost all four tentacula; two or three only, of very
small size, do not show the lower pair.

Those among them which have no apparent shell, formed in
Linneus the genus

Limax, L.,
Which we divide as follows:

LimMAxX (proper),

Have the body elongated, and for a mantle a fleshy compact
1

eePs y

1 Arter empiricorum:. 4 Testacellis haliotideus.

2Limas vartegatus. 5 Parmacella’ Oliviert.

5 Vitrina pellucada. 6 Read &. of Parmacella palliolum.

7 Vaginula’ Taunay sw.

London, Published by Whittaker & 0° Ave

Marta’ Lane, s833

ORDER PULMONARIA. A f

disk, which occupies only the forepart of the back, and only
covers the pulmonary cavity. It contains, in many species, a
small oblong and flat shell, or at least a calcareous concretion,
which holds the place of it. ‘The orifice of respiration is on
the right side of this sort of sucker, and the anus is found at
the edge of this orifice. ‘The four tentacula issue out and re-
enter by being turned inside out, like the finger of a glove,
and the head itself can be partly withdrawn under the disk of
the mantle. The organs of generation open under the supe-
rior right tentaculum. There is but one upper jaw to the
mouth, in the form of a denticulated crescent, which enables
them to gnaw herbs and fruits with great voracity, among
which they make great hayock. ‘Their stomach is elongated,
simple, and membranaceous.

M. de Férussac distinguishes the ARIONS, in which the
orifice of respiration is towards the anterior part of the shield ;
there is nothing in the shield but calcareous grains. Such is

Limax rufus, L., Féerussac, Mull. Terr. et Fluy., pl. i. and iii.
which is to be met with at every step we take in wet weather,
and which is sometimes almost entirely black.—Jdid, ii. 1, 2.
The soup of this slug is made use of in maladies of the chest.

And the LimAs, in which this orifice is towards the poste-
rior part; their shell is often better defined. Such is

L. maximus, L.; Lim. antiquorum, Feéruss. pl. iv. and
vill. A. fi. 1.; ZL. Sylvaticus, Drap. Miill. ix. 10.

Often spotted, or striped with black. Found in cellars and
dark forests.

L. agrestis, L., Féruss. pl. v. fi. 5—10.

Small, without spots. One of the most abundant and most
mischievous.

VAGINULUS, Féruss.,

Have the mantle compact, without shell, and stretched over
the whole length of the body; four tentacula, the inferior a

28 CLASS GASTEROPODA.

little forked. The anus is altogether at the posterior extremity,
between the point of the mantle and that of the foot ; and the
same orifice conducts to the pulmonary cavity, situated along |
the right side. The orifice of the male organ of generation is
under the inferior right tentaculum, and that of the female
organ under the middle of the right side. These organs, as
well as those of digestion, are very similar to those of the
snail. . |

These mollusca belong to both Indies, and are very similar
to our slugs.

TESTACELLA, Lam.,

Have the orifice of respiration and the anus at the posterior
extremity ; their mantle is very small, and situated on this
same extremity. It contains a small oval shell, with very
wide aperture, and a very small spire, not equalling the tenth
part of the length of the body. For the rest, these animals re-
semble slugs.

A species is found tolerably abundant in our southern
departments (Testacella haliotoidea, Draparn.), Cuv. Ann.
Mus. V. xxvi. 6—11, which lives under ground, and feeds
chiefly on earth-worms. M. de Férussac has observed that
its mantle is extraordinarily developed when it finds itself
in too dry a place, and thus affords it a kind of shelter.

PARMACELLA, Cwv.,

Have a membranaceous mantle, with loose edges, placed on
the middle of the back, and containing, in its posterior part,
an oblong flat shell, which exhibits behind a slight com-
mencement of spire. The orifice of respiration and the anus
are under the right side of the middle of the mantle.

The first known species is from Mesopotamia, Parmacella
Olivieri, Cuv. Ann. Mus. V. xxix. 12—15.

There is one belonging to Brazil (P. palliolum, Féruss. pl.
vil. A.), and some others of the Indies.

lL Helier mera.

2 Helix viridis Desm.
3Valudina subcostata.
4 Telia Cunninghame.
5 Helir Lamarchit.

6 Helix Lrascrz.

Mollusca’ Ft

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ORDER PULMONARIA. 29

In the terrestrial pulmonaria with complete and apparent
shell, the edges of the aperture are most frequently raised like
a pad in the adult.

Linneus refers to his genus

HELIX,

All the species in which the aperture of the shell, a little
intruded upon by the projection of the last whorl but one, thus
assumes a circumscribed and crescented form.

When this crescent of the aperture is as broad, or broader
than it is high, they are

HELIX (properly so called), Brug. and Lam.

Some have the shell globular. In this number, every one
knows the common snail (Hel. Pomatia, L.), common in gar-
dens, vineyards, with reddish shell, marked with paler bands,
a food very much in request in some places; and H. nemo-
ralis. L., with a shell diversely and vividly coloured. In wet
seasons it 1s very injurious to wall-fruit.

Add Helix glauca, Citrina, Rapa, Castanea, Globulus,
Lactea, Arbustorum, Fulva, Epistylium, Cincta, Ligata,
Aspersa, Extensa, Nemorensis, Fruticum, Lucena, Vittata,
Rosacea, Itala, Lusitanica, Aculeata, Turturum, Cretacea,
Fuscescens, Terrestris, Nivea, Hortensis, Lucorum, Grisea,
Hemastoma, Pulla, Venusta, Picta, Gm., &c.

There is no one who has not heard of the curious experi-
ments which have been made on the reproduction of their
amputated parts.—Consult Spallanzani, Scheeffer, Bonnet, &c.

Others have the shell depressed, that is, with flatted spire.
Such are Hel. lapicida, H. cicatrosa, H. egophthalmus, H.
albella, &c.

Among them some may be remarked that have ribs project-
ing interiorly, Hel. sinuata, H. lucerna, &c.

And particularly those in which the last whorl is suddenly

30 CLASS GASTEROPODA.

recurved in the adult, and assumes an uregular and plaited
form. (H. ringens, Chemn.)

VITRINA, Drap. HeEttico-Limax, Feérus.,

Are snails with a very thin flatted shell, no umbilicus, large
aperture, and margin not swelled. The body is too large to
be withdrawn entirely into the shell. The mantle has a dou-
ble border; the upper one, which is divided into several lobes,
may extend considerably beyond the shell, and fold back on it
to rub and polish it.

Those which are known in Europe live in humid places, and
are very small. (Helix pellucida, &c.)

There are larger ones in the hot climates.

We should approximate to these some snails, which, with-
out having the double border, do find some difficulty in with-
drawing into their shell. (Helix rufa et brevipes, Féruss.)

When the crescent of the aperture is higher than it is wide,
a disposition which always obtains when the spire is oblong
or elongated, it constitutes the

BuLIMUS TERRESTRIS, Brug.,

Which requires a still further sub-division : as follows.

BULIMUS (proper), Lam.

Margin of the aperture tumid in the adult, but without den-
ticulations. .

Hot climates produce large and beautiful species; some of
these are remarkable for the size of their eggs, the shell of
which is of a stony hardness; others for their awkward-look-
ing shell.

Several moderate sized or small species are found in France,
one of which (Helix decollata, Gm.) Chemn. cxxxvi. 1254—
1257, has the singular habit of successively fracturing the
whorls of the top of the spire. ‘This is the example referred |

ORDER PULMONARIA. 3

to as a proof that the muscles of the animal can be detached
from the shell; for, at a particular epoch, of all the whorls of
the spire originally possessed by this bulimus, not a single one
remains. Add Helix ovalis, Gm.; H. oblonga, Chemn., &c.

Pupa, Lam.

Summit of the shell very obtuse ; the last whorl in the adult
narrower than the others, giving it the form of an ellipsoid,
and sometimes almost that of a cylinder. The surrounding
margin of the aperture is tumid, and encroached on at the side
next to the spire by the preceding whorl. ‘The species are
small, inhabiting humid places, among mosses, &c.

Sometimes there is no denticulation. (Bulimus labrosus,
Oliv., &c.)

More commonly there is one in that portion of the aperture
which is closed by the penultimate whorl. (Turbo uva, L.)

It is frequently observed, also, inside the external edge.
(Hel. vertigo, Gm., &c.)

CHONDRUSs, Cuv.

The aperture, as in the last-mentioned pupz, indented on
the side next to the spire, by the preceding whorl, and
bordered with salient lamine or teeth. But the form is more
ovoid, like that of a common bulimus.

Some of them have teeth on the margin of the aperture.
(Bulimus zebra, Oliv., &c.)

Others are furnished with more deeply-seated laminz. (Bu-
limus avenaceus, Brug., &c.)

Here terminates that series of terrestrial helices, the adult
shells of which have a tumid margin round the aperture.

SUCCINEA, Drap.

Shell oval; the aperture higher than it is broad, as in
bulimus, but larger in proportion ; margin of the aperture not

4 CLASS GASTEROPODA.

tumid, and the side of the columella almost concave. The
shell will not receive the entire animal, and it might almost be
considered as a large-shelled testacella. Its inferior tentacula
are very small, and it lives on the plants and shrubs which
line the borders of rivulets, a circumstance which has caused
the genus to be considered as amphibious. Swccinea amphi-
bia, Drap. (Helix putris, L., &c.)

CLAUSILLA, Drap.

These mollusca formerly belonged to the genus Turbo of
Linneus, from which it has been found necessary to separate
them, in order to approximate them to the terrestrial helices.
The shell is long, slender, and pointed ; the last whorl in the
adult narrowed, compressed, slightly detached, and terminated
by a complete aperture, with a tumid margin, frequently den-
tated, or furnished with lamine. In the contraction of the
last whorl we usually find a little plate, bent into an §, the use
of which to the living animal is unknown.

The species are very small, living in masses at the foot of
trees, &c. A great many of them are reversed. (Turbo per
Versus Lin., &c. &c.)

ACHATINA, Lam.,

Necessarily separated from the bulle of Linneus, and placed
here. The aperture of the oval or oblong shell is higher than
itis broad, as in the bulimi, but wants the tumid margin; the -
extremity of the columella also is truncated, the first indica-
tion of the emarginations, which we shall find in so many
marine gasteropoda. ‘These achatine are large helices, which
devour trees and shrubs in hot countries. (Bulla zebra, Lin.,
Chem., &c.)

Montfort distinguishes such as have in the last whorl a cal-
lus or peculiar thickening (Lzguus, Mont.) ‘This whorl is
proportionably lower in them than in the others. (Bulla
virginea, L., &c.)

7
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OMUSCA

1 Bidinus Guadalupensts. 5 Achatina Mullert. 9 Chonarus avenaceus.

2 lymnaus stagnalis. 6 Clausitia’ inflata’ 10 Planorbis Guadalupensis.

5 Pupa striatela: 7 Helix corocella: 11 Searabus impium.
42hyvsa Noveliclandie: & Auricuda’ Mide. 12 Suectnea’ rubescens.
1 13 Conovulus Tasciatus .

London; Published by Whittaler &C° Ave Marta Lane, 1833.

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ORDER PULMONARIA. ou

And those in which the extremity of the columella is curved
towards the inside of the aperture (Polyphemus, Mont.), the
last whorl is higher. (Bulimus glans, Brug.)

The AQUATIC PULMONARIA

Have but two tentacula, as already stated ; they are continu-
ally compelled to rise to the surface for the purpose of breath-
ing, so that they cannot inhabit very deep water. ‘They are
usually found in fresh-water or salt-ponds, or at least in the
vicinity of the sea-coast, and of the mouths of rivers. Some
of them have no shell; such as

ONCHIDIUM, Buchanan.

A broad fleshy mantle, in the form of a shield, overlapping
the foot at all points, and even covering the head when it
contracts; two long retractile tentacula; and on the mouth an
emarginated veil, formed of two triangular and depressed
lobes.

The anus and respiratory orifice are under the posterior
edge of the mantle, where, a little more deeply, we also find
the pulmonary cavity. Close to them, on the right side, opens
the female organ of generation ; that of the male, on the con-
trary, is under the right great tentaculum, the two openings
being united by a furrow, which extends along the under part
of the whole right margin of the mantle. These mollusca,
destitute of jaws, have a muscular gizzard, followed by two
membranous stomachs. Several of them inhabit the sea-shore,
but in places where the ebb leaves them uncovered, so that
they can readily breathe the air as is natural to them.

The name of ONCHIDIUM was given to this genus because
the first species (Onchidium typhe, Buckan.), was tubercu-
lous. I now know one that is smooth (O. levigatum, Cuv.),
and four or five that are tuberculous.

The aquatic pulmonaria with complete shells were also

VOL, XII. D

34 CLASS GASTEROPODA.

placed by Linneus in his genera HELIX, BULLA, and Vo-
LUTA, from which it has been found necessary to separate
them.

In the first were comprized the two following genera, where
we find the internal edge of the aperture crescent-shaped, as
in helix.

PLANORBIS, Brug.

The planorbes had been already distinguished from the
helices by Bruguiéres, and even previously by Guettard, on
account of the slight increase of the whorls of their shell, the
convolutions of which are nearly in one plane, and because
the aperture is wider than itis high. It contains an animal
with long, thin, filiform tentacula, at the inner base of which
are the eyes, and from the margin of whose mantle exudes a
quantity of a red fluid, which is not, however, its blood. Its
stomach is muscular, and its food vegetable, like that of the
Limnzi, of which, in all our stagnant waters, it is the faithful
companion. (Hel. vortex, H. cornea, H. spirorbis, &c.)

LIMNZUS, Lam.,

Separated from the bulimi of Bruguiére by M. de Lamarck,
has, like a bulimus, an oblong spire, and the aperture higher
than it is wide ; but the margin, like that of succinea, is not
reflected, and there is a longitudinal fold in the columella,
which runs obliquely into the cavity. ‘The shell is thin; the
animal has two compressed, broad, triangular tentacula, near
the base of whose inner edge are the eyes. They feed on
plants and seeds, and their stomach is a very muscular giz-
zard, preceded by acrop. Like all the pulmonariz, they are
hermaphrodites, and the female organ of generation being far
from the other, they are compelled so to copulate, that the in-
dividual which acts as a male for one serves as a female for
a third ; long strings of them may be observed in this position.

ORDER PULMONARIA. 35

They inhabit stagnant waters in great numbers; they also
abound with the planorbes, in certain layers of marl and calca-
reous strata, which they evidently prove were deposited in
fresh water. (Hel. stagnalis, Lin., of which H. fragilis is a
variety ; H. palustris, H. limosa, &c.)

Puysa, Drap.

The physe, which were gratuitously placed among the
bulla, have a shell very similar to that of a limneus, but
devoid of the fold in the columella, as of the reflected edge,
and very thin. When the animal swims or crawls, it covers
its shell with the two notched lobes of its mantle, and has two
long, slender, and pointed tentacula, on the greatly enlarged
internal base of which are the eyes. They inhabit springs, &c.

One of them, Bulla fontinalis, L., which is convoluted
towards the left, is found in France.

The neighbouring species, Bull. hypnorum, L.; and Physa
acuta; and Scaturiginum, Drap.; require a fresh examina-
tion of their animals.

According to the observations of Van Hasselt, we should
place here the

ScARABZUS, Montf.,

Which has an oval shell, the aperture narrowed by projecting
and stout denticulations, both on the side next the columella
and that towards the external margin. This margin is en-
larged, and as the animal renews it after each semi-whorl, the
shell projects most on two opposite lines, and has a compressed
appearance.

They feed on aquatic plants in the Indian Archipelago.
(Helix Scarabeus, Lin.)

The two following genera were among the volute.

AURICULA, Lam.,

Differing from all the preceding aquatic pulmonaria in the
D2

36 CLASS GASTEROPODA.

columella, which is marked with wide and oblique grooves.
Their shell is oval or oblong, the aperture elevated as in buli-
mus, and the margin tumid. Several are large. We are not
certain whether they inhabit marshes, like the limnzi, or
simply their borders, like the succinez.

Auricula myosotis, Drap. iii. 16, 17.; Carychium myosotis,
Féruss., is the only species in France. The animal has but
two tentacula, and the eyes are at their base. From the
shores of the Mediterranean. Add Voluta auris Mide, L.;
Voluta auris Jude, &c. &c.

Conovu.Lus, Lam., MELAMPES, Mont.

Projecting folds in the columella, as in the auricule, but the
margin of the aperture is not tumid, and the internal lip is
finely striated. The general form of the shell is that of a cone,
of which the spire forms the base. ‘They inhabit the rivers of
the Antilles. (Voluta minuta, Lin. &c.)

THE SECOND ORDER OF GASTEROPODA.

THE NUDIBRANCHIATA

HAVE neither shell nor pulmonary cavity; their gills are
exposed on some part of the back. They are all hermaphro-
dites and marine animals, frequently swimming in a reversed
position, with the foot on the surface, concave, like a boat,
and employing the margin of their mantle and their tentacula
as oars.

ORDER NUDIBRANCHIATA. 37

Doris, Cuv.

The anus opens on the posterior part of the back, the gills
being arranged in a circle round it, under the form of little
arbuscule, the whole resembling a sort of flower; the mouth
is a small proboscis, situated under the anterior margin of the
mantle, and furnished with two little conical tentacule. Two
other claviform tentacula arise from the anterior and superior
part of the mantle. The openings of the genital organs are
approximated under its right margin; the stomach is membra-
nous; a gland, interlaced with the liver, excretes a peculiar
fluid through a hole near the anus. The species are nume-
rous, and some of them large. ‘They are found in every sea,
where their eggs, like gelatinous bands, are diffused over
stones, sea-weed, &c.

Species with an oval mantle projecting beyond the foot,
Doris verrucosa, L.; Doris argo, L.; Doris obvelata, &c.

Prismatic species, where the mantle is almost as narrow as
the foot, Doris lacera, Cuv.; D. atromarginata, Id., &c.

ONCHIDORA, Blainv.,

Only differs from doris in the separation of the genital organs,
the orifices of which communicate by a furrow running along
the right side, as in onchidium. (Onchidora Leachii, Blainv.)

PLOCAMEROS, Leuckard,

Have all the characters of the onchidore, in addition to which
the anterior margin of their mantle is ornamented with nume-
rous branched tentacula. (Plocameros ocellatus, Leach.)

POLYCERA, Cww.

The gills, as in doris, on the hind part of the body, but
more simple, and followed by two membranaceous lamine,
which cover them in moments of danger. Anterior to the

38 CLASS GASTEROPODA.

claviform tentacula, similar to those in doris, are four, and
sometimes six others, simply pointed. (Doris quadrilineata,
Miill., &c.)

TRITONIA, Cuv.

The body, superior tentacula, and genital organs, as in doris;
but the anus, and orifice through which the peculiar liquid
is secreted, are on the right, behind the organs of generation.

The gills, which resemble little trees, are arranged along the
sides of the back ; and the mouth, provided with broad mem-
branous lips, is armed inside with two horny and trenchant.
lateral jaws, which may be compared to a pair of sheep-shears.

Trit. Hombergii, Cuv. Ann. du Mus. I. xxxi. 1,2; a large
species, of a copper colour, from the coast of France.

The same locality produces many others, which vary greatly
in size and the form of their gills. Several of them are very
small. (TZrit. elegans, Trit: rubra, Trit. glauca, &c.)

THETHYS, Lin.

Two rows of gills, resembling branching tufts, along the
back, and a very large, membranous, and fringed veil, upon
the head, which shortens as it curves under the mouth. This
latter is a membranous proboscis, without jaws. On the base
of the veil are two compressed tentacula, from the margin of
which projects a small conical point. The orifices of the
genital organs, of the anus, and of the peculiar fluid, are
situated as in the tritoniz; the stomach is membranous, and
the intestine very short.

T. fimbria, L., Cuv. Ann. du Mus. XII. xxiv.: grey,
spotted with white. A beautiful species, from the Mediter-
ranean.

ScYLLEA, Lin.

Body compressed; the foot narrow, and marked with a

ORDER NUDIBRANCHIATA. 39

furrow, which enables it to clasp the stems of the fuci; no
veil; the mouth resembling a little proboscis ; orifices as in
thethys; the compressed tentacula terminated by a cavity,
from which issues a little uneven point; two pairs of mem-
branous crests on the back, bearing on their internal surface
pencils of filaments, which are the gills. ‘The middle of the
stomach is invested with a fleshy ring, internally armed with
horny and trenchant lamine like knives.

S. Pelagica, L., Cuv. Ann. du Mus. VI. Ixi. 1. 3. 4: com-
mon on the floating fucus of almost every sea.

GLAUCUS, Forster.

Body elongated; orifices of the anus, and of the genital
organs, as in the preceding ; four very small conical tentacula ;
and on each side three gills, each of which is formed of long
slips, arranged like the sticks of a fan, which also aid them in
swimming. These are the beautiful little animals that inhabit
the Mediterranean and the Atlantic, prettily coloured with blue
and mother-of-pearl. They swim on their back with great
swiftness. ‘Their anatomical structure is very similar to that
of the tritonia; but the species are not yet well ascertained.
(Doris radiata, Gm., &c.)

LANIOGERUS, Blainv.

Two series, on each side, of small and finely-pectinated
lamine, which are the gills; the body, shorter and thicker
than that of a glaucus; but there are four small similar tenta-
cula. (Laniogerus Elfortii, Blainv. Malac. pl. xlvi. f. 4.)

Eo.iptia, Cuv.,

Resembles a small limax in form: four tantacula above and
two on the sides of the mouth ; the gills, composed of lamine,
arranged like scales, more or less crowded, on each side of the
back. Found in every sea. (Doris papillosa, Zool. Dan., &c.)

40 CLASS GASTEROPODA.

CAVOLINA, Brug.

The tentacula of the eolidia, with retiform gills, ar-
ranged in transverse rows on the back. (Doris peregrina,
Gm., &c.)

N.B. This genus must not be confounded with the cavolina
of Abildgaard, which is the hyalea.

FLABELLINA, Cuv.

The tentacula of the eolidiz, with radiating retiform gills,
supported by five or six pedicles on each side. They are
closely related to the glauci; and, in fact, all the nudi-
branchiata, whose gills are situated on the sides of the back,
are nearly allied. (Doris affinis, Gm., Cavol., Polyp., Mar.
vii. 4.)

TERGIPES, Cuv.

The form of the eolidia, but only two tentacula, with a
range of cylindrical gills on both sides of the back, each of
which is terminated by a little sucker or cup, and which are
used by the animal as feet to walk upon its back. ‘The
species known are very small. (Limax tergipes, Forskal, &c.)

BusIris, Risso,

The body oblong, and back convex ; two filiform tentacula,
and behind them, on the nape, two plumiform gills. (Busi-
ris griseus, Risso.)

PLACOBRANCHUS, Van Hasselt.

Two tentacula, and as many labial lobes. The whole back,
widened by its margin, is covered with numerous radiating
striez, which are the gills. In its ordinary condition the
widened borders of the mantle are turned up, and cross each

ORDER INFEROBRANCHIATA. 41

other, to form an envelope for the gills, which are thus
enclosed, as in a cylindrical case.

They are small mollusca from the Indian Ocean. In the
species known, (Placobranchus Hasselti, Cuv.) the branchial
striz are green, and the body a brown grey, sprinkled with
little ocelli. Van Hasselt; Bullet. Univ. Oct. 1824, p. 340.
Messrs. Quoy and Gaymard found it at the Friendly Islands.

THIRD ORDER OF GASTEROPODA.

INFEROBRANCHIATA.

THE Inferobranchiata have nearly the same form and organi-
zation observed in doris and tritonia, but their gills, instead
of being placed upon the back, resemble two long series of
leaves, situated on the two sides of the body, under the pro-
jecting margin of the mantle.

PHYLLIDIA, Cuv.

The mantle naked, usually coriaceous, and without any
shell; the mouth a small proboscis, each side of which is fur-
nished with a tentaculum ; two others project above from two
small cavities in the mantle. The anus is on the hind part
of the mantle, and the genital orifices forward, under the night
side; the heart near the middle of the back; the stomach
simple and membranous, and the intestine short.

Several species inhabit the Indian Ocean. (Phyllidia tri-
lineata, Seb., &c.)

42 CLASS GASTEROPODA.

DIPHYLLIDIA, Cuw.

The gills similar to those of the phyllidiz, but the posterior
part of the mantle more pointed. On each side of the semi-
circular head, a pointed tentaculum and a slight tubercle ; the
anus on the right side. (Diphyllidia Brugmansi, Cuv.)

FOURTH ORDER OF GASTEROPODA.

TECTIBRANCHIATA.

THE gills along the right side, or on the back, in the form of
leaves, more or less divided, but not symmetrical: they are
more or less covered by the mantle, in the thickness of which
a, small shell is generally contained. They approach the pec-
tinibranchiata in the form of the organs of respiration, and
like them inhabit the ocean ; but they are all hermaphrodites,
like the nudibranchiata and the pulmonaria.

PLEUROBRANCHUS, Cuv.

The body equally overlapped by the mantle and by the
foot, as if it were between two shields. In some species, a
little oval calcareous lamina is contained in the mantle, and a
horny one in that of others; the mantle is emarginated above
the head ; the gills are attached along the right side in the
furrow, between the mantle and the foot, forming a series
of pyramids, divided into triangular leaflets; the mouth, a
small proboscis, is surmounted by an emarginated lip, and by

ORDER TECTIBRANCHIATA. 43
two tubular and cleft tentacula ; the genital orifices are before,
and the anus behind the gills. There are four stomachs, the
second of which is fleshy, and sometimes armed with bony
appendages, and the third furnished internally with salient
longitudinal lamine ; the intestine is short.

Various species inhabit both the Mediterranean and the
Atlantic, some of which are large, and marked with the most
beautiful colours. (Pleuwrobranchus Peronti, Cuv., &c.)

PLEUROBRANCH&A, Meckel. PLEUROBRANCHIDIUM,
Blaine.

The gills and genital orifices situated as in pleurobran-
chus, but the anus is above the gills; the margin of the
mantle and foot project but little, and on the fore-part of the
former are four short distant tentacula, forming a square, that
reminds the observer of the anterior disk of the akere. I can
find but one stomach, which is merely a dilatation of the canal,
with thin parietes. A multifid glandular organ opens behind
the genital orifices. ‘There is no vestige of a shell.

Pleurob. Meckelii (Leve, diss. de Pleur. 1813), is the only
species known in the Mediterranean.

APLYSIA, Linn.

The margin of the foot turned up into flexible crests, sur-
rounding the back, and even susceptible of being reflected over
it; the head supported by a neck more or less long; two
superior tentacula, excavated like the ears of a quadruped,
with two flattened ones on the edge of the lower lip; the eyes
beneath the former; the gills are on the back, and consist of
highly complicated lamellz, attached to a broad membranous
pedicle, and covered by a small membranous mantle, in the

‘thickness of which is a flat and horny shell; the anus opens
behind the gills, and is frequently concealed under the lateral
crests; the vulva is before, on the right, and the penis pro-

44 CLASS GASTEROPODA.

jects from under the right tentaculum; the seminal fluid is
conducted from the penis to the vulva by a groove which
extends from one to the other. An enormous membranous
crop leads to a muscular gizzard, armed internally with carti-
laginous and pyramidal corpuscles; which is followed by a
third stomach, sown with sharp hooks, and by a fourth, in the
form ofa ccecum. The intestine is voluminous; and the ani-
mal feeds on fucus. A limpid humour, secreted by a particu-
lar gland, and which in certain species is said to be extremely
acrid, is exuded through an orifice near the vulva; and from
the edges of the mantle oozes an abundant liquid, of a deep
purple colour, with which, when in danger, the animal tinges
the water to a considerable extent. The eggs are deposited
in long glairy strings, interlaced, and fine as packthread.

In the seas of Europe we have Apl. fasciata, Poiret, Rang.,
Apl. pl. vi. vii.: black, bordered with lateral red crests. One
of the large species.

Apl. punctata, Cuv. Ann. du Mus. tome ii. p. 287, pl. 1. f.
2—4; Rang. Apl. pl. xviii. f. 2: lilac, sprinkled with greenish

_ points.

Apl. depilatus, L., Bohatch. Anim. Mar. pl. i. and ii.;
- Rang. pl. xvi.: blackish, with large greyish, clouded spots.

Several other species are found in distant seas (Apl. brast-
liana, &c.). Itis well, however, to observe, that most of the
aplysie, having been drawn from specimens preserved in
spirits, the truth of the specific characters of some of them
may be doubted.

DOLABELLA, Lam.

The dolabellz only differ from the aplysiz in the position
of the branchiz, and their surrounding envelope; they are
at the posterior extremity of the body, which resembles a
truncated cone. Their lateral crest presses closely on their
branchial apparatus, merely leaving a narrow furrow. Their

ORDER: TECTIBRANCHIATA. 45

shell is calcareous. ‘They are found in the Mediterranean and
in the Indian Ocean. (Dolabella Rumphii, Cuv. Ann. du
Mus., &c.)

NoTARCHUS, Cuv.

The lateral crests united and covering the back, a longi-
tudinal emargination excepted, that leads to the branchiz,
which have no mantle to cover them, but are otherwise like
those of the aplysiz; the rest of their organization is always
the same. (Notarchus gelatinosus, Cuv., &c.)

BURSATELLA, Blainv.

The lateral crests are united in front in such a manner as
only to leave an oval aperture for the transmission of water to
the gills, which are also deprived of a protecting mantle.
(Bursatella Leachii, De Blainv.)

These two genera, however, probably form but one,

AKERA, Miiller.

The branchiz covered as in the preceding genera, but their
tentacula are so shortened, widened, and separated, that they
seem to be totally wanting, or rather to form a large fleshy and
nearly rectangular shield, under which are the eyes. In
other respects, the hermaphroditism of these animals, the
position of their genital organs, the complication and armature
of their stomach, and the purple liquid effused by several of
their species, approximate them to the aplysia. The shell, of
such as have any, is more or less convoluted, but with little
obliquity, and without a projecting spire, emargination, or
canal; the columella, making a convex projection, gives a
crescented figure to the aperture, the part opposite to the
spire being always the broadest and most rounded.

M. de Lamarck names those in which the shell is concealed
in the thickness of the mantle BuLLAA. It has but

46 CLASS GASTEROPODA.

very few whorls, and the animal is much too large to
enter it.

Bullea aperta, Lam.; Bulla aperta and Lobaria quadri-
loba, Gm.; Phyline quadripartita, Ascan. Miill. Zool. Dan.
1II. pl. ci.; Planc. Conch. Min. Not. pl. xi.; Cuv. Ann. du
Mus. t. I. pl. xii. 6. The animal is whitish, and about an
inch long; the fleshy shield formed by the vestiges of its ten-
tacula, the lateral swellings of its foot, and the mantle occu-
pied by the shell, seem to divide its upper surface into four
lobes. Its thin, white, semi-diaphanous shell, is nearly all
aperture, and its gizzard is armed with three very thick rhom-
boidal pieces of bone. It is found in almost every sea, where
it lives on oozy bottoms.

The Sormet of Adanson is a species closely allied to Bul-
lea; but I cannot establish a genus, or even a species, upon
so imperfect a document. '

M. de Lamarck leaves the name of BULLA to those species
whose shell, merely covered with a slight epidermis, is large
enough to shelter the animal. It is somewhat more convoluted
than in Bullea.

The genus bulla of Linnzus not only comprised the akere,
but also the auricule, agatine, physe, ovule, and terebelle,
animals between which there is much difference. Bruguiéres
commenced the work of reformation, by separating the aga-
tine and the awricule, which he united with the lymnei to
the genus bulimus. M. de Lamarck finished it by creating
all the, genera we have just named.

Bulla lignaria, L., Martini. I. xxi. 194—95; Cuv. Ann.
du Mus. XVI. 1.; Pol. Test. Map. III. pl. xlvi. The oblong
shell, with its concealed spire and ample aperture, very wide
anteriorly, resembles a loosely rolled lamina, stretched in the
direction of its whorls. ‘The stomach of the animal is armed
with two large semi-oval osseous pieces, and with a small
compressed one. Gioéni having observed this stomach sepa-

1

ORDER TECTIBRANCHIATA. 47
rate from the animal, took it for a shell, and made a genus of
it, to which he gave his own name. He even went so far as
to describe its pretended habits. Draparnaud was the first
who perceived this mixture of error and fraud.

Bulla ampulla, L., Martini. I. xxii. 20. 204; Cuv. Ann. du
Mus. XVI.i. The shell oval, thick, clouded with grey and
brown; the stomach furnished with three black, very convex,
rhomboidal pieces.

Bulla hydatis, L., Chemn. IX. exviii. 1019; Cuv. Ann. du
Mus. xvi. 1. Shell round, thin, and semi-diaphanous, the last
whorl, and consequently the aperture, higher than the spire ;
three small scutelliform pieces in the gizzard.

Add Bulla naucum, Bulla physis, &c.

We reserve the name of AKERA, properly so called, (Dort-
DIUM, Meck.; LOBARIA, Blainv.) for those species which
have no shell whatever, or only a vestige of one behind,
although their mantle has its external form.

A small species, Bulla carnosa, Cuv. Ann. du Mus. xvi. 1;
Meck. Anat. Compar. IT. vii. 1. 3; Blainv. Malac. pl. xlv. f.
3; 1s found in the Mediterranean. ‘The stomach is no more
armed than the mantle; its fleshy cesophagus is extremely
thick.

We also find in the same sea a tuberculous species, Dor?-
dium Meckelii, Delle Chiaie Memor. pl. x. f. 1—5.

GASTROPTERON, Meck.,

Appears to be an akera, the margin of whose foot is developed
into broad wings, serving for swimming, which it performs on
its back. It has no shell nor stony armature to the stomach.
A slight fold of the skin is the only vestige of a branchial
operculum that is visible.

The known species is also from the Mediterranean, Gas-
tropteron Meckelit, Kosse. Diss. de pteropodum ordine. Hale.
1813, f. 11—13; and Blainv. Malacol. pl. xv. f.5; or Clio

48 CLASS GASTEROPODA.

amati, Delle Chiaie. Memor. pl. ii. f. 1—8; a small animal,
an inch long and two broad, when the wings are extended.

GASTROPLAX, Blain. UMBRELLA, Lam.

Until the anatomy of this singular genus be more closely
studied, we must place it in the order tectibranchiata, and
even near pleurobranchus. The animal is large and circular,
the foot projects considerably beyond the mantle, and its
upper surface is studded with tubercles; the viscera are in a
round, superior, and central part; the mantle is visible only
by its slightly projecting and trenchant edges along the whole
of the front and of the right side; the lamellated pyramidal
gills, like those of pleurobranchus, are under this slight
margin, and behind them is a tubular anus. Under this same
margin, and forwards, are two tentacula, longitudinally cleft,
still as in pleurobranchus; and at their internal base are the
eyes: between them is a sort of proboscis, which perhaps is
the organ of generation. ‘There is a large concave space in
the anterior margin of the foot, the edges of which can be
drawn up like a purse, and at the bottom of which is a tubercle
pierced by an orifice, which perhaps is the mouth, and sur-
mounted by a fringed membrane. The inferior surface of the
foot is smooth, and serves the animal to crawl on, as in the
other gasteropoda.

The shell is strong, flat, and irregularly rounded, thickest in
the middle, with trenchant edges, and marked with slightly
concentric strie. It was at first thought to be attached to the
foot, but more recent observation has proved that it is on the
mantle, and in the usual place.

In the specimen from the British Museum, described by M.
de Blainville, under the name of GASTROPLAX, the shell is
in fact attached to the under part of the foot, and it is difficult
to determine by what means; the mantle is, however, so thin,
that it seems as if it must have been protected by the shell.

ORDER HETEROPODA. 49

M. Reynaud has just brought an individual which had lost its
shell, but where, it appears, traces of the membranes which
attached it to the mantle may be perceived, notwithstanding
which, no remains of muscles are visible. A similar shell is
also found in the Mediterranean : its animal, however, has not
yet been observed.

FIFTH ORDER OF GASTEROPODA.

HETEROPODA, Lam.

THESE are distinguished from all the others by their foot,
which, instead of forming a horizontal disk, is compressed
into a vertical muscular lamina, which they use as a fin, and
on the edge of which, in several species, is a dilatation form-
ing a hollow cone, that represents the disk of the other orders.
Their gills, formed of lobes like feathers, are situated on the
hind part of the back, directed forward; and immediately in
their rear are the heart and a small liver, with part of the
viscera, and the internal organs of generation. ‘Their body, a
gelatinous and transparent substance, lined with a muscular
layer, is elongated, and usually terminated by a compressed
tail. There is a muscular mass belonging to the mouth, and
a tongue furnished with little hooks; the wsophagus is very
long, their stomach thin; two prominent tubes on the right
side of the visceral bundle afford a passage to the fceces,
semen, and eggs. They usually swim on their backs, with
the foot upwards. This mode of swimming having induced
Peron to think that the natatory lamina was on the back, and
VOL. XII. E

50 CLASS GASTEROPODA.

the heart and gills under the belly, has given rise to many
errors respecting the place of these animals. A simple in-
spection of their nervous system led me to suppose, in my
memoirs on the mollusca, that they were analogous to the gas-
teropoda. A more exact anatomical investigation, made since
then, and that given by M. Poli in his third volume, fully con-
firm my opinion. The fact is, that there is but little difference
between the heteropoda and the tectibranchiata ; notwith-
standing which M. Laurillard believes their sexes to be sepa-
rated. They have the faculty of distending their body, by
filling it with water, in a way not well understood. Forskal
comprized them all in his genus,

PTEROTRACHEA, Forsk.,

But it has been found necessary to sub-divide them.

CARINARIA, Lam.

The nucleus, formed of the heart, liver, and organs of gene-
ration, covered by a slender symmetrical shell, the point of
which is bent backwards, and frequently raised by a crest,
under the anterior edge of which float the feathers of the gills.
On the head are two tentacula, and behind their base the eyes.

There is one species in the Mediterranean, Carinaria cym-
bium, Lam., Péron, Ann. du Mus. XV. iii. 15; Poli. ITI. xliv. ;
Ann. des Sc. Nat. tome XVI. pl. i.

Another, the Carinaria fragilis, Bory St. Vincent, (Voy. aux
isles d’Afr. I. vi. 4.), is found in the Indian Ocean.

Add Carinaria depressa, Rang. Ann. des Sc. Nat. Feb.
1829, p. 136.

The Argonauta vitrea of authors, Favanne vii. c. 2; Mar-
tini, I. xiii. 163., must be the shell of a large carimaria, but
the animal is not yet known.

ORDER HETEROPODA. 51

ATLANTA, Lesueur.

These mollusca, according to the recent observations of M.
Rang, should belong to this order. Their shell, instead of
being widened like that of the carinariz, has a narrow cavity,
spirally convoluted on one plane; its contour is raised by a
thin crest.

They are extremely small shells, from the Indian Ocean, in
one of which Lamanon thought he had discovered the original
Cornu ammonis. Atlanta Peroniti and Atlanta Keraudrenii,
Lesueur, Journ. de Phys. Ixxxv. November, 1817, and Rang.
de la Soc. d@’Hist. Nat. tome. III. p. 373, and pl. ix.

N. B. We must not confound the Atlante of Lesueur with
the Atlas described by him in the same place, and which, so
confined is his description, I do not know where to class.

Firona, Peron.

The body, tail, foot, gills, and visceral mass, as in the cari-
nariz, but no shell has ever been observed; the snout is
elongated into a recurved proboscis, and the eyes are not pre-
ceded by tentacula. From the end of the tail is frequently
observed to proceed a long articulated filament, which Forskal
took for a tenia, and the nature of which is not yet very clearly
understood.

One species, the Pterotrachea coronata, Forskal, Peron,
Ann. du Mus. XV. ii. 8, is very common in the Mediter-
ranean ; and M. Lesueur describes several from the same sea,
which he considers as different, Journ. Acad. Nat. Soc. Philad.
vol. i. p. 3, but which require further comparison. (Lrola
mutica, F. gibbosa, &c.)

M. Lesueur distinguishes the FIROLOIDE, where the body,
instead of terminating in a compressed tail, is abruptly trun-
cated behind the visceral bundle.—Jbid. p. 37. (Firoloida,
Demaresiia, &c.)

52 CLASS GASTEROPODA.

To these two, now well known genera, I presume we must
add, when better known,

TIMORIENNA, Quoy et Gaim., Zool. de Freyc. pl. Ixxx. f.
1, which appear to be firole deprived of their foot and bundle
of viscera.

And the

MonoPHorRa, id. ib. f. iv. and v., which has nearly the
form of a carinaria, but is without a foot, distinct bundle of
viscera, and shell.

We must not confound them with the monophore of M.
Bory St. Vincent (Voy. aux Isles d’Afr.), which are pyrosome.

It is not certain that we should place here

PHYLLIROE, Péron, Ann. du Mus. XV. pl. ii. f.1., where the
transparent and strongly compressed body has a snout before,
surmounted by two long tentacula without eyes, a truncated
tail behind, and which allows its heart, nervous system,
stomach, and the genital organs of both sexes, to be seen
through the integuments. The genital orifices and the anus
are on the right side, and sometimes a tolerably long penis is
visible. I can find no other organ of respiration than its thin
and vascular skin.

THE SIXTH ORDER OF GASTEROPODA.

THE PECTINIBRANCHIATA

Form, beyond all comparison, the most numerous division,
inasmuch as they include the whole of the spiral univalves,

ORDER PECTINIBRANCHIATA. 53

and several that are simply conical. ‘Their gills, composed of
numerous lamelle or strips, laid parallel with each other, like
the teeth of a comb, are attached on one, two, or three lines,
according to the genus, to the ceiling of the pulmonary
cavity, which occupies the last whorl of the shell, and which
has a large opening between the edge of the mantle and the
body.

In two genera only, Cyclostoma and Helicina, do we find,
instead of gills, a vascular net-work covering the ceiling of a
cavity that is otherwise similar; they are the only ones that
respire the natural air, all the others respire water.

All the pectinibranchiata have two tentacula and two eyes,
sometimes placed on particular pedicles, and a mouth, resem-
bling a more or less elongated proboscis. The sexes are sepa-
rate. The penis of the male, attached to the right side of the
neck, cannot usually be retracted within the body, but is
reflected into the cavity of the gills; itis sometimes very stout.
The paludina is the only one which can retract it through an
orifice perforated in its right tentaculum. The rectum and
oviduct of the female also run along the right side of this
cavity, and between them and the gills is a peculiar organ,
composed of cells, from which exudes an extremely viscid
fluid, serving for the formation of a common envelope which
contains the eggs, and is deposited with them. ‘The figure of
this envelope is often very complex and singular.

Their tongue is armed with little hooks, and by slow and
repeated rubbing acts upon the hardest bodies.

The greatest difference in these animals consists in the pre-
sence or absence of the little canal formed by a prolongation
of the edge of the pulmonary cavity, on the left side, and
which passes through a similar canal or emargination in the
shell, to enable the animal to breathe without leaving its
shelter. There is also this distinction between the genera,
that some of them have no operculum. The species differ

54 CLASS GASTEROPODA.

from each other by the filaments, fringes, and other ornaments
of the head, foot, or mantle.

These mollusca are arranged in several families, according
to the forms of their shells, which appear to be constantly in
relation to that of the animal.

The first family of the gasteropoda pectinibranchiata, or the

TROCHOIDA,

Is known by the shell, the aperture of which is entire, with-
out an emargination or canal for a siphon of the mantle, as the
animal has none, and is furnished with an operculum or some
organ in place of it.

Trocuus, Linn.,

Have shells; in which the external margin of the angular
aperture approaches more or less to a perfect quadrangular
figure, and is in an oblique plane with respect to the axis of
the shell, because the part of the margin next to the spire
projects more than the rest. Most of these animals have
three filaments on each edge of the mantle, or at least some
appendages to the sides of the feet.

Of those which have no umbilicus, there are some in which
the columella, having the form of a concave arch, is continu-
ous with the external margin without any projection. It is
the angle and projection of this margin which distinguish them
from turbo. These are the TEcTARIA, Montf.; Troch. iner-
mis, Chemnitz, &c.

Several are flattened with a trenchant edge, which has
caused them to be compared to the rowel of a spur. (CAL-
cAR, Montf.; Turbo calcar, L., &c.)

Some, again, are slightly depressed, orbicular, and shining,
with ahalf-rcunded aperture, the columella convex and callous.
(ROTELLA, Lam.; Troch. vestiarius, L.)

The columella of others is distinguished near the base by a

Mollusca’

1 Trechus bicarinatus. + Natica Pluctiuata
2 Nakca bitasctata. 5 Laludina Chinensis.
jLitteraria pulchra. 6Laludina pulchra.

7 Trochus Cunninghame.

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ORDER PECTINIBRANCHIATA. 55

little prominence or vestige of a tooth, similar to that of the
monodontes, from which these trochi only differ in the angle
of their aperture, and the projection of their margin. The
aperture is usually about as high as itis wide. (CANTHARIS,
Montf.; Troch. iris, Chemn., &c.)

In some of them, on the contrary, the aperture is much
wider than it is high, and their convex base approximates
them to the calyptracea. (INFUNDIBULUM, Montf.; Tro-
chus concavus, Chemn.)

In others, where the aperture is also much wider than it is
high, the columella forms a spiral canal. (Trochus foveola-
tus, Chemn.)

Those which have a turreted shell approach cerithium,
(TELEScoPIUM, Montf. ; Trochus telescopium, Chemn.)

Among the umbilicated trochi there are some in which
there is no projection in the columella; most of them are
flattened, and have the external angle trenchant. Of this
number is

Tr. agglutinans, L., Chemn. V. clxxii. 1688—9, remark-
able for the habit of glueing to its shell, and even incorporat-
ing with it, as fast as it increases in size, various foreign
bodies, such as little pebbles, fragments of other shells, &c.
It frequently covers its umbilicus with a testaceous plate.
Add Troch. indicus, Chemn., &c.

The margin of others, however, is rounded; such as

Tr. cinerarius, L., Chemn. V. clxxi. 1686: asmall species,
and the most common on the coast of France; greenish, ob-
liquely streaked with violet.

Other umbilicated trochi have a prominence near the bot-
tom of the columella. (77. virgatus, Chemn., &c.)

And finally, there are some in which it is longitudinally
crenate. (Zr. maculatus, Chemn., &c.)

56 CLASS GASTEROPODA.

SOLARIUM, Lam.,

Is distinguished from all other trochi by a very broad conical
spire, at the base of which is an extremely wide umbilicus, in
which may be seen the external edges of all whorls, marked
by a crenated cord. (Tr. perspectivus, I..)

EVOMPHALUS, Sowerby.

Fossil shells, resembling a solarium, but wanting the denta-
tions on the internal whorls of the umbilicus. (Hvomphalus
pentangulatus, Sowerb.) The genus

TuRBO, Lin.,

Comprehends all the species with a completely and regularly
turbinated shell, and a perfectly round aperture. Close obser-
vation has caused them to be greatly subdivided.

TURBO (proper), Lam.

The shell is round or oval, and thick ; the aperture is com-
pleted on the side next to the spire by the penultimate whorl.
The animal has two long tentacula, and the eyes placed on
pedicles at their external base ; the sides of the foot are pro-
vided with membranous wings, sometimes simple, at others
fringed, and occasionally furnished with one or two filaments.
To some of these belong those petrous and thick opercula
which we see in cabinets, and which were formerly employed
in medicine under the name of wnguis odoratus.

Some of them, MELEAGER, Mont/., are umbilicated.
(Turbo pica, L., &c.)

Others are not. (TursBo, Montf.; Turbo petholatus,
List., &c.)

DELPHINULA, Lam.

The shell thick, as in turbo, but convoluted nearly in the

ORDER PECTINIBRANCHIATA. 57

same plane; the aperture completely formed by the last whorl,
and the margin not tumid: the animal similar to that of a
turbo.

The most common species, Turbo delphinus, Lin., List.
608. 45, takes its name from the ramous and convoluted spines,
which have caused it to be compared to a dried fish. Add
Turbo nodulosus, Chemn., &c.

PLEUROTOMA, Defrance.

Fossil shells, with a round aperture, on the external margin
of which is a narrow incision, ascending considerably. It is
probable that it corresponded, like that of the siliquari, to
some cleft in the branchial part of the mantle.

M. Deshayes already enumerates upwards of twenty fossil
species. The Sc_sSURELLE of M. dOrbigny are living
species of the same.

.

TURRITELLA, Lam.

The same round aperture as in turbo properly so called, and
completed also by the penultimate whorl; but the shell is
thin, and is so far from being convoluted in one plane, that its
spire is prolonged into a turreted obelisk. ‘The eyes of the
animal are placed on the:external base of its tentacula; the
foot is small. (Turbo imbricatus, Martini, &c.)

They are found in great numbers among fossils. ‘The
Proto, Defr., should be approximated to them.

ScALARIA, Lam.

The spire, as in turritella, elongated into a point, and the
aperture, as in delphinula, completely formed by the last
whorl; it is, moreover, surrounded by a ridge, which the
animal renews from space to space as its shell increases in
size, so that it forms as it were steps. The tentacula and
penis of the animal are long and slender.

58 CLASS GASTEROPODA.

One species, celebrated for the high price it commands, the
Turbo Scalaris, L., Chemn., LV. clii. 1426, &c.—vulgo, Sca-
lata,—is distinguished by the whorls only coming in contact
at the point where the ribs unite them, the intervals being
open.

A second species, the Turbo clathrus, Linn., List. 588, 50,
51, is not marked by this peculiarity : it is more slender, and
is commonly found in the Mediterranean.

Some terrestrial or fresh-water subgenera, in which the
aperture is entire, round, or nearly so, and operculated, may
be placed here. Of this number is the

CycLostoma, Lam.

The cyclostoma should be distinguished from all the others
because they are terrestrial, as, instead of gills, the animal has
merely a vascular net-work spread over the parietes of its
pectoral cavity. In every other respect, however, it resem-
bles the other animals of this family : the respiratory aperture
opens in the same way above the head by a great solution of
continuity ; the sexes are separated ; the penis of the male is
large, fleshy, and reflected into the pectoral cavity ; the two
tentacula are terminated by blunt tubercles, and two other
tubercles placed on their external base support the eyes.

The shell isa spiral oval, with complete whorls, trans-
versely and finely striated ; and its aperture in the adult is
surrounded witha small ridge. Itis closed by a small round
operculum. Found in woods, under moss, stones, &c.

The most common is the Turbo elegans, List. 27, 25, about
six lines in length, and of a greyish colour; found under all
the mosses. Add Turbo lincina, List., &c.

VALVATA, Miill.

The valvata inhabit fresh water; their shell is convoluted
in almost one plane, like that of a planorbis, but the aperture

Mollusca/ PU.23. *

1 Gyelestoma’ articulata’

2 Helix argellacea.

3 Cyelestema’ pulchra.
4 Cye. Madagascariensis.
5 Cyc. auriculare’.

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ORDER PECTINIBRANCHIATA. 59

is round, and furnished with an operculum; the animal, which
has slender tentacula, with the eyes at their anterior base, re-
spires by means of gills. In a species found in France,

Valv. cristata, Miill., Drap. 1. 32,33; Gruet-Huysen. Act.
Nat. Cur. X. pl. xxxviii., the gills, formed like a feather, pro-
ject from under the mantle, and float externally, vibrating with
the breathing of the animal ; on the right side of the body is
a filament, which resembles a third tentaculum ; the foot is
divided anteriorly into two hooked lobes; the penis of the
male is slender, and reflected into the branchial cavity ; the
shell, which is hardly three lines broad, is greyish, flat, and
umbilicated. Found in stagnant water. Add Valvata pla-
norbis, Drap., &c.

It is here that we must place the completely aquatic shells,
or those respiring by gills, which belonged to the old genus
HELIX: 7. e. those in which the penultimate whorl forms, as
in the helices, lymnez, &c., a depression, which gives the
aperture more or less the form of a crescent.

The first three genera are still closely allied to turbo.

PALUDINA, Lam.

This genus has been lately separated from the cyclostoma,
because there is no ridge round the aperture of the shell;
because there is a small angle to that aperture, as well as to
the operculum; and finally, because the animal, being pro-
vided with gills, inhabits the water like all other genera. of
this family. It has a very short snout, and two pointed ten-
tacula ; eyes at the external base of the latter, but on no par-
ticular pedicle ; and a small membranous wing on each side of
the fore-foot of the body. The anterior edge of the foot is
double, and the wing of the right side forms a little canal,
which introduces water into the respiratory cavity, the inci-
pient indication of the siphon in the following family.

The common species, Helix vivipara, L.,Drap.,whose smooth

1

GO CLASS GASTEROPODA.

and greenish shell is marked with two or three longitudinal
bands, and which abounds in stagnant waters in France, pro-
duces living young ones: in the spring of the year they may
be found in the oviduct of the female, in every stage of de-
velopment. Spallanzani assures us, that if the young ones be
taken at the moment of their birth, and be reared separately,
they will reproduce without fecundation, like those of the
aphis. The males, however, are nearly as common as the
females: they have a large penis, which protrudes and
retracts, as in helix, but through a hole pierced in the right
tentaculum, a circumstance which renders that tentaculum
_ apparently larger than the other, and which furnishes us with
a mode of recognizing the male.

Add Cyclost. achatinum, Drap.i. 18, &c.

The ocean produces some shells which differ only from the
paludine in being thick. They form the

LITTORINA, Féruss.,

Of which the common species, Le vigneau (Turbo littoreus,
L.), Chemn. V. clxxxv. 1852, abounds on the coast of France,
where it is eaten. The shell is round, brown, and longitudi-
nally streaked with blackish.

Monopon, Lam.,

Only differs from littorina in having a blunt and slightly salient
tooth at the base of the columella, which sometimes also has
a fine notch; the external edge of the aperture is crenulated
in several species. The animal is more highly ornamented,
and is generally furnished with three or four filaments on each
side, as long as its tentacula; the eyes are planted on parti-
cular pedicles, at the external base of the tentacula; the oper-
culum is round and horny.

A small species, the Trochus tesselatus, L., Adanson, Seneg.
XII. 1; List. 642. 33, 34, with a brown shell, spotted with

ORDER PECTINIBRANCHIATA. GL

whitish, is very abundant on the coast of France. Add Tro-
chus labeo, Adans., &c. &c.

PHASIANELLA, Lam.

Aun oblong or pointed shell, similar to that of several bulimi
and lymnez ; the aperture also higher than it is wide, and
furnished with a strong operculum; base of the columella sen-
sibly flattened, but no umbilicus.

They inhabit the Indian Ocean, and are much sought for
by collectors, on account of the beauty of their colours. The
animal is provided with two long tentacula, with eyes placed
on two tubercles at their external base, and with double lips
that are emarginated and fringed, as well as the wings, each
of which has three filaments. (Buccinum tritonis, Chemn.,
&e.)

AMPULLARIA, Lam.,

Have the shel] round and bellied; a short spire, as in most
of the helices ; the aperture higher than it is wide, and pro-
vided with an operculum ; the columella umbilicated.

They inhabit the fresh or brackish waters of hot countries.
The animal has long tentacula, and eyes placed on pedicles at
their base. In the roof of the respiratory cavity, by the side
of a branchial comb, according to the observations of Messrs.
Quoy and Gaymard, is a large pouch, without an issue, that is
filled with air, and may be considered as a natatory bladder.
(Helix ampullacea, L., List. 130, &c.)

The LAnist&, Montf.,

Are ampullaria, with a large, spiral, convoluted umbilicus.
Ampulla carinata, Olivier, Voy. en Turquie.

HeLicina, Lam.

Judging by the shell, the helicine are ampullariz, in

62 CLASS GASTEROPODA.

which the margin of the aperture is reflected. Hel. striata,
Blainville, Malac. XXXV. iv.

When this reflected margin is trenchant, they are the AM-
PULLIN, Blainv. ; and when it is an obtuse ridge, the micas
GIR, Say.

There is one species which is remarkable for a border, and
a stony traverse, on the internal face of its operculaaae
Hel. neritella, List.

The organs of respiration in those animals are arranged as
in the cyclostome, and like the latter they can live out of water.

MELANTA, Lam.

A thicker shell; the aperture, higher than it is wide, en-
larges opposite to the spire; the columella without folds or
umbilicus; length of the spire very various.

The melanie inhabit rivers, but are not found in France;
the animal has long tentacula, the eyes being on their exter-
nal side, and at about the third of their length. Mélanie
thiare (Melania amarula, Lam.), Chemn. Tab. 134, f. 1218
and 1219, from the Isle of France and Madagascar. Add
Mel. truncata, Lam., &c.

Rissoa, Fremin. ACMEA, Hartm.

Differs from melamia, because the two edges of the aperture
unite above. (Riss. Freminvilii, &c.)

MELANOPSIS, Féruss.

Where the form, nearly that of a melania, differs from it ina
callus on the columella, and in a vestige of an emargination
near the bottom of the aperture, which seems to indicate a re-
lation with the terebre of Bruguiéres. (Mel. buccinoidea,
Féruss.) In the

Mollusca: PL, 13

1 Certthium trancatums 3 Melania Careline:

2 Melania STHenriette: 4 Mel. lineclata.

5 Turittla’ sulurnalis.

Londonfublished by Whittaker t: Ave Marie, Lane, 4853.

1 Cerithium zenate:

5 Mel. cenica:

2 Mdanias Frethit 6 Mel. globuloesa:
3 Mel. quadrisertiata. 7 Mel. subcarinata:
4. Mel. lineelata & Mel. levis.

9 Mel. relusa.

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ORDER PECTINIBRANCHIATA. 63

PIRENA, Lam.,,

We find not only this little sinus below, but likewise a second
on the opposite side. (Pir. terebralis, Lam.)
These two subgenera, as well as the melania, inhabit the
rivers of Southern Europe and of all hot countries.
_ There are two genera detached from the volute, which, but
that they are operculated, and have two tentacula, would
resemble the auricule. We think they may be placed here.

AcTZON, Montf. TORNATELLA, Lam.,

Where the shell is elliptical, the spire but slightly salient, the
aperture lengthened into a crescent and widened below, and
the base of the columella marked by one or two large folds or
oblique callosities. ‘They must be carefully distinguished
from the acteons of Oken, which appear to be allied to the
aplysiz. (Voluta tornatilis and bifasciata, Lin., &c.) And the

PYRAMIDELLA, Lam.,

Where the spire is turreted, the aperture crescent-like and
wide, and the base of the columella obliquely contorted and
marked with sharp spiral plice. (Trochus dolabratus.)

JANTHINA, Lam.

The form of the animal separates the Janthine from all the
preceding genera; their shell, however, is similar to that of
the terrestrial limaces, the columellar margin being also
indented, but slightly angular at the external edge, and the
columella, somewhat extended beyond the half oval, which,
without this prolongation, would be formed by that edge.

The animal has no operculum, but the under surface of its
foot is furnished with a vesicular organ resembling a bubble
of foam, but composed of a solid substance, which prevents
it from crawling, but allows it to float on the surface of the

64 CLASS GASTEROPODA.

water. The head, a cylindrical proboscis, terminated by a
vertically cleft mouth, and armed with little hooks, has a bifur-
cated tentaculum on each side.

The common species, Helix Janthina, Lin., has a pretty
violet shell, and is very abundant in the Mediterranean. When
the animal is touched, it sheds a thick fluid, of a deep violet
colour, that dyes the surrounding water.

NERITA, Lin.

The columella of the neritz being in a straight line, renders
the aperture semi-circular or semi-elliptical. This aperture is
generally large in comparison with the shell, but is always
furnished with an operculum that completely closes it. The
spire is almost effaced, and the shell semi-globular.

NATICcA, Lam.,

Are nerite with an umbilicated shell. The animal of the
species known has a large foot, simple tentacula, with the eyes
at their base, and a horny operculum.

NERITA, Lam. PEULORONTA, Oken.,

The umbilicus is wanting, the shell thick, columella den-
tated, and operculum stony; the eyes of the animal on pedi-
cles, by the side of the tentacula, and a moderate foot.

VELATA, Montf.,,

Where the side of the columella is covered with a calcareous,
thick, and convex layer, is distinguished from the above, but
perhaps without any good reason. (Nerita perversa, Gmel.)
A large fossil species. Also the

NERITINA, Lam.,

Where the shell has no umbilicus, and is thin, with a horny
operculum; the animal is like a true nerita, and most

ORDER PECTINIBRANCHIATA. 65

generally the columella is not dentated. It inhabits fresh
water.

A small species, very prettily coloured, abounds in the
rivers of France; it is the Nerita fluviatilis, L., Chemn. IX.
exxiy. 188. Add Nerita turrita, Chemn.

The columella in others, however, is finely crenulated
(Nerita pulligera, Chemn.), and of this number there are
some in which the spire is armed with long spines. (CLITHON,
Mont.; Nerita corona, Chemn.)

According to our recent investigations, it is to the trochoida
that we must approximate a family, which we shall call

CAPULOIDA,

And which comprehends five genera, four of which have been
dismembered from the patelle: they all have a widely
opened, scarcely turbinated shell, with neither operculum,
emargination, nor siphon. The animal resembles the other
pectinibranchiata, and has the sexes separate. There is but
one branchial comb, transversely arranged on the roof of the
cavity, and its filaments are frequently very long.

CAPULUS, Mont. PiLEopts, Lam.

A conical shell, with a recurved and spiral summit, which
has long caused it to be placed with the patelle ; the gills are
in one range, under the anterior margin of the branchial cavity ;
the proboscis is long, and there is a closely-plaited membran-
ous veil under the neck; the eyes are at the external base of
the conical tentacula. (Patella Hungarica, List. 544. 32.)

Htpronyx, Def/r.,
Would appear from the shell to be a fossil capulus, very re-
markable, however, for a bed formed of calcareous matter, on
which it rests, and which probably exuded from the foot of
the animal. (Putella cornucopie, Lam.)
VOL. XII. K

66 CLASS GASTEROPODA.

CREPIDULA, Lam.

The shell oval, with an obtuse horizontal point, directed ob-
liquely backwards and laterally, the aperture forming the base
of the shell, which is half closed beneath, and behind with a
horizontal plate ; the abdominal sac which contains the viscera
is on this plate, the foot beneath, and the head and gills for-
wards: the latter consist of a range of long filaments, attached
under the anterior margin of the branchial cavity ; the eyes
are at the external base of two conical tentacula, (Patella
fornicata, List. 545. 33. 35, &c.)

PILEOLUS, Sowerby,

Appears a crepidula, in which the transverse plate occupies
half the aperture; the shell, however, is more like that of a
patella. (Pileolus plicatus, Sowerb.) ‘They are only found
fossil.

SEPTARIA, Fér. NAVICELLA, Lam.
CIMBER, Mont., 82.

The shell resembles a crepidula, except that the summit is
symmetrical, and laid on the posterior margin, and that the
horizontal plate is less salient. ‘The animal is also provided
with an additional irregularly shaped testaceous plate, attached
horizontally to the superior surface of the muscular disk of its
foot, and covered by the abdominal sac, which it partially
supports. It is probably analogous to an operculum, but
does not exercise its functions, being, in a measure, situated
internally. The animal has long tentacula, at whose external
base are pedicles which support the eyes. They inhabit the
rivers of hot countries. (Patella neritoidea, List. 545. 36, &c.)

CALYPTREA, Lam.,

Have a conical shell, in the hollow of which is a little lamina
1

ORDER PECTINIBRANCHIATA. 67

that projects inwards, forms, as it were, the commencement of
a columella, and interposes itself between a fold of the abdo-
minal sac; the gills are composed of a range of numerous
filaments, long and slender, like hairs.

In some of them this lamina adheres to the bottom of the
cone, being itself bent into a portion of a cone or of a tube,
and descending vertically. (Patella equestris, L., List. 546.
38, &c.)

In others it is almost horizontal, and adheres to the sides of
the cone, which is marked above by a spiral line, that esta-
blishes some relation between this shell and that of a trochus.
(Patella contorta, &c.)

SIPHONARTA, Sowerb.

The shell of the siphonariz, which have been recently
separated from the patellz, at the first glance seems very simi-
lar to a flattened patella with radiating furrows; but its mar-
gin projects rather more on the right side, and is excavated
beneath by a slight furrow, terminating at this projection, to
which also corresponds a lateral hole in the mantle, for the in-
troduction of water into the branchial cavity placed on the
back; at all other points it is completely closed. The respi-
ratory organ consists of a few small lamelle, arranged in one
transverse line on the roof of this cavity; the tentacula seem
to be wanting, the head being merely furnished with a narrow
veil. (Patella sipho, Sowerb., &c.)

There are some species in which even this slight appear-
ance of the canal in the shell is effaced, resembling altogether
that of a patella, except in its summit, which is behind.
(Stphonaria tristensis, Sowerb.) :

SIGARETUS, Adans.

The shell is flattened, its aperture ample and round, and the
spire very moderate; its whorls rapidly enlarging, and seen
2

68 CLASS GASTEROPODA.

within, but concealed, during the life of the animal, in the
thickness of a fungous shield, which projects considerably
beyond it, as well as the foot, and which is the true mantle.
In front of this mantle are an emargination and a semi-canal,
which serve to conduct water into the branchial cavity, and
which form a transition to the following family, but of which
there are no impressions on the shell; the tentacula are coni-
cal, with the eyes at their external base ; the penis of the male
is very large.
Some species are found on the coast of France.

CoRIOCELLA, Blainv.,

Consists of sigareti, the shell of which is horny and almost
membranous, like-that of the aplysie. (The Coriocelle noire,
Blainv.) This animal is not without a shell, as the author of
this genus imagined, but it is thin and flexible.

CrypTostoma, Blainv.

The shell, resembling that of a sigaretus, borne with the
head and abdomen, which it covers, on a foot four times larger,
cut square behind, and forming before a fleshy oblong bundle _
that constitutes nearly one-half of its mass. The animal has
a flat head, two tentacula, a broad branchial comb on the roof
of its dorsal cavity, and a penis under the right tentaculum ;
but I can find no emargination in the mantle. Besides the
species in the British Museum, Cr. Leachii, Blainv., we have
one, Cr. Carolinum, Cuv., sent from Carolina by M. L’Her-
minier.

The third family of the gasteropoda pectinibranchiata,
or the

BUCCINOIDA,

Has a spiral shell, in the aperture of which, near the extre-
mity of the columella, is an emargination, or a canal, for

ORDER PECTINIBRANCHIATA. 69

transmitting the siphon or tube, which is itself but an elon-
gated fold of the mantle. ‘The greater or less length of the
canal, when there is one, the size of the aperture, and the
form of the columella, furnish the grounds of its division into
genera, which may be variously grouped.

Conus, L.,

So called from the conical shape of the shell ; the spire, either
perfectly flat, or but slightly salient, forms the base of the
cone ; its point is at the opposite extremity ; the aperture is
narrow, rectilinear, or nearly so, extending from one end to
the other, without enlargement or fold, either on its edge or on
the columella. The thinness of the animal is proportioned
to the narrowness of the aperture through which it issues.
Its tentacula and proboscis have great capacity of elongation.
The eyes are placed on the outer side of the former, and near
the point ; the operculum, situated obliquely on the hind part
of the foot, is too narrow and short to close the whole of the
aperture.

In placing here the genera with a straight aperture, we must
not be understood as meaning to approximate them to the
preceding family, but only to present them first, as possessing
the most striking characters of all those which are furnished
with a siphon.

The shells of this genus being usually ornamented with the
most beautiful colours, are very common in cabinets. The
seas of Europe produce very few.

They are distinguished by the flatness or slight projection
of the spire; by the whorls being tuberculated or not; by its
being more salient, and even pointed, and furnished, or not,
with tubercles.

There are some in which the spire is sufficiently salient to
give them a cylindrical appearance, in which case it may be

70 CLASS GASTEROPODA.

either smooth or tuberculated. Species with a crowned spire :
Con. cedonulli, L., &c. Species with a simple spire: Con.
litteratus, L., &c. The appellation of crowned spire is ap-
plied to that which is studded with tubercles.

Cypreaa, L.

The spire projecting but little, and the aperture narrowed,
and extending from one extremity to the other; but the shell,
which is: protuberant in the middle, and almost equally
narrowed at both ends, forms an oval, and the aperture in the
adult animal is transversely wrinkled on each side. The
mantle is sufficiently ample to fold over and envelope the shell,
which, at a certain age, it covers with a layer of another
colour, so that this difference, added to the form acquired by
the aperture, may easily cause the adult to be taken for ano-
ther species. The animal has moderate tentacula, with the
eyes at their external base, and a thin foot without an opercu-
lum.

The colours of these shells also are extremely beautiful :
they are very common in cabinets, though with very few ex-
ceptions they all inhabit the seas of tropical countries. They
are termed Porcelainous.

ANULA, Brug.

The shell is oval, and the aperture narrowed and long, as in
cyprxa, but without folds on the side next to the columella;
the spireis concealed, and the two ends of the aperture equally
emarginated, or equally prolonged in a canal. Linnzus con-
founded them with the bulle, from which Bruguiéres has
very properly separated them. The animal has a broad foot,
an extended mantle which partly folds over the shell, a mode-
rate and obtuse snout, and two long tentacula, on which, at
about a third of their length, are the eyes.

ORDER PECTINIBRANCHIATA. qi

Montfort particularly designates, by the name OVUL&,
those in which the external margin is transversely wrinkled,
(Bulla ovum, L.)

Those in which the two extremities of the aperture are
prolonged into a canal, and in which the external margin is
not wrinkled, he denominates VOLV&. (Bulla volva, L.)

When this external margin is not wrinkled, nor the extre-
mities of the aperture prolonged, he styles them CALPURNE.
(Bulla verrucosa, L.)

TEREBELLUM, Lam.

An oblong shell, with a narrowed aperture, without folds or
wrinkles, and increasing regularly in width to the end opposite
to the spire, which is more or less salient, according to the
species. The animal is not known. (Zerebellum subulatum,
Lam., &c.)

VoLuTA, Lin.,

Varies as to the form of the shell and that of the aperture, but
is recognized by the emargination, without a canal, which
terminates it, and by the salient and oblique folds of the colu-
mella. From this genus Bruguiéres first separated

OLIvA, Brug.,

So named from the oblong or elliptical shape of the shell, the
aperture of which is narrowed, long, and emarginated oppo-
site to the spire, which is short; the folds of the columella are
numerous, and resemble strize; the whorls are sulciform.
These shells are quite as beautiful. as the cyprea. (Oliv.
subulata, Lam., &c.)

The animal has a large foot, the anterior part of which
(before the head), is separated by an incision on each side ;
its tentacula are slender, and bear the eyes on their sides,
about the middle of their length; the proboscis, siphon, and

72 CLASS GASTEROPODA.

penis, are tolerably long, but it has no operculum. MM.
(uoy and Gaymard have observed an appendage on its poste-
rior portion, which enters the furrow of the whorls.

The remainder of the genus voluta was afterwards divided
into five by M. de Lamarck, exclusive of the tornatelle and
pyramidelle already mentioned.

VOLVARIA, Lam.,

Closely resembles the oliva in its oblong or cylindrical form ;
but the aperture is narrow, and its anterior edge ascends to the
top of the spire, which is excessively short. There is one
fold, or several, at the foot of the columella. The lustre and
whiteness of this shell are such that on the coasts it is used
for making necklaces. (Volv. monilis, Lin.) A small fossil
species is found in the vicinity of Paris. (Volvaria bulloides.)

VOLUTA (proper), Lam.

The aperture is ample, and the columella marked with
large folds, the one farthest from the spire being the largest.
The degree of projection in the spire varies greatly.

In some of them, CymMBiuM, Montf.; CyMBA, Sowerb.,
the last whorl is bellied. ‘The animal has a large thick and
fleshy foot, without operculum, and a veil on the head, from
the sides of which issue the tentacula; their eyes are on this
same veil, outside of the tentaculum; the proboscis is toler-
ably long, and there is an appendage on each side of the base
of the siphon. They attain a large size, and many of them are
extremely beautiful. (Volv. Avthiopica, List. 797. 4., &c.)

In others, VoLUTA, Montf., the last whorl is conical, be-
coming narrower at the extremity opposite the spire. (Voluta
musica, List., &c.) The foot of the animal is not so large as
that of the preceding ones; their shells are frequently remark-
able for the beauty of their colours, or the figures traced on
them.

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L Conus caledonicius. 5 duimal of Cyp. pedicutlus.9Terebellum subrdatum. V3 Ol. auricularta

2 Animal of Onus bandanus. 6 Cvila. lriticea. 10 Volt nivosa. 14 Volvarta’ pallida:

4 Conus tendinens. 7 Cvula velva. UW dAnimal ef Tel. atitopica ds Marginela nubeculati
+ Crprea stelida. & Calpurnus verrucosus, V2 Oliva fsprdetle 1G Mara. bullata.

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ORDER PECTINIBRANCHIATA. ves

MARGINELLA, Lam.

Form of the shell similar to that of a true voluta, but the
external margin of the aperture is tumid; the emargination is
but slightly marked. The foot of the animal, according to
Adanson, is very large, and has no operculum. By turning
up the lobes of its mantle, it partly covers the shell. The
eyes are on the external side of the base of its tentacula.
(Voluta glabella, Adans., &c.)

M. de Lamarck also distinguishes the COLOMBELLA, in
which the folds are numerous, and the rim of the external
margin is enlarged at its centre. It appears that the opercu-
lum is wanting. (Voluta mercatoria, List., &c.)

Mirra, Lam.

The aperture oblong, with a few large folds on the columella,
the one nearest the spire being the largest; the spire usually
pointed and elongated. Several species are brilliantly spotted
with red on a white ground. ‘The foot of the animal is small ;
the tentacula are of a moderate length, with the eyes on the
side, near their inferior third ; the siphon is also of a moderate

length, but it frequently protrudes a proboscis longer than its
shell.

CANCELLARIA, Lam.

The last whorl swollen out, aperture ample and round, the
internal margin forming a plate on the columella; the spire is
salient and pointed, and the surface of the shell marked with
crossing furrows. (Voluta cancellata, L.)

BuccinuM, Lin.,

Comprises all the shells furnished with an emargination, or a
short canal inflected to the left, and in which the columella is
destitute of folds.

74 CLASS GASTEROPODA.

Bruguiéres has divided them into four genera, of Buccinwm,
Purpura, Cassis, and Terebra, part of which have been again
subdivided by Messrs. de Lamarck and Montfort.

BuccinuMm, Brug.,
Includes the. emarginated shells without any canal, whose
general form, as well as that of the aperture, is oval. ‘The
animals, all such as are known, are deprived of the veil on the
head, but are furnished with a proboscis, two separated ten-
tacula, on the external side of which are the eyes, and a horny
operculum. ‘Their siphon extends out of the shell.

The name of Buccinwm is especially applied by M. de
Lamarck to those in which the columella is convex and
naked, and the margin without folds or rim. ‘Their foot is
moderate, their proboscis long and thick, and their penis fre-
quently excessively large. (Buecinum undulatum, L., List.
662. 14, &c.)

NAssa, Lam.

The side of the columella is covered by a more or less broad
and thick plate, and the emargination is deep, but without a
canal. The animal resembles a true buccinum, and there are
gradual transitions among the shells from one subgenus to the
other. (Buccinum arcularia, List. 970, 24, 25, &c.)

EBuRNA, Lam.

Those which to a smooth shell, without a folded margin,
add a widely and deeply-umbilicated columella. The general
form of the shell is closely allied to that of the Olive. Their
animal is unknown. (Buccinum glabratum, List. 974. 29. &c.)

ANCILLARIA, Lam.

The same smooth shell, and at the lower part of the colu-
mella a marked lip. There is no umbilicus, neither is the spire

Pp
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Mollusca 2UAC

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2 Natsa Northie: 4 Voluta’ pallida:

London: Published: by Whittascer &C8 Ave Maria Land 1833

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ORDER PECTINIBRANCHIATA. 79

furrowed. The animal of several species resembles that of
the Olive, the foot being still more developed. (Ancillaria
cinnamomea, Lam., &c.)

Douium, Lam.

Those in which projecting ribs that follow the direction of
the whorls render the margin undulated ; the inferior whorl is
ample and swollen. Montfort subdivides them into

Do.LiuM, properly so called, when the lower part of the
columella is twisted. (Buc. olearium, List., &c.) And

PERDIX, when it is trenchant. (Bucc. Perdix, List.)

Their animal has a very large foot widened before, a pro-
boscis larger than its shell, and slender tentacula, on the
external side of which, and near the base, are the eyes; the
head has no veil, nor has the foot an operculum.

HARPA, Lam.

The harpe are easily recognized by the projecting trans-
verse ribs on the whorls, the last of which forms a lip on the
margin. The shell is beautiful, and the animal has a very
large foot, pointed behind, and widened in its anterior portion,
which is distinguished by two deep emarginations. ‘The eyes
are on the sides of the tentacula, and near their base. It has
neither veil nor operculum. Buccinum harpa, L., and the
other species long confounded with it, &c. Messrs. Reynaud,
Quoy, and Gaymard have observed, that, under certain cir-

cumstances, the posterior part of the foot is spontaneously
detached.

PURPURA, Brug.,

Is known by its flattened columella, which is trenchant near
the end opposite to the spire, and which, with the external
margin, forms a canal there, sunk in the shell, but not salient.
The purpure were scattered among the buccina and the

76 CLASS GASTEROPODA.

murices of Linneus. The animal resembles that of a true
buccinum. (Buccinum persicum, List., &c.)

The genus LicoRNE, Mont/., MONOCEROS, Lam., consists
of shells similar to the purpure, but in which the external
edge of the emargination is furnished with a salient spire.
(Buccinum monodon, Gm., &c.)

Others, also resembling purpure, in which the columella,
or at least the margin, is provided, in the adult, with teeth,
which narrow the aperture, form the SistrA, Monff., or the
RICINULA, Lam. (Murex ricinus, L., &c.)

CoNCHOLEPAS, Lam.

The general characters of the purpure; but the aperture is
so enormous, and the spire so small, that the shell has almost
the appearance of a capulus, or one of the valves of an arca.
A small salient tooth is visible on each side of the emargina-
tion. ‘The animal resembles that of a true buccinum, with
the exception of its foot, which is enormous in width and
thickness, and that it is attached to the shell by a muscle,
shaped like a horse-shoe, as in the capuli. It has a thin,
narrow, and horny operculum.

But a single species is known, the Buccinum concholepas,
Brug., Argeny. pl. ii. f. F. D.; and Sowerb. Gen. of Shells,
No. VI. From the coast of Peru.

Cassis, Brug.

The shell oval; aperture oblong or narrow ; the columella
covered with a plate, as in Nassa, and that plate transversely
folded, as well as the external margin; the emargination ter-
minating in a short canal that is reflected and pushed back, as
it were, to the left; varices are frequently observed upon it.
The animal resembles that of a true buccinum, but its horny
operculum is denticulated, in order to pass between the folds
of the external margin.

1 Zhurna spirrata.

2 Ricinula arachnetdes.
3 Terelra muUscaria.

4 Mitra vulpecula

5 Harpa ventrtcesa’.

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6 Natsa relicidata

7 Concholepas Feruvianus.

8 Catsis decadsata.
9 Cafidarta echinephera

lW Delian perdix

Mi Cancellaria asperula:

2 Petamis tragtis.
13. Andlaria: cinnamomea.

14 Purpurea lrechlea:

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ORDER PECTINIBRANCHIATA. ra)

In some, the lip of the margin is denticulated externally near
the emargination. (Buccinum vibea, Martini, &c.)

In others it is entire: the Buccinum of the second division
of Gmelin, except the B. echinophorum, strigosum, No. 26,
and tyrrhenum, which are cassidariz. It must also be recol-
lected that among the true cassides, Gmelin appears to have
made several repetitions.

Morto, Montf. CAssiIpARtA, Lam.

Was separated from cassis by Montfort. The canal curves less
suddenly, and the whole shell leads directly to certain muri-
ces. The animal resembles that of a buccinum, but its foot is
more developed. (Buccinum caudatum, L., &c.)

TEREBRA, Brug.

The aperture, emargination, and columella of a true bucci-
num, but the general form is turriculated; that is to say, the
spire is lengthened into a point. ‘The whole of the last sub-
division of the Buccina, Gm.: such as Buc. maculatum, 1.
In the

CERITHIUM, Brug.

Very properly separated from the MUREX of Linneus, we
observe a shell with a turriculated spire. The aperture is oval
and the canal short, but well marked, and reflected to the left or
backwards. The animal has a veil on its head, and is furnished
with two separated tentacula, on the side of which are the
eyes, and with a round horny operculum.

Many are found fossil, Murex vertagus, List., &c., with the
numerous fossil species described by M. de Lamarck, Ann.
du Mus.

It is also near the cerithia that we must place several fossil
shells which form the genus nerinea of M. Detrance. This
genus is distinguished by strongly marked folds on each

78 CLASS GASTEROPODA.

whorl, and on the columella, the centre of which, besides, is
hollow throughout. Nine species are already ascertained.
M. Brongniart separates from the cerithia, the

PoTAMIDA, Brong.,

Which, with the same form of shell, has a very short and
scarcely emarginated canal, no furrow on the upper part of the
right margin, and the external lip dilated. ‘The potamida
inhabit rivers, or at least their mantles, and fossil specimens
are found in strata which contain other fresh-water or land
species only.—See Brongn, Ann. du Mus. xv. 367. In this
subgenus should be placed the Cerithiwm atrum, Brug., and
some other cerithia of the same writer, and among the fossils
the Potamida Lamarckii, Brongn.

MuREX, Lin.,

Comprises all those shells in which there is a salient and
straight canal. The animal of each subgenus is furnished
with a proboscis, long approximated tentacula, on the external
side of which are the eyes, and with a horny operculum: the

_veil on the head is wanting; and, the length of the siphon ex-
cepted, it otherwise resembles that of the buccina.

To this genus Linneus has added several purpure, in
which the canal is not salient, and all the cerithia, in which it
is recurved.

Bruguiéres divides them into two genera, which have been
since subdivided by Messrs. Lamarck and Montfort.

MuREX, Brug.,

Includes all those which have a salient and straight canal,
with varices across the whorls. These varices are projecting
rims, with which the animal edges its mantle, at each inter-
ruption in the growth of its shell.

ORDER PECTINIBRANCHIATA. 79

Lamarck appropriates this name to those in which the
varices are not contiguous on two opposite lines.

If their canal be long and slender, and the varices armed
with spines, they become the MUREX, properly so called, of
Montfort. (Murex tribulus, List., &c.)

When, with this long canal, the varices are mere knobs,
they form the BRontis, Montf. (Murex haustellum, List.,
&c.)

Some of them, which, with a moderate canal, have project-
ing tubes, which penetrate into the shell between spiny vari-
ces, constitute the TyPHIS, Montf. (Murex tubifer, Roissy.
Brug. Journ. d’Hist. Nat. I. xi. 3.)

When, instead of spires, the varices are furnished with
folded lamellz, slashed, or divided into branches, they are the
CHICORACEA, Montf. Their canal is long or moderate, and
their foliaceous productions vary infinitely in figure and com-
plication. (Murex ramosus, List., and all its varieties. Mur.
Scorpio, Mart., &c.)

When, with a moderate or short canal, the varices are
merely knotty, and the base is provided with an umbilicus,
they form the AQUILLA, Montf. Several species inhabit the
coast of France. (Murex cretaceus, L., &c.)

If the umbilicus be wanting, they are his LOTORIUM.
(Mur. lotorium, L., &c.)

Finally, when the canal is short, the spire elevated, and the
varices simple, they are his TRITONIUM. ‘Their mantle is
usually folded transversely on both margins. Very large ones
inhabit the seas of Europe. (Mur. tritonis. L.)

The varices are sometimes numerous, compressed, and
almost membranous, constituting the TROPHONA, Montff.
(Mur. magellanicus, Martini.)

At other times they are compressed, very salient, and but
few in number. (Mur. tripterus, Born. x. 18,19, &c.)

SO CLASS GASTEROPODA.

M. de Lamarck separates from all the murices of Bru-
guiéres, the

RANELLA, Lam.,

Characterised by opposing varices, so that the shell is
burdened with them on both sides; their canal is short, and
their surface studded with mere tubercles; margins of the
aperture folded. (Mur. Bufo, Mont., &c.)

The APOLLES, Montf:, are merely umbilicated ranelle.
(Murex gyrinus, List. 939. 34.)

Fusus, Brug.,

Comprises all shells with a salient and straight canal, which
are destitute of varices.

When the spire projects, the columella is without folds, and
the margin is entire, they are the FUSUS, properly so called,
Lam., which Montfort again subdivides ; when they have no
umbilicus, they are his Fusus. (Mur. cochlidium, Seb., &c.)

The shortest and most swollen gradually approach the form
of the buccina. (MM. tslandicus, Martini, &c.)

When provided with an umbilicus, they are his LATHIRA.
(Mur. Vespertilio, Martini.)

The STRUTHIOLARIE are distinguished from the true fusi
by a border which surrounds their aperture, and which covers
the columella. ‘The margin of the adult is inflated, which
connects them with the murex. (Mur. stramineus, Gmn., &c.)

When the spire is salient, the columella without folds, and
there is a small indentation or well-marked notch in the
margin near the spire, they are the PLEUROTOMA, Lam.
(Mur. babilonius, L., &c.)

The CLAVATUL, in which the emargination is wide, and
reaches to the spire, are also properly distinguished.

When the spire is but slightly marked, flattened, or rounded,

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2 Strombus pupilre. 7 Fasctolaria trapexium.

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4 Murer brandaris. 9 Turbinella pyran.

5 Pyrida perbersa. JO Hippocrenes macreplera .

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ORDER PECTINIBRANCHIATA, Sl

and the columella is without folds, they are the Pyruta,
Lam.

Some are umbilicated: Mur. rapa, Martini, &c.

And others not: Bulla ficus, L., &c.

From these pyrule Montfort again separates the species
with a flattened spire, internally striated near the lip, by the
name of FULGuUR. ‘They are a sort of pyrule with a folded
columella, the folds being sometimes almost insensible.
(Murex perversus, L., &c.)

Among these divisions of the fusi of Bruguiéres, the Fascro-
LARIZ, Lam., are distinguished by some oblique and well-
marked folds on the columella, near the origin of the siphon.
(Mur. tulipa, L., &c.)

TURBINELLA, Lam.,

Also consists of shells with a straight canal, but without varices,
distinguished by the large transverse folds on their columella,
which extend the whole length of the aperture, and which
closely approximate them to the conical volute; they only
differ from the latter in the elongation of their aperture into a
sort of canal: the line that separates them is not easily traced.
(Mur. Scolymus, Martini, &c.)

STROMBUS, Lin.,

Includes those shells with a canal that is either straight or re-
flected towards the right, of which the external margin of the
aperture dilates with age, but still preserves a sinus towards
the canal, under which passes the head of the animal, when
it extends itself.

In most of them the sinus is at some distance from the
canal. ‘They are subdivided by M. de Lamarck into two
subgenera.

VOL. XII. G

82 CLASS GASTEROPODA.

STROMBUS (proper), Lam.,
In which the margin expands into a wing of more or less ex-
tent, but not digitated. The foot is proportionally small, and
the eyes are supported on lateral pedicles of the tentacula,
thicker than the tentacula themselves ; the operculum is horny,
long, and narrow, and placed on a thin tail. Nearly all the
strombi comprised in the second and third division of Gmelin,
observing, that owing to the various degrees of development
acquired by the external margin, there are several repetitions.

PTEROCERA, Lam.

The margin in the adult is divided into long and slender
digitations, varying in number, according to the species. The
animal is the same as that of the true strombus. (Strombus
lambis, Rondel. 79, &c.) . .

In other strombi the sinus of the external margin is con-
tiguous to the canal, forming the ROSTELLARIA, Lam. ‘There
is usually a second canal ascending the spire, formed by the
external margin, and by a continuation of the columella.

In some of them the margin is still digitated. Their animal
resembles that of a murex, but has only a very small oper-
culum. (Strombus pes pelicani, L., &c.)

In others we merely observe a detached margin. Their
canal is long and straight. (Strombus fusus, L.)

In some, again, that margin is entire; they are the HIPPo-
CRENES, Montf. (Strombus amplus, L.)

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ORDER TUBULIBRANCHIATA.

SEVENTH ORDER OF THE GASTEROPODA.

TUBULIBRANCHIATA.

THE tubulibranchiata should be detached from the pectini-
branchiata, with which they are very closely allied, because
the shell, which resembles a more or Jess irregularly shaped
tube, only spiral at the commencement, attaches itself to
various bodies ; they consequently are deprived of copulatory
organs, and fecundate themselves. In the

VERMETUS, Adans.,

We remark a tubular shell, whose whorls, at an early age, still
form a kind of spire, but afterwards continue in a tube more or
less irregularly contorted, or bent like the tubes of a serpula.
This shell usually attaches itself by interlacing with others of
the same species, or is partly enveloped by lithophytes. The
animal having no power of locomotion, is deprived of a foot
properly so called; but the part which in ordinary gasteropoda
forms the tail, is here turned under it, and extends to beyond
the head, where its extremity becomes enlarged, and finished
with a thin operculum. When the animal withdraws into its
shell, it is this mass which closes the entrance. It is some-
times seen with various appendages, and in certain species the
operculum is spiny. ‘The head of the animal is obtuse, and
has two moderate tentacula, on the external sides of which,
at the base, are the eyes. The mouth is a vertical orifice, be-
neath which is a filament on each side, that has all the appear-
ance of a tentaculum, but belonging in reality to the foot.
G2

84 CLASS GASTEROPODA.

The branchiz form but a single range along the left side of
the roof of the branchial cavity. The right side is occupied
by the rectum and the spermatic canal, which also transmits
the ova. There is no penis, the animal fecundating itself.

The species are numerous, but not very distinct. Linnzus
left them among the serpule.

The VERMILI, also left by M. de Lamarck near the ser-
pul, are similar to the vermeti.

MaeiLus, Monty.

The magili have a longitudinally carinated tube, which is
at first regularly spiral, and then extends itself in a line more
or less straight. Although the animal is unknown it is
highly probable that it should be placed near the vermeti.
The

SILIQUARIA, Brug.,

Resembles Vermetus in the head, the position of the opercu-
lum, and in the tubular and irregular shell; but there isa
fissure on the whole length of this shell which follows its con-
tour, and which corresponds to a similar cleft in that part of
the mantle which covers the branchial cavity. Along the
whole side of this cleft is a branchial comb, composed of nu-
merous loose and tabular-like lamellae. Linnzus left them
with the serpulz, and till very lately they were considered as
belonging to the class of the annelides.

ORDER SCUTIBRANCHIATA. 85

EIGHTH ORDER OF GASTEROPODA.

SCUTIBRANCHIATA.

THE scutibranchiata comprise a certain number of gastero-
poda, similar to the pectinibranchiata in the form and position
of the gills, as well as in the general form of the body, but in
which the sexes are united, in such a way, however, as to allow
them to fecundate themselves. Their shells are very open,
without an operculum, and for the most part without a trace of
turbination, so that they cover these animals, and particularly
the gills, in the manner of a shield. The heart is traversed by
the rectum, and receives the blood from two auricles, as is the
case in the greater number of bivalves.

* Hatyoris, Lin.,

Is the only genus of this order in which the shell is turbinated ;
it is distinguished from that kind of shell by the excessive
amplitude of the aperture, and the flatness and smallness of
the spire, which is seen from within. This form has caused
it to be compared to the ear of a quadruped.

HALYOTIS (proper), Zam.,

Or the true Halyotis. The shell is perforated along the side
of the columella by a series of holes; when the last hole is
not terminated, it gives to that part the look of an emargina-
tion. The animal is one of the most highly ornamented of all
the gasteropoda. A double membrane, cut into leaves, and
furnished with a double range of filaments, extends, at least in

86 CLASS GASTEROPODA.

the most common species, round the foot, and on to the mouth.
Outside its long tentacula are two cylindrical pedicles, which
support the eyes. The mantle is deeply cleft on the right side,
and the water, which passes through the holes of the shell,
penetrates through this cleft into the branchial cavity. Along
its edges we observe three or four filaments, which the animal
can protrude through these holes. ‘The mouth is a short pro-
boscis. All the halyotides of Gmelin, except ¢mperforata and:
perversa. This genus has its counterpart among the fossils.

The PapoLu®, Montfort, have a circular shell, in which
the holes are nearly obliterated ; and there is a deep furrow
that follows the middle of the whorls, and is marked exter-
nally by a salient ridge.

STROMATIA, Lam.

The shell more hollow, the spire more salient, and the
holes wanting; otherwise, like that of the halyotides, which
it thus connects with certain species of turbo. The animal is
much less ornamented than that of halyotis.

In the following genera, which are separated from the patellz,
the shell is perfectly symmetrical, as well as the position of
the heart and branchie. In

FISSURELLA, Lam.,

We perceive a broad fleshy disk under the belly, as in the
patella, a conical shell placed on the middle of the back, but
not always completely covering it, and perforated at its sum-
mit by a small orifice, which affords at once an issue for the
feeces and a passage to the water, required for respiration ; this
orifice penetrates into the cavity of the branchie, situated on
the fore part of the back, and in the bottom of which ter-
minates the anus; a cavity otherwise widely opened above the
head. A branchial comb is symmetrically arranged on each
side; the eyes are on the external base of the conical tenta-
13

ORDER CYCLOBRANGHIATA. 87

cula, and the sides of the foot are furnished with a range of
filaments.

EMARGINULA, Lam.

The structure of the emarginule is similar to that of a
fissurella, except that instead of the hole in the summit,
there is a small cleft or emargination in the anterior margin of
their mantle and shell, which also penetrates to the branchial
cavity ; the margin of the mantle envelopes and covers a great
part of that of the shell; the eyes are placed on a tubercle of
the external base of the conical tentacula, and the margin of
the foot is furnished with a range of filaments.

PARMOPHORUS, Lam.

A great portion of the shell curved by the reflected margin
of the mantle, as in the emarginule ; the shell itself oblong,
slightly conical, and without hole or emargination ; the bran-
chiz and other organs, as in the preceding genera.

NINTH ORDER OF GASTEROPODA,

CYCLOBRANCHIATA.

THE branchiz of the cyclobranchiata resemble small lamelle,
or little pyramids forming a cordon, more or less complete,
under the borders of the mantle, very nearly as in the infero-
branchiata, from which they are distinguished by the nature of
their hermaphroditism ; for, like the preceding genus, they

88 CLASS GASTEROPODA.

have no copulating organ, but fecundate themselves. Their
heart does not embrace the rectum, but varies as to situation.
But two genera of this order are known, in both of which the
shell never approaches in the least to the turbinated form.

PATELLA, Lin.

The entire body covered with a shell, formed of a single
piece, in the form of a broad-based cone; a cordon of little
branchial lamella under the margin of the mantle; the anus
and genital orifices somewhat to the right and above the head,
which is furnished with a thick and short snout, and two
pointed tentacula, on the external base of which are the eyes;
the mouth is fleshy, and containing a spiny tongue, which in-
clines backwards, and is reflected deeply in the interior of the
body. ‘The stomach is membranous, and the intestine long,
thin, and greatly flexed; the heart is forwards, above the neck,
and a little to the left.

Some species abound on the coast of France.

CHITON, Lin.

A range of testaceous and symmetrical scales along the back
of the mantle, but not occupying its whole breadth ; edges of
the mantle coriaceous, and furnished either with a naked skin
or little scales, which give it the appearance of shagreen, or
with spines, hairs, or setaceous fasciculi. Under these edges,
on each side, is a range of lamellar, pyramidal branchie ; and
before, a membranous veil on the mouth supplies the want
of tentacula. ‘The anus is under the posterior extremity.
The heart is situated behind, on the rectum; the stomach is
membranous, and the intestine very long and greatly con-
torted. ‘The ovary is situated over the other viscera, and ap-
pears to open on the sides by two oviducts.

A few small species are found on the coast of France; very
large ones abound in the seas of hot climates.

CLASS ACEPHALA. 89

FOURTH CLASS OF THE MOLLUSCA.

ACEPHALA.

THEY have no apparent head, but a mere mouth concealed in
the bottom, or between the folds of their mantle: the latter is
almost always doubled, and encloses the body, as a book is
clasped by its cover ; but it frequently happens that in conse-
quence of the two lobes uniting before, it forms atube. Some-
times it is closed at one side, and then it represents a sac.
This mantle is generally provided with a calcareous bivalve,
and sometimes multivalve shell, and in two genera only is it
reduced to a cartilaginous or even membranous nature. The
brain is over the mouth, and there are also one or two other
ganglia; the gills usually consist of large leaves, covered with
vascular net-work, under or between which the water passes ;
they are more simple, however, in the genera without a shell.
From these gills the blood proceeds to the heart, generally
simple, which distributes it throughout the system, returning
to the pulmonary artery, without the aid of another ventricle.
The mouth is always toothless, and can only receive the
molecules brought to it by the water; it leads toa first stomach,
to which is sometimes added a second; the length of the in-
testines is very various; the bile is thrown into the stomach
by several pores, and the stomach itself is surrounded by the
mass of the liver.
__ All these animals fecundate themselves, and in several tes-
tacea the young ones, which are innumerable, pass some time
in the thickness of the gills, previously to being brought to
light. All the acephala are aquatic.

90 CLASS ACEPHALA.

THE FIRST ORDER OF ACEPHALA.

TESTACEA.

TESTACEOUS acephala, or acephala with four branchial
leaflets, are, beyond all comparison, the most numerous: all
the bivalves, and some genera of the multivalves, belong to
this order. ‘Their body, which contains the liver and viscera,
is placed between the two laminz of the mantle; forwards,
and still between these laminz, are the four branchial leaflets,
transversely and regularly striated by the vessels; the mouth
is at one extremity, the anus at the other, and the heart to-
wards the back; the foot, when it exists, is inserted between
the four gills; on the sides of the mouth are four other trian-
gular leaflets, which are the extremities of the two lips, and
serve as tentacula ; the foot is amere fleshy mass, the motions
of which are effected by a mechanism analogous to that of the
tongue of the mammalia; its muscles are attached to the bot-
tom of the valves of the shell: other muscles which form some-
times one and sometimes two masses, cross transversely from
one valve to the other, to keep them closed, but when the
animal relaxes these muscles, an elastic ligament, placed be-
hind the hinge, opens the valves by its contraction.

A considerable number of bivalves are provided with what
is termed a byssus, or a bundle of threads, more or less loosely
connected, which issue from the base of the foot, and by
which the animal adheres to various bodies. It uses its foot
to direct the threads, and to agglutinate their extremities : it
even reproduces them when cut; but the nature of the pro-
duction is not thoroughly. ascertained. Reaumur considered

ORDER TESTACEA. 91

these threads as a secretion, spun and drawn from the furrow
of the foot. Poli thinks that they are mere prolongations of
tendinous fibres.

The shell essentially consists of two pieces, called valves, to
which, in certain genera, are added others, connected by a
hinge that is sometimes simple, and sometimes composed of a
greater or smaller number of teeth and plates, which are
received into corresponding cavities.

There is usually a projecting part near the hinge, called
the summit, or nates.

Most of these shells fit closely when the animal approxi-
mates them, but there are several which exhibit a gaping por-
tion either before or at the extremities.

The first family of the testaceous acephala, or

THE OSTRACEA,

Have the mantle open, without tubes, or any particular aper-
ture.

The foot is either wanting in these mollusca, or is small ;
they are for the most part fixed bythe shell or byssus to rocks
and other submerged bodies. ‘Those which are free seldom
move, except by acting on the water, by suddenly closing
their valves.

Ty the first subdivision, there is nothing but a muscular
mass, reaching from one valve to the other, as seen by the
single impression left upon the shell.

It is thought proper to class with them certain fossil shells,
the valves of which do not even appear to have been held
together by a ligament, but which lay together like a vase and
its cover, and were connected by muscles only. They form
the genus

92 CLASS ACEPHALA.

AcARDA, Brug. OsTRACITA, La Peyr.,

Of which M. de Lamarck makes a family, that he names
RupistTa. The shells are thick, and of a solid or porous
tissue. They are now divided into the

RADIOLITES, Lam.,

In which the valves are striated from the centre to the circum-
ference : the one is flat, the other thick, nearly conical, and
fixed.

SPH ZRULITES, Lameth,

Where the valves are roughened by irregularly raised plates.
It is also thought that we may add the

CALCEOLARIA,

One valve of which is conical but free, and the other flat, and
even somewhat concave, so that they remind us of a shoe;
and even the

HIPPURITES,

Where one valve is conical or cylindrical, with two obtuse
longitudinal ridges on the inside. ‘The base even appears to
be divided into several chambers, by transverse partitions ;
the other valve fits like a cover.

BaTOLITHES, Montf., 334,

Are cylindrical and straight hippurites. They are frequently
found greatly elongated. There is much uncertainty, how-
ever, with respect to all these bodies.

As to the well known living testaceous acephala, Linnzus
had united in the genus

ORDER TESTACEA. 93

OsTREA, Lin.,

All those which have but a small ligament at the hinge, in-
serted into a little depression on each side, and without teeth
or projecting plates.

OsTREA, Brug.

The true oysters have the ligament as above described, and
iregular inequivalve, and lamellated shells. They adhere to
rocks, piles, and even to each other, by their most convex
valve.

The animal (PELOoRIS, Pol) is one of the most simple of
all the bivalves, possessing nothing remarkable but a double
fringe round the mantle, the lobes of which are only united
above the head, near the hinge; but there is no vestige of a
foot.

Every one is acquainted with the common oyster (Ostrea
edulis, L.), which is gathered upon the rocks, and reared in
depots, to be ready when wanting. Its fecundity is as
astonishing as its flavour is agreeable.

Among the neighbouring species we should notice

The little Mediterranean oyster. (Ostrea cristata, Poli.
IT xx.)

Among the foreign species we should remark

The Parasite oyster (Ostrea parasitica, L.), Chemn. VIII.
Ixxiv. 681,

Round and flat, which fixes itself on the roots of the man-
groves and other trees, which the salt water can reach.

The leaf oyster (Ostrea folium, L.) Ibid. lxxi. 662—666.
Oval, with the margins folded in zig-zags, which attaches
itself by the indentations of its convex valve to the branches
of the Gorgoniz and the other Lithophytes.

M. de Lamarck separates by the name of

94 CLASS ACEPHALA.

GRYPHAA, Lam.,

Certain oysters, mostly fossil, of the ancient calcareous and
schistose strata, in which the summit of the most convex
valve greatly projects and curves more or less into a hook or
portion of a spiral; the other valve is frequently concave.
The greater number of these shells appear to have been free ;
some of them, however, seem to have adhered to other bodies
by their hook. |
G. tricarinata. The only living species known.

PECTEN, Brug.,

Very properly separated from the oysters by Bruguicéres,
although they have the same kind of hinge. They are easily
distinguished by their inequivalve semi-circular shell, almost
always regularly marked with ribs, which radiate from the
summit of each valve to the edge, and furnished with two
angular productions called ears, which widen the sides of the
hinge. The animal (ArGus, Poli) has but a small oval foot,
placed on a cylindrical pedicle, before a sac-like abdomen
that hangs between the gills. Some species, known by a
deep emargination under their anterior ear, are furnished with
a byssus; the others cannot adhere, and even swim with
rapidity by suddenly closing their valves. The mantle is
surrounded with two ranges of filaments, several of the exter-
nal ones being terminated by a little greenish globule; the
mouth has numerous branched tentacula, in place of the four
usual labial leaflets. The shell is frequently tinged with the
most lively colours.

The great species of the French coast (Ostrea maxima,
Linn.), has convex valves, one whitish and the other reddish,
each having fourteen ribs, broad, and longitudinally striated.
The animal is eaten. We may also remark the sole of the
Indian Ocean (Ostvea solea), Chemn. VII. 1xi. 595, with ex-

ORDER TESTACEA. 95

tremely thin and almost equal valves, one brown, the other
white ; and internal ribs, fine as hairs, approximated two by
two.

Lima, Brug.

The lime differ from the pectens, in the superior length of
their shell, in a direction perpendicular to the hinge, the ears
of which are shorter, and the sides less unequal, thus forming
an oblique oval. The ribs of most of them are raised with
scales. The valves cannot join during the life of the animal,
whose mantle is furnished with numberless filaments of differ-
ent lengths, without tubercles, and more internally with a
large border, which closes the opening of the shell, and even
forms a veil in front; the foot is small, and the byssus trifling.
The lime swim with rapidity, by means of their valves.

One species, the Ostrea lima, L., Chemn. VII. lxviii. 651,
of a fine white, inhabits the Mediterranean. It is eaten.

PrepwuM, Brug.

The oblong and oblique shell, with small ears of the lime ;
but the valves are unequal, and only the most convex has a
deep emargination for the byssus. The animal is similar to
that of a lima, but its mantle is only furnished with a single
range of small slender tentacula. Its byssus is larger.

Buta single species is known ; it inhabits the Indian Ocean.
(Ostrea spondyloidea, Gm.)

Certain fossils may be placed here, which have the hinge,
ligament, and central muscle of the ostrea, pectines, and
lime, but are distinguished by some of the details of the
shell.

HINNITA, Defr.

The hinnitz appear to be ostrez, or lime with small ears,
and adhering, irregular, and very thick shells, the convex

96 CLASS ACEPHALA.

valve in particular. A depression is observed at the hinge for
the ligament.

PLAGIOSTOMA, Sowerb.

The oblique shell of a lima, flattened on one side; very
small ears; the valves more convex, striated, without scales ;
the opening for the byssus smaller. ound in formations an-
terior to chalk.

PACHYTES, Defr.

Nearly the same form as the pectines: shell regular, with
small ears; a flattened transverse space between their sum-
mits, which in one of the valves is marked by a triangular
notch, in which passed the ligament. Found in chalk. In
the :

DIANCHORA, Sowerb.,

The valves are oblique and irregular ; one of them adherent,
and with a perforated summit, the other free, and with ears.

Popopsis, Zam.

Regularly striated valves, without opercula; the summit of
one of them more salient, truncated, and adherent, frequently
very thick, and forming a sort of pedestal to the shell.

Although multivalve, we should approximate the

ANOMIA, Brug.,

To the ostree. The anomie have two thin, unequal, irregu-
lar valves, the flattest of which is deeply notched on the side
of the ligament, which is similar to that of the ostree. The
greater part of the central muscle traverses this opening, to be
inserted into a third plate, that is sometimes stony and some-
times horny, by which the animal adheres to foreign bodies,
and the remainder of it (the muscle) serves to join one valve

ORDER TESTACEA. 97

to the other. The animal (EcHt1on, Pol) has a small vestige
of a foot, similar to that of a pecten, which slips between the
emargination and the plate that closes it, and perhaps serves
to direct water to the mouth, which is close to it.

These shells are found attached to various bodies, like the
ostreee. They occur in every sea.

PLACUNA, Brugq.,

A small genus, allied to the anomiz, in which the valves are
thin, unequal, and frequently irregular, as in the latter, but both
entire. Two projecting ribs, like a chevron, are seen in the
inside of one of them, near the hinge.

The animal is not known, but it most resembles that of the
ostreze, or that of the anomie.

SPONDYLUS, Lin.,

A rough and foliaceous shell, as in the ostrez, and frequently
spiny, but the hinge is more complex ; besides the cavity for
the ligament, analogous to that of the ostrez, there are two
teeth to each valve, that enter into fosse in the opposite one.
The two middle teeth belong to the most convex valve, which
js usually the left one, and which has a projecting heel flat-
tened as if sawed through behind the hinge. The animal,
like that of a pecten, has the borders of its mantle furnished
with two rows of tentacula, some of the external ones being
terminated by coloured tubercles; before the abdomen is a
vestige of a foot formed like a broad radiated disk, on a short
pedicle, and endowed with the faculty of contraction and ex-
pansion. From its centre hangs a filament terminated by an
oval mass, the use of which is unknown.

The spondyli are eaten like oysters; their shells are fre-
quently tinged with the most brilliant colours; they adhere
to all sorts of bodies.

VOL. XII. H

98 CLASS ACEPHALA.

PLICATULA, Lam.

The plicatula, separated by Lamarck from the spondyli,
have nearly the same kind of hinge, but no heel, and flat,
almost equal, irregular, plicated, and scaly valves, as in many
of the ostrez.

MALLEUS, Lam.

A simple depression for the ligament, as in the ostrex,
where the mallei were left by Linneus on account of their
having the same irregular and inequivalve shell; but they are
distinguished by a notch on the side of this ligament for the
passage of a byssus.

The most known species, ostrea malleus, Lin., which ranks
among the number of high priced and rare shells, has the two
ends of the hinge extended, and forming something like the
head of a hammer, of which the valves, elongated in a trans-
verse direction, represent the handle. It inhabits the Archi-
pelago of India.

There are some others, possibly young ones of the same
species, in which the hinge is not prolonged: we must be
careful not to confound them with the vulselle.

VULSELLA, Lam.,

A little plate projecting inwards at each side of the hinge,
from one of which to the other extends the ligament; other-
wise similar to that of the ostree. By the side of this plate
is a notch for the byssus, as in the mallei. The shell is
elongated in a direction perpendicular to the hinge. |

The most known species inhabit the Indian Ocean.

PERNA, Brug.,

Several parallel cavities across the hinge, opposed to each

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Mollusca’ PUA.

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2 Perna ephippium. 6 Calillus Cuvierti.
3 Genahila avieutlarts. 7 Pulvinites Adansenit.
4 Gervilia: sclenctdes. &\Etheria elliplica.

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ORDER TESTACEA. 99

other in the two valves, and lodging as many elastic liga-
ments; the irregular and foliaceous shell marked on the
anterior side beneath the hinge by a notch traversed by
the byssus. The perne were also left by Linnzus among the
ostrez.

CRENATULA, Lam.

The crenatula, lately separated from the perne, instead of
having transverse cavities on a broad hinge, are furnished
with oval ones on the very margin, where they occupy but
little of its breadth. The byssus seems to be wanting; and
they are frequently found among sponges.

It is thought that we may approximate to the perne, cer-
tain fossil shells, in which the hinge is also furnished with
cavities, more or less numerous, that correspond to each
other, and thus appear to have furnished points of attachment
to ligaments; thus, those of the

GERVILLIA, Defr.,

Have a shell closely resembling that of the vulselle, but with
a kind of double hinge, externally with opposed cavities, re-
celving as many ligaments, and internally furnished with
very oblique teeth in each valve. Their impressions are
found along with ammonites in compact limestone.

INOCERAMUS, Sowerb.,

Ts remarkable for the elevation and inequality of the valves,
the summit of which curves in a hook towards the hinge;
their texture is lamellated.

CaTILLuS, Brong.,

Independently of the depressions for the ligament, the
eatilli have a conical furrow sunk in a rim, which is bent at
a right angle, to form one of the margins of the shell. ‘The

H 2

100 CLASS ACEPHALA.

valves are about equal, and of a fibrous texture. ‘They ap-
pear to have had a byssus.

PULVINITES, Defr.,

A regularly triangular shell, in which the few depressions
diverge from the summit on the inside. The impression is
found in chalk.

In the second subdivision of the ostracea, as well as in
almost all the bivalves which follow, besides the single trans-
verse- muscular mass of the preceding genera, there is a
bundle which is placed before the mouth, and extends from
one valve to the other. It is apparently in this subdivision
that we must place the

ETHERIA, Lam.,

Large inequivalve shells, as irregular as those of the ostrex,
and more so; no teeth to the hinge; the ligament partly
external and partly internal. They differ from the ostrez
chiefly in having two muscular impressions. The animal is —
not seen to produce a byssus.

They have lately been discovered in the upper Nile.

AVICULA, Brug.,

An equivalve shell with a rectilinear hinge, frequently ex-
tended into wings, at its extremities, furnished with a narrow
and elongated ligament, and sometimes with small denticula-
tions near the mouth of the animal. In the anterior side,
a little beneath the angle of the side of the mouth, is a small
notch for the byssus. The anterior transverse muscle is still
excessively small.

The species with less salient ears form the PINYADINAE,
Lam., or MARGARITA, Leach.

The most celebrated (myiilus margaritiferus, Lin.) has
nearly a semicircular shell, greenish without, and ornamented

Mollusca’ Fi. 39

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2 Avicula’ heteroptera. 7 Trigonia’ pectinata. 12 Arca’ granosa:

3Lima glacalis. 5 Placuna’ placenta 13 Petricola’ tucinalis.
4 Plicalutw cristata‘ 9 Pintadina margariteram. \& Leripes lactea.
5 Fecter gibbosus . 10 Cardita caliculata-

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ORDER TESTACEA. 101

with the most beautiful mother-of-pearl within. The latter
is employed in the arts, and it is from the extravasation of
this substance that are produced the oriental or fine pearls,
taken by the divers at Ceylon, at Cape Comorin, and in the
Persian Gulph.

The name of AVICULA is appropriated to such as have
more pointed ears and a more oblique shell. The vestige of
a tooth, of which traces are visible in the pintadine, is ob-
servable on the hinge, before the ligament.

One species (mytilus-hirundo, Lin.) that inhabits the Me-
diterranean is remarkable for the pointed ears which extend
its hinge on each side. Its byssus is coarse and stout, re-
sembling a little tree.

PINNA, Lin.

The pinne have two equal valves, forming a segment of a
circle, or resembling a half-opened fan, which are closely
united by a ligament along one of their sides. ‘The animal,
the CHIMERA, Poli, is elongated, like its shell; the lips,
gills, and other parts are in the same proportion. Its mantle
is closed along the side of the ligament; its foot resembles a
little conical tongue excavated by a furrow; it is furnished
with a small transverse muscle, situated at the acute angle
formed by the valves, near which is the mouth, and with a
very large one in their broader portion. By the side of the
anus, which is behind this large muscle, is a conical ap-
pendage peculiar to the genus, susceptible of expansion and
elongation, the use of which is unknown.

The byssus of several species of pinna is as fine and
brilliant as silk, and is employed in fabricating the most pre-
cious stuffs; such is the

P. Nobilis, Lin., which is moreover recognized by the
valves being roughened with recurved and semi-tabular plates.

102 CLASS ACEPHALA.

It rem:ins half buried in the sand, and anchored by its
byssus. In the

ARCA, Lin.,

The valves are equal and transverse, that is to say, the hinge
occupies the longest side. It is furnished with a large num-
ber of small teeth, which interlock with each other, and, as
in the subsequent genera, with two bundles of transverse and
nearly equal muscles inserted into the extremities of the
valves, which seem to close them. In

ARCA, (properly so called) Lam.,

The hinge is rectilinear, and the shell most elongated in a
direction parallel to it. ‘The summits are generally convex,
and curve over the hinge, but are separated from each other.
The valves do not close perfectly in the centre, because there
is a horny plate or tendinous band before the abdomen of the

‘animal that serves for a foot, and by which it adheres to sub-
merged bodies. ‘They are found in rocky bottoms near the
shore, and are usually covered with a hairy epidermis. 'They
are not much esteemed for the table.

Some species are found in the Mediterranean, and a great
many fossil, in strata anterior to the chalk, particularly in
Italy.

Certain arce, in which the teeth of the two ends of the
hinge assume a longitudinal direction, are distinguished by
Lamarck under the name of CuCULL@A, (arca cucullata),
Chemn.

We ought also, it is probable, to separate the species with
well marked ribs, and completely closing and interlocking
edges, for we may presume that their animal is not fixed, but
rather resembles that of a pectunculus.

We have a still better warrant for removing the arca tor-

ORDER TESTACEA. 103

duosa, Chemn., in its fantastic figure and unequally oblique
valves.

PECTUNCULUS, Lam.,

The hinge ferming a curved line, and the shell lenticular; its
valves always close completely, and their summits are ap-
proximated. The animal AxIMEA, Pol?, is furnished with a
large compressed foot with a double inferior margin, which
enables it to crawl. They live in ooze. Some species are
found upon the coast of France.

Nucu.La, Lam.

The nuculz are arc in which the teeth are arranged in a
broken line. Their form is elongated and narrowed near the
posterior extremity. Their animal is unknown, but is pro-
bably not far removed from those of the preceding shells,
(arca pellucida,) Chemn.

This has long been the place assigned to the

TRIGONIA, brug.,

So remarkable for the hinge, which is furnished with two
plates like a chevron, crenulated on both faces, each of which
penetrates into two cavities, or rather between four plates of
the opposite side, similarly crenulated on the internal surface.
The internal impressions on the shell had already warranted
the supposition that the animal was not provided with long
tubes. Messrs. Quoy and Gaymard have lately discovered
living specimens of this genus, and, in fact, its mantle, like
that of the arce, is open, and without any separate orifice
even for the anus. The foot is large, its anterior portion
trenchant, and like a hook.

The living trigoniz resemble the cardiz in the form of their
shell and the ribs which furrow it: its anterior is composed
of mother-of-pearl. (Trigonie nacrée, Lam.)

104 CLASS ACEPHALA.

The fossil trigonia are different. Their shell is flattened
on one side, oblique, longest in a direction perpendicular to
the hinge, and traversed in a contrary direction by a series
of tubercles. (Trig. Scabra, Encyc. Meth.)

In the second family of the testaceous acephala, the

MYTILACEA,

The mantle is open before, but has a distinct aperture for the
feeces. ;

All these bivalves have a foot, used in crawling, or at least,
serving to draw out, direct, and place the byssus. They are
commonly known under the generic name of mussels.

MytTIuus, Lin.

The true mytili, or ‘sea-mussels, have a closed shell, with
equal, convex, and triangular valves. One of the sides of the
acute angle forms the hinge, and is furnished with a long
narrow ligament. The head of the animal is in the acute
angle; the other side of the shell, which is the largest, is the
anterior one, and allows the passage of the byssus ; it termi-
nates in a rounded angle, and the third side ascends towards
the hinge, to which it is joined by an obtuse angle. Near
this latter is the anus, opposite to which the mantle forms an
opening or small particular tube. The animal (CALLI-
TRICHE, Poli,) has the edges of its mantle provided with
branched tentacula, near the rounded angle, as it is there that
the water enters required for respiration. Before, and near
the acute angle, is a small transverse muscle, and a large one
behind, near the obtuse angle. Its foot resembles a tongue.

In the true mytili the summit is close to the acute angle.
Some of them are striated and others smooth.

Myt. Edulis, L. This common mussel is frequently seen
suspended in extended clusters, along the whole coast of
France, to rocks, piles, &c. It forms a considerable item of

1 Anedontea’ Susanna.

2 Unie tenuis.

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ORDER TESTACEA. 105

food, but is dangerous if eaten to excess. Add mytilus bar-
batus, L., &c.

Some of them are found fossil, and have been formed into a
sub-genus by M. Brongniart, under the name of MYTILOIDA.
In the

Mopiouus, Lam.,

Separated from the mytili by Lamarck, the summit is lower
and nearer the third of the hinge. This summit is also more
salient and rounded, approximating the modioli more closely
to the ordinary form of the bivalves. We may also separate
from the mytili,

LITHODOMUS, Cuwwv.,

In which the shell is oblong and almost equally rounded at
the two ends, the summit being close to the anterior ex-
tremity. The species of this sub-genus at first simply attach
themselves to stones, like the common mytili; subsequently,
however, they perforate and excavate them in order to form
cells, into which they enter, and which they never quit after-
wards. Once entered, their byssus ceases to grow.

One of them, the mytilus lithophagus, Lin., is very com-
mon in the Mediterranean, where, from its peppery taste, it is
esteemed as food.

A second (modiola caudigera, Encyc. pl. xxcci. f. 8.) has a
very hard small appendage at the posterior extremity of each
valve, which perhaps enables it to excavate its habitation.

ANODONTES, Brug.,

The anterior angle rounded like the posterior, and that next
to the anus obtuse and almost rectilinear. The shell thin,
and moderately convex, has no appearance whatever of a
tooth at the hinge, being merely furnished with a ligament

106 CLASS ACEPHALA.

which extends along its whole length. 'The animal (LIM-
NA, Poli,) has no byssus; its foot, which is very large,
compressed, and almost quadrangular, enables it. to crawl
upon the sand or ooze. The posterior extremity of its mantle
is provided with numerous small tentacula. ‘The anodontes
inhabit fresh water.

Several species are found in France, one of which, (mytilus
cygneus, Lin.) very large, is common in ponds, &c. with oozy
bottoms. Its light and thin shells are used for milk-skimmers,
but its flesh is not eaten in consequence of its insipidity. Add
M. Anatinus, Chemn., &c.

An oblong species, in which the hinge. is granulated
throughout its entire length, is distinguished by M. de La-
marck under the name of IR1ipINA (Jrid. exotica, Encyc.
Method.) ; the hind part of its mantle is somewhat closed.

And Dr. Leach distinguishes by the term DIPSADA ano-
ther, which has its angles more decided, and in which there
is a vestige of a tooth upon the hinge.

Unio, Brug.,

These mollusca resemble the anodontes, both in their animal
and shell, with the exception of their hinge, which is more
complex. ‘There is a short cavity in the anterior part of their
right valve which receives a short plate or tooth from the left
one, and on its posterior part is a long plate, which inserts
itself between two others on the opposite side. They also
inhabit fresh water, preferring running streams.

Sometimes the anterior tooth is more or less stout and un-
equal, as in

Mya margaritifera, L., a large thick species, the mother-
of-pearl of which is so beautiful, that its concretions are used
in dress as pearls. Found in France, as is the

Unio littoralis, Lam., a smaller and square species.

—

2 Tellina Guldfordie.

1 Cylherea Dronea. var.

5 Anaden Ceorgine.

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ORDER TESTACEA. 107

At other times the anterior tooth is lamelliform, as in the

Mya pictorum, L., an oblong and thin species known to
every one.

Lamarck distinguishes the

HYREA, Lam.

In which the angles are so decided that the shell is nearly
triangular. (H. rugosa, Encyc. Meth.)

CASTALIA, Lam.,

When the slightly heart-formed shell is striated in radii; the
teeth and plates of the hinge are transversely sulcated, which
gives them some affinity with the trigoniz. (Castalia ambigua,
Lam.)

There are certain marine mollusca which have a similar
animal, and about the same kind of hinge, that should be
placed near the unios; the summits of the shell, however, are
more convex, and it is marked by projecting ribs, extending
from the summits to the edge. ‘They form the

CarpITA, brug.,

Which are more or less oblong, or heart-shaped; the inferior
margin in some gaping. (Chama antiquata, Chemn., &c.)

CYPRICARDIA, Lam.

Carditz, in which the tooth under the summit is divided
into two or three. ‘Their form is oblong, and their sides un-
equal. (Chama oblonga, Gm., &c.)

M. de Blainville also separates the

CORALLIOPHAGA, Blainv.,

Where the shell is thin, and the lateral plate considerably
effaced, which may cause their approximation to venus.
13

108 CLASS ACEPHALA.

One of them is known, which excavatcs coral masses to
form its habitation. (Chama coralliophaga, Gm., &c.)

VENERICARDIA, Lam.,

Only differ from the carditz in the circumstance that the pos-
terior plate of their hinge is shorter and more transverse, which
caused their approximation to venus; their form is almost
round. Judging from the impression of its muscles on them,
their animal must resemble that of the carditz and unios.
(Venus imbricata, Chemn., &c.; and the fossil species, Lam.)

Both of them approach the cardia in their general form and
the direction of their ribs. I suspect that this is also the
place for the |

CRASSATELLA, Lam. PAPHTIA, Roiss.,

Which has sometimes been approximated to mactra, and at
others to venus; the hinge has two slightly marked lateral
teeth, and two very strong middle ones, behind which, extend-
ing to both sides, is a triangular cavity for an internal liga-
ment. The valves become very thick by age, and the impres-
sion made by the margin of the mantle leads to the belief that,
as in the preceding, there are no protractile tubes. (Venus
ponderosa, Chemn. VII. lxix. A. D.)
The third family of the testaceous acephalz, or

CHAMACEA,

Have the mantle closed, and perforated only by three holes,
through one of which passes the foot ; the second furnishes an
entrance and exit to the water requisite for respiration, and the
third for the excretion of feces: these two latter are not pro-
longed into tubes, as in the subsequent family. It only com-
prises the genus

CHAMA, Lin.,

Where the hinge is very analogous to that of a unio; that is

—— a

LUnto Lea.

2 Unio Deuglasia.

3 Une Grave.

Tendon Published hy Whiltaicer & tee Masia Larte

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z Maltese GW L

1 Tridacna gigas. 7 Galathea radiata.

2 Téllina linguarelis. 6 Mactra Braxiliana.
3 Cardum fimbriahanv. 9 Denaaw hilatrea:

4 Venus. 10 Venus Danmonensis.
5 Chama’ croceata- U Linna angqustana.

6 Lucina Jamaicensis. 2 Venus exoletas

London; Published by Whittaker &C° AveMaria’ Lane:1833.

MCz EIBRARY
HARVARD UNIVERSITY
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ORDER TESTACEA. 109

to say, the left valve near the summit is provided with a tooth,
and further back with a salient plate, which are received into
corresponding fosse of the right valve. This genus has
necessarily been divided into the

TRIDACNA, Brug.

The shell greatly elongated transversely, and equivalve ; the
superior angle, which answers to the head and summit, very
obtuse.

The animal is very singular, inasmuch as it is not, like many
others of the kind, placed in the shell, but its parts are directed,
or, as it were, pressed out towards the front. The anterior
side of the mantle is widely opened for the passage of the
byssus ; a little below the anterior angle is another opening,
which transmits water to the gills; and in the middle of the
inferior side is a third and smaller one, which corresponds to
the anus, so that the posterior angle transmits nothing, and is
merely occupied by a cavity of the mantle, open only at the
third orifice, of which we have just spoken.

There is but a single transverse muscle, corresponding to
the middle of the margin of the valves. In

TRIDACNA, Lam.,

Or the tridacna properly so called, the front of the shell, as
well as of the mantle, has a wide opening with notched edges
for the transmission of the byssus, which latter is evidently
tendinous, and is uninterruptedly continuous with the muscu-
lar fibres.

Such is the celebrated and enormous shell of India, the
Chama gigas, L., Chemn. VII. xlix. which is decorated with
broad ribs, relieved by projecting semi-circular scales. Speci-
mens have been taken that weighed upwards of three hundred
pounds. The tendinous byssus that attaches them to the

110 CLASS ACEPHALA.

rocks is so thick and stout that the axe is required to sever
it. The flesh, though tough, is edible. In

HIPPOPUS

The shell is closed and flattened before, as if truncated.
(Chama Lazarus,Chemn.) In the

CHama, Brug.,
Or the true chame, the shell is irregular, inequivalve, usually
lamellar and rough, adhering to rocks, corals, &c., like that of
an oyster. Its summits are frequently very salient, unequal,
and curled up; the internal cavity frequently has the same
form, without any external indication of the fact. The ani-
mal (PSILOPUS, Poli) has a small foot, bent almost like that
of a man; its tubes, if it have any, are short and disjointed,
and the aperture in the mantle which transmits the foot is not
much larger. Some species are found in the Mediterranean.
There are also several that are fossil.

DicERAS, Lam.

Between diceras and the chame there is no essential diffe-
rence, only the cardinal tooth of the former is very thick, and
the spiral lines of the valves are sufficiently prominent to re-
mind us of twohorns. Fossil shells from the Jurassic strata.
(Dic. arietina, Lam.) In the

IsocaRDIA, Lam.,

The shell free, regular, and convex, with spirally-curled sum-
mits, divided anteriorly. The animal (GLossus, Poli) only
differs from that of an ordinary chama in having a larger and
more ova! foot, and because the anterior opening of its mantle
begins to resume its ordinary proportions.

——

ORDER TESTACEA. Ill

A large smooth red species, (the Chama cor. L., Chemn.
VII. xlviii. 483), inhabits the Mediterranean.
In the fourth family of the testaceous acephala, the

CARDIACEA,

The mantle is open before, and there are besides two separate
apertures, one for respiration, and the other for the feces,
which are prolonged in tubes, sometimes distinct, and at
others united in one single mass. ‘There is always a trans-
verse muscle at each extremity, and a foot generally used for
crawling. It may be considered as a general rule, that those
which are furnished with long tubes live in ooze or in sand.
This mode of organization may be recognized on the shell, by
the more or less depressed contour described by the insertion of
the edges of the mantle, previously to its uniting with the im-
pression of the posterior transverse muscle.

CARDIUM, Lin.

The cardia, like many other bivalves, have an equivalve
convex shell, with salient summits curved towards the hinge,
which, when viewing it sideways, give it the figure of a heart :
hence its name of cardium, heart, &c. Ribs, more or less
elevated, are regularly distributed from the summits to the
edges of the valves; but what chiefly distinguishes the cardia
is the hinge, where we see, on one side and the other, towards
the centre, two small teeth, and at some distance, anteriorly
and posteriorly, another tooth, or projecting lamina. ‘The
animal (CERASTES, Poli) has generally an ample aperture in
the mantle, a very large foot bent in the middle, and with its
point directed forwards; and two short or but moderately long
tubes.

Numerous species of cardia are found upon the coast of
France, some of which are eaten, such as the C. edule, L.,

112 CLASS ACEPHALA.

Chemn. VI. xix. 194. Fawn-coloured or whitish, with
twenty-six transversely-folded ribs.

Under the name of HEMICARDIUM we might separate
those species in which the valves are compressed from before,
backwards, and strongly carinated in the middle ; for it seems
almost certain that a modification of the animal must be a
necessary consequence of this singular configuration. (Car-
dium cardissa, VI. xiv. 143—146, &c.)

DOoNAX, Lin.

The donaces have very nearly the same kind of hinge as the
cardia, but their shell is of a very different form, being a tri-
angle, of which the obtuse angle is at the summit of the valves,
and the base at their edge, and of which the shortest side is
that of the ligament, or posterior side, a rare circumstance in
this grade among bivalves. ‘They are generally small, and
prettily striated from the summit to the edges. Their animal
(PERONZA, Poli) is furnished with long tubes, which are
received into a sinus of the mantle. Some of them are found
upon the coast of France. (Donax rugosa, Chemn. VI. &c.)

CycLas, Brug.

Separated from venus by Bruguiéres. Like the cardia and
donaces, has two teeth in the middle of the hinge, and before
and behind two salient and sometimes crenulated plates; but
the shell, as in several species of venus, is more or less
rounded, equilateral, and transversely striated. The animal
has moderate tubes; the external tint is usually grey or
greenish. The cyclades inhabit fresh water.

One species, the Tellina cornea, L., Chemn. VI. xiii. 133,
is very common on the coast of France. M. de Lamarck sepa-
rates the

CYRENA, Lam.,

Where the shell is thick, slightly triangular and oblique,

ORDER TESTACEA. 113

covered with an epidermis, and otherwise distinguished from
the cyclades by having three cardinal teeth. The cyrene
also inhabit rivers, but there are none in France. (Tell. flu-
minea, Chemn.)

CYPRINA, Lam.,

Also separated from the cyclades by Lamarck. ‘The shell is
thick, oval, with recurved summits, and three stout teeth ; fur-
ther back is a plate, and under the teeth a large cavity, which
receives a part of the ligament. (Venus islandica, Chemn.,
&c.)

GALATHAA, Brug.

The shell triangular; three teeth on the summit of one
valve, and two on the other, like a chevron. The lateral plates
approximated. (Egeria, Roiss.; or Galathea, Brug., &c.}

But one is known, found in the fresh-water of India.

It is here also must be placed another genus, separated from
venus—the

CorBis, Cuv. FImMBRIA, Megerl.

Marine testaceous acephala, transversely oblong, which
have also the stout middle teeth and well-marked lateral
plates; their external surface is furnished with transverse
ribs so regularly crossed by rays that it may be compared to
wicker-work.

The impression of their mantle exhibiting no flexure, their
tubes must be short. (Venus Fimbriata, Chemn.)

Some of them are fossil. In the

TELLINA, Lin.,

There are in the middle one tooth on the left and two teeth

on the right, frequently forked, and at the same distance be-

fore and behind, on the right valve, a plate, which does not
VOR, Xt. I

114 CLASS ACEPHALA.

penetrate into a cavity of the opposite one. There is a slight
fold near the posterior extremity of the two valves, which
renders them unequal in that part, where they are somewhat
open.

The animal of the Tellina (PERONZA, Poli), like that of
the donaces, has two long tubes for respiration and for the
anus, which withdraw into the shell, and are concealed in a
duplicature of the mantle.

Their shells are generally transversely striated and deco-
rated with beautiful colours.

Some of them are oval and thick.

Others are oblong and strongly compressed.

Some, again, are lenticular, where, instead of a fold, there is
frequently nothing but a slight deviation of the transverse
striz.

We might separate certain oblong species which have no
lateral teeth, and others which, with the hinge of the telline,
have not the fold of the posterior extremity. They are the
TELLINIDES, Lam.

It is necessary to distinguish from the tellin the

LorIPEs, Poli.,

Which have the shell lenticular, the central teeth almost
effaced, and a simple furrow for the ligament behind the
nates. The animal is furnished with a short double tube,
and its foot is prolonged into a kind of cylindrical cord.
Besides the usual impressions, we may observe on the inside
of the shell a line running obliquely from the print of the an-
terior muscle, which is very long towards the nates. There is
no flexure in the print of the mantle for the retractor muscle of
the tube. (Tellina lactea.)

Lucina, Brug.

Separated lateral teeth, as in the cardia, cyclades, &c.,
13

ORDER TESTACEA. 115

penetrating between the plates of the other valve; in the
middle are two teeth frequently but slightly apparent. The
shell is orbicular, and without any impression of the retractor
muscle of the tube ; that of the anterior constrictor, however,
is very long. Possessing similar traits of character with the
loripedes, their animals must be analogous. (Venus Pennsyl-
vanica, Chemn. VII. xxxvii. 394—396, &c.)

The living species are much less numerous than those that
are fossil; the latter are very common in the environs of
Paris. (Lucina saxorum, Lam., &c.)

We should approximate to the lucine the UNGULIN&,
which also have an orbicular shell and two cardinal teeth ;
the lateral ones, however, are wanting, and the anterior mus-
cular impression is not so long. (Ungulina transversa, Kam.,
Sowerb., Gen. of Shells, No. X.) The genus

VENUS, Lin.,

Comprizes many testacea whose general character consists in
the teeth and plates of the hinge being approximated under
the summit in a single group ; they are usually more flattened
and elongated in a direction parallel to the hinge than the
cardices. The ribs, when there are any, are almost always
parallel to the edges, being directly the reverse of their arrange-
ment in the cardia.

The ligament frequently leaves an elliptical impression
behind the summits, which has received the appellation of
vulva; and before these same summits there is almost always
an oval impression termed the anws or lunula.

The animal is always furnished with two more or less pro-
tractile tubes, sometimes united, and with a compressed foot,
which enables it to crawl.

M. Lamarck appropriates the name of VENUS to those
which have three small diverging teeth under the summit.

12

116 CLASS ACEPHALA.

This character is particularly well marked in the oblong and
slightly convex species. (Venus litterata, Chemn.)

Some of them (the ASTART#, Sowerb., or CRASSINE, Lam.)
have only two diverging teeth on the hinge, and approach the
crassatelle in their thickness and some other characters.
(Venus Scotica, &c.)

Among the heart-shaped species, that is, those which are
shorter, and have more convex nates, with more closely ap-
proximated teeth, we should remark those where the plates
or transverse striz terminate behind in crests or tuberosities,
and those that have longitudinal ribs and crests elevated be-
hind. (Venus dysera, Chemn.; Venus puerpera.)

We subsequently and gradually come to the CYTHEREA,
Lam., which have a fourth tooth on the right valve, project-
ing under the /wnula, and received into a corresponding cavity
in the right one.

Some of them have an elliptical and elongated form:
Venus gigantea, &c.

Others are convex: Ven. meretria, &c.

Among these we must place a celebrated species (Venus
Dione, 1..), from whose form originated the application of the
name Venus to the genus. Its transverse plates terminate be-
hind in salient and pointed spines.

There are some species of an orbicular form, and with
slightly hooked summits, in which the impression of the re-
tractor of the tubes forms a large and almost rectilinear tri-
angle. (Venus exoleta.)

When their animals are better known, we shall most pro-
bably have to separate from cytherea—

1. Those species of a compressed lenticular form, in which
the nates are united into a single point; the fold of the con-
tour of the mantle is wanting, and shows that their tubes are
not protractile. (Venus scripta.)

Cy =

ORDER TESTACEA. i

2. Those of a convexly orbicular form, in which the fold is
not only wanting, but where, as in the lucine, the impression
of the anterior muscle is very long. (Venus tigerina, Chem.)

3. The thick species with radiated ribs, in which the fold is
also wanting, and which connect the genus Venus with that
of the Venericardia. (Venus pectinata.) In the

Capsa, Brug.,
Already separated from the former, there are two teeth on the
hinge at one side, one only, but bifid, at the other; the lunula
is wanting, the shell convex, and the fold indicative of the
retractor of the foot, considerable. (Venus deflorata.)

PETRICOLA, Lam.,

Also separated from the same genus: the petricolz on each
side have two or three very distinct teeth on the hinge, one of
which is forked; the shell is more or less heart-shaped, but as
they inhabit the interior of stones, it sometimes becomes very
irregular. Judging from the marginal impressions of the
mantle, their tubes must be very large. (Venus lapicida,
Chemn., &c.)

CoRBULA, Brug.

Similar in form to the triangular cytherez or cordate: but a
single stout tooth in the middle of each valve, corresponding
to the side of its antagonist ; the ligament is internal, the tubes
must be short, and the valves but rarely equal.

The fossil species are much more numerous than the living
ones. (Corbula gallica, &c.)

Some of them live in the interior of stones. (Venws mon-
strosa, Chemn.)

MactTRA, Lin.

The mactre are distinguished from the other testacea of

118 CLASS ACEPHALA.

this family by their ligament being internal and lodged
throughout in a triangular depression, as in the oysters ; they
all have a compressed foot fit for crawling. In the

MactTrRA, Lam.,

Or the Mactre properly so called, the ligament is accompanied
on the left valve, before and behind, by a projecting plate,
which is received by two otlers on the right one; close to
the ligament, near the lunule, is, on each side, a little plate
chevron-formed. ‘The tubes are united and short.

After abstracting the lavignons and lutrarie, the genus
mactra of Gmelin may remain; the species, however, are far
from being well distinguished. Add Mya Australis, Chemn.

Some of these mactre are found on the coast of France.

In the LAVIGNONS the lateral plates are almost effaced ;
but a single small toothis observable near the internal ligament;
there is also a second and internal ligament. ‘The posterior
side of the shell is the shortest; the valves are somewhat
open, and the tubes are separate and very long, as in the
telline.

There is one found on our coast (Mya hispanica, Chemn.
VI. i. 21), which lives in the ooze, at the depth of several
inches.

The fifth family of testaceous acephala, or that of

INCLUSA,

Have the mantle open at the anterior extremity, or near the
middle only, for the passage of the foot, and extended from the
other end into a double tube, which projects from the shell,
whose extremities are always gaping. Nearly all of them live
buried in sand, stones, ooze, or wood. Those of the genus

Mya, Lin.,

Have but two valves to their oblong shell, the hinge of which

ORDER TESTACEA. 119

varies; the double tube forms a fleshy cylinder, and the foot
is compressed. The different forms of the hinge have fur-
nished Messrs. Daudin, Lamarck, &c. with the following sub-
divisions, in the first three of which the ligament is internal.

LUTRARIA, Lam.

The lutrariz, like the mactre, have a ligament inserted into
a large triangular cavity of each valve, and before this cavity a
small chevron-formed tooth, but the lateral plates are wanting;
the valves gape widely, particularly at the posterior extremity,
through which passes the thick, double, fleshy, respiratory
and anal tube, a disposition which attaches them to this
family ; the foot, which issues at the opposite end, is small
and compressed.

Some of them are found in sand, at the mouths of rivers in
France. (Mactra lutraria, List., &c.) In

Mya, Lam.,
Or Mya proper, one valve is furnished with a plate which pro-
jects into the other, furnished with a cavity; the ligament
stretches from this cavity to that plate.
Some species are found in the sand along the coast of
France. (Mya truncata, Lin.)

ANATINA, Lam.

The anatine of Lamarck should be approximated to the
preceding myz: each of their valves has a small projecting
plate inside, with the ligament extending from one to the
other.

One oblong and excessively thin species is known, the valves
of which are supported by an internal ridge, Solen anatinus,
Chemn.; and another of a squarer form, without the ridge,
Corbule, Encyc. 230—6.

120 . CLASS ACEPHALA.

SoLemya, Lam.

The ligament is seen on the outside of the shell, part of it
remaining attached to a horizontal internal spoon-like im-
pression on each valve. There is no other cardinal tooth, and
a thick epidermis projects beyond the edges of the shell.

One species (the Tellina togata, Poli IJ. xv. 20), is found
in the Mediterranean.

GLYCYMERIS, Lam. CYRTODARIA, Daud.

Neither teeth, plates, nor cavities on the hinge, but a simple
callous enlargement, behind which is an external ligament.
The animal resembles that of the myz.

The most common species (Mya Stliqua, L., Chemn. XI.
193. fi. 194.) is from the Arctic Ocean.

PANOPEA, Mesnard, Lagr.

A stout tooth anterior to the callous enlargement of the pre-
ceding sub-genus, and immediately under the summit, which
crosses with a similar one of the opposite valve, a character
that approximates the panopez to the solines. A large
species is found in the hills at the foot of the Appenines in so
high a state of preservation that it has been mistaken for a
recent sea-shell. (Mya glycimeris, L.)

Another fossil species may perhaps be separated from it,
which is completely closed at its anterior extremity. (Panope
de Fawas, Mesnard, Lagr., Ann. du Mus. IX. xii.)

After all these various modifications of the myz, we may
place the

PANDORA, Brug.,

In which one valve is much flatter than the other; the in-
ternal ligament is placed transversely, accompanied in front
by a projecting tooth of the flattened valve. The posterior

Mollusca’ PL. 12

1 Mva truncata. 6 Byssomta pholadis
2 Lutrarta’ elliptica. 7 Hiatella arctica

3 Anatina hispidula: & Selen vagina.
4 Glycimeris stliqua. 9 Sanguinolaria livida.

5 Fanopwa Aldrovandt. 10 Psamimethea’ candida.

Lenden, Published by Whittaker & C\. Ave Marta Lanesé33.

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ORDER TESTACEA. 121

side of the shell is elongated. The animal withdraws more
completely into its shell than the preceding one, and its valves
shut more closely ; its habits, however, are the same.

But a single species is well known; it inhabits the seas of
Europe, (Tellina inequivalvis.)

Here also we find a group of some small and singular
genera, such as

BYSSOMIA, Cuwv.,

Where the oblong shell, which has no marked tooth, has the
opening for the foot at about the middle of its edge, and op-
posite the summits. The byssomia also penetrate into stone,
corals, &c.

A species which is provided with a byssus abounds in the
Arctic Ocean. (Mytilus pholadis, Miill. Zool. Dan.)

HIATELLA, Daud.,

The shell gaping, to allow the passage of the foot, near the
middle of its edges; but the tooth of the hinge is better
marked than in the preceding genus. Ranges of salient spines
are frequently observed on the hind part of the shell. ‘They
are found in sand, zoophytes, &c.

The North Sea produces a small species, (Solen minutus,

Lin.)
SOLEN, Lin.,
The shell only bivalve, oblong or elongated, but the hinge

always furnished with salient and well marked teeth, sue the
ligament external. In the

SoLEN, Cue. (proper),

The shell is cylindrically elongated, and has two or three
teeth in each valve near the anterior extremity, where the foot
issues. The latter is conical, and enables the animal to bury

122 CLASS ACEPHALA.

itself in the sand, which it excavates with considerable
rapidity on the approach of danger.

Several species are found along the coast of France.

We might distinguish those species in which the teeth ap-
proximate in the middle: some of them have still a long and
narrow shell. (Solen legumen, Chemn. VI. v. 32—34.)

In others it is wider and shorter; their foot is extremely
thick. ‘Two of the latter inhabit the Mediterranean. ° (Solen
strigilatus, &c.) In

SANGUINOLARIA, Lam.,

The hinge is nearly the same as in the wide solens, and has
two teeth in the middle of each valve, but the valves, which
are oval, are much closer at the two extremities, where they
merely gape, as in the mactre. (Solen Sanguinolentus,
Chemn.)

PsAMMoBIA, Lam.,

The psammobiz differ from the sanguinolarie in having but
a single tooth in the middle of one valve, which penetrates
between two on the opposite one, (Tellina gari, &c.)

PSAMMOTHEA, Lam.,

But a single tooth to each valve; otherwise resembling the
psammobize. (Psammothea violacea, Lam., &c.)

PHOLAS, Lin.,

The pholades have two principal valves, broad and convex
towards the mouth, narrow and elongated on the opposite
side, and having a large oblique opening at each extremity ;
their hinge, like that of a true mya, is furnished with a plate
projecting from one valve into another, and with an internal
ligament running from that plate into a corresponding cavity.
Their mantle is reflected externally upon the hinge, where it

*

tc

Mollusca’ PL. 31.

1 Sclen novaculina, —-& Sellen’ tenuis. * .
2 Glyeymeris apinensis. 5 Villorita evprincides..

3 Selen Savi. 6 Paten purpureus .
s Esa y
Zendom, Published: by Whittadcer 2! Ave Maria Tare; 1833

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ORDER TESTACEA. 125

sometimes contains two or three supernumerary calcareous
bodies. ‘The foot issues through the aperture on the side
next to the mouth, where it is widest, and from the opposite
end project the two tubes, which are united, and capable of
enlarging themselves in every direction.

The pholades inhabit canals which they excavate, some in
ooze, and others in stone, like the lithodomi, petricole, &c.
They are much sought for on account of their agreeable
flavour.

Several species are found on the coast of France: such is
the Dail commun. (Pholas dactylus, L., &c.)

TEREDO, Lin.,

The mantle extended in a tube much longer than the two
small rhomboidal valves, and terminated by two short tubes,
the base of which is furnished on each side with a strong and
moveable kind of operculum or palette. These acephala,
while quite young, penetrate and establish their habitations
in submerged pieces of wood, such as piles, ships’ bottoms,
&c., perforating and destroying them in every direction. It
is thought, that in order to penetrate as fast as it increases in
size, the teredo excavates the wood by means of its valves;
but the tubes remain near the opening by which its entrance
was effected, and through which, by the aid of its palette, it
receives water and aliment. The gallery it inhabits is lined
with a calcareous crust, which it exudes, and which forms a
second kind of tubular shell. Itis a noxious and destructive
animal in the sea-ports of Europe.

Teredo navalis, L. This species, which is the most com-
mon, and is said to have been introduced into Europe from
the torrid zone, has more than once threatened Holland with
ruin by the destruction of its dikes. It is upwards of six
inches in length, and has simple palettes.

Larger species inhabit hot countries, whose palettes are

124 CLASS ACEPHALA.

articulated and ciliate. ‘They should be remarked on account
of the analogy which they establish with the ee Such
is the Teredo palmulatus, Lam.

FISTULANA, Brug.

Separated from teredo: the external tube is entirely closed at
its larger end, and is more or less like a bottle or club. The
fistulane are sometimes found in submerged fragments of
wood, or in fruits that had sunk in the water, sometimes
simply enveloped in sand. The animal, like that of a teredo,
has two small valves and as many palettes. Recent specimens
are only obtained from the Indian Ocean, but they are found
fossil in Europe. (Teredo clava, Gm., &c.) We should ap-
proximate to them the

GASTROCHENA, Spengler,

In which the shells are deprived of teeth, and their edges being
wide apart, anteriorly, leave a large oblique opening, opposite
to which there is a small hole in the mantle for the passage of
the foot. The double tube, which can be retracted com-
pletely within the shell, is susceptible of being greatly elon-
gated. It appears that they are certainly furnished with a
calcareous tube.

In some of them, as in the mytili, the summits are at the
anterior angle, (Pholas hians); in others they are placed near
the middle.

They inhabit the interior of madrepores, which they per-
forate. Two genera of acephala, furnished with tubes like
the teredines, have been detected among fossils, but the first
of them, the

TEREDINA, Lam.,

Has a little spoon-shaped impression on the inside of each of
its valves, and a small, free, shield-shaped piece on the hinge.
(Teredina personata, Lam.) In the second,

\Thofas ottiate 4 Gastrechena cuuctermts.
2tecde navalts. 9 Teredtina personata.
3 fishilana qregeata 6 Clavaucdla cvorenata.

7. Ispeotllar vaginitevan .

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ORDER ACEPHALA NUDA. 125

CLAVAGELLA, Lam.,

One of the valves is clasped by the tube, leaving the other
however free. (Cl. echinata, Lam.)
A single living species has been found in the madrepores of
the Sicilian seas, which has been described by M. Audouin.
Some naturalists think we should also place in this family
the

ASPERGILLIUM, Lam.,

The shell of which is formed of an elongated conical tube,
closed at its widest extremity by a disk perforated with nu-
merous small tubular holes; the little tubes of the outer range,
being longest, form a kind of corolla about it. The reason
for approximating them to the acephala with tubes is found
in the fact that there is a double projection on one part of the
cone which really resembles the two valves of the acephala.
The affinity between these little tubes and those which enve-
lope the tentacula of certain terebelle, formerly caused this
animal to be referred to the annelides.

The species most known (Asper. gavanens. Mart. Conch. I.
pl.i. fi. 7.) is seven or eight inches in length.

THE SECOND ORDER OF ACEPHALA.

ACEPHALA NUDA

Are very few in number, and are sufficiently remote from the
ordinary acephala to constitute a distinct class, should such a
separation be deemed expedient. Their gills assume various

126 CLASS ACEPHALA.

forms, but are never divided into four leaflets; the shell is re-
placed by a cartilaginous substance, sometimes so thin that
it is as flexible as a membrane.

We form two families of them; the first comprehends the
genera whose individuals are isolated, and without any
organic connexion one with the other, although they fre-
quently live in society.

BipHora, Brug. THawia, Brown. SALPA, and
DAGYSA, Gm.,

Have the mantle and its cartilaginous envelope oval or cylin-
drical, and open at both ends. On the side of ‘the anus the
aperture is transverse, wide, and furnished with a valvule,
which permits only the entrance of water, and not its exit;
on the side of the mouth it is simply tubular. Some muscu-
lar bands embrace the mantle and contract the body. The
animal moves by causing the water to enter through the pos-
terior aperture, which has a valvule, and by making it issue
through that on the side of the mouth, so that it is always
pushed backwards, which has caused the posterior aperture
to be taken by some naturalists for the true mouth. It also
generally swims upon its back. Its gills form a single tube
or riband, provided with regular vessels, placed obliquely in
the middle of the tubular cavity of the mantle, in such a
manner that it is constantly bathed by the water as it tra-
verses that cavity. The heart, viscera, and liver are clustered
up near the mouth, and towards the back, but the position of
the ovary varies. The mantle andits envelope, when exposed
to the sun, exhibit the colours of the rainbow, and are so
diaphanous that the whole structure of the animal can be seen
through them; in many they are furnished with perforated
tubercles. The animal has been seen to come out from its
envelope without appearing to suffer pain. The most curious
circumstance respecting them is their remaining united for a

Mollusca’ PU.9

\ Thatta cristata 5 Sal. longieauda. 9 Sal. Prramidatis.
2 Salpa seuligera. 6 Sal. fusiformis. JQ Beltentay evttera,
’ Sal. intndtiahiormis. 7 Sal. zenarte, LL Cyathia’ memis.

A Sal. ietcuspéis. & Sal. Cylindrica. 2 Phallusia nigra.

14 Clavellina borealis.

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ORDER NUDA. Ley

long time, just as they were in the ovary, and thus swimming
in long chains where the individuals are disposed in different
ways, but each species always according to the same order.

M. de Chamisso assures us that he has verified a still more
singular fact relative to these animals ; it is, that the indivi-
duals which have thus issued from a multiplex ovary are not
furnished with a similar one, but produce isolated young
ones of various forms, which have an ovary like that which
produced their parent, so that there is alternately a genera-
tion of a few isolated individuals, and another of numerous
and aggregate ones, and that these two alternating genera-
tions do not resemble each other.

It is very certain that in some species little individuals
have been observed adhering to the interior of large ones by
a peculiar kind of sucker, which were different in form from
those that contained them.

_ These animals are very abundant in the Mediterranean and
the warmer portions of the ocean, and are frequently phos-
phorescent.

The THALIAZ, Brown, have a small crest or vertical fin
near the posterior extremity of the back. (Holothuria thalia,
Gm., &c.)

Of the SALP#, properly so called, some have a gelatinous
dark-coloured plate in the substance of the mantle, and above
the visceral mass, which may be the vestige of a shell. (Salpa
scutigera, Cuy., &c.)

In others it is a simple prominence of the same nature as
the rest of the mantle, but thicker. (Salpa Tilesii, Cuv., &c.)

Others, again, have neither plate nor prominence, but their
mantle is extended by points, and of them

Some have a point at each extremity. (Salpa maazima,
Forsk., &c.) Others have two at the extremity nearest the
mouth. (Salpa democratica, Forsk., &c.) ; and even three, or
more, as Salpa tricuspis Id. .

128 CLASS ACEPHALA.

Some have but a single one at this same extremity. (Holo-
thuria Zonaria, Gm., &c.)

The greater number is simply oval or cylindrical. (Salpa
octofera, Cuv., &c.) In the

AscipiA, Lin., THEYTON of the ancients,

The mantle and its cartilaginous envelope, which is fre-
quently very thick, resemble sacs every where closed, except
at two orifices which correspond to the two tubes of several
bivalves, one serving to admit water, and the other to give a
passage to the feces. The gills form a large sac, at the
bottom of which are the mouth and the visceral mass. The
envelope is much larger than the mantle, which is fibrous and
vascular, and on which, between the two tubes, is one of the
ganglions. These animals attach themselves to rocks and
other bodies, and are deprived of all power of locomotion.
The chief sign of vitality which they exhibit consists in the
absorption and evacuation of water, through one of their
orifices: when alarmed they eject it to a considerable dis-
tance. They abound in every sea, and some of them are
eaten. The whole genus ASCIDIA, Gm. with some addi-
tional species.

Some species are remarkable for the long pedicle which
supports them. (Ascidia pedunculata, Edw., &c.)

The second family of naked acephala,

AGGREGATA,
Consists of animals more or less analogous to the ascidiz, but
united in a common mass, so that they seem to communicate
organically with each other, and in this respect to connect
the mollusca with the zoophytes ; but, independent of their
peculiar organization, these animals, according to the obser-
vations of Messrs. Audouin and Milne Edwards, at first live
and swim separately, only becoming united at a certain sub-

ORDER NUDA. 129

sequent period, a fact which is in direct opposition to this
opinion.

Their gills, as in the ascidiz, form a large sac, traversed
by the aliment before it arrives at the mouth; their principal
ganglion is also situated between the mouth and the anus; a
nearly similar disposition obtains with respect to the viscera
and ovary.

Notwithstanding this, some of them, like the biphora, have
an opening at each extremity; such is the

BOTRYLLUS, Gerin.,

Of an oval form, fixed on various bodies, and united by tens
or twelves like the rays of a star. The branchial orifices are
at the external extremities of these rays, and the anus termi-
nates in a common cavity, which is in the centre of the star.
If an orifice be irritated, but a single animal contracts; if the
centre be touched, they all contract. ‘These very small ani-
mals attach themselves to ascidie, fuci, &c. (Botryllus Stel-
latus, Gertn., &c.)

In some particular species three or four stars appeared to
be piled one upon the other. (Botryllus conglomeratus,
Geertn.)

Pyrosoma, Péron.,

The pyrosome unite in great numbers, forming a large
hollow cylinder, open at one end and closed at the other,
which swims in the ocean by the combined contraction and
dilatation of all the animals which compose it. The latter
terminate in a point on the exterior, so that the whole ex-
ternal surface of the tube is bristled with them ; the branchial
orifices are pierced near these points, and the anus opens in
the internal cavity of the cylinder. A pyrosoma may be thus
compared to a great number of stars of botrylli strung toge-
ther, the whole of which is moveable.
VOL, XII. K

130 CLASS ACEPHALA.

The Mediterranean and the ocean produce large species,
the animals of which are arranged with but little regularity.
They exhibit a phosphorescent appearance during the night.
Several of the polyclina and aplidia of Savigny.

A smaller species is also known, where the animals are
arranged in very regular rings. (Pyrosoma Allanticum,
Peron, &c.)

The remainder of these aggregated mollusca, like the
ordinary ascidie, have the anus and branchial orifice approxi-
mated to the same extremity. The species known are all
fixed, and till now they have been confounded with the alcyo-
nia. ‘The visceral bundle of each individual is more or less
extended into the common cartilaginous or gelatinous mass,
more or less narrowed or dilated in certain points ; but each
orifice always forms a little six-rayed star on the surface. We
unite them all under the name of

POLYCLINUM.

Some of them are extended over bodies like fleshy crests.

Others project in a conical or globular mass. The euce-
lium, Savig., the distomz, are arranged in the same manner.

Or expand into a disk, comparable to that of a flower or of
an actinia. (The genus diazona, Sav.)

Or are elongated into cylindrical branches, supported by
slender pedicles, &c. (The genus sigillina, Sav.)

Or form parallel cylinders. (The genus synoicum, Lam.)

Recent observations even seem to show that the ESCHAR®,
hitherto placed among the PoLypt, belong to this family of
the mollusca.

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Molliscr Pl. 1.

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1 Betwus pelveyelus. 4. Folyclinum constellatum
2 Pyresoma rution. 5 Lucatiam hospitrelum.

3 Lyr. giganteum, details of. 6 Aplidiam: lebatum,

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CLASS BRACHIOPODA. 131

THE FIFTH CLASS OF THE MOLLUSCA.

BRACHIOPODA.

THE mollusca brachiopoda, like the acephala, have a
bilobed mantle, which is always open. Instead of feet, they
are provided with two fleshy arms, furnished with numerous
filaments, which they can protrude from and draw into the
shell. The mouth is between the base of the arms. Neither
their organs of generation, nor their nervous system, are well
known.

All the brachiopoda are provided with bivalve shells, fixed
andimmovable. But three genera are known.

LINGULA, Brug.

Two equal, flat, oblong valves, the summits of which are at
the extremity of one of the narrow sides, gaping at the other
end, and attached between the two summits to a fleshy pedi-
cle, which suspends them to the rocks; the arms become
spirally convoluted previously to entering the shell. It ap-
pears that the gills consist of small leaflets, disposed around
the internal face of each lobe of the mantle.

But a single species, Lingula anatina, Cuv. Ann. du Mus.
I. vi.; Seb. II. xvi. 4, is known. It inhabits the Indian
Ocean, and has thin, horny, and greenish valves.

TEREBRATULA, Brug.

Two unequal valves, united by a hinge ; the summit of one,
more salient than the other, is perforated to permit the passage
K 2

132 MOLLUSCA.

of a fleshy pedicle, which attaches the shell to rocks, madre-
pores, other shells, &c. Internally, a small bony piece of
frame-work is observed, sometimes sufficiently complex, com-
posed of two branches that articulate with the imperforated
valve, and that support two arms, edged all round with a long
close fringe, between which, on the side next to the large
valve, is a third simply membranous, and much longer ap-
pendage, usually spirally convoluted, and edged like the arms
with a fine and close fringe. The mouth is a small vertical
fissure between these three large appendages. ‘The principal
part of the body, situated near the hinge, contains the nume-
rous muscles, which reach from one valve to the other, and
between them are the viscera, which occupy but little space.
The ovaries appear to be two ramified productions adhering to
the parietes of each valve. I have not yet been able to ascer-
tain exactly the position of the gills.

Numberless terebratule are found fossil or petrified in cer-
tain secondary strata of ancient formations. The living spe-
cies are less numerous. (Anomia scobinata, &c.)

The shell of some is broader transversely, or longer in a
direction perpendicular to the hinge, with an entire or emar-
ginated contour, divided into two or several lobes; some of
them are even triangular. ‘The surface is either smooth, fur-
rowed in radii, or veined; they are thick, and thin, and even
diaphanous. In several of them, in lieu of the hole in the
summit of the thin valve, there is a notch, and this notch is
sometimes partly formed by two accessory pieces, &c. It is
probable that when better known their animals will present
generic differences. Already, in the

SPIRIFER, Sowerb.,

Two large cones have been recognized, formed of a spiral
thread, which appear to have supported the animal. In

OE

‘ Mollusca Tage

1 Zingula anatina. 3 Spiriter igonalis.

2Terebratila Gaudichaudi. & Orbicula laevigata.

5 Granta personata.

London, Published by Whittaker & C2 Ave MartaLone4833

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CLASS BRACHIOPODA. 133

THECIDEA, Defr.,

This support seems to have been incorporated with the small
valve. (Thecidia Mediterranea, Risso.)

ORBICULA, Cuv.

The orbiculz have two unequal valves, one of which, that
is round and conical, when viewed by itself, resembles the
shell of a patella; the other is flat, and fixed to a rock. The
arms of the animal (Criopus, Poli), are ciliated and spirally
recurved, like those of the lingule.

The seas of Europe produce a small species, Patella ano-
mala, Miill. Zool. Dan. V. 26 ; Anomia turbinata, Poli, XXX.
15; Brett., Sowerb., Lin. Trans. XIII. pl. xxvi. f. 1.

The Discina, Lam., are orbicule, the inferior valve of
which is marked by a fissure. The

CRANIA, Brug.,

Should be approximated to the orbicule. The arms of the
animal are also ciliated, but the shells have internally deep
and round muscular impressions, that have caused it to be
compared to the figure of a skull.

One of them inhabits the European seas, Anomia cranio-
laris, L., or Crania personata, Bret., Sowerb., Lin. Trans.
XIII. pl. xxv. f. 3. Several are fossil, such as the Cran.
antiqua, and the others, of which M. Heeninghaus has given
an excellent monograph.

134 MOLLUSCA.

THE SIXTH CLASS OF THE MOLLUSCA.

CIRRHOPODA.

LeEpAS and TRITON, Lin.

THE cirrhopoda, in several points of view, are intermediate be-
tween this division and that of the articulata: enveloped by a
mantle and testaceous pieces which frequently resemble those
seen in several of the acephala, their mouths are furnished with
lateral jaws, and the abdomen with filaments named cirri,
arranged in pairs, composed of a multitude of little ciliated arti-
culations, and corresponding to a sort of feet or fins, similar to
those observed under the tail of several of the crustacea; their
heart is situated in the dorsal region, and the gills on the sides;
the nervous system forms a series of ganglions in the lower part

of the abdomen. ‘These cirri, however, may be considered as

analogous to the articulated appendages of certain species of
teredo; while the ganglions, in some respects, are mere repe-
titions of the posterior ganglion of the bivalves. ‘The position
of these animals in the shell is such, that the mouth is at the
bottom, and the cirri near the orifice. Between the last two
cirri is a long fleshy tube, that has sometimes, but erroneously,
been taken for their proboscis, and at the base of which, near
the back, is the opening of the anus. Internally, we observe
a stomach, inflated by a multitude of small cavities in its
parietes, which appear to fulfil the functions of a liver, a sim-
ple intestine, a double ovary, and a double serpentine oviduct,
supplying from its walls the prolific fluid, and prolonged
through the fleshy tube to open at its extremity. These ani-

a

CLASS CIRRHOPODA. 135

mals are always fixed. Linneus comprised them all in one
genus, LEPAS, which Bruguieres divided into two, that have
in their turn been subdivided.

ANATIFA, Brug.

A compressed mantle, open on one side, and suspended to a
fleshy tube, varying greatly as to the number of testaceous
pieces with which it is furnished ; twelve pair of cirri, six on
each side, those nearest to the mouth being the thickest and
the shortest; the gills are elongated pyramidal appendages,
that adhere to the external base of the whole of the cirri, or
part of them.

The two principal valves of the most numerous species
(PENTALASMIS, Leach), resemble those of a mytilus; two
others seem to complete a part of the edge of the mytilus
opposite to the summit, and a fifth azygous unites the posterior
edge to that of the opposite valve. These five pieces cover
the whole of the mantle. From the usual place of the liga-
ment arises the fleshy pedicle; a strong transverse muscle
unites the first two valves near their summit; the mouth of
the animal is concealed behind it, and the posterior extremity
of its body, with all the little articulated feet, is a little be-
yond it, between the first four valves.

The most common species of the European seas, Lepas
anatifera, L., owes its specific appellation to the fable which
represents it, as producing the Barnacles, a story founded
on the rude resemblance that has been observed to exist
between the pieces of this shell and a bird. The anatife
adhere to rocks, piles, keels of vessels, &c.. We may distin-
guish from them,

POLLIcIPEs, Leach,

Where, besides the five principal valves, there are several
small ones near the pedicle (Lepas pollicipes, L., &c.), some of

136 MOLLUSCA.

which, in certain species, are nearly as large as the former
(Lepas mitella); frequently there is an azygous valve oppo-
site to the ordinary one of the same description. In the

CINERAS, Leach,

The cartilaginous mantle contains: but five small valves,
which do not occupy the whole of its extent. (Cineras vit-
tata, Leach.)

Orion, Leach.

The cartilaginous mantle contains but two very small valves,
with three little grains that hardly merit that name, and has
two tubular auriform appendages. (Otion Cuvieri, Leach.)

TETRALASMIS, Cuv.

But four symmetrical valves, which surround the aperture,
two of them longer than the others. The animal is partly con-
tained within the pedicle, which is large, and covered with
hair. They are a kind of tubeless balani. (Tetral. hirsutus,
Cuv.)

BALANUS, Brug.

The principal part of the shell of the balani consists of a
testaceous tube attached to various bodies, the aperture of
which is more or less closed by two or four valves. This tube
is formed of various pieces which appear to be detached and
separated, in proportion as the growth of the animal requires
it. The gills, mouth, articulated tentacula, and anal tube,
differ but little from those of the anatife. In

BALANUS,
Properly so called, the tubular portion is a truncated cone,
formed of six projecting pieces, separated by as many de-
pressed ones, three of which are narrower than the others.

Mollusca

1 Anahra lerfs. 6 Cineras viitata.

2 Felltcipes cornucopta. © Olron: Cuvierit.
4 Poll. mitedla . 7 Tetralesmis hirsutus.

4. fell. scalpelum. & Triton (Alepis) tascteutalus .

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2 Animal &f bal sulcatus. 7 Pyrgema cancellata: 12 Ochthosia streemithanzant.

3 deasta spinesula. & The same atter Savigny la Cerenula balenarts .

A. dea. Montague. 9 Creusia spinesila. 4 Tnbicindla balanarum.

5 Conta radiata. 10 Chthamatus stellatus, Peli? \i Diadema (Cerenulatadema Lo

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CLASS CIRRHOPODA. isi

Their base is usually formed of a calcareous lamina, and fixed
to various bodies. The four valves of their operculum close
the orifice exactly.

The rocks, shells, &c. of all our coasts are, in a manner,
covered with a species of balanus, the Zepas balanus, L.,
Chemn. VIII. xcvii. 826. Naturalists have separated from it

The Acasta, Leach, whose base is irregular, convex
towards the exterior, and which does not become fixed.
Most of them are found in sponge. (Acasta Montaguz, Leach.)

The Coni#, Blainv.; the tube of which has but four
salient pieces. (Conta radiata, Blainv.)

The ASAM2, Ranzani, where the tube has no decidedly
salient pieces. (Lepas porosus, Gm.)

The PyrGom#, Savig., whose tubular part, forming a
strongly depressed cone, has but a very small orifice, almost
like the shell of a fissurella. (Pyrgoma cancellata, Leach.)

The OcTHos1®, Ranzani, which have but three salient
pieces in the tube, and only two valves to the operculum.
(Lepas stremii, Mill. Zool. Dan.)

The Creusia, Leach, with four salient pieces and two
valves to the operculum. (Creusia spinulosa, Leach.)

M. de Lamarck, under the name of CORONULZ, separates
the very wide species, where the parietes of the cone are occu-
pied by cells: so large that they resemble chambers. (Lepas
balenaris, L., &c.) And under that of
_ TUBICINELL&, those in which the tubular portion is
elevated, narrower near the base, and divided into annuli,
which mark its growth. (The Tubicinella, Lam., Ann. du
Bind. To xcx., 1, 2;)

There are some species of these last two subgenera which
affix themselves to the skin of the whales, and even penetrate
into their blubber.

To the preceding subgenera must be added the

138 MOLLUSCA.

DIADEMA, Ranz.,

Where the tubular portion is almost spherical, and which has
but two small valves hidden in the membrane which closes the
operculum. ‘The opercular valves would not effectually close
the orifice without the membrane which unites them.

They also live on the balenz, and otiones are frequently ob-
served attached to their surface. (Lepas Diadema, Chemn.
VIII. xcix. 848, 844.)

ae

SUPPLEMENTARY TREATISE

ON THE

MOLLUSCA.

I. ON THE DIVISION IN GENERAL.

IT is now five or six and twenty years since naturalists first
so designated under the general name of MOLLUSCA a
numerous portion of the Animal Kingdom, including not
only the true mollusca of Aristotle and Pliny, but also the
testacea of these ancient writers.

This name, mollusca, comes from the Greek word paAaka, in
Latin, mollia (soft), because the majority of the animals to
which this denomination has been applied are remarkable for
the softness of their flesh, or more properly speaking, of their
general envelope.

The science which treats of this portion of zoology has as
yet received no peculiar name. Conchology, it must be re-
membered, is applicable only to the investigation and arrange-
ment of the shells of such of these animals as have them.

M. de Blainville has proposed the name of malacozoology,
or thus abbreviated, malacology, compounded of padakoc,
Ewov, and Aoyog; that is to say, a scientific discourse or trea-
tise on the soft animals.

Aristotle, the most ancient and important of the natural

140 SUPPLEMENT

historians of antiquity, was the first writer who made use of
the term mollusca. But under this name he comprehended
but a portion of those animals which are at the present day
classified under this type, giving that of ostracodermata (tes-
taceous animals) to those which have a calcareous envelope, of
greater or less hardness.

Pliny, and in general all the ancient Latin naturalists, have
employed the same denominations, which they have translated
into their own language by the words mollia and testacea.
#lian and the other Greek naturalists have followed Aristotle.
Isidore de Seville, Wotton, Belon, Rondelet, have adopted
the same denominations, as well as Gesner, Aldrovandus, and
his abbreviator, Johnston.

Ray, the precursor of Linnzus, appears to have been the
first who, having applied the name of worms to all white-
blooded animals, or the invertebrata of modern naturalists,
(the insects and crustacea excepted) has employed the names
of molluscous worms and testaceous worms, which correspond,
however, to the divisions of Aristotle, though the term worms,
or vermes, is certainly most strangely inapplicable.

Adanson, perhaps the first who considered shells in a proper
point of view, employed the term testacea (coguillages in
French) in a classical manner; but under this name he merely
comprised the species of mollusca which are invested with
shells. Linnzus and his entire school have followed Ray.
Pallas, after some very important observations on the subject,
of which we shall speak hereafter, has shown for what animals
the name of mollusca should be reserved.

The Baron Cuvier, a name which cannot now be pro-
nounced without the deepest regret of every lover of science,
appears to have been the first who fully appreciated the obser-
vations of Pallas, who carried them into operation, and united
in one treatise all the animals indicated by the last-mentioned
traveller and naturalist, comprehending them definitively under

ON MOLLUSCA. 141

the classic name of mollusca, whether they were naked or in-
vested with a shell of one or more pieces. ‘This example was
imitated by M. de Lamarck and almost all the French naturalists.
Nevertheless, M. de Lamarck, in the last edition of his inverte-
brated animals, no longer employs the name of mollusca alto-
gether in the same manner, and only applies it to a part of the
mollusca of M. Cuvier, which nearly corresponds to his
ancient division of the cephalous mollusca. M. Rafinesque,
some years before, had designated this group under the deno-
mination of malacosia.

M. de Blainville proposes the name of malacozoaires for the
type which contains the true mollusca, and malentozoaires for
the sub-type formed of the articulated mollusca.

Aristotle defined his mollusca properly so called, as animals
which have no blood, the fleshy parts of which are external
and the solid within ; the reverse of this constitutes his defini-
tion of the testacea. Pliny, and all the zoologists, at the revi-
val of letters, have pretty nearly admitted the same definition.

Adanson understands by the word testacea, or coquillages,
animals whose body is soft, without any sensible articulation,
and covered altogether, or in part, with a stony crust, called a
shell, to which it is attached by one or more muscles.

This is the definition of Linneus: MoLLuscaA—A. simpli-
cia, nuda, absque testa, artubus instructa. 'TESTACEA—
A. simplicia, domo, seepius calcareo, obtecta.

Bruguiéres, in separating the mollusca from the insects,
gives them as common characters, the being without bones,
without stigmata, without feet, or without articulations. He
distinguishes the mollusca, properly so called, because they
are naked, from his testacea, which are contained in a shell of
one or more valves.

M. Cuvier defines them according to their anatomical
characters: animals without vertebre or articulated skeleton,

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nervous system not collected into a spinal marrow, but merely
into a certain number of medullary masses, dispersed over
different parts of the body, the principal of which, termed the
brain, is situated on the cesophagus, which it encircles with a
nervous collar; blood cold, whitish or blueish; circulation
double; hearts often numerous.

M. de Lamarck admits nearly the same definition: ovipa-
rous animals, with soft body, not articulated in its parts, and
having a variable and muscular mantle; respiration by diver-
sified gills; a brain, some ganglia, and nerves to give sensi-
bility and irritability to the organs; but no spinal marrow ;
conglomerate glands; a shell enveloping or enveloped, and
sometimes none.

M. de Blainville proposes the following :

Animals with the body and its appendages soft, not arti-
culated, enveloped in a skin or muscular dermis (mantle), of a
variable form, in or on which is most frequently developed a
calcareous part (the shell), of one or two pieces; circulation
complete, with white blood, heart essentially aortic, and supe-
rior to the intestinal canal, except in the brachiocephala ;
respiration aquatic or aerial; nervous system composed of a
cerebriform ganglion, sub-cesophageal, communicating with
the ganglia of the different functions; those of locomotion
being lateral.

As to the place of the mollusca in the series of animals,
Aristotle separates his two groups by the crustacea. Aldro-
vandus, Johnston, Ray, Linnzus, his whole school, and M.
Dumeril, place them after the insects; Cuvier, Lamarck, and
their followers, place them at the head of the invertebrated
animals.

In considering these animals as constructed on a peculiar
plan, and forming a distinct type, they might even be
approximated to man, the top of the animal scale, as may the

ON MOLLUSCA. 143

insects, but in a different direction. Nevertheless, we think
that if, in truth, the structure of the first genera possesses
something of that of vertebrated animals, in the rudiments of
skeleton which envelope the brain, yet the last are conside-
rably degraded, and pass quickly into the lowest type of
animals, so that we may place them in a line parallel to the
animals articulated externally, and as it were passing to the
actinozoaires, by the ascidia, &c.

Although nearly to these latter times, as we shall see in
noticing the history of this part of zoology, these animals have
been very much neglected, for the almost exclusive examina-
tion and study of their envelopes or shells, they do not the
less present a very considerable degree of interest in many
respects, so as to induce us to smooth the difficulties involved
in their investigation. ‘Thus the anatomist, and more espe-
cially the physiologist, will find that their study throws no in-
considerable light upon certain general questions of the first
interest and importance : they will find, for instance, the organ
of hearing reduced, so to speak, to its most simple expression,
to that which is absolutely essential to it,in the sepza and the
neighbouring genera ;—they will find the principal organ by
which the blood is moved divided into several parts, and
sometimes presenting the singular disposition of appearing to
be traversed by the intestinal canal. In studying the organs
of generation in these animals, they may form more correct
notions of hermaphrodism, complete or incomplete ; thus, in a
great number the organs, both male and female, exist in the
same individual, though such individual cannot fecundate it-
self; so that the species is necessarily composed of two indi-
vidual hermaphrodites, while in others, in which the female
organs alone are perceptible, generation takes place by means
of a single individual.

Geology will derive not less advantage from the minute
study of the shells or envelopes of the mollusca, to assist in

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the determination of the identity of the different strata of the
earth. It will discover, in the innumerable quantity of these
animals, succeeding each other from generation to generation,
in the depths of the sea, one of the evident causes of the in-
crease of continents. |

But man can find, in the knowledge of the mollusca, appli-
cations still more direct to his well-being in society, either in
the advantages or disadvantages which he may derive from
them. Thus a considerable number of species are proper to
supply him with food; the sepia, and especially the calmar,
or ink-fish, are in great request in Greece, and even in seve-
ral parts of Italy ; the larger species of snails, many buccine,
and some cognate genera, are in tolerable estimation in several
countries, and were so much so among the ancient Romans,
that Pliny has not disdained to recount the names of those
who thought proper to collect them in depéts, and to provide
them with abundant nourishment, to fatten them, and render
them more succulent. Oysters and muscles also constitute a
prime object of commercial speculation in our own days.

Although not very numerous, the advantages which the
mollusea present to us are nevertheless much greater than
the injuries we receive from them ; and it is probable that we
cannot stigmatize among them an animal truly hurtful, except
the teredo (ship-worm), which, attacking the wood of our
vessels and dikes, often occasions very considerable mis-
chief. The knowledge, therefore, of its habits and manners,
is of the first necessity in those countries which are infected
by it. Slugs and snails are also strongly and justly dreaded
enemies in our gardens.

It may neither be unuseful nor uninteresting to give a brief
sketch here of the history of this part of zoology.

All the ancient authors, such as Aristotle, Pliny, and their
abridgers, appear to have been very little acquainted with
these animals: they place them among those which they

ON MOLLUSCA. 145

designated easanguza, a division which corresponds altogether
with the white-blooded animals of Linnzeus, and the inverte-
brated animals of modern naturalists ; not that they conceived
these animals to have no blood, but they termed them so
merely in comparison with the red-blooded animals. They
contented themselves with dividing them into two sections, the
mollusca and testacea, in which they were followed by the
naturalists at the revival of literature, who, however, added
but little to the facts already detailed by the ancients. But
soon, the easy collection of the envelopes of these animals,
often of the most extraordinary beauty, having become an
object of curiosity, and even of rivalship, among the rich, the
study of the animal itself was forgotten in an exclusive atten-
tion to the shell. Thus arose that part of natural history
properly called conchology, on which. we have so many mag-
nificent works, mere objects of luxury, almost in all countries.
On this department we shall bestow a few general remarks in
the proper place In vain did our celebrated countryman,
Lister, before him Fabius Columna, and after, Willis, Heyde,
Swammerdam, &c., give the anatomy of many molluscous
animals; no attention was paid to establish their classification,
on their external organization, on their form, and still less on
their internal structure. It is true that Linnezeus, in the earlier
editions of his Systeme Nature, speaks of the animal of his
testacea, before he exposes the characters of the genera; but
he confines himself to citing the name of his mollusca, with
which they have the greatest relation, and the genus is really
established on nothing but the form of the shell.

The great majority of the naturalists of the last age followed
the example of this great man, as we shall see by and by;
but some French naturalists began to see the necessity of re-
curring to the animals to arrive at a proper classification of
the shells. Thus, in 1743, Daubenton read to the Academy
of Sciences, of which he was not yet a member, a memoir on

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the methodical distribution of these envelopes, in which, after
having proved that the knowledge of them may suffice, he
nevertheless remarks that that of the animals is indispensable
to form a complete system of conchology, and a natural distri-
bution of shells. We do not, however, find that he carried this
principle into execution; at least there is no mention of his
having done so, in the extract given from his memoir by the
secretary of the Academy.

In 1766, Guettard, a member of the same society, was the
first who put in practice what Daubenton merely hinted; for
in a very detailed article, inserted in the Acts of the Academy,
the covert object of which appears to have been a criticism of
some observations of Buffon, at the commencement of his
description of the ass, on species and its distinction,—not only
does he establish on indubitable principles the necessity, in
the classification of shells, of having recourse to the animal
which they contain, and of which they form a part, but he
characterizes a certain number of genera, at least among the
univalves, extremely well.

Although in this memoir Guettard tells us that the genera
of bivalves ought also to be susceptible of being equally cha-
racterized from the animal, he confesses that his observations
on them have been too few to enable him to make the trial;
but he very well discriminates how far the division of shelled
mollusca into terrestrial, fresh-water, and marine, is exact.
He likewise pays great attention to the presence or absence of
the operculum.

These new observations of Guettard doubtless determined
d’Argenville, in the second edition of his Conchology, in 1757,
to add a great number of figures, unfortunately very bad, of
animals, under the name of zoomorphoses, but without serving
any purpose in the characters of his genera of shells, which
had been justly criticised by Guettard, in the memoir just
noticed.

‘N

ee ee

ON MOLLUSCA. 147

In the same year, 1757, Adanson, who grouped animals in
families on no arbitrary system, but according as they exhi-
bited the greatest number of relations among themselves, made
a more extended application of these principles to the conchi-
ferous mollusca, which he designates under the classific name
of coquillages, in the first and only volume which he pub-
lished of his Voyage to Senegal. He studies with care, dis-
tinguishes, and denominates in a suitable manner, all the
external parts, both of the animals and their shells. He then
occupies himself in arranging those which he had observed in
Senegal into a great number of systems, or tables of relation,
considering, for instance, in the shell of the helix, the summit,
the aperture, the opercle, the periosteum; in the conchs, the
valves, according as they are equal or unequal, &c.

Then passing to the animals, and always admitting his
original division, into helices and conchiferous mollusca, he con-
siders, in the first, the tentacula or horns, the eyes, their absence,
existence, or situation in the head,the mouth, either with two
jaws and without proboscis, or with proboscis and without
jaws, &c. In the conchs he considers the mantle, the trachea,
&c. He then describes and figures the species of shells, which
he observed in Senegal.

We may remark, that this work of Adanson’s, if not the first
in which the principle of classification, by which the animal
is regarded as well as the shell, is established, is at least that
in which the means of applying this principle are to be found.
It must be confessed, however, that Adanson has not always
employed with success the excellent materials which he had
prepared in so suitable a manner. In fact, the distinction of
his genera is very far from being complete, especially in the
conchifera: his approximations are not always very natural,
in a variety of cases. To him, however, we are indebted for
a knowledge of the numerous relations between pholas and

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teredo; but of him, likewise, has science to complain, for the
erroneous approximation of oscabrio and patella.

Another French naturalist, to whom the science of malaco-
logy is indebted for the use of the same principle, first broached
by Guettard, and so well supported by Adanson, is Geoffroy,
the physician of Paris. We find, in effect, in his little trea-
tise on the terrestrial and fresh-water shells of the environs of
Paris, published in 1766, the description of the animals to
which they belong; and the characters of the few genera which
this book contains are equally derived from the animal and
the shell. He speaks but of five genera of univalves, among
which there is but one new one, anciliwm, adopted by all
modern zoologists. Although he has established pretty nearly
the same genera as Guettard, cochlea, bucctnum, planorbis,
and nerita, he has not been equally happy in their circum-
scription: for instance, he has confounded physis with plan-
orbis, and in his genus nerita he has placed terrestrial and
aquatic cyclostomata, &c. As to the two only genera of
bivalves which he establishes, those of camus and mytilus, he
places in the first the cyclas fluviatilis, in the second an
anodon and a unio.

Miiller, the celebrated author of the Danish Fauna, was the
first foreign zoologist who adopted the same principle in his
history of terrestrial and fresh-water worms. But in general
his system of classification, though more complete than that
of Geoffroy, since it extends to all the conchyliferous animals,
is yet by no means natural, and is much inferior to that of
Adanson.

About the same period, we begin to discern certain import-
ant changes in the distribution of molluscous animals, in the
Systema Nature of Linneus.

In the first nine editions, Linnzus does not appear to have
yet employed the denomination of mollusca, the naked species

ON MOLLUSCA. 149

being placed in his order zoophytes, class vermes, and the
conchyliferous, in his third order of the same class, under the
name of testacea. Though he does not yet distinguish his
different genera but by a very small number of characters
derived from the shell, he nevertheless cites the naked animal,
which he supposed to belong to it, and which he had placed
in his zoophytes, but that evidently in an accessory manner.

But in the tenth edition we find considerable augmenta-
tions, and still more in the twelfth, which may be considered
as having received the finishing hand of its celebrated author.
The class vermes is there divided into five sections, the se-
cond of which has the name of mollusca, and contains eight
genera of the true mollusca, ascidia, limax, aplysia, doris,
tethis, sepia, clio, and scyllea. The third is almost entirely
consecrated to the testacea, divided into multivalves, bivalves,
and univalves.

In the characters of their genera, however, Linnzus always
confines himself to the citation of an analogous naked mol-
luscum; so that if the work of Adanson had any influence
over the last editions of the Systema Nature, it was only in
the more numerous division of the genera of shells, and in
their better circumscription. But it had little real effect on
the part relating to animals. Thus we find among the mol-
lusca of Linneus some which are articulated and others
which are radiated animals. In his testacea also there are
several inconvenient approximations.

Though the French zoologists whom we have mentioned
may be considered the founders of a scientific arrangement of
these animals, yet they paid no attention except to the ex-
ternal parts of the animal body inhabiting the shell, and
moreover, took no notice whatever of the naked mollusca.

Nevertheless, the impulse given to his age throughout
Europe, by the system of Linnzus, and in France by the
writings of Buffon, occasioned many naturalists to publish

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the anatomy and description of a considerable number of
molluscous animals. This was done by Bohatsch, Baster,
Forskahl, Fabricius, Miiller, &c. Besides, the application to
the different parts of zoology, of the principles so happily
imagined for botany by Bernard de Jussieu and Adanson,
changed in some measure the mode of considering the classi-
fication of animals. Wishing to arrange them in such a
manner as less to interrupt the natural relations, zoologists
felt the necessity of a knowledge of their internal structure,
and Pallas may be regarded as the chief of this new school,
which the French philosophers have supported with so much
success, and which is now fast propagating throughout all
enlightened Europe.

It was in his Miscellanea Zoologica, published in 1766,
that Pallas exhibited, as it were, the germ of those ameliora-
tions of which the methodical arrangement of the malaco-
zoaria, was susceptible. He proves that Linnzus, in the
disposition of his molluscous worms, has departed very con-
siderably from nature: that his sub-division of testacea, con-
sidering the shell and not the animal, could not be preserved,
and that in general he was totally wrong in separating these
two orders. Accordingly, he proposes to unite in the uni-
valves, as forming a natural order, not only the univalve tes-
tacea but also the limaces, (and under this name he compre-
hends doris, tethys, and scyllza,) as well as the sepia, and
perhaps, adds he, the medusa; but this is evidently wrong.
In the second order, he thinks, should be placed all the bi-
valve testacea (joining with them the teredo), of which the
ascidia appears to him to be the analogue, or to speak more
properly, the naked type.

Notwithstanding this, Bruguiéres, an author to whom con-
chology is greatly indebted, has almost completely imitated
the arrangement of Linneus. His genera of testacea are,
however, more numerous, and better defined.

a eo

ON MOLLUSCA. 151

Gmelin, who was too little of a zoologist to profit by the
labours of the writers we have named, has scarcely made any
change in this department, in his edition, the thirteenth, of
the Systema Nature.

An Italian physician, M. Poli, was the first | to establish the
genera of mollusca, according to the animal alone, without
paying any attention to the shell. In 1791 appeared the first
volume of his magnificent work, on the testacea of the two
Sicilies. It appears that he took into consideration all the
molluscous animals, whether naked or testaceous, and divides
them into three orders: 1. Mollusca brachiata, characterized
by having several arms, in the manner of the hydra; 2. Mol-
lusca reptantia, creeping after the manner of snails, by means
of one broad foot, and always having a head and eyes; and
3. Mollusca subsilientia, provided with a long foot, fixed to
rocks, or not, and constantly devoid of head and eyes; this
contains the bivalves and multivalves.

During the ten or twelve years of the revolutionary whirl-
wind which agitated Europe but few works appeared on this
department of zoology ; indeed, it appears to have lain almost
uncultivated, if we except some facts recorded in journals, and
the establishment of some new genera. Thus the science re-
mained stationary until, in 1798, our illustrious author, feeling
like those we have before mentioned, that the methodical sub-
division of the mollusca, like that of all other animals, should
rest upon the study of organization, proposed his new classifi-
cation. He thought in the first instance that the whole divi-
sion of the malacozoaria should rise a degree in the animal
series, and precede the entomozoaria, or animals articulated
externally ; a second innovation’ was to unite definitively, as
Pallas had done, under the classific name of mollusca, the
molluscous worms of Linnzus, to his testaceous worms, that
is, to consider the existence or absence of the shell, as but a
very secondary consideration. He therefore made a distinct

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class of this great group, which he still named white blooded
animals, and which were soon to be known by the denomina-
tion of invertebrata, characterized them in a clear and precise
manner, as well as the other three, those of insects, worms,
and zoophytes, which he admits among the animals without
internal articulated skeleton ; then taking into consideration
the form of the mollusca, he divides them into three sections,
cephalopods, gasteropods, and acephala. In the first he
placed not only the sepia of Linnzus, but also the argonauta.
But it would be superfluous to enlarge further here on the
labours of Cuvier.

M. de Lamarck had chiefly confined his speculations on
this subject to a consideration of the shells, but in his work
on invertebrated animals, published in 1801, he has pretty
nearly followed the example of M. Cuvier. He imitates him
at first in this, that the class of the mollusca is put at the head
of the invertebrated tribes. But subsequently he departs from
his plan pretty often. Thus his first division of mollusea into
two orders rests on the presence or absence of the head, a
division which is merely implied in the systems of Poli and
Cuvier.

In spite of this evident march towards perfection in the
classification of the mollusca, some persons even in France
thought proper to stick to the system of Linnzus, improved
by Bruguicres: such, for example, was M. Bosc. In his sup-
plements to Buffon, although he felt the value of the innova-
tions which had been made, he nevertheless adopted the divi-
sion of the molluscous worms for the naked mollusca, and of
testaceous worms for the conchyliferous species; and in each
of these divisions he exactly followed Bruguiéres, adopting,
however, the new generic division of Cuvier and De Lamarck.
M. Bosc, however, who has often had occasion to study living
mollusca, has introduced many new facts into their history,
and has also established some genera.

i 10

ON MOLLUSCA. 153

The first work which collected all these recent labours was
the Natural History of the Mollusca just commenced by
Denys de Montfort, and executed almost altogether by M. de
Roissy, a work which constitutes a part of the edition of Buffon
by Sonnini, and which developed in a suitable manner the
system of Cuvier.

In 1809 M. de Lamarck, obliged by his place of Professor
of the natural history of invertebrated animals, to follow the
progress of the science, and to put together the new facts
which it had acquired, proposed a new distribution of those
animals, in his work entitled Philosophie Zoologique. Divid-
ing the animal kingdom into six degrees of organization, he
places in the fourth, ascending from the lowest, and in the
third, taking an inverse course, the animals with which we
are now occupied. But he divides them into two classes, one
to which he leaves the name of mollusca, while to the other
he gives the new designation of cirrhipoda. In this new
system, though considerably improved, M. de Lamarck had
still established some unnatural approximations, and in 1812
he found it necessary to make some further alterations in his
general classification of these animals. On this occasion we
may observe, that in the prodromus of his course M. de
Lamarck divides the animal kingdom into three primary sec-
tions, 1. apathetic animals ; 2. sensible animals, (these two
divisions composing the invertebrata) ; and 3. intelligent or
vertebrated animals. ‘The philosophic propriety of this divi-
sion is more than questionable.

Towards the end of 1814 M. de Blainville published his
first notions on the methodical arrangement of the malacozo-
aria, in which he particularly established the necessary rela-
tion between the shell and the organs of respiration. He also
drew from this the new character of the symmetry or non-
symmetry of those organs for the establishment of his orders.

To carry this history further would be tedious: suffice it to

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say, that this branch of zoology has been much indebted to
the subsequent labours of the French naturalists we have
already cited, and to others of the same nation; to some
zealous philosophers of Germany, such as Oken and Dr.
Goldfuss; to some of the United States of America, as Mr.
Say; and last, though not least, to some distinguished men
amongst ourselves, of whom we shall merely mention Dr.
Leach and Mr. Gray. To enter into an analysis of their
systems and improvements would be wholly beside our pre-
sent purpose.

We shall now briefly treat first of the form and organization
of the animals of this class.

The form of the body of the molluscous animals is extremely
variable, though it presents the constant negative character
of being never articulated. ‘Thus, though most usually oval,
more or less elongated, convex above, plane underneath, as in
doris, limax, &c., yet it is sometimes equally oval and con-
vex, above and underneath, as in sepia, elongated and sub-
cylindrical, as in certain loligines, globular, as in octopus, it
is often compressed more or less strongly on the sides, as in
scyllea, and particularly in all the lamellibranch acephala.
It may also be very much elongated and claviform, as in the
teredo and neighbouring genera. In many cephala a large
portion of the body is rolled, like the shell, into a spiral more
or less elevated, and of different forms. Ia fine, the form may
be so irregular that the animal scarcely appears symmetrical
externally, as is the case with the ascidiz and neighbouring
genera, and even in the biphore.

A tolerable number of these animals presents a very clear
separation between the head and the rest of the body, as in
octopus. Sometimes, however, it is much less marked, as in
doris, &c.; and finally, in an entire class, consequently named
acephalous, this separation no longer takes place, and no head
properly so called exists.

a te ——

ON MOLLUSCA. 155

The distinction of neck, breast, abdomen, and tail, is still
less evident ; the body forming but a simple mass, or some~-
times subdivided in a vertical direction, but never in a longi-
tudinal.

The body is but rarely provided with locomotive appendages
properly so called, but sometimes presents cutaneous expan-
sions, more or less extended, which serve to locomotion. It
is only in some that the disposition of the appendages assumes
a form a little analogous to that which takes place among the
entomozoaria.

The skin which envelopes the body of the malacozoaria
presents a peculiar character in its softness, its sponginess,
and especially in the manner in which the dermis is con-
founded with the subjacent muscular fibre, so that it is con-
tractile in all points and in all directions. This dermis, as to
the rest, may either be tuberculous, or very smooth; the vas-
cular net-work there, is moreover, very considerable. ‘The
colouring pigmentum is often very lively. It is also probable
that the nervous stratum may be tolerably complete, from the
great quantity of nerves which repair thither. As for the epi-
dermis, it is often reduced to a nullity.

If we may judge from the great quantity of mucosity which
is spread in general over the surface of the skin of the mol-
lusca, we should believe that the mucous crypt there were
very numerous; but it is often very difficult to demonstrate
their presence. We find parts, however, where the mucous
pores are evident, as at the thickened edge of the mantle,
which constitutes the collar of the conchyliferous cephala, and
probably at the place which often forms numerous folds in the
bottom of the respiratory cavity, towards the anus, and which
have been designated under the name of mucous folds. In
effect, there issues from these places in the skin much more
mucus than from all the others.

We never observe genuine hairs in any animal of this type ;

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sometimes, however, the epidermic mucous part of the shell is
prolonged, as it were, externally, and is rounded or flatted,
so as to present a pilose aspect, as may be seen in certain spe-
cies of helix, and of bivalve shells.

In the oscabrions, this disposition is still more marked upon
the skin itself, and sometimes we find in certain species bun-
dles of corneo-calcareous hairs on each side of the body.

As it happens pretty often that the skin of the mollusca is
larger than necessary to surround the body exactly, or the
mass of the viscera, and that the folds which it forms seem to
envelope it, as our body might be in a mantle or cloak, this
name (pallium) has been generalized to designate the skin of
the mollusca, though in reality this disposition does not
always exist.

~The general disposition of the mantle of the mollusca pre-
sents so great a number of differences, that it would be almost
tiresome to enumerate them; we shall therefore confine our-
selves to the principal ones. In octopus, sepia, and loligo, it
forms a sort of purse or very thick sheath, open at the lower
circumference of the neck, and it is through this aperture that
the water penetrates into the branchial cavity which it consti-
tutes. In the conchyliferous acephaia, the part of the skin
which covers the viscera is excessively slender; it thickens
gradually towards the edges of the mantle, and forms round
the pedicle which joins the foot to the visceral mass a sort of
ring, more slender behind, much thicker in front, and to which
the name of collar is often given. Itis in the thick part of
this free edge of the mantle that are found in the greatest
abundance the mucous pores which produce the shell, and it
is into the middle of these edges that the head and foot of the
animal re-enter when it is desirous of a complete shelter in its
shell. The extent and form of the aperture of the mantle are
always in relation with the bulk of the pedicle of the feet ; ac-
cordingly, very much contracted in the buccina and the neigh-

EE

a

ON MOLLUSCA. 157

bouring genera, which constitute the family of the siphono-
branches; and even in those of the pulmobranch family, where
it really merits the name of collar, it is very long and very
narrow, in the cones, the olives, the porcelaines, where it is
constituted of two lobes, more or less unequal, and which may
sometimes greatly pass the aperture of the shell, and be curved
over it, so as to envelop it totally. Finally, the aperture of the
mantle may be oval or circular, as in the symmetrical or un-
symmetrical cervico-branches. In the naked or almost naked
cephalous mollusca, the mantle being very thick in its whole
extent, or a very little more so on its edges, or otherwise
covered with tubercles, as in doris, peronia, tritonia, and even
in limax, the projecting edges nevertheless pass the foot, so as
to resemble a species of large buckler.

In the lamellibranch acephalous mollusca, whose body is
usually very much compressed, the mantle constantly very
slender, if we except towards the edges, is divided into two
great lateral lobes, equal, or nearly so, which fall back on each
side of the body, compress it between them, and often very
much exceed it. ‘This is an arrangement pretty much analo-
gous to that of the porcelaines; and it is here that this part of
the envelope really deserves the name of mantle. Always
united in a greater or less extent along the dorsal line, the
lobes of the mantle of the lamellibranches may be separated in
all the rest of their extent, as in the oysters ; half separated,
as in unio, cardium, venus; are well joined, so as to consti-
tute a sheath, opening only in front and behind, as in solens
and many other genera; or finally, form a sac, pierced only
with two posterior apertures, approximated as in the ascidie,
or more or less distant, as in the biphores, in which the mantle,
in its external stratum, becomes almost cartilaginous.

The edges of the aperture of the mantle in the cephalous
mollusca are often simple ; that is to say, without elongations,

158 SUPPLEMENT

without lobules, or digitation, or tentacular cirrhi, as in sepia
and the neighbouring genera; but it often happens that the
upper edge advances a little to form a sort of shelter for the
head, as in onchidia, and even in limax, or that it is consider-
ably prolonged by the addition of a thick muscular appendage,
in the form of a cornet, open below, but constituting a com-
plete tube, more or less elongated, and serving as an introduc-
tion for the water into the branchial cavity. ‘This is obser-
vable in all the siphonobranches, in which the aperture of the
shell is emarginated or siphonated.

We find a small number of species of mollusca of this class,
in which the lateral edges of the mantle are lobate or digitate;
but there are a few more which have them furnished with
fringes or tentacular cirrhi. The cervicobranches, and espe-
cially the patella and haliotides, are the species which more
particularly present this character.

But it is especially in the class of the acephala that the
marginal cirrhi of the mantle acquire the greatest develop-
ment, both in size and number. In the lime, for example,
they are almost small cylindrical tentacula, forming a quadru-
ple cordon round the edges of the mantle. In pecten, the
cirrhi, which are also large and numerous, are intermixed with
small oval plates, iridescent, in the form of eyes, regularly
intervalled, and the use of which is completely unknown.

In this same class of animals, the edges of the mantle pretty
frequently present lobules, or digitations, more or less marked;
and in the species in which the labial lobes are more or less
completely united, they are so behind, by means of one or two
muscular tubes, entirely contractile, distant or not, short, or
very much elongated, whose orifices are often furnished with
cirrhi, and assume an almost radiated arrangement. These
tubes seem, one, or the ventral, for the introduction of food,
the other, or the dorsal, for the ejection of excrement. In the

ON MOLLUSCA. 159

biphorz, where they are so much separated that they seem to
be at the two extremities of the body, one of them, the dorsal,
is provided with a valvular apparatus.

But a more singular character of the skin, in a great number
of these animals, is, that in a part of its thickness, and most
frequently between the vascular net-work and the pigmentum,
a mucous matter is deposited, mixed with a greater or less
quantity of cretaceous substance, the accumulation of which,
when dried up, produces a protecting body, or in other words,
a shell.

We shall say something hereafter concerning the forms of
shells, and those of their different parts, so as to draw from
them the characters of this accessory branch of zoology. Our
business at present with these bodies is as to the relations of
their structure, chemical composition, the manner in which
they originate, grow, and are modified with age; and finally,
of their connexion with the animal.

A true shell is always composed of mucoso-calcareous
strata or laminz, applied one inside the other, the oldest and
smallest being outside, and the newest and largest being the
last inside. ‘This is evidently observable in the foliated
shells, such as oysters, especially, when by exposure to the
heat, or by long action of the air, the mucous matter which
connected not only the molecules of each lamina, but also those
of the two superposed ones, has been removed. The edges of
the composing laminz, which are seen at the external face of
the shell, constitute what are named the strie of augmenta-
tion.

This structure, the best known of all, is the foliated struc-
ture. But there is another which differs from it, by the com-
posing strata being much better connected, and their calca-
reous molecules more approximated together: such is that of
the shells of pecten and patella. Accordingly, these shells

160 SUPPLEMENT

may be heated very considerably without breaking, which is
the reason why the first of them is often used as a sort of
dish.

Sometimes, when the calcareous molecules are depositing
themselves in the formation of one of the composing lamine,
they correspond or place themselves one above the other in all
those which compose the shell, and from this results the
fibrous structure, in which.the sbell is more easily broken in
the direction of the fibres than in that of the lamine. 'Thisis
often very observable in the shell of the pinna.

We find some shells in which these two structures may
alternate; that is, one part of their thickness is simply
foliated, and the other fibrous. This is the fibro-lamellary
structure.

A structure much approaching to this is that which we
remark in nacre-shells, or those which produce mother-of-
pearl, whether univalve or bivalve. The nacreous part appears
to be always lamellated, and the other to be fibrous, or more
or less oblique.

When a shell is arrived to the degree of size of which it is
capable, the dermis of the animal appears to produce a greater
quantity of calcareous matter and less mucous matter, and
the molecules which compose it are no longer deposited by
lamine, or regular strata. They are very much crowded,
heaped together, and assume a vitreous structure, which is
polished more and more with age, by the rubbing of the parts
of the mantle, which may be remarked in all the univalve
shells, at their internal surface, and especially near the
aperture, as in galea, for example; but it is seen still better
in the porcelaines, and some neighbouring genera, where,
in consequence, the animal being provided with two large
lateral lobes to its mantle, the shell is almost every where
enveloped by it.

ON MOLLUSCA. 161

It is with this matter that the holes are filled, which
accident may have made in the shell. The posterior part
of the spire of those which are turriculated is also thus
filled, which forces the animal to abandon it, and even the
tubes or calcareous tunnels, which are formed by certain
acephalous bivalve mollusca at particular periods of their
life, are also filled in the same manner. In fine, it is by this
vitreous deposited substance that the aperture of a tolerable
number of univalve shells is narrowed, and that it often
assumes quite another form than that which it had before the
adult age of the animal.

This part of the shell of the mollusca is so far remarkable
that it is very brittle in all directions, somewhat after the
manner of glass; this explains what is named by naturalists,
the decollation of the spire in many cephalous mollusca.

It is very rarely that the shell is coloured in its composing
strata; in fact, in the far greater number of cases it is white:
but, on the contrary, it is sometimes coloured in some parts
of its internal surface, and almost always at the exterior.

Every shell which is completely dermal is never coloured,
which may be easily supposed, as the pigment remains at that
part of the skin which covers it.

The coloration which is sometimes remarked at the internal
face, which seldom occurs, as would appear, except in the
bivalves, belongs to the matter of deposition, and appears to
be produced by an impregnation which extends by almost
imperceptible degrees in surface and in depth. It is therefore
probable that it is owing to some humour of the animal, pro-
duced in an organ whose contact with the shell tinges it
with the colour of this humour. This at least appears cer-
tain as to the yellow or brown colour which is sometimes seen
in the univalve shells. It is unquestionably owing to the
contact of the liver. That of the janthina is in the same case;

VOL. XII. M

162 SUPPLEMENT

it is a true colouring of impregnation, which appears to pro-
ceed from the depurating organ.

As for the nacreous or iridescent coloration which is still
more frequently remarked at the interior of univalve and bi-
valve shells, the experiments of Mr. Brewster (of which more
hereafter) put it out of doubt that it is owing to the mechanical
disposition of the molecules, and not to a really colouring
matter. .

The coloration of the external surface of the shells is alto-
gether different, and in reality does not belong to them. It is
always extremely superficial, and produced by the coloured
pigmentum of the edge of the skin. These are the coloured
molecules which are deposited above the calcareous deposi-
tion, and which are of another nature, since they disappear in
the course of time and by the action of heat. Accordingly
the colour is so much the more lively, as the animal is
younger, and as the produced part of the shell is more new.
We are indebted to Reaumur for experiments which prove
that it is only the anterior border of the mantle, which thus
produces coloured molecules. In effect, it is quite certain
that the new piece which is formed to fill a hole made in
another part of the shell than its edge, is constantly white.
We see, besides, that in the helix nemoralis, on which he
made his experiments, and whose robe is agreeably zoned with
black on a yellow ground, the part of the collar which corres-
ponds to the black zones presents a tint of this colour, so that
if we break a portion of the edge of the shell the piece which
is reproduced is black opposite the black part of the border
of the mantle, and yellowish on the rest. Although we have
no direct proofs that such is the case with all the other shells
which are coloured by zones decurrent from the summit to
the base, analogy permits us to conclude that it is likely to
be so; it must be confessed, however, that in the species

ON MOLLUSCA. 163

whose coloration is by oval, square, or irregular spots, and
especially by transverse bands in the direction of the striz of
augmentation, this analogy becomes less evident, unless we
admit with Bruguiéres, that there is a change, a displace-
ment, irregularly or not, in the parts of the border of the
mantle which produce the coloured deposition, phenomena of
which itis much more difficult to give an explanation, and
which it would be necessary to submit to new observations.

We have said just now that the coloration of the shells is
constantly superficial; there is, however, one group in which,
notwithstanding the existence of this superficial colouring,
there is another deeper and not visible, and always very
different not only in its kind but in its form. This group
consists of the porcelains and some olives. Bruguiéres has
perfectly explained this fact. During the course of a pretty
long life these animals are invested, as we have seen above,
with a very thin shell, its edges not denticulated, the spire
visible, &c., and which is especially coloured at its superficies,
as are the majority of shells. This coloration, owing to the
edges of the mantle, takes place by degrees, along with the
growth of the shell; but at a later period, perhaps when the
animal is adult, the cutaneous appendages, which from each
side of the body rise over the back of the shell, as ‘the animal
crawls, deposit a calcareous ebony-coloured matter, which
thickens by degrees, and at the same time a colouring matter,
which constantly presents a disposition totally different from
that of the first. We must then admit that the upper face of
these cutaneous lobes presents spaces where the pigment is
produced which colours the cutaneous matter thence exhaled;
and, as in the development of these lobes, it is rare that
these spaces fall precisely in the places of the first deposi-
tions, we may conceive how this new coloration not only
never takes place by decurrent bands, but is always exhibited
in rather irregular spots.

M 2

164 SUPPLEMENT

Light unquestionably has a very powerful influence on the
coloration of shells, since those which are altogether interior,
or deposited in some large lodge of the dermis, are always
white, in the same manner as those of animals which live
constantly in holes from which they never come forth. But
another proof of this fact is, that in certain bivalve shells,
which are always fixed somewhere, more or less horizontally,
the fixed valve is constantly white, while the upper one is
often coloured in a very lively manner. The spondyli, and a
considerable number of pectines present examples of this.
We must then admit here that one lobe of the mantle, not
receiving the exciting action of the light, does not produce
any coloured pigmentum, while the reverse is the case with
the other; or, to express ourselves with more precision, the
pigmentum is coloured by this action alone ; so that if one of
those shells should be designedly reversed there would be a
reverse in the coloration of the valves, as actually does take
place with the sides of certain pleuronectes.

In general the coloration of shells is so much the more
lively as the animals from which they proceed are more ex-
posed to the action of the light. The helices, terrestrial
animals, are,in fact, those whose shell varies the most in
colour; the tubicole, among the bivalves, have, on the con-
trary, their shell constantly white. Olivi, who has made
some researches on this subject, has equally remarked, that
the shells which are enveloped by sponges or alcyones, or
which live in sand, or even in places which are constantly
shaded, are much paler than those which are constantly un-
covered in places greatly exposed. The same shell too is
often more coloured in its uncovered parts than in those which
are concealed.

We find almost all kinds of colour on the external surface
of shells, most commonly however brown and fawn-colour,
but green less frequently. There are a great number of sys-

:

ON MOLLUSCA. 165

tems or arrangements of coloration, sometimes uniform, some-
times pitted, or spotted, sometimes striped longitudinally or
transversely.

Finally, a last part which enters into the composition of
shells is the epidermis, which covers the colouring pigment,
and which is sometimes named epzphlosis. It is evidently
in the epidermis of the skin that the shell is deposited. This
epidermis is formed of a mucous or corneous matter dried up ;
sometimes producing a stratum more or less thick and smooth
at the surface of the shell, and sometimes rising in lamine, or
filiform productions, flatted or conical, and sometimes elon-
gated, so as to resemble kinds of hairs. In the bivalves this
part is of the same nature as the ligament, and it sometimes
envelopes the valves altogether, as in solen. It is this part
which first begins to be formed in the growth of a shell, uni-
valve or bivalve, and whether it is to remain with an epidermis
or not.

After what we have said concerning the structure of the
shell of the mollusca, it is certain that it is chemically com-
posed of two substances; 1. of an animal mucous matter, more
or less abundant, according to the age of the molluscum, the
part of the shell analyzed, and its structure ; 2. of a calcareous
salt, but which varies in quantity according to the age of the
conchyliferous mollusca. Although the analysis of shells
given by chemists is very incomplete, inasmuch as it is exer-
cised on all their parts at once, without distinction of age, we
can nevertheless recognize that the differences in the results
are pretty much in relation with the differences of structure.

The species which contain in general the largest portion of
animal matter appear to be those which possess the fibrous
and nacreous structure. According to Mr. Hatchett they are
formed of subcarbonate of lime and coagulated albumen. ‘The
mother-of-pear! itself, in 100 parts is composed of 66 of the
first and 34 of the second.

166 SUPPLEMENT

The shells of oysters contain much less animal matter, and
this matter resembles more a gelatinous substance. M. Vau-
quelin has found there, besides the organic matter, some sub-
carbonate and phosphate of lime, subcarbonate of magnesia
and oxide of iron.

The shell of the patelle, which presents a very close la-
mellated structure, approximates still more in its chemical
composition to those whose structure in general is vitreous.

The latter, according to Mr. Hatchett, who names them por-

celaine shells, contain but a very smali quantity of azotic
matter; we find there, on the contrary, much subcarbonate of
lime, but without any traces of phosphate or sulphate of the
same basis.

After what we have now said, it is evident that the shell of
the wolluscous animals, a mucoso-cretaceous substance, is not
a hardening of the skin by the deposition of calcareous mole-
cules in the meshes of a cellular tissue, but truly a deposition
of mucoso-calcareous matter, not however excreted at the su-
perficies of the skin, but between two of its parts, the vascular
net-work and the epidermis, and sometimes even in the dermis
itself; and, in fact, it is connected organically with the rest
of the animal, and especially with the muscular or contractile
fibre, while a simple calcareous tube, like that which exists in
the tubicole, is in reality but a deposition, an exhalation alto-
gether external, and accordingly is not, properly speaking,
attached to any part of the animal. It is this point of relation
of the animal with the shell which produces the impressions
of variable form which are remarked in different parts of the
shell, and especially in the bivalves. ‘This necessary relation
then does not permit us to suppose that a conchyliferous mol-
luscous animal, whose shell had been removed, could re-
produce it, still less that it could quit it of its own accord, as
Bruguiéres supposed in the case of the porcelaine shells.
Neither does it permit us to adopt.the notion of Klein and

a

ON MOLLUSCA. 167

Bonnet, that the shell grows by intus-susception. In fact,
the experiments of Reaumur, in which he has shown that a
hole made in the shell, or in a part of its spire, or even at the
edge, is not filled by the circumference, but at once and inde-
pendently of the shell itself, have placed the matter beyond
the reach of doubt.

The form of this shell, and even the predominance of animal
over mineral matter, must then be in relation with the form of
the skin, or mantle, and with the age of the animal. Accord-
ingly the tubular, spiny, lamellary elongations which we often
remark at the surface of a shell, are only elongated productions,
lobes, strips as it were of the mantle; in the same manner as
the sinuses, the emarginations are produced by the habitual
but intermittent production of some organ, such as the respir-
atory tube, the head itself, the oviduct, &c.; but properly to
comprehend their formation, we should follow the developments
of a conchyliferous molluscum, from the moment of its appear-
ance in the egg from which it has issued up to the completion
of its growth, and from that point to its death.

Every molluscous animal, however large and dispropor-
tionate to its body the shell may become in the course of
time, has once presented an inverse disproportion, that is, the
shell which is perceptible very early in the egg, has been at
first much smaller than the body, and was consequently very
far from being able to contain it, as may be seen in the helico-
limax. It has equally commenced by being almost entirely
membranaceous ; originally then its free edges were really in
the skin itself, since they did not yet attain the limits of the
mantle. By the addition of new interior strata, and the in-
crease of the quantity of calcareous molecules, the shell is
thickened and solidified, but at the same time it has grown in
such a manner that the edges of its aperture have attained to
the limits of the mantle, at first only in the state of repose or
retraction. However, the animal has issued from the egg

168 SUPPLEMENT

pretty nearly at this epoch, and its growth has continued.
For the purpose of seeking its food, and placing itself in such
circumstances as may be generally necessary to its develop-
ment, it has been obliged to extend the different parts of its
mantle, and especially the lobules, the strips, the digitations
with which it is provided, and which are always more large
proportionally, and even more numerous in youth than at the
period of decrepitude, when they have a tendency to disap-
pear. It is then that the edges of the aperture of the shell are
extended and pass those of the retracted mantle, that the
deposition of new strata augments incessantly, and so much
the more that the animal, from some circumstance, is obliged
to contract and retract itself still more. The shell has become
a Shelter, a protecting organ, so much the better and so much
the more complete as the animal has more approached to the
summum of development of which it is susceptible. If the
edges of the mantle were simple those of the shell are so
likewise ; if, on the contrary, they were prolonged in any di-
rection to facilitate some function, the edges of the shell have
followed these prolongations, and similar prolongations result
in the envelope. We must admit, however, that the pro-
longations of the mantle had the organization necessary for
excreting along with the mucous matter which the skin of the
mollusca always throws out, a sufficient quantity of cretaceous
matter. Without this it would be impossible to explain why,
among the siphonobranches, there are species whose cuta-
neous tube has produced a tube to the shell, as in the siphon-
ostomata, and merely an emargination, as in the entomosto-
mata. Itis thus we may explain not only the formation of
the siphon, and of the spines which it has, but also that of
the points or desections, more or less numerous, of the right
edge of the aperture ofa shell, &c. As a general proposition,
it is certain that the spines, tubercles, and prickles of a shell,
however solid they may be, have at first been channelled;

att -

ON MCLLUSCA. 169

those whose canal or scissure is within, and these are the
most numerous, have been produced by digitations of the
mantle; those in which the scissure is external, as the horn
of the purpura monoceros, and the spines of the corslet of the
venus dionea, appear, on the contrary, to have been made by
the concavity of an appendage of the mantle, which projects
externally.

But these lobules, these desections of the mantle, have not
existed, as it would appear, at all periods of the active life
of the animal, and then the shell could not have been furnished
with corresponding desections. ‘This may be seen very well
in the pterocéres and neighbouring genera, whose shell, in
youth, much resembles that of a cone. We must then con-
clude that in these genera the right lateral lobe of the mantle
is dilated and widened, and sometimes digitated in rather an
irregular manner, with age, and it is then that the shell pre-
sents the wing or the digitations which characterize it. We
must also necessarily admit that this disposition of the mantle
diminishes, by little and little, at the period of old age, since
the digitations of the shell, at first evidently canaliculated,
are filled and solidified completely, and the right lobe of the
mantle presents no trace of division at the places correspond-
ing to those digitations of the shell now become solid.

In a tolerably great number of mollusca, it appears that
during the period of growth their activity suffers no interrup-
tion, which probably is to be attributed to the constant reunion
of favourable circumstances, more especially in temperature
and nourishment ; and then the growth of the shell, more or
less slow, is however uniform, until it has attained the swmmum
of its development. But there are also many others of them in
which, from the intermission of favourable circumstances, the
animal, being forced to diminish the intensity of its vital acti-
vity at certain periods of the year, or of its life, the shell pre-
sents indications of these periodical intermissions in the swel-

170 SUPPLEMENT

ling or thickening of the right edge of the aperture in the uni-
valves, or of the entire free edge in the bivalves, which is to
be noticed at very different intervals in the extent of the spiral
cone; while between these intervals the shell is more smooth
and slender. Are these intermissions themselves determined
by that of the activity of the digestive organs, or by that of
the generative organs? This‘is a point not easy to ascertain or
to decide, but which might nevertheless be plausibly referred
to the state of either of these organic systems. We may con-
ceive, in fact, that during the period of generative activity, the
vital congestion being carried to the organs of generation,
would proportionally diminish that of the skin, and of the
cretaceous excretion, and then that the growth of the shell
would go on as usual, from whence are the interme-
diate spaces at the swelled or thickened parts; but when
this congestion had ceased, it would be directed towards
the skin, whence an accumulation of calcareous matter
at the edge of the aperture, which would produce simple or
ramified swellings, according to the simplicity or the sub-
division of the edges of the productive mantle. The rarity or
the frequency of these subdivisions would determine the num-
ber and distance of the swellings, sometimes very close and
crowded, as in scalaria, lyra, and certain species of venus, or
widely intervalled, as in tripterous and dipterous murices, and
triton, where these swellings in the growth of the spire are
regularly disposed, three in number, one on each side, and one
medio-dorsal ; or two in number, symmetrical, one on each
side, which gives to the shell generally considered a flatted
form; or two in number, not symmetrical. But we must re-
mark that these swellings are always formed of vitreous and
not of lamellary substance.

When the animal has arrived at the term of its growth, and
within limits of bulk sufficiently variable, its shell is always
terminated by a swelling or thickening in the species of which

10

ON MOLLUSCA. 74

we have been just speaking. But even in those in which the
intermissions of the growth are not so sensible, and are marked
only by simple striz, the termination of the growth is very
often indicated by a swelling more or less thick, sometimes
simple, sometimes denticulate, and which is equally formed of
a vitreous substance. It is also at this epoch, that in the
univalves the vitreous substance of the interior depot, and even
exterior, as in the porcelaines, increases, thickens, appears as
it were to extravasate, and tends to diminish the aperture, the
form of which it very often changes, as may be seen in the true
cassides and certain helices, so as sometimes to join the two
edges, and form a sort of continuous peristoma. ‘The orifice
of a univalve shell is also often modified by the formation of
teeth, not only at the internal side of the right edge, but again
upon the left edge, and the columella itself. These teeth are
evidently produced by the cannelures of the mantle which
accompany the pedicle, that joins the foot of the animal to
the tortuous part of its body.

The explication of the formation of sinuses, notches, emar-
ginations, is similar to that of tubercles, canals, swellings, and
varices, with this difference, that these solutions of continuity
in the edge of univalves or bivalves, are owing to some move-
able projecting part, which is alternately put forth and with-
drawn. ‘Thus, in the univalve shell, the anterior emargination
of the aperture is, as we have already had occasion to observe,
owing to the tube formed by the edge of the mantle. ‘The
sinus which is sometimes remarked in the anterior part of the
right edge, as in pterocera and strombus, results from the pas-
sage of the head; the medial or sub-posterior notch of the
same edge, and which is found in pleurotoma, and in many
other genera, is referrible to the exsertion of the female organ
of generation or the oviduct. In all probability this does not
exist except in female subjects. It is at least certain that this
disposition has not been hitherto found except in the dicecious

172 SUPPLEMENT

species. As to the sinus, sometimes extending to the length
of a spur, and forming a sort of gutter, it appears owing to a
prolongation or fold of the mantle, and perhaps also to the
organ of generation.

Another consideration to which the examination of shells
gives rise, and of which it will be proper to say something, is
that of the muscular impression produced, as we shall see far-
ther on, by the communication or adherence of the muscular
fibre with the shell. This adherence, so strong in the living
state, is nevertheless very little so after death. Does it con-
sist in a simple application? This appears very probable.
Whatever it may be, the traces of it which remain upon the
shell are always more or less evident, and form very fine strie,
more or less parallel or concentric. In the univalves there is
almost always but a single muscular impression produced by
the dorsal bundle of the columella, and which perfectly well
indicates its form. Little or not at all visible in the spirivalves,
in consequence of its depth, it becomes so in the species where
the last turbination is very large, as in concholepas, haliotides,
and the argonauts. But it is especially so in the patelloid
species, or those in which the shell is not rolled: its form is
then almost always like a horse-shoe, open in front, for the
passage of the head of the animal, and with branches more or
less unequal. On some species of the non-symmetrical patelle
of Linnzus, the right branch of the horse-shoe is divided
into two by a smooth space, or canal, of ne great depth,
through which, without doubt, the water proceeds to the
gills. Some other species of true patelle have their mus-
cular impression, as it were, lobate, or strangulated from
space to space; and finally, some species not symmetrical,
have really two distinct impressions, the horse-shoe being
interrupted behind.

The shell of the acephalous mollusca presents, on the con-
trary, several muscular impressions, much more frequently

CO

ON MOLLUSCA. 173

than one. They are deeper, and result as well from the attach-
ment of the ligamentous fibres as of the muscles.

We shall see by and by that the first, which have so much
analogy with the epidermis, have not less with the dried mus-
cular fibres of the byssus. Accordingly, the impressions which
they leave upon the shell are absolutely of the same aspect ;
but two sorts have been observed, one external, or extero-
internal, more or less elongated, occupying the dorsal part of
the valves behind, and very rarely in front of the summits; the
other, entirely or almost altogether internal, usually rounded
under the summits, as in mactra, crassatella, &c.

The impressions produced by the muscular fibres are much
more numerous. They may be divided into those of the ad-
ductor muscles, of the retractor muscles of the foot, of the
attachment of the edges of the mantle, and finally of the
attachment of the tubes.

The impression of the adductor muscles is sometimes sim-
ple, or unique, central or not, as may be seen in the ostracea
or sub-ostracea, and in the pholades. It is sometimes sub-
divided, as in anomia.

It appears again to be unique in the mytilacea, but on con-
sidering it attentively, we see, altogether in front, a very small
impression, which is the commencement of the double muscu-
lar impression, that is found in almost all the lamellibranch
acephala, one part of which is buccal and the other anal.
The form, the proportion, and even the position of these two
impressions, vary very much, and furnish good characters for
conchology.

The impressions of the retractor muscles of the foot are
always much smaller, and are frequently confounded, espe-
cially the posterior ones, with those of the adductor muscles,
where they form a sinuosity. They are numerous in the
mytilacea ; in the conchacea, the anterior one, alone distinct,
ascends over the hinge.

The impression of the edges of the mantle, and that of the

174 SUPPLEMENT

attachment of the tubes, constitute what we name the abdomi-
nal impression ; the one descending from the anterior ad-
ductor muscle follows the direction of the shell, in a variable
breadth, and at a variable distance, and arrives at or passes
the impression of the attachment of the tubes, which forms
an excavation, or a sinuosity more or less deep, and open
behind.

When a shell is finally come to its greatest degree of
development in extent, the changes which it undergoes,
always in relation with those of the animal, which tends to
contract itself, especially in the lobes of its mantle, consist of
little more than its augmentation in thickness, not by the aug-
mentation of the strata which compose it, but by that of the
vitreous matter, and in its increase of weight, by the diminu-
tion of the proportion of organic to inorganic matter in its
composition. The external strata lose more and more the fili-
form productions, and the little epidermis which they might
have had. The colours grow pale, are effaced, and disappear ;
the striz, the tubercles, and even the varices, grow blunt, wear
out, and become more and more levelled ; the shell is covered
with earthy cretaceous deposits, and with animals which
excavate lodges there; the spiny and tuberculous elongations
are filled and solidified. On the contrary, the ordinary sinu-
ses grow hollow and become larger. Some cavities of this
kind are even developed, especially in the female individuals,
in places where there were none during the greater part of
life, so as to form plewrotomata in a great number of genera.
The aperture is narrowed, the posterior extremity of the cavity
is filled or partitioned by the successive advancement of the
animal, and the death of the latter, the necessary consequence
of life, determines that of the shell. This shell then loses by
little and little the animal matter which it contained, and
finishes by being nothing but a composition of carbonate of
lime, and consequently often becomes very friable. The in-
sensible movement produced by the laws of attraction between

ON MOLLUSCA. 175

the molecules, brings them to unite under an inorganic form,
and to crystallize; and then the testaceous spoils of the mol-
lusca have a greater or less tendency to disappear, and to form
calcareous masses by their agglomerations, and especially by
that of their pieces or detritus, which constitutes the forma-
tions of the shelly limestone.

According to all that we have now said, the shells present
very considerable differences, according to the age of the ani-
mal to which they belong; and these differences sometimes
prevail on the form of the aperture, and especially on that of
the right edge of the univalve shells.

They also present differences according to the sexes in the
dioecious groups, that is, where the male sex characterizes one
individual and the female another, as we shall see by and by.

We shall now cast a glance on another production of the
skin, the use of which is to render the protecting apparatus
still more complete, and which is designated under the name
of operculum, because it serves to close more or less com-
pletely the aperture of the shell, even at its orifice, or more or
less deeply. Some authors, and among others Adanson, have
regarded it as the analogue of one of the valves of a bivalve
shell; but this is clearly incorrect, for its position, in relation
to the body of the animal, indicates no analogy of the kind.
The two valves of a bivalve are placed one on each side of its
body, except, perhaps, in the palliobranches, while in the oper-
culated mollusca the shell alone, dependent on the mantle,
constantly occupies its dorsal face, and the opercle has never
any connexion but with the upper dorsal face of the foot,
sometimes at the angle of its junction with the pedicle of the
body, rarely at its posterior extremity, and most frequently in
its middle part. It is evidently the production of the skin
which covers the foot. ‘This production is, without doubt, an
excretion of calcareous or corneous matter; but how a plane,
oval, or circular surface produces a substance which rolls

176 SUPPLEMENT

itself into a spire, and often in a very regular manner, and
sometimes forming a great number of turbinations, is a ques-
tion to which it is extremely difficult to reply, and more espe-
cially so as the subject has been by no means sufficiently
studied. From this, however, may be derived good characters
for genera and families, for the opercle differs not only in its
point of attraction, in its size, relatively with that of the orifice
of the shell, but also in its form, its chemical nature, and its
mode of adherence. |

We have already observed its principal differences with
respect to its point of attachment.

As to its size, it is often sufficiently developed to close the
aperture of the shell even atits orifice, as in all the cyclostomata,
being applied almost on the edges. But sometimes it is much
less so, and does not close it but when it has been more or less
sunk in the spiral cavity. This is the case with almost all the
siphonobranches. Finally, it also happens that it is almost
rudimental ; that is to say, that it can only close a very small
part of the aperture of the shell, as in some purpure, in strom-
bus, and more particularly in the cones.

This facility with which the opercle can enter more or less
into the aperture of a univalve shell, has a necessary influence
on its general form. In fact, when it remains at the orifice
itself, applied in the little widening formed by the peristoma,
it has constantly the form of its aperture ; accordingly, almost
circular in the cyclostomata, it is elliptical in the ellipsosto-
mata, semi-circular in the hemi-cyclostomata, or nerites, &c.
In the species where it sinks into the spiral cavity it again
pretty nearly presents the form of its orifice, but it is much
smaller. Finally, in those where it is only rudimentary, there
are no longer any relations between its form and that of the
aperture of the shell.

As to its specific form, it also varies in a manner determi-
nate for each very natural group: oval or rounded in the shells

SS

ON MOLLUSCA. | wi

of the siphonostomata, where it is always corneous; it is not
formed into a spiral, but on one side we see the striz of aug-
mentation, which have commenced towards one of the extre-
mities, and on the other a space more or less ovaliform, orna-
mented with subregular striz, at the middle of a border or
smooth swelling, much broader on one side than the other.

Another form is that of the calcareous or corneous operculum
of the anentomostomata. It presents, in fact, constantly, a
spiral enrolment on one and the same plane, more or less
visible on the two faces, and constantly so on the internal one.
But the summit of the spire varies much in its degree of
eccentricity; sometimes it is even altogether central, as in the
corneous opercle of the trochi, which is formed of nine or ten
spiral turbinations; it is much less so in that of turbo; and
finally, in nerites it is completely lateral. ‘The presence or
absence of colour on the external face of this kind of opercle,
the disposition of the striae which adorn it, the furrows with
which the internal or adherent face is often marked, may also
furnish excellent characters to confirm the distinction of genera
and species. Unhappily, this part of the organization of the
mollusca has been too much neglected.

This same property of entering or not with the animal into
the shell, appears also to have some influence on the chemical,
corneous, or calcareous nature, and on the thickness of the
operculum. In fact, in the first case, it is constantly corne-
ous, and most frequently slender and flexible, especially on the
edges, while in the second it is often calcareous and very
thick. It may, however, be simply corneous; accordingly,
we sometimes find in the same natural genus of the anento- °
mostomata some species which have a corneous operculum,
and others a calcareous operculum, which is never observed
among the siphonostomata and entomostomata.

Finally, the last relation under which the operculum can
vary, is that of adherence. All the calcareous opercula, and

VOL. XII. N

178 SUPPLEMENT

even a part of the corneous, appear to adhere through all their
internal or inferior surface, so as to leave nothing free but their
circumference ; while the corneous opercula of all the ento-
mostomata are fixed to the skin only by a small part of the
same surface, at their base, and are free in all the rest. This
may be perfectly well seen in murex, buccinum, purpura, &c.
In the hemicyclostomata, the adherence to the foot is made by
means of one or two processes of the anterior or right edge,
and the operculum seems to be articulated with the internal
edge of the shell.

We must take care to distinguish the piece of the shelly
envelope of which we have just spoken from the epiphragma,
because, if there is any relation of the usage, which is completely
to close the aperture of the shell, there is none of structure,
nor even of position in relation to the animal. ‘The epiph-
ragma, or temporary operculum, is, in fact, but an aggregation
of dried calcareous molecules produced by the edges of the
mantle, or the collar of certain species of helix, when they
have completely withdrawn their head and foot within the
mantle. The stratum, more or less thick, which results, ad-
heres in no wise to the animal, and several may be succes-
sively formed, in proportion as the unfavorable circumstances,
such as cold, great drought, or absence of nourishment, which
forced it to re-enter the shell, are more prolonged.

After this digression, into which we have been obliged to
enter, respecting the shell as a dependence on the skin, or
seat of touch, we shall now proceed to the examination of the
apparatus of this sense, and successively of the rest.

The apparatus of the sense of touch in the mollusca con-
sists in the tentacula, or the tentaculary cirrhi, with which
the edges of the mantle may be furnished, and of which we
have already spoken. We may also include certain tentacu-
lary appendages, sometimes in the form of a fringed membrane,
as in the Janthini, or even true flatted tentacula, as in certain

a

ON MOLLUSCA. 179

turbines, monodontes, and nerites, which are on each side of
the pedicle of the foot. Frequently, when these appendages
are broader, they answer the purposes of swimming.

This sense becomes less delicate in the species whose ex-
ternal envelope, being always uncovered, is more or less tuber-
culous, and appears to be almost lost in those whose envelope
is more or less solidified.

The organ of taste, when it exists, is doubtless, as in supe-
rior animals, situated at the lower part of the buccal cavity,
where may be frequently remarked a lingual swelling; but
it must be owned that the skin which invests this part does
not appear to differ much from that which is at the orifice of
the mouth itself, and in many other portions of the body. We
shall presently see, however, that this skin is furnished with
little corneous hooks, arranged symmetrically, which have
some analogy with those which are observed at the superficies
of the tongue of certain mammifera, and that it receives a
great number of nerves.

The acephalous mollusca have no trace of this swelling.

The seat of the sense of smelling, which appears to exist
only in the cephalophorous mollusca, is not, perhaps, as yet
sufficiently determined ; and in fact the nature of the skin of
the mollusca, resembling in general, in its structure, the olfac-
tory membrane of vertebrated animals, many persons have
thought that the mollusca might have the power of smelling in
all parts of their skin.. Others having assumed, as a princi-
ple, that an odorant molecule must be suspended in a gaseous
vehicle, have supposed that it was only the species which
breathe the atmospheric air that could smell, and that conse-
quently the seat of the function must be the edge of the respi-
ratory orifice? But this is to deny without any reason the
existence of this sense in the aquatic species, who questionless
must smell as well as the others. Another opinion has ob-
tained with some naturalists, and one which is sanctioned

N2

180 SUPPLEMENT

by the authority of M. de Blainville, that the extremities of
the true tentacula form the organ of olfaction. In fact, the
skin there is softer, more smooth, and more delicate than in
any other part, and the nerve which repairs thither is more
considerable.

That certain of the cephala do smell, may be inferred from
the fact that slugs and snails seek after particular plants in
perfect darkness. .

The organ of vision has not given rise to so many opinions,
because in its structure the relation of cause and effect is much
more evident. It is wanting in all the articulated mollusca,
and in all the acephalous. It is,on the contrary, almost certain
that it exists in all the cephalophorous races, the hipponices
perhaps excepted. But it is susceptible of very different de-
grees of development.

The eyes of these animals are never more than two in num-
ber, disposed very symmetrically, one on each side of the
head, or of the anterior part of the body, in case the head is
not very distinct.

Certain fibrous, vascular, and nervous coats may be recog-
nized in the structure of these eyes; but the cornea belongs
only to the skin. We also see there some humours and a
crystalline very distinct. Sometimes there are even small
muscles which can move them a little in a sort of orbit, or pro-
tecting cavity, as takes place in sepia and other neighbouring
genera. But in general, these eyes would be immoveable, if
they were not pretty frequently more or less pedicled ; that is
to say, carried at the extremity ofa sort of tentaculum, analogous
to that of olfaction, as may especially be observed in the family
of the limacines, and by which their eyes can be directed by
the animal in a great number of ways; or on the olfactory
appendage itself, in a point of its extent, more or less elevated,
as in the buccina, strombus, &c. In the instances where they
are sessile, their position varies much, in relation to the true

a

ON’ MOLLUSCA. 181

tentacula, for they may be anterior to them, posterior, exte-
rior, or interior, all which positions furnish good characters in
zoology.

The organ of hearing presents much fewer differences in the
mollusca, and is found no farther than in the brachiocephala
and a few other genera, where it is reduced to a small sac,
hollowed at the lower lateral part of the cephalic cartilage,
and which has not even any immediate communication with
the exterior.

We shall now advert to the apparatus of locomotion.

We have observed, in treating of the structure of the skin in
the mollusca, that the contractile fibre is not often distinct from
the dermis itself, properly so called ; hence it happens that all
the points of this skin are susceptible of contraction in all
directions. Itis, in fact, a thing perfectly certain, that all the
external parts of a molluscum, and even the gills, can execute a
number of vibratory movements; but that would produce lit-
tle more than a sort of partial locomotion. ‘The general loco-
motion is determined by a true distinct muscular fibre, visible
at the internal face of the skin, and disposed in bundles, hav-
ing a determinate form and direction. It sometimes has its
point of rest on the solidified part of the skin, but nevertheless,
it is very seldom that this part can, in reality, serve for the
purposes of locomotion, except in the articulated mollusca.

The disposition, the number, and even the form of the mus-
cles, in this type of animals, are necessarily in relation with
their general form. ‘Thus, wherever there is a well-marked
separation between the head and trunk, there are superior
lateral and inferior muscles, as is observed in the brachioce-
phalous mollusca; but in all the rest of the trunk this distinc-
tion does not take place. In the oscabriones it is different,
each articulation of the back having its particular muscles ;
but they can scarcely be considered as genuine mollusca.

The mantle which envelopes the body of the mollusca,

182 SUPPLEMENT

although the muscular stratum which doubles it does not form
distinct muscles, presents differences only in the thickness of
this stratum in different points of its circumference. Thus,
sometimes, this thickness is pretty nearly the same, whence
results a sort of sac, as in sepia, &c.; but more frequently it
is much greater at the lower part of the body, where even the
fibres, though longitudinal, experience frequent intersections,
and a sort of muscular disk, more or less thick, is thus formed,
to which the name of foot is given. :

In a number of cases, this sort of foot extends through the
whole length of the body, or rather of the mass of the viscera
which is above, and forms a kind of sole, somewhat varying
in form, by the assistance of which the animal creeps, and
which occupies its entire belly. From this conformation comes
the denominations of repentia, or gasteropods, which have
been given to the limaces, and neighbouring genera.

In some species the visceral mass comes forth, as it were,
beyond the mass of the body, being rolled more or less spirally ;
and the foot, containing no more viscera in its posterior part,
where it is free, appears to be no further attached to the body,
except before or behind the head, at the part which might be
regarded as the neck; from which arrangement these mollusca
have obtained the name of trachelipods. Most of the cepha-
lous conchyliferous mollusca are thus formed, especially when
the shell is strongly spiral and rolled.

The proportional size, and even the form of this foot, vary
much, sometimes even in genera pretty much approximating
to each other. Thus it is almost circular in the patella, oval
and very thick in the haliotides, rounded in front, and slender
on the sides in the turbines, buccina, &c. It is auriculated on
each side in some. In a great number of genera of the order
cyclostomata, it is cut by a transverse furrow at its anterior
edge. The foot of the auricula pecten is divided into two heels
by a broad transverse furrow.

ON MOLLUSCA. 183

All the species of cephalous mollusca are eminently gaste-
ropods. It is not thus with the conchyliferous species: they
are not necessarily trachelipods, though this be most com-
monly the case. But what they present in common is, that
the shell is in muscular communication with this foot, so that
the latter can be drawn in more or less deeply, as well as the
head itself, by a muscular bundle called the muscle of the
columella, because, in the spiral shells, it is to that part it is
attached. ‘The disposition of this bundle of muscles differs
much, according to the form of the foot, and especially accord-
ing to that of the shell. ‘Thus, when the latter is simply
covering, and not spiral, as in the patelloides, the bundle in
its dorsal attachment forms a sort of horse-shoe, open in front
or behind, and the termination of the foot extends almost
through its entire circumference. In those whose shell is a
turriculated spiral, the common bundle is pointed at the colu-
mella, and is carried more or less obliquely from the hinder
part to the front, and from top to bottom, towards the middle
of the foot, so that by its contraction it almost bends the latter
in two in withdrawing it within the shell. In the species
where the rolling is lateral, as in the porcelaines, it is, on the
contrary, a broad muscular band, which is longitudinally in-
serted at the columella, and which terminates at the foot, in
such a manner as to bend the latter in its length, to draw it
within the shell.

We may also regard as making a part of this muscular bun-
dle the more or less considerable muscles, which are carried
forward to proceed to the tentacular and ocular appendages,
where these organs can be withdrawn internally, as is the case
with the limacines. They penetrate, in fact, into these ten-
tacula, and proceed as far as their extiemity, surrounding the
nerve, which also repairs to the organ.

In the species which have these sorts of tentacula, and
have not a crustaceous shell, and whose foot has consequently

184 _ SUPPLEMENT

no retractor muscles, we do not the less find the retractor
muscles of the tentacula. But their origin takes place above
the muscular partition, which separates the visceral cavity
from the pulmonary cavity, pretty nearly at the same point as
in the conchyliferous species.

It is also nearly from the same point that proceeds the re-
tractor muscle of the excitator organ when it-exists.

Finally, it is also from the muscular: bundle of the colu-
mella that springs the retractor muscle of the operculum,
where this part exists, and to which is attached the siphon of
such species as are provided. with one.

We have observed, a little farther back, that some cephalous
mollusca are provided on each side with locomotory ap-
pendages, pretty considerable, as the sepiz, calmars, and
pteropods generally speaking. In this case these appendages
have levator or depressor muscles, which are carried from the
back or the belly to their roots. But when the appendages
do not really serve for locomotion, they are formed of a con-
tractile dermis, in which it is not possible to distinguish true
muscles.

The acephalous mollusca present a disposition of loco-
motive organs considerably different, and which appears still
more so when the passage from the cephala to the acephala
has not been very precisely observed, as in all the mollusca;
in general, all the parts of their envelope, whether branchial
or not, are really contractile. But we sometimes remark
besides some distinct muscular fibres, which, from the
edges of the mantle, more or less thick, proceed to fix them-
selves to the shell at alittle distance from its circumference, so
as to be capable of drawing those edges in more or less; and
more rarely we perceive small slender muscles, which pro-:
ceeding from the adductor muscles, of which we are about to

_speak, direct themselves into the different points of each lobe
of the mantle. In the cases where the latter has only this

7

ON MOLLUSCA. 185

last sort of muscle the shell does not present any submarginal
impression, and the mantle is considerably retractile; but in
the contrary case an impression is very perceptible, in the
form of a strip, which follows more or less regularly the edge
of the shell, descending from the anterior muscle, and which
often forms behind a large flexuosity drawn inwards, and
‘which indicates tolerably well the size of the posterior and
tubular. elongations of the mantle. In this last disposition
the mantle has no part contractile but that which is between
its edge and this line of insertion.

We often find, besides, that the middle of the abdomen is
occupied by a muscular mass more or less thick, polymor-
phous, and which, besides its intrinsic contractile fibres, has
also its extrinsic muscles. This mass has received the name
of foot, as that which occupies the lower part of the gaster-
opods, of a form and size extremely variable, to such a degree
that there sometimes exists no trace of it, as in the oysters, it
is attached more or less in front, which depends upon the
habitual position of the animal; but, besides, it may be carried
in different directions by true muscles, which divided into one
or a greater number of bundles, direct themselves to different
points of the shell, and especially in front, behind, and in the
intermediate space, as is observed in the mussels, anodon, &c.
This extensible foot sometimes resembles a sort of cupping-
glass, as in the nucule, sometimes a sort of tongue, as in the
mussels where it is channelled behind ; sometimes it is like a
hatchet, as in Venus, sometimes like a sort of human hand,
as in camus, and finally, like a sort of whip, as in the lori-
pedes, &c.

Besides these muscles of the foot, which have evidently
some analogy with those which we have seen serve for its
retraction in certain gasteropod mollusca, as the patella,
there are some others directed transversely, that is, from
one side to the other of the animal, and each extremity of

186 SUPPLEMENT

which is attached to one of the valves in such a manner as by
their contraction to approximate one to the other. These
are the adductor muscles; sometimes they form but a single
mass drawn together in the middle of the valves, at other
times the mass tends to subdivide into two or three; finally,
in a great number of cases there are two very distinct, one
anterior and the other posterior, the form and proportion of
which, moreover, are variable. It is the insertions of these
muscles in the valves of the shell which form what are named
the impressions or the muscular attachments, in the same
manner as it is that of the edges of the mantle which forms at
the inferior and posterior edges of the shell a line more or
less broad, more or less sinuous, or retracted backwards,
which we have already noticed in treating of the shell, and
the consideration of which is not without importance in con-
chology.

In the locomotory apparatus of the bivalve mollusca we
ought also to consider the mode in which the pieces of the
shell unite, or their system of articulation, and especially
the ligaments, which serve not only to retain them in a
determinate relation, but also to act as antagonists of the
adductor muscles. On the first we shall make a few remarks
when we come to speak a little more on conchology. As to
the ligaments, we may add here, that, formed of a corneous
substance, evidently epidermic, they are composed of trans-
verse fibres which pass from one valve to the other, just as do
the contractile fibres of the adductor muscles, and which have
much resemblance to those which constitute the dried part of
the true byssus, and still more of the tendinous foot of the
tridacne. 'The ligaments observed in the shell of the ace-
phalous mollusca may be distinguished into epidermic, ex-
ternal and internal. ‘The epidermic ligament is that which
is formed by the epidermis itself of the valves, which is con-
tinued in passing from one to the other, as in solens, &c.

ON MOLLUSCA. 187

Perhaps we should consider in the same way the ligament of
the arca and some kindred genera. ‘The external ligament is
always more thick, more gibbous, and more elastic. It
always occupies the back of the shell, just behind the sum-
mits. Finally, the internal ligament, simple or multiple, is
that which is more inside than the line of articulation. Its
fibres are usually short and straight. ‘The mactra, crassatella,
pectines, &c, present us with examples of this kind of liga-
ment.

One of the most remarkable peculiarities in the acepha-
lous mollusca is, that in many species, a greater or less
number of the fibres of the adductor muscles may be attached
and agglutinated to foreign bodies, so as to serve for an ex-
ternal point of attachment for the animal. It is this which
constitutes the byssus in the pinna, and the mytilacea, and the
tendinous foot of the tridacne, and. certain species of arca.
This byssus is not really formed, as some authors have as-
serted, of a mucosity secreted by a gland, and spun (like the
silken productions of insects) in a groove in the foot. It is
nothing but an assemblage of muscular fibres, dried up in
a portion of their extent, still contractile and living at their
origin, and which were so throughout their whole length, at
the period in which they became attached.

Another singularity, not less worthy of remark than the
preceding, is the observation of the march, or change of place
of the adductor muscles, in proportion as the animal grows, as
well as its shell. In fact, if in a very young shell the muscle
is subcentral, it must necessarily happen that, to retain this
position when the shell is twice as large, it must have moved
as the shell grew. It is admitted, that in aspiri-valve shells
the muscle seems to descend with the animal in like man-
ner as in a bivalve shell the subcentral muscle advances, not
that it detaches itself all at once, but that an anterior rank of
fibres is detached at the same time that a posterior rank is

13

188 SUPPLEMENT

produced. But if it was exactly this, we ought to find at an
advanced period of the animal and its shell a part of the im-
pression which would: be without muscular fibres, and this
has not been observed, even in oysters and other bivalve
shells, where it would.be necessary besides that it must exist
in an inverse direction for every muscle. It therefore may be
preferable to admit that the muscles grow like all the rest of
the organization, throughout their whole circumference, but
especially on the side where the shell grows the most, as
behind, which is the case with oysters; perhaps it might
also be supposed that the muscle altogether is at a certain
point detached when the new stratum of growth is formed,

and that itis thus that its apparent movement takes place, —

for the thickness increases equally at the place of the attach-
ment of the muscles, where the strata are, however, in general
more crowded, which causes this impression very frequently
to form a sinking in, and in the fossil state occasions this
part to be preserved longer than the rest

The apparatus of locomotion is yet more different in the
balani'and anatife. In the first the mantle is very slender,
and presents no muscle but at its posterior or open extremity,
for the movements of the pieces of the operculum. In the
second it presents, besides, this singularity, that at its cephalic
or inferior extremity, in consequence of the position of the
animal, itis prolonged into a fibro-contractile flexible tube,
which attaches the animal in a fixed manner to submarine
bodies. ‘There is, moreover, an adductor muscle between the
two principal valves of the shell. .

As to the muscles of the animal itself, or of the trunk and
its appendages, their disposition evidently begins to approxi-
mate to that of the entomozoaria.

The oscabriones have also in the assemblage of their loco-
motory apparatus something of the true mollusca and some-
thing of the last mentioned class. In fact, the whole inferior

a a i

ON MOLLUSCA. 189

part of the body is occupied by a sort of foot very analogous
to that of the patella, phyllidii, &c., while the back, in its
conchyliferous part, presents as many double pairs of oblique
muscles, one at the right and the other at the left, as there
are testaceous pieces.

The faculty in the molluscum of changing its relations with
external bodies being generally in a direct proportion with
the quantity of the sensibility, it is evident that the locomo-
tion of the malacozoaria cannot be very active, must be con-
fined in its range, and often does not exist at all.

The brachiocephala (cephalopods), being those mollusca
whose sensorial faculties are most extended, are also those
which move with the greatest quickness, and in all directions.
The acephala, and especially the last of them, such as the
ascidiz, are exactly in the opposite extreme, and in fact they
live fixed upon immerged bodies.

We remark, however, among the mollusca, many kinds of
locomotion : a certain number swim by the aid of fins, or sorts
of appendages, in pairs, such as the calamary, the sepia, the
pteropods in general, and many monopleurobranchia, pretty
nearly in the same manner, as do the fish with their pectoral
fins. These organs even enable them sometimes to issue from
the water and shoot into the air, to different degrees of dis-
tance. This is a certain fact with respect to the calamary.
The same may be said of certain species of bivalves, which
thus employ the valves of their shell as a sort of wings, with
which they take their point of support upon the water.

Another sort of motion is that which is performed by an
odd middle fin, or by a very compressed foot, and consequently
by alternate movements to right and left, as may be seen in
the firole and carinarie.. But in this case motion appears
never to take place but in a reversed situation ; that is to say,
the back being under and the belly uppermost.

190 SUPPLEMENT

There is a third method, more singular, and which is to be
met with in the first species of the type and in the last. It is
executed by the contraction of the envelope, which thus ex-
pels the fluid with which it has been filled in its dilatation,
from which results a movement of translation, often very
quick. The sepia, the calamary, or loligo, and the biphore,
move in this manner.

Some mollusca sail upon the surface of the waters, impelled
by the current, or by the wind, some by the assistance of a sort
of hydrostatic bladder, as the janthinz and others, by unfurl-
ing a sort of sail, formed by the salient edge of the mantle, or
by some widened appendage, while they row with others, as is
related of the argonaute. In the first instance, it appears
that the animal is always at the surface of the water, for it
cannot make the bladder re-enter, which is subcartilaginous.
In the second, the octopus can, it is said, at will, develope its
sail and oars, or refold them within the shell, which serves it
as a boat, and then sink more or less deeply. But after all,
may not some degree of doubt yet attach to the truth of this
ingenious manceuvre ?

Perhaps it is the octopi only which perform a sort of walk,
by means of the long appendages which crown their head ; but
then they have the mouth below and the trunk uppermost. It
appears also that they can roll over and over at the bottom of
the sea with great velocity, and without fixing themselves by
their tentacula.

Some species of auricule, and even the terrestrial cyclosto-
mata, also make sorts of steps, by taking a resting point on
the anterior part of the foot, or on the advanced muzzle, and
approximating to it the posterior part or centre foot all at once.

A much greater number crawl on the surface of the ground,
either on land or in the waters, by means of the foot or mus-
cular disk with which their belly is provided. But this sort

ON MOLLUSCA. 191

of reptation has no resemblance to that of reptiles : it is rather
a kind of sliding of the foot, produced by extremely fine undu-
lations of all the little longitudinal fasciculi which compose it,
and which proceed in succession from the first to the last, each
being alternately the point of resting, or the fixed point for the
following. By this mode of locomotion, the animal touches one
after another all the eminences, all the anfractuosities of the
ground on which it moves; its advance is therefore in general
very slow. Nevertheless, the species whose foot is broad, thick,
extended, and has no shell to drag along, especially where the
distinct contractile fibres have an evident fascicular direction,
as in the limaces, helices, &c., can get on with a much greater
degree of rapidity than one would be led to suppose from their
first aspect. Others, on the contrary, such as the patelle
and the haliotides, though possessed of a broad foot, creep
so slowly, and so rarely change place, that some persons have
erroneously believed that they never do so. They are capa-
ble, besides, of adhering to a fixed point with very great force,
through the viscosity of their foot and the vacancy which it
can make, either altogether or in little fossettes.

The hipponyces and some others remain fixed to the bodies
on which they have fallen when born. Accordingly, their foot
is scarcely muscular, and much resembles the horse-shoe mus-
cle of the back, which serves as an attachment for the shell.

The scyllz, whose foot is extremely narrow, and, as it were,
canaliculate, cannot move but along the stalks and pedicles
of plants, and always in a gliding manner.

A tolerable number of species can also creep along the sur-
face of the water, taking as a point d’appui a light stratum
of this fluid. But then they are obliged to do it in an inverted
position ; that is to say, the shell being under, and the inferior
surface of the foot above. This is observable in the limnee,
the planorbes, the paludine, glaucus, doris, thethys, &c. ‘The

192 SUPPLEMENT |

theory of this movement is in other respects precisely the same.
as that of the reptation of ordinary gasteropods.

The movements of the acephalous mollusca are often con-
fined to the trifling opening of the valves of their shell, and to
their complete occlusion. The first is the natural position, or
the repose of the animal ; and in fact it is only then that it can
receive the water which brings it nutriment, especially when,
its mantle is not provided with external tubes., It is produced
by the disposition of the ligament of the hinge, the perpendi-
cular fibres of which, at each valve, are drawn or, compressed,
according to their position without or within the point of sup-
port, when an attempt is made to cause the two valves’ to
touch. Their closure is, on the contrary, entirely active; that
is to say, owing to the contraction of. the fibres of the adduc-
tor muscles, which are the antagonists of the ligament. Willis,
and more lately, Dr. Leach, have considered, that in oysters,
a part of the central adductor muscle was formed of elastic
substance, an antagonist of the other part which should be
alone contractile. Some doubt seems to attach to this notion.

The family of the palliobranchia contains many genera, in
which, instead of a ligament, the two valves of the shell are
united at their summit by a long elastic ‘tube, which is fixed
to submarine bodies, and which might even perhaps be a little
contractile. Nevertheless, the animal has no other movement
than that of opening and closing the shell, like the other
acephala.

In the species fixed immediately by the shell, or by a tube,
—such are the only motions permitted,—there is then not the
slightest degree of transference of situation. In all the others
there is one, though to very different degrees. Thus many
species are almost in the situation of those of which we have
just spoken ; that is to say, they are fixed, but it is with a cer-
tain degree of mobility. Such are they whose attachment is

ON MOLLUSCA. 193

made by dry muscular fibres or byssus, as some species of
pectines, the lime, the crenatule, and especially the mussels,
and the pinne. In this case, it appears that the filaments of
attachment are fixed to solid bodies, by means of the canalicu-
late foot with which these animals are provided, and which in
fact appears very extensible and very long. They cannot
detach themselves from their position, but if they have been
thus detached accidentally, they can re-attach themselves to
their post.

The arce, and even the tridacne, can also fix themselves to
solid bodies, by a sort of agglutination of their foot, something
like the byssiferous species, but en masse, and not fibre by
fibre. Accordingly, it may happen that from the growth of the
animal it becomes naturally detached. This is at least pre-
sumable from the observation that the shell of the tridacne
loses, in becoming more bulky, the great precordial aperture
which it had when small, and through which the muscular
bundle passes.

In most cases, the acephalous mollusca not being adherent,
can change place. They move by the assistance of their foot.
Some, however, are confined to a movement of ascent or
descent in the hole which they inhabit, whether it be exca-
vated in a stone, in the sand, or in mud. Their foot, attached
- more anteriorly than in the other species, comes out more or
less, is elongated, and takes its point of support on the bottom
of the lodge. This is the case with all the pyloridz, and per-
haps a little with the tubicole.

All the other bivalve mollusca, although again they fre-
quently live more or less buried in mud or sand, can issue
from their retreats at will, and consequently completely pos-
sess the power of motion. Some of them move by leaping,
almost as if they were impelled forward by a spring. For
this purpose their foot, very much extended, is bent length-
wise, and then suddenly straightened. It is this singular

VOL. XII. O

194 SUPPLEMENT

mode of locomotion which caused M. Poli to extend, though
evidently erroneously, the denomination of swbszlentia to all
the acephala; for if most of the animals of the family of the
conchs can leap in this manner, the submytilacea, the ar-
cacea, &c. cannot, and appear in reality to crawl with their
foot ; much less can a similar power belong to the species
which have but a rudiment of this organ, or to those which
do not possess it at all.

The oscabriones move by crawling with their abdominal
foot pretty much in the same way as do the patelle. As for
the nematopods, no species belonging to them possesses the
faculty of changing place altogether. The appendages of
their caudiform abdomen can issue from the shell, and move
in the water, but, as far as it appears, only to determine the
current of that fluid into the interior of the mantle of the
animal, and to seize the little animals that pass within reach.

The composition of the mollusca is complete, that. is, it is
formed of organs of digestion, of respiration, and of circula-
tion. We shall first treat of those of digestion.

The mouth is always anterior in the mollusca, although it
be not constantly terminal or visible. It is sometimes alto-
gether inferior, as in doris, onchidion, scyllza, oscabrio, &c.
In fact, it does not appear that it is ever situated superiorly,

Its form is extremely variable, depending on the disposition
of the lips, which is different in the different groups. Thus
in sepia and the neighbouring genera it is a sort of circular
veil, sometimes double, pierced in its middle and fringed in
its circumference. In the polybranches, cyclobranches, in-
ferobranches, and even in many cervicobranches, they form
a thick semicircular pad, in the inferior middle of which is
the mouth, and which is prolonged sometimes on each side
into a sort of appendage, which forms the labial tentaculum.
In many species of doris, in tritonia, &c. the anterior edge of
this labial pad is dilated, fringed, and forms a membranaceous

’
4
\

ON MOLLUSCA. 195

veil of greater or less extent; at other times we find that the
lips are prolonged into a sort of cupping-glass, inthe bottom
of which is the proboscis, as in the cones; finally, we often
remark that they are prolonged in the same way, but acquir-
ing a tolerable degree of thickness, and there results a probos-
cidiform muzzle, as in a great number of species of the family
of cyclostomata, an organ susceptible of contraction or elonga-
tion, but without ever being able to re-enter into the buccal
cavity, which distinguishes it from the true proboscis, of which
we shall presently speak. .

Within these contractile lips, and sometimes provided with
some small specific muscles, are often found corneous or cal-
careo-corneous organs, to which the name of jaws has been
erroneously applied; these in fact are genuine teeth produced
from the skin, which they cover, and the structure and mode
of formation of which are altogether analcgous.

We rarely find two of these teeth acting vertically one upon
another, as in sepia, or horizontally, as in tritonia. In such
cases they are surrounded at their bases by a thick circular
muscle, which presses them strongly one against the other,
after they have been separated by the action of the levator
muscles of the upper, and the depressor of the lower.

In a much greater number of cases there is but one upper
tooth in the form of a comb, curved and denticulated on the
edge. It is then pretty nearly immoveable, and the tongue,
of which we shall presently speak, acts upon it. This is what
may be seen in all the animals of the family limacines, in that
of lymnza, of auricula,.and even of patella.

In a much greater number, again, there is no trace of true
marginal teeth, as in all the cephalous mollusca, provided
with a proboscis, and in the entire class of the acephala.

At the lower face of the buccal cavity there often exists a
swelling more or less considerable, which has been compared
with some justice to that which forms the tongue in the boned

02

196 SUPPLEMENT

animals. This swelling is regular and symmetrical, and re-
ceives a considerable number of nerves. Its upper surface is
most usually furnished with very small corneous hooks, the
point of which is directed backwards, and which are disposed
in a very symmetrical manner. These are again depend-
ences, productions of the skin, but which cannot be compared.
in consequence of their disposition and place to the marginal
teeth. |

This sort of tongue is never exsertile in front but along with
the whole buccal mass, but it is sometimes prolonged in a
singular manner behind, into the interior of the visceral
cavity, being contorted like the spring of a watch. In ge-
neral its disposition differs according to that of the teeth.

In the species which have two teeth opposed, as in sepia,
&c., the lingual plate is not very projecting nor very mobile.

In those which have an upper tooth the lingual swelling is
thicker, more mobile, but much shorter, and is easily carried
forward by the motion of the adductor muscles. This may
be seen in the limaces, helices, bulimus, limnee, &e.

In the species which have no teeth whatever to the buccal
orifice we find that the tongue forms a long narrow band,
which is prolonged backwards into the abdominal cavity,
rolling spirally. Its surface is bristled by a number of little
hooks, bicuspid or tricuspid, directed backwards, and whose
solidity or resistance, proceeds always decreasing from the
base to the point, where they are soft and very little apparent.
This singular kind of tongue is found in the porcelains, cones,
patelle, and even in the oscabriones.

Finally, in a great number of species which have no teeth,
properly speaking, we observe that by a singular disposition
of the cesophagus it may be prolonged externally or re-enter
into the buccal cavity under the form of a cylindrico-conical
organ, to which the name of proboscis has been given. Be-
side the muscular dermis which. composes this organ, and

ON MOLLUSCA. 197

which is capable of being elongated or shortened, according
as the longitudinal or transverse fibres act, we find at its base
some extrinsic muscles which facilitate this action, some in
drawing it backwards and others in carrying it forward.

In the species which are provided with this sort of pro-
boscis there has not been seen any lingual swelling, properly
so called, and consequently no corneous hooks. But this
swelling is pretty frequently replaced by a double group of
hooks placed at the right and left, and which are more or less
deeply sunk into the proboscis, so that they do not become
marginal but when it is strongly turned back. ‘This takes
place in buccinum and neighbouring genera. In the vis
maculata, which has also a very long proboscis, there is no
trace of these hooks.

Other species have been remarked whose palate is armed
with a plate of corneous teeth, like the tongue; such are
many monopleurobranches, and among others bulla and um-
bracula.

No acephalous molluscum presents any traces of teeth, nor
any lingual swelling whatever. But the aperture of the
mouth, of variable form, though ordinarily very large, and
almost always inferior, is accompanied with two lips, most
frequently simple, sometimes fringed, which are prolonged at
their angles into labial or tentacular appendages. ‘These ap-
pendages, of a triangular form and very variable size, are
striated, especially at their internal face, so as a little to re-
semble gills, with which their connexion is always tolerably
intimate. They are almost always very soft, and directed
backwards. In the nucula they are, on the contrary, stiff,
and directed towards the mouth, so as to represent sorts of
jaws.

The salivary apparatus, deficient in all the acephala, pre-
sent in most of the cephalophora, is ordinarily simple, that is

198 SUPPLEMENT

to say, formed on each side of a single salivary gland, which
commencing more or less behind, on the sides of the intes-
tinal canal, or even placed free in the visceral cavity, tra-
verses the nervous ring, to open into a part of the buccal
aperture. Sometimes the salivary apparatus is composed of
two glands on each side, one disposed like that which we
have just described, and the other filiform, and often ex-
tended very far along the intestinal canal. The cones have
one very singularly formed, unequal, situated in the visceral
cavity, and of which the excretory duct, very long and re-
entering, proceeds to open at the base of the tongue.

The union of organs of which we have just spoken consti-
tutes a mass more or less considerable, ordinarily oval, which
is sometimes perceptible through the skin, but most frequently
indistinct. ‘This buccal mass is surrounded by a great
number of muscles, which can draw it forward, carry it back,
and sometimes make the lower part act upon the upper.

No indication of this is found in the acephala ; it is, on the
contrary, very strong in most of the cephalophora, especially
where there is a true mastication.

It is almost always at the superior and posterior part of
this mass that the intestinal canal, properly so called, com-
mences with an cesophagus, whose diameter is always more
narrow than its own.

The intestinal canal of the mollusca, taken generally, is
composed of an internal mucous membrane, most usually
forming longitudinal folds, and of a muscular stratum more
or less distinct, but evidently contractile in all its points. Its
extent, its stomachal swellings, its direction, and its circum-
volutions seem to present a great number of variations.

Thus we sometimes find an cesophagus long and narrow as
far as the stomach, or an cesophagus very broad, very large,
as in most of the phytophagous mollusca. We also see,

ON MOLLUSCA. 199

though more rarely, a sort of distinct crop, as in some brachio-
cephala. Its direction, sometimes almost medial, as at its
origin, is often from right to left, so as to unite itself to the
stomach on this last side.

The stomachal swelling, often simple and indistinct, is on
the contrary, in a great number of species, divided into se-
veral pouches or lodges. Sometimes even one of these pouches
has its parietes comprised between two muscles very thick,
almost as is the case in the gizzard of birds. In peronia and
limneea the conformation is similar. We find also in many
species, and among others in the monopleurobranches, that
the internal membrane of the stomach is armed with corneo-
calcareous productions, very analogous in their structure and
composition to teeth, which occurs even in the shell.

The stomach of the acephalous mollusca has not its parietes
distinct. Of a form usually irregular, it appears hollowed in
the tissue itself of the liver, which envelopes it on all sides,
and pours in the bile through numerous apertures or sinuses,
very large, in which very singular bodies are observable,
whose use and mode of formation are completely unknown.
They are named crystalline stylets, because they are usually
in the form of stylets, the point of which is in the canals, and
they are a little transparent.

In the cephalous mollusca, where nothing similar has been
yet remarked, the liver never completely envelopes the sto-
mach, neither does it adhere to it. It is even most frequently
carried back into the remotest part of the visceral mass, and
to the very point of the spire. It is composed of lobes and
lobules, the last of which are in the form of hollow globules.
From each of these lobules springs one of the minute biliary
ducts, which successively uniting, constitute one or three or
four thick canals, opening freely into the stomach itself, or
sometimes into the commencement of the intestine. This
structure of the liver often permits it to be inflated with the

200 SUPPLEMENT

greatest facility. This is most especially evident in the bra-
chiocephala.

The liver sometimes appears more considerable in the phy-
tophagous mollusca than in the zoophagous.

The intestine, properly so called, varies more than the
stomach in its diameter, the number and form of its circum-
volutions, in its direction, and in the point of its termination.

Most usually its circumvolutions between the lobes of the
liver, from which it is at times rather difficult to separate them,
are in the posterior part of the body of the animal. It is dis-
engaged from them pretty often, proceeding in a middle line
underneath and in front, or above and behind, but often also
proceeding from left to right, or in front towards the anterior
and right side of the animal, where the anus exists.

The acephala offer perhaps less variations in the extent, the
circumvolutions, and especially in the mode of termination of
the intestine; in fact, after having formed a sort of handle,
more or less large, in the liver, and sometimes a ceecal sinus
at the root of the foot, it re-ascends towards the back of the
animal, places itself in the middle line, and directs itself from
front to rear, where it is terminated in the cavity of the mantle
by a free elongation, more or less considerable, at the ex-
tremity of which is the anus.

The position of the anus in this class of mollusca is thus
almost constantly the same, and it is pretty generally pedicled.
The same is not the case with the cephalous mollusca; in
these the anus, sometimes medial, inferior and anterior, as in
the brachiocephala, is sometimes medial, posterior, superior
or inferior, as in doris and peronia. Finally, in most cases it
is placed at the right, sometimes altogether in front, as in
limax, or altogether behind, as in onchidia. When it is at
the left the animal and its shell are so. The haliotides and
ancile, nevertheless, have it on this side, and are rolled from
left to right.

ON MOLLUSCA. 201

The mode of nutrition in the malacozoaria is in general
much less known than that of their locomotion.

A very small number can seize their prey before they intro-
duce it into the buccal cavity. To effect this, the singular
appendages with which their head is provided interlace and
attach themselves very closely, by the aid of the sort of cup-
ping-glasses with which they are furnished, to the living
animal which is about to be devoured.

The mollusca whose buccal orifice is furnished with teeth
appear to be able to seize and chew their food with them.
When there is but one tooth above it serves as a resting point
on which the lingual swelling acts in its anterior part, which
is very observable in the limaces, helices, and approximating
genera.

We are not equally well acquainted with the mode of action
of the proboscis in such mollusca as are provided with one.
It is believed, however, that the teeth with which it is often
armed at its extremity, when it is sufficiently unrolled, may
serve to make a hole in the shell of other mollusca, through
which this proboscis may be introduced to tear or suck the
soft parts ; but this is very far from being indubitably ascer-
tained.

The mollusca feed on all kinds of substances, animal or
vegetable, in all states, living or dead, fresh or putrified; but
each species, and even each genus, but less certainly each
family, confines itself to one or other kind of these aliments.

All the known cryptodibranchia are nourished upon living
animals, which they tear, and perhaps break, but which pro-
bably they do not masticate.

The siphonobranchia appear also to be all carnivorous ; but
it is probable that they rarely swallow their prey entire, but
that they suck it, draw it into their proboscis, armed or un-
armed, but that they do not chew it, being unprovided with
organs adapted for true mastication.

202 SUPPLEMENT

The asiphonobranchia appear in general to be less car-
nivorous; perhaps they are not so at all, or take indifferently
animal or vegetable nourishment, in a state of putrefaction.
They seem, in fact, to make use of their proboscidiform un-
armed muzzle rather to swallow rotten vegetable matter, than
to masticate it. This is certain, at least, in the terrestrial
cyclostomata.

The pulmobranchia, on the contrary, are most generally
phytophagous, and they chew or cut the substance of which
they make their nutriment in small pieces, which they swallow
by little and little. We have already seen that their mouth is
armed always with an upper cutting tooth, and denticulated
on the opposite side of the lingual mass. It is said, however,
that the testacella swallows earth-worms whole, drawing them
by little and little into the intestinal canal.

The chismobranchia, the monopleurobranchia, are probably
in the same situation as the asiphonobranchia, since they have
no teeth to the mouth.

The pteropods also appear not likely to chew their prey,
but to suck it, or take it in a state of decomposition, for the
same reason.

We may say as much of the cyclobranchia, inferobranchia,
and even of the polybranchia, although in this last order there
are some genera, such as those of tritonia and scyllea, in
which there are two jaws acting laterally, like the blades of
scissors, and which consequently ought at least to cut their
nutriment.

As to the nucleobranchia, it appears that they feed on small
animals. The cervicobranchia are perhaps in the same way,
but it is more probable that their aliment is composed of sub-
stances in decomposition.

In the entire class of the acephalophora, this must be still
more necessary, since the mouth of these animals, soft in all its
parts, could not exercise the least action on bodies of the

«

a

ON MOLILUSCA. 203

slightest solidity. Accordingly, it is probable that they feed
upon animal and perhaps vegetable particles, the result of the
decomposition of the beings of either of these kingdoms, and
which are drawn along with the fluid which enters into the
cavity of the mouth for respiration. It might also happen
that their nutriment is composed of the innumerable animal-
cule which the microscope enables us to observe in the water
where these animals live, and which are of an extreme soft-
ness. The nucule may perhaps feed on substances of greater
solidity, as might be supposed from the disposition of their
labial appendages.

According to the nature of the aliment, and the state in
which they seize it, it is evident that the means which the
mollusca employ to take it must be very different.

Species, such as the brachiocephala, and even the testacellz,
which feed upon living fugitive prey, are obliged either to pur-
sue it when they have the means, as the sepiz and loligines,
or to wait in ambuscade and cast themselves suddenly upon it.
This is the case with the octopi, and probably with the testa-
cella.

Those which, on the contrary, feed on living animals, but
immoveable, attach themselves upon them, pierce their en-
velopes, of whatever nature they may be, by the assistance
of the hooks with which their proboscis is armed, and conse-
quently have but little difficulty in finding their prey, which
is generally incapable of all sort of motion.

The mollusca which feed on animal or vegetable substances
in a state of decomposition, seek them, without doubt, guided
essentially by the smell, and have need of no great efforts
to obtain them.

There are even some among those which, like the greater
portion of the limacinz, compose their aliment of living vege-
table substances, more or less solid. ‘They have only to seek
them out, and cut them into small pieces.

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204 SUPPLEMENT

Finally, for the species whose nutriment consists of mole-
cules already disunited, or of microscopical bodies suspended
in the fluids in which they live, there is no necessity of re-
search or prehension. It is sufficient for the animal to pro-
duce in the water an almost circulatory movement of this fluid
which should bring with it the nutritive substance, and pro-
bably to swallow this substance and the vehicle at once.

The mode in which the species with a spiral tongue use
that organ is totally unknown.

We know but little more concerning the method by which
the acephala take their food. It would appear that it must be
almost in a molecular state, suspended in the water, and carried
by the buccal appendages to the mouth ; for there is no indi-
cation of masticatory and salivary apparatus.

The palliobranchia, by the aid of their long labial append-
ages, should be better able to seize their food, since they can
put them forth out of their shell, and agitate them in all direc-
tions. The ascidiz and biphore, having no appearance of
such apparatus to the mouth, must be placed in a situation
altogether opposite.

Deglutition, at least in the cephala, must take place as in
animals of a higher grade.

The organs of respiration are pretty nearly known in all the
true malacozoaria and in all the malentozoaria ; but they vary
considerably, not only with respect to form and situation, but
even as regards structure.

In fact, in this last respect, although in most mollusca the
part of the exterior envelope, modified to form the organ of
respiration, be disposed like gills—that is, in such a manner
that it shall be an organ capable of immersion in the ambient
fluid—it sometimes happens that there is a contrary disposition,
and that it forms a sort of pouch or cavity, into which the
ambient fluid shall penetrate, which constitutes an aérial or pul-
monary organ ; and then the afferential and efferential vessels

-

ON MOLLUSCA. 205

invest the internal face of this cavity. This disposition takes
place in the different species of mollusca which live habitually
in the air; but these mollusca may really appertain to diffe-
rent families. The greatest number, however, belong to those
of the limacine and limnexe; but there are some also in the
family of the cyclostomata, and that of the cyclobranches, and
even, according to M. de Blainville, in that of the cervico-
branches; for it would seem that the true patella respire by
a lung, and not by gills.

The form of the organs of respiration varies still more. In
fact, in the aérial mollusca it is always a cavity more or less
inclining towards oval; but in the aquatic, the organ may be
simple or multiple: it may be formed of species of ramified
arbuscula, as in the tritonia; of little tufts, as in scyllea; of
lamine, or shred-like strips, asin the caroline and eolides ; of
triangular pyramids, very large, one on each side, as in sepia,
&c.; or very small and numerous, as in phyllidia and osca-
brio, the latter of which, nevertheless, so much differ from the
former ; of sorts of combs more or less elongated, as in most
spirivalve cephala, in the dismembered genera of the patelle ;
and of large semi-circular plates, as in most of the acephala ;
or, finally, of a reticulated tissue, as in the ascidiew; or of a
long fringe, as in the biphore.

The situation of the respiratory organ presents, perhaps,
still greater variations than its form. Thus, ina great number
of species, it is exterior, and can then be constituted only by
gills. ‘This is observed in all those genera which, from this
circumstance, have been named by M. Dumeril dermo-
branches, and by M. Cuvier nudibranches. It even occurs in
the inferobranches. This disposition would be still more evi-
dent in the pteropods, if it were certain that the gills formed a
net-work at the surface of the natatory appendages. In all the
others, the respiratory organ is more or less interior, but more
in the pulmonary than in the other genera, where it may be

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205 SUPPLEMENT

almost exterior, as in certain monopleurobranches and cervi-
cobranches. In the brachiocephala, the gills are contained in
the sac formed by the mantle.

In all the acephala, the gills are between the mantle which
conceals them and the body.

The place which the organ that we are now examining
occupies also varies in a notable manner. ‘Thus it is some-
times at the upper and posterior part of the body, as in doris,
peronia, and even in the testacelle ; it is at other times on
each side of the back, as in scyllea, the eolides, the tritoniz ;
in other species it passes underneath, all around the edge of
the mantle, between the foot and this last, as in phyllidia, um-
bracula, and even a little so in oscabrio. But rarely the respi-
ratory organ is on each side of the body, in the sac formed by
the mantle, asin the brachiocephala, or only on the right side,
as in all the monopleurobranches. In fine, most generally it
is at the anterior and upper part of the origin of the back, and
of the back itself, that we observe the respiratory organ, as in
most cephalous mollusca, whether pulmonary or branchife-
rous, and even in the dentales.

Tn all the conchiferous acephalous mollusca, on each side of
the body, between it and the mantle, are two large semi-lunar
lobes, which are generally regarded as the gills of these animals.

In the order of naked acephala, the respiratory organ is in
a sort of tube, which conducts from the posterior part of the
body to the mouth.

As to the structure of the gills of the cephalous mollusca, it
reminds us of that of these organs in the fish. Whether it be
sorts of triangular lamine, ranged like the teeth of acomb upona
common axis, or sorts of tubercles irregularly collected, in the
manner of granulations, the skin which constitutes them is
considerably attenuated, although it preserves its contractile
quality. Its principal afferential vessels may be very well in-
jected, whose ramifications, often very fine, proceed to unite in

——

a

ON MOLLUSCA. 207

a principal efferential trunk, which is so directed as to come
forth from the organ in an inverse direction from that of the
afferential vessel. ‘The projection of these branchial combs,
or of these tubes, is sometimes not inconsiderable.

The gills of the acephalophora are composed, in most cases,
of two pairs, more or less unequal, of semi-lunar plates, placed
vertically between the abdomen and the lobes of the mantle,
and applied one against the other. Separated or united more
or less in the extent of their lower edge, that of one side is
joined to its correspondent on the other, through a part more
or less considerable of its superior or dorsal edge. But it is
attached on the sides of the belly by its anterior extremity, the
other being often free. Each of these four gills is itself formed
of two plates, which leave between them a free space, divided
into a great number of vertical lodges, open at the dorsal edge,
by numerous triangular partitions. These plates are consti-
tuted by two strata of parallel vessels, vertical, and united by
other transverse vessels. One of these strata is formed by the
ramifications of the branchial artery, and the other by those of
the vein. These ramifications unite in two thick trunks,
which border the back of the branchial plate, and which are
in communication, one with the auricle, on its side, and the
other with the venous system of the rest of the body.

In the lingule and approximating genera, it appears that
the gills are a little different in their structure and in their
position, since they are in the form of a comb, applied to the
internal face of each lobe of the mantle.

In the naked acephala, the branchial apparatus is still more
anomalous. In fact, in the ascidiz, it is formed by a net-work,
with quadrangular meshes, which invests the cavity of the tube
as far as the mouth; and in the biphore it is a kind of narrow
plate, almost free, and directed obliquely.

The nematopods have their respiratory apparatus approxi-
mating to that of the entomozoariez, if it be certain that it is

208 SUPPLEMENT

formed by small triangular plates, attached to the root of the
first pair of appendages, as is the opinion of Baron Cuvier.
We may also conceive that the filaments which bristle these
appendages might take place of them, and then these appen-
dages might be considered as gills.

The oscabriones have their respiratory system formed almost
as in the phyllidiz, of small triangular plates placed under the
edges of the mantle.

According to the structure, the form, and even the position
of the respiratory organ, the apparatus by means of which the
ambient fluid is brought in contact with the modified cuta-
neous envelope, must of necessity be different.

There was no need of any when the gills were external,
either on the back or under the edges of the mantle.

When, on the contrary, they have become internal, some
particular modification was necessary in the edges of the
cavity which contains them, and even in the shell which
covers and protects them. Thus in a great number of the pec-
tinibranch species the anterior edge of the mantle is prolonged
into a tube, while others have but a sort of inferior auricle in
place of this tube, or present but a broad cleft, which conducts
into the branchial cavity. The pulmonary species have only
a hole pierced into the thickened edge of the mantle.

In almost all the acephala the water arrives at the gills
through an aperture formed by the two lobes of the mantle,
which are often prolonged behind by the addition of a long
contractile tube, distinct, or united to that of the anus, as
before observed.

The theory of the function of respiration, independently of
the organs, appears pretty nearly the same as in the more
elevated types of animals. We know, in fact, that the mol-
lusca absorb the oxygen of the air in which they are retained.
But is this done alone by the organ of respiration? That is
by no means probable, the general envelope being by its

——

ON MOLLUSCA. 209

nature so absorbent; but as this organ contains a much greater
number of vessels than any other part, the aerial absorption
should be much stronger there.

We also know that the species which are provided with a
pulmonary cavity die in a short time after they have been
retained a certain depth under the water, without allowing
them to re-ascend to its surface; and that, on the contrary, the
species with gills cannot live for any time in the atmospheric
air, especially when those gills are uncovered. When they
are internal, the animal can survive for a long time, in conse-
quence of the water by which they are moistened, and which
does not quickly evaporate.

The mechanism by which the ambient fluid is brought in
contact with the elaborating fluid, or the blood, is in general
rather simple.

In the species whose gills are exterior, as tritonia, scyllea,
phyllidia, &c., it is sufficient for the animal to swim for the
purpose of respiring.

Those, on the contrary, which have the respiratory organs
formed by the parietes of a cavity, as the pulmobranchia, or
contained in the cavity, as almost all the other cephalous mol-
lusca, the ambient fluid (air or water) is introduced or expelled
by the dilatation or contraction of the cavity, and of its sim-
ple or tubular orifice ; and these two effects are facilitated in
all the species, and especially in such as are provided with a
shell, by the extension or contraction given to the anterior
part of the body where the apparatus exists, and by its ad-
vancement into the broadest part of the shell. But in no case
is there any regularity in the inspiration and expiration: they
do not even exist (as independent motions) in the brachio-
cephala, where the water introduced into the cavity of the
mantle occupied by the gills serves at the same time for loco-
motion.

‘he acephalous malacozoaria, which are all aquatic, present

VOL. XL, P

210 SUPPLEMENT

pretty nearly all of them the same mode of respiration. ‘The
labial appendages with which the mouth is provided appear,
by their continual movements, to produce a sort of current in
the water where the animal is plunged. This is very well dis-
tinguished, especially in the species in which the posterior
extremity of the mantle is prolonged into two tubes, more or
less long; the water enters by the lower, and issues out by
the upper. Itis thus in the ascidiz, and perhaps also in the
biphore. It is at the time of the passage of the fluid into the
branchial cavity that the effects of respiration take place.

In all the malacozoaria the circulating system is complete,
although the re-entering or absorbing centripetal system is
only formed by veins.

These vessels have their parietes extremely thin, and often
so much confounded with the tissue of the parts, especially in
the dermoid envelopes, that it is often rather difficult to per-
ceive them; and sometimes they really exist only through the
internal membrane, as in the bivalves. ‘They sometimes pre-
sent this peculiarity, that they are pierced with gaping orifices,
tolerably large, at least in the visceral cavity, as may be well
observed in the aplysiz. We also find that they sometimes
bristle with sorts of little spongy bodies, also proceeding into
the visceral cavity.

As in the animals of more elevated types, the veins spring,
without doubt, in part, from the continuity of the arteries, and
in part from the tissue itself of the organs, but they never con-
stitute more than two systems, one which returns from the
whole body, and the other from the special organ of respira-
tion; that is to say, there is no system of the vena porte. The
venous radicles of the general system of the body, after having
been successively united in trunks more and more thick, dis-
tinguished, however, for some time into those of the viscera, and
those of the sensible contractile envelope, arrive towards the
respiratory organ, and according as it is simple or complex,

a

ON MOLLUSCA. , Set

symmetrical or not symmetrical, act in somewhat a different
way. In fact, in the first case all the veins of the body unite
into a single gross trunk, which most usually, without the
intervention of a muscular swelling or heart, is subsequently
changed into a pulmonary or branchial artery. In the second
case, on the contrary, the veins unite into two principal trunks,
which are subdivided into as many branchial arteries as there
are gills. At the point of this transformation there is never
any true heart or organ of impulsion, but in all the branchio-
cephala, and even in a small number of cephalous species,
and probably in the acephala, we find in this place a venous
sinus, to which the name of heart has been sometimes given,
but which probably cannot be so designated, as it possesses
no muscularity. Be this as it may, the branchial or pulmo-
nary artery, simple or multiple, is ramified in a manner more
or less regular, according to the form of the respiratory organ
in the modified skin which constitutes it.

It is from the capillary extremities of the branchial artery,
subdivided in the respiratory organ, that the second venous
system originates. After that the ramifications, disposed like
those of the arteries, have been successively united in
branches more and more thick, there results from them finally
a gross trunk, which issues from the respiratory organ, and
repairs into an aortic heart situated in a different manner, ac-
cording to the position and symmetry of the gills.

The heart of the mollusca, in the greater number of cases
situated in the back, above the intestinal canal, unless per-
haps in the brachiocephala, where it is inferior, is placed, as
in osseous animals, at an equal distance from each respiratory
organ when there are two, or obliquely to the left, and rarely
to the right, when the organ is odd. ‘This heart is not con-
tained in a true pericardium, but in a muscular lodge of the
diaphragm kind, which separates the visceral cavity from that
of the gills. As to the rest, it is formed of an auricle, some-

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912 SUPPLEMENT

times double when the gills are symmetrical and lateral, as
in the brachiocephala and conchiferous acephala, and of a
ventricle.

The auricle, of a very variable form, ordinarily oval, some-
times triangular, has its parietes very slender. We may ob-
serve, however, at the interior some muscular cords which
traverse it. It does not appear that there is any valvule at
the entrance of the branchial or pulmonary vein into this
auricle.

Its communication with the ventricle is made by a sort of
pedicle or contraction, often pretty long, as in the calmars, for
example, and by means of a narrow orifice usually transverse,
situated between two folds of the internal face of the ventricle,
but without valvules, properly so called, something in the way
that the small intestine opens into the ccecum in the human
species.

The ventricle, in general much thicker, is also of a form and
direction very variable; its parietes are always thicker than
those of the auricle, and we can very well distinguish the
transverse muscular bundles which form it, between two of
which is the auriculo-ventricular orifice.

It is from its point, or from one of the extremities of its
greatest diameter, that the arterial or centrifugal system pro-
ceeds, most usually by a single trunk, but sometimes also by
two, as may be well observed in the calmars.

The arteries of the mollusca have evidently their parietes
more thick and more resistant than the veins. They possess
great elasticity; and in the largest of these animals, they
appear of a gelatinous tissue, without any trace of fibres.

Their distribution is too variable to speak generally con-
cerning it; nevertheless, most commonly there are two prin-
cipal trunks, one anterior and the other posterior. ‘The first
furnishes branches to the head and to its different parts, to
the esophagus, and even to the anterior organs of generation ;

a

ON MOLLUSCA. 213

while the second, which has more resemblance to the ceeliac
tripod, sends its ramifications to the stomach, to the rest of
the intestine, to the liver, and to the secretory organs of ge-
neration.

In the acephalous mollusca the circulatory apparatus pre-
sents some differences from that of the cephalous. ‘The veins
of each gill are united in a lateral auricle, placed on each
side, and after a contraction often very sensible, each of the
two auricles opens into a ventricle, which is situated in the
medio-dorsal line. ‘This ventricle is usually fusiform ; but
what it exhibits most remarkable is, that it appears to be
traversed by the rectum, because, in its breadth it recurves
around this intestine, so that the two extremities of its trans-
verse diameter appear to touch. From the root of this ven-
tricle spring two aortz: a posterior one, smaller, which passes
under the rectum, and gives out branches to the posterior
parts of the body, and an anterior much more considerable,
which proceeds as far as the anterior adductor muscle, fur-
nishes branches to the stomach, to the liver, to the foot, and
to the other surrounding parts, recurves below by an anas-
tomosing branch, which follows the edge of the mantle, to
unite itself to a similar branch of the posterior aorta, and
forms a large arch, of which the lower branches go to the
tentacula of the edge of the mantle, while the others, more
considerable, remount and distribute themselves to all its
parts.

The venous radicles of the belly, and of all the anterior
parts of the body, unite in two gross trunks, which proceed
from the hepatic region below the rectum, and after having
received, by many radicles, two veins, which have followed the
edge of each lobe of the mantle, they open at the anterior ex-
tremity of a sort of auricle or venous reservoir, placed longi-
tudinally under the heart in the dorsal line. This reservoir
receives by its posterior extremity two other veins, tolerably

214 SUPPLEMENT

thick, which have taken up the blood of the posterior parts of
the body, and even of the edges of the mantle.
This medial sinus, which is surrounded by a brown organ,

of which we shall speak further on, when we come to treat of ~

urinary depuration, appears also to receive a considerable
number of vessels from it, or perhaps those vessels may
originate from the former and proceed to distribute themselves
to this organ, while a much greater number unite in the
branchial arteries. These are two in number, one on each
side. ‘They are considerable, and placed longitudinally along
the upper edge of the branchial plates, thicker in the middle,
they diminish in diameter, and finish in a point at the ex-
tremity in proportion as they have furnished branches to the
gills. ‘Those branches form two planes, one for the internal
face of the external leaflet, and the other for the external face
of the internal leaflet of the gills, descend vertically, dimi-
nishing as far as the edge of the leaflet, and furnish numerous
longitudinal anastomosing branches, so that from them results
a net-work with square meshes. From this same net-work
spring, by a contrary disposition, the branchial veins, whose
net-work occupies on each leaflet the face opposite to the
arterial net-work, and they unite in as many thick longitudinal
veins as there are branchial plates, at least in front, where

they are perfectly separated at the superior edge; for behind |

there are but three, the medial being common to the two in-
ternal plates, which are united. The external branchial vein
changes into a sort of sinus or long auricle, with which the
external vein communicates by several venous pedicles ; and
this auricle itself, after having been narrowed, opens into the
ventricle.

The palliobranch species appear to have the auricles still
more distinct than the ordinary acephala, and it is probable
that it is this which has caused it to be admitted that they
had two hearts.

——

ON MOLLUSCA. 915

The oysters have also the heart placed differently, and not
occupying the back of the animal, but the anterior part of the
central muscle.

In the naked acephala it occupies pretty nearly the same
place as in the conchiferous, but it is perhaps less symme-
trical.

It is completely so in the nematopods, and especially in the
oscabriones, whose ventricle occupies the posterior part of
the back, along with a large auricle, very symmetrical on each
side.

We shall now speak briefly of the urinary and generative
processes.

The apparatus of urinary depuration, in general very simple,
appears to exist in all the malacozoaria, that have been suffi-
ciently examined. It always accompanies the termination of
the intestinal canal. In the cephala it is found sometimes
described under the names of the organ of glue, or the cal-
careous sac, and in the acephala under that of pulmonary
organ.

In the first it consists of a single secretory organ, not sym-
metrical, of very variable form, often situated near the organ
of respiration, making a projection into the interior of the
cavity which contains it. From it springs an excretory canal,
which, after a passage more or less long, often accompanying
the rectum, terminates externally by a rounded sessile orifice,
at a small distance from the anus.

In the class of the acephala the depurator organ is double,
or at least symmetrical. It is situated equally on each side
of the rectum underneath it, in front of the posterior adductor
muscle, and behind the connexion of the branchial lobes. Its
colour is usually of a deep green. Its form is more or less
cylindrical, its structure is cellular or vascular, and it receives
a great number of arterial, and more especially of venous
vessels. It appears that the excretory canal is not sufficiently

216 SUPPLEMENT

known. The organ, however, is contained in a pouch open-
ing by a very small orifice into the upper and anterior part of
the branchial cavity, according to M. Bojanus, which has led
him to think that this organ is a true lung, those which have
been hitherto regarded as gills being, in his opinion, the
organs for the deposition of the eggs. According to many this
organ is behind, and under the rectum, which appears to be
more in analogy.

The apparatus of generation, which is more or less com-
pletely known in all the animals of this type, is often very’
complicated, and at other times reduced to the greatest pos-
sible simplicity. In fact, it is sometimes composed of the
female part only, as in all the acephala and some cephala,
which causes all the individuals of one species to be similar.
There are found a tolerably great number of mollusca in which
the sexes are distinct, but both existing in the same indivi-
dual, from which it results that they again are all similar.
Finally, there are also many in which the sexes are separated,
thus producing in the same species the distinction of male
and female individuals.

The female apparatus of generation, in the cases where it
exists alone, is formed but of one or two secretory organs or
ovaries, situated a little differently in the acephala from the
cephala. From this ovary there proceeds a canal or oviduct,
which, after being for some time swelled in a part of its extent,
directs itself forward or backward, and terminates on one
side or the other, but more usually on the right than on the
left.

In the acephala the ovary may be single in its origin, and
capable, by its successive enlargements, of extending itself
into all parts of the mantle. It appears always to be prolonged
by two distinct oviducts, which are placed, being directed
from front to rear, on each side of the abdomen, where they
terminate by a rounded orifice, at the extremity of an elonga-

ON MOLLUSCA. OTe

tion, of greater or less extent, situated between the second
branchial plate and the body. Before this termination the
oviduct contains at a certain period a milky white liquor.
Some authors, and among others MM. Bojanus and Mery,add
to this essential part of the generative organ of the bivalves
the organs which we have already described under the name
of gills, and which they regard as depositaries for the eggs.

In the monecious cephala, such as the patelle, haliotides,
&c., the ovary is always single, and on one side. It is the
same with the oviduct, which is constantly directed from
behind to front, sometimes at the left, but more frequently at
the right side, where it terminates by a very short tube in the
respiratory cavity.

The disposition which constitutes the union of two distinct
sexes in the same individual obtains only among the cephalo-
phorous malacozoaria, and only in a certain number.

The female part is formed by a single ovary, situated pos-
teriorly in the liver; from it proceeds a first oviduct, which
originates by ramifications, like those of the biliary canal in
the liver. Very fine at first, its bulk increases; it bends, runs
into heaps more or less compact, approaches the male part,
becomes intimately united with it, and finally opens into a
second oviduct, much wider, with thick folded parietes, se-
creting an abundant viscous matter, and which is sometimes
designated under the name of matrix. Near its mediate or
immediate termination at the exterior is remarked that of a
canal more or less long, proceeding from an oval or spherical
bladder, contained in the great visceral cavity, and the use of
which is entirely unknown. Might it not be a sort of
prostate ?

The male part is also composed of a secretory organ or
testicle, situated most usually on the left side, and in front of
the ovary. ‘The deferential canal which springs from it, after
an intimate union with the first oviduct, follows the passage

218 SUPPLEMENT

of the second, against which it is cemented more or less
closely, forming sometimes a sort of epidydymis by its nu-
merous folds, then is changed into a cylindrical canal with
thick muscular parietes. ‘This is directed towards a species
of excitatory organ, at the base of which it terminates in the
majority of cases. ‘This organ is only a sort of long hollow
tentaculum, contractile in all its points, of a form extremely
variable even in species of the same genera, and which most
generally retracted into the interior of the visceral cavity, by
the aid of a retractor muscle, may also, from the disposition
of muscular annular fibres, be turned outwards, like the finger
of a glove.

At the point where the deferential canal terminates we
sometimes find a heap of cylindroid organs, or kind of hollow
coeca, variable in number, and which successively united at
their base, finish by opening through a single orifice. These
have been called the vesicule seminales.

Finally, in a certain number of hermaphrodite mollusca we
remark another organ again neighbouring to the external
termination of the male apparatus. It consists of a muscular
mucous pouch, in the form of a bladder, which produces and
contains in its interior a labial corneo-cretaceous’ body, in the
form of a dart, or poignard ; this body can issue forth through
the orifice of the pouch, which is situated near that of the
rest of the male apparatus.

In spite of the intimate connexion which subsists between
the two parts of the genital apparatus of these hermaphrodite
mollusca in their passage, they may terminate at distances
more or less considerable from one another, although always
on the right side. Thus in some species the termination of the
female organ is altogether behind, and that of the male organ
in front, more or less near the tentaculum on that side, as in
the veronicellz and onchidia. In some others the separation
is less great; many have them united in the same external

——

ON MOLLUSCA. 219

tubercle, as doris, tritonia, &c. Finally, in all the pulmo-
branch species these terminations are made in a sort of com-
mon vestibule at the root of the right tentaculum, so that in
a state of inaction but a single orifice is seen at the exterior ;
but in the act of coupling the vestibulary pouch is reversed,
and the two terminations become apparent.

The third disposition of the genital apparatus of the mol-
lusca constitutes the division or isolation of each sex ina
distinct individual, whence result females and males. As for
the rest, each apparatus is pretty nearly conformed according
to the preceding disposition. We find, however, perhaps
more frequently in the female sex, the swelling of the second
oviduct performing the office of matrix, and in the male sex
we remark that the vesicule seminales are sometimes re-
placed by a single swelling situated towards the end of the
deferential canal. Finally, another difference is that the
excitatory organ, when it exists, never appears to be com-
pletely retractile, but only contractile, so that it is always
more or less visible at the right and anterior side of the
animal, sometimes being recurved into the branchial cavity.

With respect to the products of the organs of generation,
that of the male sex, when it exists, appears to be always a
fluid of a viscous white, but in general it is little known. We
are not even acquainted positively with the mode in which
it is ejected, whether at once or by little and little, nor into
what part of the female organ it penetrates. ‘The product of
the female sex is much more known, and always constitutes
a true egg, composed of envelopes of a vitelline mass, and
a germ placed upon this mass, which no doubt makes part
of it.

The form of the eggs of the mollusca does not fail to ex-
hibit a good number of varieties ; sometimes being spherical,
as in those of the limaces; sometimes ovaliform, as in a great

220 SUPPLEMENT

number of species, or even more or less longitudinally pe-
dicled, as those of many buccina.

Those envelopes which may be called adventitious or
casual, usually viscous at first, to determine the adherence of

the egg, pass subsequently to a corneous or concrete mucous.

state, and sometimes even to a cretaceous state, so that they
resemble tolerably well the calcareous envelope of the egg of
a bird. This may be observed in many terrestrial mollusca.

The proper envelopes are but little known, but it is pro-
bable that they do not differ much from those of the eggs of
animals of a higher rank.

We are not much better acquainted with the form and dis-
position of the germ, except when it may be sufficiently de-
veloped to resemble the parents which gave it birth. We
only see that this germ is contained at first in a lodge or
superficial excavation of a true vitellus, which communicates
as usual with the intestinal canal, perhaps even altogether
near the mouth. This vitellus is evidently a mucous or gela-
tinous matter concrescible by alcohol, translucid, and not very
thick in the fresh state.

The development of the germ in the interior of the egg of
the mollusca is so complete that the little animal which comes
from it almost entirely resembles its parents. Accordingly it
often happens that this development takes place in some part
of the mother, and that both in the cephala and the acephala.
They, therefore, in such cases bring forth their young living,
and these mollusca are termed viviparous. All the acephala
appear to be in this predicament.

The disposition of the eggs, laid by the malacozoaria, ex-
ternally is also very variable. Thus sometimes they are
placed and attached one by one on submarine bodies, as in a
great number of cephalous mollusca, but at other times they
are joined together so as to form masses more or less consi-

ON MOLLUSCA. 294

derable, and which more or less resemble clusters of grapes,
especially when the eggs are of a black colour, as those of
sepia. Often they are united by a gelatinous substance, in
which they are plunged, like those of the limnzz, planorbes,
and aplysiz. At other times many of these eges are enclosed
in sorts of corneous envelopes, piled like pods one after the
other, an arrangement which is observable in some species of
fusus.

We next proceed to the nervous system of the mollusca, or
that portion of the organization on which the irritability of
the animal and its susceptibility to external impressions, en-
tirely depends.

This apparatus of the nerves, as may be seen in the general
characters of the type, presents a disposition somewhat sin-
gular. It is, however, always composed of a central portion,
or brain, situated above the intestinal canal; of ganglions, for
the special organs of the senses, where these exist, as well as
for the apparatus of locomotion; of some visceral ganglia ;
and finally, of conducting threads or nerves, the structure of
which is sometimes singular, in that they have a fibrous en-
velope larger than the nervous cord, so as to permit, as some
say, their injection, which appears very doubtful.

The general disposition, and especially the proportion of
the parts of the nervous system, are very different in the two
classes of the malacozoaria, and especially in the sub-type of
the malentozoaria.

In the cephalous mollusca the brain, composed of two
similar parts, more or less bulky, more or less united by a
sort of commissure, is sometimes contained in a sort of
cranium or cartilaginous box, which serves as a support to the
contractile fibre. But in a great number of cases it is scarcely
covered with cellular tissue, and it is placed at the origin of
the cesophagus, behind the buccal mass, so that it follows
their movements.

293 SUPPLEMENT

With this brain communicates the ganglion of the organ of
vision, which is always placed immediately behind the bulb
of the eye, as well as that of hearing, when there is any, and
from it proceed the different nerves, which repair to the ten-
tacula as well as to the lips.

Beside the communication more or less close which there
is above the cesophagus, between the two parts of the brain,
there is another inferior one, which passes under the ceso-
phagus, and constitutes a sort of ring or collar surround-
ing it.

The nervous system of the sensitive and locomotive appa-
ratus is formed only by a single ganglion situated on each
side, sometimes tolerably distant from the brain, with which
it always communicates by a cord, but most frequently so.
near this organ that it really appears to form a part of it.
In both cases it gives out the more or less numerous threads,
which repair to all the parts of the musculo-cutaneous en-
velope, and especially to those which serve essentially to
general locomotion, as for instance, to the foot of the gastero-
pods and trachelipods, to the sac of the brachiocephala, to
the wings of the pteropods, &c.

The visceral ganglia appear to be but two in number ; the
one which appertains especially to the male excitatory organ
is usually situated near the orifice through which that organ
issues, and it furnishes threads to the organ as well as that
by which it communicates with the brain. The other vis-
ceral ganglion is more constant in its situation; it is usually
placed towards the stomachal swelling, and the nervous
threads which it furnishes are equally of two sorts, those
which proceed to the intestinal canal and those which ascend
to communicate with the brain, through the medium of the
cesophageal ring.

It is unnecessary to observe that the development of the
different parts of this nervous system is proportional to that

13

ON MOLLUSCA. 935

of the organs to which they appertain, and that consequently
it is much greater in the brachiocephala, which stand at the
head of the class, than in the patella, &c., which close it.

This observation is equally applicable to the nervous system
of the acephalous malacozoaria; in fact, it is so very little
developed in them that its very existence was for a long time
unperceived. Their brain is no more than a double ganglion,
or rather a sort of flatted cord, situated always above the
cesophagus. It appears that there are no threads which
should form round the latter a true ring, as in the cephalous
mollusca. From this sort of brain there proceed two long
cords, but they go much farther behind, and proceed to estab-
lish the communication between this organ and the ganglion
of locomotion which is found underneath the adductor and
posterior muscle, and which, in fact, receives threads from
them, as do the mantle and the tubes, when there are any.

In the common mussel (Mytilus edulis), the nervous system
seems to be more evident than in any other species of acepha-
lous mollusca. It is composed of three pairs of ganglia; the
first, the most anterior, is certainly placed under the cesopha-
gus, or rather under the anterior retractor muscle of the foot,
in part covered by the posterior edge of the union of the
second pair of labial tentacula. The lesser ganglia of which
it 1s composed are of triangular form, and of a white opake
colour: they furnish, first, a very fine transverse net, which
serves as a commissure between them; second, a thicker
branch, which is distributed to the anterior adductor muscle,
and to the labial appendages ; and third, from their hinder
termination, a very thick thread, which proceeds externally, is
applied on the membrane of the liver, traverses obliquely
the anterior retractor muscle of the foot, follows the sides of
the abdomen above the termination of the ovary, and pro-
ceeds to join the posterior ganglion.

The second pair of ganglia, which alone can be regarded as

224 SUPPLEMENT

a little superior to the intestinal canal, is placed above the an-
terior retractor muscle of the foot, applied immediately upon it,
below the liver, against which it is cemented. It is a double
ganglion, or divided into two lateral parts by a medial furrow,
of a softer consistence, and more pulpy appearance than the
other two pairs. ‘There is seen to issue forth in front a very
fine thread, which perhaps proceeds to join the anterior gan-
glion; a fact, however, that M. de Blainville, from whom we
derive this information, was not able precisely to ascertain.
Behind, there is another thread, which repairs to the muscles
of the abdomen.

The third pair of ganglia is altogether behind, below, and
a little external to the anterior part of the posterior adductor
muscle; that of one side is separated from that of the other by.
the entire thickness of the muscle. 'They furnish, first, a very
fine thread as a transverse commissure ; second, behind, a
thicker thread, which penetrates into the muscle itself; third,
from their external and posterior angle, two threads, which go
backwards, probably to the edges of the mantle ; finally,
from their anterior and external angle, the thick cord, by
which they anastomose with the anterior ganglion.

In the oscabriones the nervous system approaches more to
what it is in the cephalophorous malacozoaria, with this diffe-
rence, that the two lateral locomotive ganglia are replaced by
two sorts of cords, which follow the sides of the back, and
furnish threads to each kind of articulations.

In the nematopods, or balani, we find almost completely the
disposition which exists in the entomozoaria, or articulated
division of animals, the nervous system of locomotion having
passed below the intestinal canal, and being composed of as
many small ganglia as there are articulations in the caudiform
part of the body.

At the end of a series of reproductions more or less
repeated, the molluscous animal tends to its decomposition,

ON MOLLUSCA. 295

or in other words, to death. We are completely ignorant of
the duration of its natural life, but it is probable that it is
tolerably long, if at least we may judge by the duration of its
growth, and because it passes its life under circumstances of
no great variety. Nevertheless, we possess no positive data
on this subject, and it must be confessed that it is exceed-
ingly difficult to procure any.

As to the duration of the shell, and the changes which it is
susceptible of experiencing from the action of the air, and
in the bosom of the earth, all this depends much upon its
structure, its solidity, its bulk, and some accessory circum-
stances.

If it is exposed to the action of the air, and to the vicissi-
tudes of temperature and humidity, it at first loses its colours,
which are very quickly changed (the ferrugineous resist the
longest), and it usually becomes of a tarnished white; the
animal matter is destroyed, and disappears by little and little.
The composing lamine being no longer connected, exfoliate,
expecially from the alternation of heat and cold; and soon, by
this continual action, the lamine themselves become resolved
into a sort of calcareous dust, which is drawn along by the
currents of the water.

The particular structure of the shell, its age, and even its
bulk and thickness, facilitate or arrest more or less its terreous
decomposition.

If, on the contrary, the dead shells are, by particular cir-
cumstances, sunk in the sand, or in the mud, in which they
have lived, and where they have been encrusted with a creta-
ceous deposition, which takes place in greater or less quanti-
ties in all fresh and salt-water, but especially in the first; or,
finally, if by the action of currents they are accumulated
together, whether broken or not, in some localities of seas or
lakes, as in these different cases they are placed in shelter
from the vicissitudes of temperature and humidity, their de-

VOL, XII. Q

926 SUPPLEMENT

composition is infinitely more slow, and their colours are pre-
served fora much longer time. The corneous fibres of the liga-
ments are sometimes preserved for a great number of ages, and
still more their laminated or fibrous structure, to such a de-
eree, that they have often lost none of the parts which serve
as generic, and even as specific characters. Finally, when
the colours have disappeared, as well as the animal gluten,
they arrive at a point, when white, and grating to the tongue,
they may resist the inroads of time for such a number of years
as it is impossible to calculate. However, in the long run, the
pressure, determined by the new depositions which cover them,
tends to break them, by approximating the molecules together.
The diminution and disappearance of the animal matter, which
retained the inorganic substance in forms, as it were, acci-
dental to it, and determined by the living principle, facilitate
the tendency which these molecules have to approximate,
according to the simple laws of the inorganic kingdom. The
shell then tends to disappear altogether, by the successive
removal of the calcareous molecules which constitute it; but
as its cavity was filled by the pressure in all directions of the
terreous or argillaceous molecules which surrounded it, when
the true testa has disappeared, it is as it were represented and
prolonged for a lengthened period, by what is named its
mould, which exhibits all the forms of its cavity. Itis equally
possible to conceive, what indeed happens, that the calcareous
_molecules, although having obeyed the laws of crystallization,
do themselves preserve the form of the shell. The structure,
it is true, is lost, but not the form. 'This is what constitutes a
spathified shell, and prolongs, as it would appear, almost for
an indefinite period, the proof of the existence of the organized
being, through a series of ages, until at last it is converted, as
it were, by continual pressure, by the moleculary movement of
the parts which surround it, into the rock itself, which it con-
tributes to form.

|
q
4
|

ON MOLLUSCA. 227

ed nd

The diseases of the mollusca are doubtless not very numerous,
but assuredly they are not very well known, at least as far as
the animal itself is concerned. Should we regard as such the
peculiar alteration exhibited by oysters when they pass to a
state of greenness? Nothing can be less certain than this.
Nevertheless, observing that the oysters which pass into
this kind of state live in stagnant water, and that they are
in general smaller and less fleshy than the others, we may
be allowed to think that the particular vibrio, to which they
owe their green colour, does not sufficiently nourish them, and
that the water, half fresh, and seldom renewed, in which they
are, does not sufficiently excite their organic activity.

The diseases of the shell are probably more numerous, and
better known. The first is the separation or breaking of the point
of the spire. This is observed in many species of univalves, and
among others in some of the genus bulima. Although this
takes place only with shells of the turriculated form, neverthe-
less it cannot be this circumstance alone which determines
this fracture, since most shells of this form exhibit no such
appearance. It is more probably owing to the circumstance
of the animal growing very fast, and quickly abandoning the
commencement of the spire, while the vitreous matter, de-
posited to fill the deserted cavity, is more fragile and less
lamellated.

A kind of change, which is remarked at the summits or
hooks of a great number of fresh-water bivalve shells, which
compose the genera unio and anodon, has perhaps some analogy
with what we have just mentioned concerning the univalves.
This, however, is not certain ; and in fact many authors have
supposed that this kind of caries, which appears to eat in an
irregular manner, not only into the summit, but even into other
parts of the unio, and that often pretty deeply, was owing to
the destructive action of the animals which feed on the mol-

Q2

2298 SUPPLEMENT

lusca. Be this as it may, we know that this caries aug-
ments in breadth and depth with age, and that the uniones of
all countries exhibit this singularity.

The anomalies or deformities of shells are of two sorts: the
one is sufficiently explicable, the other not so.

We may rank in the first kind the relative thickness
which individuals of one and the same species may attain to
in their growth; and, in fact, we find some individuals in
certain genera, which, although complete, are much smaller
than others. This, without doubt, is owing to a difference in
the quantity of nutriment, either in the same, or in a different
locality, as may be seen among the hexapod insects. Accord-
ingly, we cannot admit the notion of Bruguiéres, that this
difference necessitates the change of skin in the animal, some-
thing like that of the epidermis in insects.

We must also consider in the same light the double swel-
lings which are formed in certain univalve individuals, after
that, having come to their full growth, the normal swelling has
been produced. This, no doubt, is referrible to an over
excitation of the vital powers, determined by some local cir-
cumstance. ‘

We must equally place in the same class the artificial form
which certain slender bivalve shells may assume, and the in-
ferior valve of which adheres in its full extent. Not only does
this assume the form of the body on which it is applied, but
the upper valve follows the form of the lower. This observa-
tion, made upon the anomie, is owing to M. Defrance, and is
explained by the circumstance, that the upper valve must
follow the form of the body, which has itself been modified by
that of the lower valve moulded on the foreign body.

A phenomenon pretty nearly inexplicable is the degree of
elevation in the spire of the univalves. In fact, we know that
the same species presents, under this relation, some differences

ON MOLLUSCA. 229

which, although contained within limits sufficiently bounded,
are not the less very evident. But it sometimes happens that
they depart considerably from the limit determined for a spe-
cies, in that the turbinations of the spire become more apart,
are elongated in a vertical direction, and are very far from
touching, which gives to the shell the appearance of a ladder,
and has given a denomination to the individuals of this ano-
malous kind derived from this resemblance. An example of
this may be found in some species of helix.

But the most inexplicable monstrosity of shells, and even of
the molluscous animals themselves, is that in which there is
an inversion in the position of the viscera, and consequently
in their termination, which, instead of taking place at the right
side, takes place at the left. *The shell having followed this
inversion, is then turbinated from right to left, and constitutes
the variety to which the denomination of sznister has been
given. There are some genera, in which this inversion is
much more common, and even to the point of serving as
a character. Such are physis and planorbis. In many other
genera we find examples of it, but more rarely ; and finally,
there are some in which it has not been observed, such as the
porcelaines and cones.

The intelligence of the mollusca, at first pretty evident in the
higher species, such as the octopi, which employ stratagems
to reach and seize their living prey, decreases very rapidly, and
arrives at its minimum in those, all of whose movements are
confined to the opening and closing the valves of their shell,
as the oyster, and which receive their nutriment in the form of
dissociated molecules, and already nearly in a fluid state ;
the habits and mamners, therefore, of this class, do not afford
much matter of interest, when compared with those of the
other classes.

The mollusca are found in habitations of all kinds. In fact,
there are some which appear to live constantly under ground,

230 SUPPLEMENT

as the testacelle ; but this is rare. More of them live in the
air, at the surface of the earth, as the limaces, helices, &c.
Some are to a certain point amphibious; that is to say, they
can breathe the air, by means of their organ of respiration, and
yet live in the water, which they quit but seldom, as for
example, the limnez and planorbis. Finally, most of the
malacozoaria live constantly in fresh or salt water, current or
stagnant, which is the case with all the acephalophora with-
out distinction. The waters of the Dead Sea, though so
strongly bituminous, contain living conchyliferous mollusca.
Some are also found in thermal waters; for example, the
turbo thermalis, a paludine species no doubt, lives in those of
Abano, the temperature of which is 40° of Reaumur, while the
Clio borealis appears to be unable to quit the polar seas.

There are some characters which indicate this difference of
media inhabited by the mollusca. ‘This is certainly the case
with the aquatic and terrestrial species, since the organ of
respiration has a peculiar structure.

But this cannot be observed of those species which are
entirely aquatic, whose gills present no difference to explain
why they should act in fresh water or insalt. Would the shell
itself alone furnish any characteristic differences which would
indicate the nature of the sojourn of the animal? Not by con-
sidering it merely in itself, but up toa certain point it will, by
comparing the shells of marine animals with the fresh-water
or terrestrial, as we shall see a little farther on, when we come
to add a few remarks on the subject of conchology.

It has been a question, whether the species which are
found habitually in salt-water can live in the fresh-water,
and vice versd. ‘This question, to which a great importance
is attached in geology, would be resolved in the affirmative, if
we were. content with analogy alone; for we know indubita-
bly that certain fishes quit the waters of the sea to live in
those of rivers, and others quit the latter for the former, as for

13

ON MOLLUSCA. 231

instance eels, and that almost suddenly. Why should not the
mollusca do the same? However, there is no very positive
fact to prove this possibility, at least for the same species ; for
it is not so with the genera. We know, in fact, that some
species of the same genus can live in the fresh-water, and
others in the salt-water. We are acquainted, for instance,
with one species of true mussel in the Danube, and many
cerites, which are equally found in fresh-water. But if the
species of mollusca cannot suddenly pass from the salt-water
into the fresh, may they not do so gradually? Do we not, in
fact, see in certain ponds, which communicate but rarely with
the sea, and the saltness of which is diminished by little and
little by rain-water, mollusca living, which are truly marine,
and appearing to exercise all their functions there in complete
perfection? ‘The fact is certain, and has furthermore been
experimentally proved by M. Beudant. But it is not equally
certain that animals habitually accustomed to live in the salt-
water, and which are thus forced by natural or artificial cir-
cumstances to live in that which is almost fresh, or altogether
so, can reproduce there. But though not placed out of doubt,
yet the fact which has been observed of marine and fresh-
water mollusca living together, in the slightly salt-waters of
the Gulf of Livonia, is in favour of this opinion, and still
more that which Nilson relates in his history of the mol-
lusca of Sweden, namely, that on the coasts of Norway, in
places where there is no mouth of a river, he has found
uniones, anodontes, and cyclades, living mixed up with mol-
lusca of the genera venus, cardium, and cytherea.

Adanson assures us positively, that during one half of the
year the Niger has only fresh water, and that nevertheless
several genera of mollusca are found there, which, during the
other six months, live in the salt-waters.

The aquatic mollusca, whether marine or fresh-water, also
do not live absolutely in the same circumstances: the latter,

932 SUPPLEMENT

which are but comparatively few, do not, however, exhibit
many differences in this respect, although some remain fixed
to the surface of the ground, like oysters ; such are the etheriz,
according to the discovery of M. Caillaud; others adhere to
submerged bodies by means of a byssus, as the mussel of the
Danube ; others move about in the mud and on its surface, as
the unio and anodontes ; and finally, others live much deeper,
and also move, as the cyclades.

The circumstances of the life of the marine mollusca are
much more variable. Thus the majority live on the sea coasts,
on rocks, and in places in the eddies and mouths of rivers,
which are hence called littoral species. But there is a cer-
tain number of others which appear to exist only at distances
more or less considerable from the shore, and at great depths,
which causes them to be distinguished under the name of pela-
gian mollusca. The terebratule appear to be in this case,
and it is supposed that the nautili and ammonites are still
more so. In fact, the calamary, the sepie, and the spirule, to
which they approximate, are animals of the high seas.

We next find, that according to their mode of locomotion,
some mollusca live continually swimming or floating at the
surface, or in the interior of the waters, or creeping on the
rocks in the middle of the varecs which cover them; others
are attached there in a fixed manner by their shell, or by a
byssus, or, finally, sunk more or less deeply into sponges, in
the mud, in the sand, in rocks, in madrepores, in other shells,
and even in non-calcareous stones, as well as in dead or living
wood.

The species which live in sponges, are in the same case as
mussels, &c. which are found in the holes of rocks; but as the
substance, in the excavation of which they have been acci-
dentally placed, increases, as long as it is living, the result is,
that they are finally completely enveloped in it, to that degree,
no doubt, that they are as it were suffocated.

ON MOLLUSCA. Ise

The mollusca which live in mud, in sand, or even in argil-
laceous earth, really operate so as to sink themselves there, in
proportion as they augment in bulk; and it is evident that this
is done mechanically, and by means of their foot. As for
those which sojourn in hard substances, as in calcareous
stones, madrepores, and shells, it has been thought that their
successive sinking was owing to some corrosive juice or acid,
which was capable of dissolving the calcareous stone. But,
besides that this is any thing but proved, the fact observed
by Olivi and Spallanzani of pholades in pieces of lava, and
that of teredines in living wood, do not permit us to adopt
this opinion.

The terrestrial mollusca present, as may well be supposed,
much fewer variations in the circumstances of their habitat.
In general it is in humid places, and more or less aquatic, that
most of them are to be found; but there are also some that
seem more to court dry places, and exposed to the sun, as is
the case with certain species of helix.

Some persons have even believed that many species were
fixed to soils of a peculiar mineralogical character; but that
does not appear to be probable.

What is most certain is, that the terrestrial mollusca, in
countries where the continuance of some unfavourable circum-
stance, such as cold or drought, forces them to suspend their
vital activity, are obliged to withdraw themselves from it, and
for this purpose they sink more or less into the earth, into the
anfractuosities of bodies, and thus enter into a sort of torpor,
analogous to that of the marmots and other animals. This is
the reason why we find in some places, or rather in one and
the same place, a great quantity of these animals, or of their
spoils, which have probably accumulated there for a long
series of years.

The scientific study of the malacozoaria is even yet so little
advanced, that we know but little concerning their total num-

234 SUPPLEMENT

ber, and their distribution into the different parts of the world.
It may be said, in a general manner, that no part of the earth
is without marine mollusca, terrestrial, lacustral, or fluviatile ;
and that the proportion of the species of these divisions must
be in relation with the extent of the seas, the continents, the
lakes, and rivers.

We may be also assured, that almost all the families exist
in the different zones of the globe, but that the genera and
species of some are much more numerous in one zone than in
another. Thus it would appear that there exist every where
octopi, sepie, and loligines. It is difficult to be so certain
respecting the genera of polythalamous shells; and in fact the
only two of which the animals are a little known, spirula and
argonauta, belong to the torrid zone. ‘The genera of sipho-
nobranchia are also found in all latitudes, but there are many
of the subdivisions which have been established on the shells
of this order, which only belong to the intertropical regions ;
such are the pleurotoma, tonna, lyra, vis, mitra, strombus,
cones, oliva, porcelaines, and ovula, genera of which scarcely
a species is known in our northern seas, and two or three only
in the ocean and the Mediterranean. The number of the
generic subdivisions of shells, of which species are wanting in
the order of the asiphonobranchia, is not very considerable, or
they are represented one by the other, so little do they mutually
differ. We also possess all the genera of the families which
compose the order of pulmobranchia, and they are found spread
over all the earth, only in proportions a little different. Thus
the species of the family of auriculacea are much more rare,
and smaller, in our climates, than in the torrid zone. It is
the same with the agathine and bulimi, dismemberments from
the genus helix. The limnez appear, on the contrary, more
numerous, and even larger, in our climates, than in the warm
countries, which is not the case with the genera planorbis and
physis. We have no species of onchidia or veronicella which

ON MOLLUSCA. 935

appear to represent in the hot climates the limaces of our
zone, as our testacelle replace the parmacelle of the torrid
zone. In all the other families, naked or conchyliferous, we
may almost generalize the same observation, in adding that
the species of the same genera are much more numerous, and
especially much larger in the equatorial than in the polar
regions, and more especially than in ours.

In the class of the acephalophora, we shall equally arrive at
the same result. In the order of the palliobranchia, the lin-
gule are only to be met with in India. We find terebratule,
orbicule, and crania, in all countries. This is still more evi-
dent respecting oysters, which are every where abundantly
distributed. It is not the same with the tridacne, which are
as yet known only in the Indian Archipelago. The pectines
and lime are found in all seas. The umbelle, the pinne, and
crenatulz, appear to belong only to the seas of warm climates.
The mussels, and even the irregular auricule, are of all seas.
It is the same with all the generic subdivisions of the family
of arcacea, and of that of submytilacea. ‘The trigoniz, of that
of camacea, have not yet been found living, except in the
austral zone. Species of all the genera of conchs have been
observed in all seas, but sometimes one of these genera is
represented by another closely approximating. Thus our
cyclades appear to be the cyrene in India, &c. It would also
appear that the venus saxicava are found every where ; and it
is the same case with the mactre. The myz appear rather to
belong to the northern seas, as well as the pandore and some
solens. The oval solens belong rather to the southern cli-
mates. We find pholades every where, and probably tere-
dines, while the fistulane, clavagelle, &c. are almost con-
stantly of the equatorial zones.

The simple or aggregate ascidiz exist also in all zones, but
nevertheless more numerous, and more developed in the equa-

236 SUPPLEMENT

torial than in the polar. This is still more evident with the
biphore, which do not even commence to appear but in the
seas of temperate regions.

The class of the oscabriones has species in all seas, but
much more numerous and larger in those of hot countries than
in others.

It is almost nearly the same thing with those of the class of
the nematopods.

We likewise may say of the families, the genera, and spe-
cies of the acephala, what we have said of the others, that
although more numerous, and of larger dimensions in the
equatorial zones, the genera are represented in all, with few
exceptions.

The relations of the animals of this type with others are not
in general very favourable to them; in other words, they are
more often obliged to fly than to seek them; and though a
certain number of them are zoophagous, there are few which
attack animals of the higher classes. Perhaps there are none
which do so except the brachiocephala, which feed on crus-
tacea and fish. All the other zoophagous species attack only
animals of their own class, and especially of the class of the
acephala, which move with difficulty. Accordingly, we may
say in a general manner, that the type of the malacozoaria
exercise but a feeble action on the preceding types, while the
latter, on the contrary, exercise upon it a very destructive one.
In fact, a certain number of aquatic mammifera, as the ceta-
cea, the morses, but above all, the birds which inhabit the
waters, the amphibious animals, and even the fish, pursue with
more or less avidity the naked or conchyliferous mollusca,
break the shell of the latter, and devour them. Accordingly,
this group of animals does not appear to escape destruction,
except from the places which they inhabit, and the immensity
of their multiplication.

ON MOLLUSCA. 1557

The human species, in its relations with these animals, also
derives many advantages from them, much counterbalancing
any annoyance which they may give us.

We find, in fact, that a very considerable number of species
of mollusca form a part of our nutriment, not only among demi-
savage people, but even among civilized. The savage people
which live on the sea-coast make great use of mollusca for
their food, as we learn from Adanson, respecting the hordes
which inhabit Western Africa; from Molina, regarding those
of Chili; from Cock, Peron, and others, as to the New Hol-
landers; and Forster, regarding the people of the South Sea
Islands. But even in the civilized countries of Europe, the
mollusca constitute a great portion of the food of the inha-
bitants of our maritime coasts, especially in places where the
population is generally poor, and where certain days of the
week or year are consecrated by religious abstinence, as in
Greece and Italy, particularly in the kingdom of Naples, and
also in some parts of France.

‘The aliment which man derives from animals of this type is
in general agreeable to the taste, wholesome, and even excit-
ing; but it is sometimes rather hard and indigestible, espe-
cially when it is taken from the muscular parts which compose
the foot, and which cannot be too much cooked.

The bivalves appear in general to be more esteemed, and of
a more agreeable flavour than the univalves, because they have
a smaller quantity of muscular fibre. In fact, among the first,
the most in request are those whose abdominal mass is
nothing, or at least very trifling, as the oysters, the mussels,
the lithodomi, the pholades, and especially. the teredines,
according to the observation of Redi, who declares them to be
much more delicate than oysters.

As the mass which composes the body of these animals,
especially when they are eaten raw, contains a greater or less
quantity of sea-water, which often acts as a purge, it is not

238 SUPPLEMENT

astonishing that man often experiences an effect of this nature
when he eats a considerable number of these animals; but
it is proved that in certain circumstances, not very easily
defined, and on certain individuals, the effect is much more
intense, and often followed by very grievous consequences.

But it is not merely as objects of nutriment that the mol-
lusca may be useful to man: some of them, few in number, it
is true, furnish him with the materials of clothing. Such are
the pinne marine, whose filaments, which constitute their
byssus, have been employed from time immemorial by the in-
habitants of the coasts of the Mediterranean, and especially by
those of Sicily, to form tissues, equally remarkable for their
beauty and the duration of their natural colour, and also for
their lightness, and their property of retaining heat.

The semi-transparence presented by the valves of the genus
placuna is the reason why the inhabitants of China and the
Philippine Islands employ them to furnish their windows,
where they answer as a substitute for glass.

The property which certain parts of univalve or bivalve
shells possess of reflecting the rays of light by decomposing
them, which characterizes the iridescent mother-of-pearl, has
caused them to be employed as objects of dress or ornament.
We also remove by art from these shells portions of greater or
less thickness of the nacre, or mother-of-pearl ; and according
to their plane or curved form, their thickness or slenderness,
we form the ornaments of a multitude of instruments, of
tables, the pannels of furniture, and of personal ornaments for
the use of women.

We have already remarked, that the human species also |
derives from the animals of the molluscous type many objects
useful in the arts of painting and of dyeing. If it is not abso-
lutely proved that the ink of China is formed of the matter
deposited in the bladder of some species of cryptodibranchia,
it is at least certain respecting the sepia, which has even

ON MOLLUSCA. 239

received its name from the colouring matter which it yields,
and which is so finely and so equally divided.

It is not less doubtful that the ancients extracted the fine
purple colour, with which they tinted the garments almost
exclusively consecrated to princes, from a species of subcepha-
lous mollusca, of the family of the purpure, which inhabited
the shores of the Mediterranean, and especially towards the
coasts of Tyre, and which no doubt it would be easy to find
again, or to replace by some species of our own seas, as has
been proposed by many other writers. But the small quantity
of this colour which was derived from each individual, and
consequently the great difficulty attached to the tincture, must
have led to the abandonment of this employment of the mol-
lusca, especially when means were discovered of replacing the
purple by a colour equally fine, furnished in abundance by the
kermes and the cochineal. .

We shall not delay long in explaining the therapeutic pro-
perties attributed by the ancient physicians to certain parts of
the mollusca, because time has not respected those opinions,
but has destroyed them in succession. The only one which
appears to have resisted its influence is that of the calming
and soothing virtues of the decoction, or rather broth, made of
snails and others of the limax and helix tribe, in affections of
the chest and lungs. This, however, is any thing but a spe-
cific remedy. We may add the slightly purgative quality of
oysters and pectines when eaten raw, which, most probably,
as we have already hinted, may be attributed to the sea-water
which they contain.

After what has been said, it is evident that the principal
utility of the mollusca to man consists in the article of diet ;
but we shall also find that these animals are less injurious to
us than useful.

The octopi are perhaps the only species which, by their
carnivorous instinct, may prove injurious to us, in the relation

940 SUPPLEMENT

of our animal nutriment. It is indeed well known, that they
cause considerable injury to fishermen employed in pursuit
of the crustacea, by the great destruction which they make
among these animals, because, like them, they inhabit rocky
places.

Our vegetable aliments indubitably suffer more considera-
ble damage from the voracity of the limaces and helices which
inhabit our fields and gardens. But this is an inconvenience
proportioned to the development of our agricultural or horti-
cultural industry, which accumulates in a small space the
substances of which these animals are fondest.

Our habitations in the open country do not appear to suffer
any damage from the mollusca; but it is not the same with
our constructions on the sea-shore, or with those which are
destined to float upon its surface: the lithophagous venus,
and especially the lithophagous mussels, and the pholades,
to lodge themselves in the stones which constitute our dikes,
pierce them in all directions; and although they do not do
this very deeply, they nevertheless hasten the destruction of
these works.

This is still more evident in the case of the teredo, the
species of which select wood in which to excavate their
dwelling. In those countries where the people are obliged
to construct dikes supported by wooden piles to protect them-
selves from the invasions of the sea, as in Holland, the damage
is considerable ; for at the end of a few years they are so much
pierced below the level of the water that it is necessary to
renew them. Vessels which remain a long time in harbour or
in docks are also exposed to the destructive action of these
animals, more especially, as it would appear, in the seas of
warm climates. In fine, even living trees, whose roots or
stem happen to be submerged, are attacked by the teredo, as
Adanson relates of certain trees on the banks of the Niger in
Senegal.

ON MOLLUSCA. 241

The relations of the mollusca with the mineral kingdom,
and consequently with the mass of the earth which it has
contributed to form, are not without interest ; for without
attempting here to resolve the physiological question whether
the conchyliferous mollusca borrow from the inorganic king-
dom the calcareous matter which composes their shell, or if
it is formed of all materials, it is however certain that they
produce no inconsiderable changes in the surface of the earth,
by accumulating this matter in some places more than in
others, and consequently, that they alter its physiognomy or
superficial structure, the study of which constitutes geology,
or as it is sometimes more properly termed geognosy.

The modes in which this accumulation is made are alto-
gether different, according as the mollusca from which the
shells proceed were fixed or not, lived embedded in mud or
sand, or were free on the superficies of the rocks or of the
soil. Thus the oysters in our climates, the pintadini or
regular avicula in warmer regions, as well as the spon-
dyles and many other Vivalves, form by their accumulation
banks more or less extended, strata more or less thick and
horizontal, in which the shells are still at the present day in
the position in which they originally lived, and almost with-
out any admixture of foreign bodies. Although this is less
evident respecting the cardia, the telline, the lutraria, the
my, &c., and all the genera of bivalves which live vertically
sunk in sand or mud, we see nevertheless that these shells
must also form sorts of strata, because the individuals newly
born are deposited by their parents above themselves, so that
the latter, sinking in the sand in proportion as they enlarge
in bulk, depress their parents, and the individuals below them
im succession, so as to remove them sufficiently from the
surface of the soil to prevent their tubes receiving any water,
the consequence of which is death. Then their shells, vertical

VOL. XII, R

242 SUPPLEMENT

while the animal was living, begin to incline by degrees,
become horizontal, are filled with the substance in which
they were sunk, resist the pressure of the accumulated strata,
so aS sometimes to remain perfectly entire, with all their
asperities, or if not so, they are broken and crushed, and
disposed in beds more or less free from every other shell, or
even from every other foreign body. This is very perceptible
in the alluvions formed at the present mouths of our great
rivers, or in the creeks of our sea-coasts, where currents pre-
vail, which justifies our presuming by analogy that at those
parts of our continents where similar accumulations are to be
found, there was formerly the mouth of ariver, or some gorge
in which the waters formed an eddy. The other mollusca,
living freely at the bottom of fresh and salt water, without
sinking in the sand or mud which constitutes this bottom, or
sunk only in the moveable part, at their death abandon their
shells. These shells, rolled, overturned, cast against the
rocks and the projections of the soil by the movements of the
waves, are broken, reduced to a fragmentary state, more or
less fine, and are then drawn along in the habitual direction
of the currents and the winds, and accumulated along the
shores, especially in bays, over an extent and to a height
often very considerable. The strata which result from these
are thus entirely composed of fragments, more or less bulky, of
shells, often rolled, which consequently have lost their aspe-
rities, and are often of very different genera, which depends a
little upon the localities. It is also remarked, that in the
structure of these strata the fragments are in general deposited
according to the laws of specific gravity, and that they are
little or not at all intermingled with mud or other foreign
substances, the entire shells which have escaped the de-
structive action of the currents, being filled even to the bottom
with detritus, or coquillaceous sand. Many specimens of this
13

ON MOLLUSCA. 243

augmentation of land are to be seen in various parts of our
coast. ‘These are the depositions which, in the course of time,
by the long continued action of the pressure of superior strata,
as well as by the tendency of inorganic matter, thus pressed
and broken, to crystallize, grow more and more solid, and are
converted into calcareous rocks, which end by no longer pre-
senting any traces of their ancient organic disposition.

Previously to turning from the consideration of this divi-
sion of the animal kingdom, as a whole, to a short review of
its several sections, it may be useful to advert to the general
principles by which these animals have been classified.
These are of the same kind which are applied to the other
types of the animal kingdom. The facility of collecting and
of preserving the shells or envelopes of these animals, the
beauty of form and colour which frequently distinguishes
them, and especially the consideration that they exist alone
in the composition of certain strata of the earth, has some-
‘times given rise to a contrary opinion: but this was truly
erroneous. Thus the principle, par excellence, that the
entire organization should be our guide, and that it is the
external organs which should represent it, and furnish dis-
tinctive characters, is equally admissible in this as in every
other part of zoology. But as the ensemble of the organiza-
tion of the moilusca is sometimes pretty rigorously translated,
so to speak, by the shell, and as the latter is evidently one of
the most prominent of the external parts, and of which there
is the most need in the accessory application to geology, a
deception has resulted in the application of the principle, and
a belief that it was possible to arrive at a methodical classifi-
cation of the mollusca, by a simple consideration of the shell;
this unquestionably appears to be a mistake.

The consideration of the local habitat should be allowed
no importance in the classification of the mollusca, still less

R 2

244 SUPPLEMENT

should that of the country, because neither furnish any cha-
racters imprinted on the animal or on its shell.

That of the nature of the aliment should not be admitted as
of much more importance, because, though it is possible to
conceive a certain correlation of visible organs with the
structure of the digestive apparatus, more or less modified for
a peculiar alimentary substance, yet such is never the case
' with the mollusca. Accordingly we find species essentially
carnivorous, as the testacelle, close by herbivorous species,
like the limaces.

The existence or absence of a protecting body is evidently
of greater importance, since it is a character altogether ap-
parent; nevertheless it is easy to see, though the number of
exceptions be not very considerable, that in the same genus
we may find conchyliferous species and others completely
naked.

The particular form of the body, the visceral part of which
constitutes a wreath more or less elevated, is yet of less im-
portance.

The appendages, the lobes, the cirrhi which border the
mantle, are of no greater import to consider, unless perhaps in
the lamellibranches, in which the consideration of the tubular
lobes, which prolong the mantle behind, present characters of
real value.

The distinction of the head from the rest of the body, as it
is complete, incomplete, or non-existent, conducts to some
divisions of the first order in the type of the malacozoaria,
but it isa character not always sufficiently well marked.

The number, the form,.the position of the tentacular ap-
pendages which accompany the head, have perhaps some-
thing still more constant, and consequently more essential to
study, for the establishment of a classification in the mol-
Jusca. We nevertheless occasionally find inexplicable ano-

a

ON MOLLUSCA. 245

malies; such is that of the carychia, in which the true ten-
tacula disappear by little and little, while all the other
animals of the same family possess them in a very evident
manner.

The position of the eyes is also worthy of some considera-
tion, but less perhaps than the tentacula. We find, in fact,
some genera of the same family, or even some species of the
same genera, which have eyes subpedunculate, and others
which have them sessile.

The form, the position of the principal organ of locomotion,
that is to say, of the foot and the natatory appendages, give
rise to considerations of still greater value in the classification
of the malacozoaria; and as the characters derived from them
are evidently exterior, it is not astonishing that they have
been employed so often, and with much advantage.

A better character perhaps in the relation of its importance,
but unhappily more difficult to observe, which no doubt has
prevented its employment, is that which may be drawn from
the armature of the mouth, either at its orifice or in its in-
terior, since it is in relation with the nature of the aliment.

Another still preferable, because it agrees with the form of
the shell in general pretty well, is derived from the position,
the symmetrical or non-symmetrical form, and even from the
structure of the organs of respiration. But unluckily, though
these organs are most frequently pretty nearly exterior, a cer-
tain degree of habit is necessary to enable us to employ this
character with advantage.

In fine, the part of the organization of the mollusca which
appears as yet to present the character of the greatest value,
is that which constitutes the apparatus of generation, com-
posed of the two sexes in different individuals, or united in
one individual, or, in fine, formed of a single female sex.
Unhappily, again, this character is entirely anatomical, and
consequently of difficult application in zoology.

246 SUPPLEMENT

Lastly, the consideration of the shell alone ought not to be
regarded as altogether of no value, or useless, especially when
we review in succession the differences according to their
degree of importance: 1. the number of pieces which enter
into its univalve, sub-bivalve, or operculate, bivalve, tubi-
valve, and multivalve composition; 2. the position on the
body of the animal, dorsal, as in all the cephala, dorsal and
ventral, as in a small number of cephala and acephala, or
finally bilateral, as in all the lamellibranches ; 3. the indices
of its relations with the respiratory apparatus, that is, the ex-
istence of an emargination or a tube at the anterior extremity
of the aperture in the univalves, or of an hiatus more or less
considerable of the posterior extremity in the bivalves; 4. the
indices of its relation with the muscular system of the animal,
simple in a great portion of the univalves, but merely visible
in the patelloides and otides, more or less complex in the
bivalves, and formed, as we have already seen, by one, two,
or even many impressions of the adductor muscles, one, two,
or a greater number of impressions of the retractor muscles of
the foot, by the abdominal ligula, an index of the attachment
of the edges of the mantle, and finally, behind, by that of the
tubes of respiration; 5. the symmetrical or non-symmetrical
form which involves the similitude or dissimilitude of the
pieces in the bivalves; 6. the form of the aperture in the
univalves, the manner in which each edge and the columella,
or its vitreous depot, contribute to form or modify it; 7. the
ligamentous system, or the dovetailing, so to call it, of the
two pieces of a bivalve shell, that is to say, those of the hinge
and of the teeth which compose it, observing that each
genuine species has a peculiar system of indentation on the
edges of the shell; 8. the consideration of the existence or of
the absence of an operculum in the univalves, of its structure,
form, &c.; 9. the total form of the shell, the proportion of
the spire, and of the aperture in the univalves, the direction

ON MOLLUSCA. P47

of the latter, and in the bivalves the proportion of the two
sides of each valve, the direction of the furrows with which
the superficies is worked, the system of coloration, of epi-
dermic covering, &c.

After this rapid sketch of the degree of relative importance
of the characters which the different parts of the organization
of the mollusca may present, and after the observation that it
is often useful to consider their spoils, or protecting bodies
isolatedly, we must add, that though this last be of real im-
portance, the true basis of classification is, as much as pos-
sible, in the general form of the body, the distinction more or
less complete or non-existent, of head and body, and the
organ which afterwards has most influence in modifying the
shell, namely, that of respiration; at the same time observing
that the same form of the shell may sometimes, though rarely,
be represented in genera sufficiently different; such, for ex-
ample, is the form of the haliotides, which exists in the pul-
mobranches, in the chismobranches, and in the otides; it is
the same with the patelloid and turriculate form, &c.

Such are the principles followed by the most recent natu-
ralists, for the divisions and higher subdivisions of the mol-
lusca; let us now briefly consider those which regard the
distinction of species, by far the most difficult part of science
im all the types of the animal series, but still more in this
than in any other, in consequence of the employment which
has been made of the shell alone for this distinction.

If the sex and age have an evident influence in determining
the differences in the molluscous animal, and consequently
in its shell, it is not less evident that circumstances not easily
explained may act less profoundly no doubt, that is, little on
the animal, but much upon the colour, size, and proportion
of the parts of the shell. Of this we have certain proofs in
species a great number of whose individuals may be seen at
once, as the helix nemoralis, the limnza stagnalis, the buc

948 SUPPLEMENT

cinum Japillus, the neritina of the rivers, the common patella,
the eatable oyster, the eatable mussel, and many species of
cardia, &c., in whom we find individuals in the same locality
differing one from the other, in all those characters of the
shell which we have enumerated above.

More justly may we conceive that an assemblage of cir-
cumstances to a certain point inexplicable, and which have
acted for a very long period, may have influenced almost in a
fixed manner a succession of individuals of the same species,
and determined in shells certain differences in size, propor-
tion, colours, system of coloration, and even in the state of
the superficies, smooth or rugose, especially when they shall
be compared to other individuals of the same species living
for a long series of ages in different localities. These differ-
ences then really constitute, as it would appear, but simple
fixed varieties, so much the more dissimilar as the localities
are more remote, and which we may, if we think proper, de-
corate with the name of local species, but which are not real
species. In fact, when we come to assemble these pretended
species from a great number of different localities, we shall
find that they pass one into another in a manner almost in-
sensible. M. Defrance, who had occasion to make the same
remarks on the distinction of fossil shells, inquires whether a
species be genuine if that to which it approaches the nearest
is to be found in the same locality? Though this rule can
hardly yet be considered as very rigorous, it may assist in a
subject so difficult, and one so important for geology. ‘The
minute study of living species can alone furnish analogical
means to diminish the difficulty, and consequently supply
geologists with data, to resolve the problems concerning the
analogy of formations in the structure of secondary and ter-
tiary strata.

Notwithstanding the great length to which this supplement
on the division has already extended, we can find no better

ON MOLLUSCA. 249

place for the insertion of a few general observations on the
principles of CONCHOLOGY, inasmuch as the naked and co-
quillaceous do not form two distinct divisions, and that such
general observations (which by the way involve all the in-
terest in the subject to all except professed conchologists,)
could with no propriety be introduced and distributed among
any subsequent remarks we may have to make on the orders
or genera.

Conchology is the art of arranging the shells, or rather the
protecting bodies of testaceous animals, so as to enable us to
recognize them promptly and certainly, without giving any
attention to the animals which they have contained, or con-
tain, or at least regarding this part as a matter of very minor
importance. We have already said quite sufficient concern-
ing the animal, and concerning the shell too, as a portion of
that living animal; what we have now to say will refer
merely to the envelopes themselves, which may be preserved
independently of the animal, and which, in fact, may have
belonged to animals of classes and even of types very different
from each other; and consequently in this point of view we
must follow the method of Linnzus and of a great number of
other naturalists, though we cannot avoid regarding it as
totally artificial.

For a long time this portion of natural history, which may
almost be said to have been invented for the gratification of
amateurs of the rare and brilliant, was regarded as a study
nearly idle and useless by all true zoologists; and this was so
far true that it was often more necessary to be acquainted
with the shells in their artificial state, to which they were
brought by the application of emery and other substances,
and by processes which removed even one or two of their
strata, than in their truly natural state, in which they were
often rejected. , Consequently, all those shells which either
naturally, or by art, presented nothing remarkable, no singu-

950 SUPPLEMENT

larity, were remorselessly excluded from the cabinets of col-
lectors. ‘The methodical zoologists would at last have ended
by totally annihilating this art or study, or by degrading it
into a mere pastime, if geology, from the lofty flight which
she has taken in these latter days, had not found the necessity
of characters extremely minute for the purposes of compa-
rison, either between fossil shells, or of the latter with living .
species. Itis really to this cause that conchology, properly
so called, owes both the continuance of its existence, and the
daily increasing efforts of enlightened naturalists, who endea-
vour to give it sure principles and rules, by means of which
geologists may be guided in their minute researches and the
very difficult problems which they propose to resolve. Con-
chology then, or perhaps a better word would be ostracology,
forms among the natural sciences a branch altogether se-
parate, which may have its proper and particular rules, and
to which there would be nothing analogous, unless we should
think proper, for example, to examine in detail the hairs of
mammiferous animals, the feathers of birds, or the scales of
fishes. It appears, however, that if we could, while we
studied conchology in a manner perfectly independent, so
manage that it might be contained altogether in malacology,
equal utility would result both to the science of animals and
to geology, or palzeozoology. 'To this object our researches
should unquestionably be directed, though at the same time
we must confess the predominant weight of geology in this
question.

Every art, be it what it may, has necessarily a greater or
less number of terms which are proper to itself, or common
terms, whose acceptations are peculiar. These we name
technical, which it is of the utmost importance properly to
define, so that they may be well understood, and which are
conveniently employed to avoid the long circumlocutions to
which we should be forced to recur by the-usage of ordinary

/4av

1 Brachionus urceclareus
2B. plicahths.

2 DB. striatus

4 2B. hracteus

5 DB. patella

6 Lurcudarta’ revivitiabiles

7 Verlicella hemispherica

8 V. secratis

9 V. buceina.

10 Vretelarta appendicula

WL corral
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14 Follicudina’ ampilla.

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2 Bursaria truicatela. IT. ignite.

3 Bur. Trrundinellar. 10 Zr. mielitea

4 Kolpoda cuctllus. WZrt. versaklis.
5 Kel. meleagres. 12 77rt. aurarntia.
6 Leucophra viridesvena, Vb Tre. bipes

7 Lew. nedulesa . M4 Tri. Jepus.

Roophytes PL. 20 .

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19 Cer. catedlus.

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ON MOLLUSCA. ATi ¢

phraseology. ‘Those technical terms we are about briefly to
explain, and we shall conclude by a sketch of the history of
this science.

We have, in reality, no other generic terms to indicate the
hard, calcareous, fragile bodies which form the object of this
part of natural history, than that of envelope, or better, per-
haps, of protecting body or of testa; for by that of shells, or
conche, we simply understand those of the molluscous ani-
mals. The Greeks had the word ostraca, whence ostraco-
dermata and ostracea ; and the Latins that of testa, whence
the denomination testacea, or animals covered with a testa or
hard envelope. Nevertheless the vulgar appellation of shells
(more vague perhaps in English than in some other lan-
guages) has prevailed, and the term conchology is in general
use.

Quitting, however, these verbal criticisms, we understand
by shells or protecting bodies, bodies of a very variable form,
cretaceous, more or less thin, breaking off readily and com-
pletely, easy of preservation, and constantly in relation with
the skin of an animal.

In considering at first these bodies in a general manner,
and under the relation of structure, we find a first division of
shells, namely, into false and true.

A false shell is that which does not belong to a molluscous
animal, or rather that which is composed of a great number
of small polygons applied side by side, and the ensemble of
which forms a calcareous, hard, and frangible envelope, which
is seen in the testa of the echinites.

A true shell is that which is formed of lamine applied one
within the other; the most recent and the largest being the
most internal, and the most ancient and smallest the most ex-
ternal, whatever its form may be and the number of pieces of
which it is composed.

252 SUPPLEMENT

The general study of this form then gives a division into
those which are tubular and those which are not.

We call tubular shells those whose transverse diameter is
considerably smaller than the longitudinal, and which are
not enrolled or turbinated, or if so, only in a very irregular
manner, and never in a spiral. ‘These are the tubes of certain
genera of setépodes, which have another distinctive character,
namely, that the summit. (head) is always open, which is
never the case with the shells of the mollusca proper.

The non-tubular shells are then divided into shells of a
single piece, these are the wntvalves; and into shells of many
pieces, or multivalves ; and these last into bivalves and multi-
valves, or dissivalves.

According to this, we must understand by valve (valvula)
a calcareous piece of a very variable form, applied on or in
the skin of a molluscous animal, and covering a greater or
less part of it; but then we must often have recourse to the
skin of the animal to judge whether a certain number of these
valves belonged to one individual; as, for example, when
they have no direct relations between themselves, but only
indirect by means of the skin. ‘This is the reason why for a
long time one valve of the testa of the lingula has been re-
garded as an univalve shell.

The multivalve shells are of three sorts; those which are
composed of many transverse imbricated pieces, as in osca-
brio, those which are formed of five or many valves, sym-
metrically ranged on the right and left, and sometimes even
placed in scales, and united together by means of the skin, as
in anatifa, (these are the dissivalves of M. Denys de Mont-
fort), and finally, those which are disposed in a manner almost
circular, as in the balani and neighbouring genera.

The bivalve shells are those which, as their name indicates,
are formed only of two pieces; sometimes, it is true, enclosed

‘
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ON MOLLUSCA. 253

in a tube, or calcareous envelope, more or less developed,
which some authors erroneously consider as another valve.
They are always applied on the sides of the animal, and con-
stantly in a relation more or less marked between themselves.
Nevertheless, we should mention that this relation between the
two pieces of a bivalve shell not being always evident, we may
be sometimes led into error, and induced to regard as having
belonged to an univalve, a piece or valve which belonged to a
bivalve, as in the lingula, some species of camus, &c.

The wnivalve shells are, on the contrary, a testa of a form
extremely variable, sometimes even almost tubular, which
covers the molluscous animal more or less, and may also be
entirely concealed in the interior of its skin.

The univalve shells may be considered under several differ-
ent relations, which we shall just briefly mention here.

1. Under the relation of the places in which they are found,
or rather of the animals to which they have belonged, it has
been thought proper to distinguish them into terrestrial,
Jluviatile, and marine. But it must be owned that this dis-
tinction is often very difficult, and that its importance has been
exaggerated, as far as the use that the study of fossils may
derive from it.

The terrestrial univalve shells are generally rather thin ;
their external surface, most frequently smooth, presents little
but the striz of growth, and never any spines or asperities
properly so called. The surfaces, both internal and external,
are never nacreous. ‘Their aperture, always entire, has very
often, at least in the adult state, and only in these species, its
edges thickened in the manner of a pad, or more or less thrown
out externally.

The univalve fresh-water shells are also pretty generally of
no great thickness ; they are sometimes furnished externally
with some striz, and even with spines; and under the epider-
mis, which is almost always thin, smooth, and of a very deep

254 SUPPLEMENT

green, we pretty frequently find that they are nacreous, or of
an exceeding whiteness. Never, at least up to the present
time, have any been found, the aperture of which is really
emarginated, and its edges are always straight and trenchant.

As for the univalve marine shells, they are often very diffi-
cult to be distinguished from the preceding. In general, how-
ever, they are thicker, and much more frequently provided
with pads, varices, spines, &c. Their aperture, very fre-
quently emarginated, or elongated like a tube, more or less long
anteriorly, is pretty often edged by a thick pad, which may be
tuberculous, scaly, or laciniated. ‘They are sometimes nacre-
ous in the interior, when they are covered by an epidermis,
which is scaly, pilose, and in general of a very different
aspect from that of the terrestrial, and even of the fresh-water
shells.

2. Under the relation of the degree of depth at which they
are found, the marine mollusca have been separated into
littoral and pelasgian, according as they are to be met with
on the sea-shore, or at depths more or less considerable in the |
high seas. But it must be allowed that this division is still
worse than the preceding, since no character inherent in the
shell can be brought in support of it.

3. Under a relation almost anatomical, a distinction of
shells has been established into external and internal. The
internal shells are in general much thinner than the external,
flat, or but slightly rolled, and without epidermis, of no colour
but white or yellowish.

4. The size is next taken into consideration, for the sepa-
ration of univalve microscopic shells, which are those, as may
easily be conceived, which are so very small, as not to be
seen but by the assistance of the microscope. But such a
division can by no means be clearly exact.

5. If we consider the general form of univalve shells, with-
out paying attention to any of their parts, denominations are

ON MOLLUSCA. 255

employed, which, though vague enough, are nevertheless
necessary to be known.

The first distinction is that which relates to the equality or
inequality of the two sides of a shell, of whatsoever form,
separated by a fictitious axis, taken from the head to the base,
or from one extremity to the other. A shell is named symme-
trical, the two sides of which are perfectly equal, and non-
symmetrical when such is not the case. Thus the bone of the
sepia, the shell of the argonaut, that of the patelle, &c. are
symmetrical. ‘The Chinese patelle, the sigaret, and many
others are not symmetrical.

The flat shells are those which have no cavity, as the bone
of the sepia, the Chinese patella, &c.

The tubular, those whose diameter is considerably less than
the length.

Covering or sheathing, those which are conical, and with-
out any spire, properly so called, as in the patelle.

Spiral, those which are more or less turned, and in differ-
ent directions, as we shall presently explain. But it is first
necessary to define some terms, which belong to the shell con-
sidered in the mass. We name,

Discoid, those which more or less resemble a disk, and
which, considering the manner in which the spire is rolled,
are termed rolled, as in the ammonites.

Depressed, the species oval or rounded, whose form is very
much flatted, and the spire very short—for example, the
sigaret.

Globular, those of which all the diameters are obviously
equal, in consequence of the great development of the last
turbination of the spire, which is much larger than that which
precedes, as in the ampullariz, &c.

Oval, or ovoid, the species whose longitudinal diameter is.
a little longer than the transverse, as in the porcelaines, and a
considerable number of the helices.

256 SUPPLEMENT

Navicular, some shells which, when turned on the back,
with the aperture upwards, have a certain resemblance to a
small boat, as the argonauta.

Pyriform, when one of the extremities is thick or swelled,
and rounded, and the other pointed in the form of a tail—for
example, the pyrula.

Conical, when one of the extremities, being widened, is as
it were cut squarely, the other being pointed and forming the
summit. When it is the summit or head of the shell itself
which forms the summit of the cone, the shell is named tur-
binated, as in the trochi; and it is called conical or convoid,
when, on the contrary, the summit of the cone is at the ante-
rior part of the aperture, as in the coni properly so called.

Cylindrical, when the shell is elongated, and of a breadth
or bigness pretty nearly similar, both in front and back. Such
are most of the involuted shells, as the olives, &c.

Fusiform, those which, swelled in the middle, are pointed
at the two extremities—for example, the fusi.

Turriculated, or turreted, those which are very much elon-
gated; that is to say, whose longitudinal diameter is much
longer than the transverse, which depends upon the manner
in which the spire is formed—for example, the turritelle.

6. The univalve shells may finally be considered in the
relation of the distinction of each of their parts.

A univalve shell may be conceived always to have a sum-
mit or point where it has begun, a base which is its actual
termination, and an intermediate body, with a cavity sometimes
almost imperceptible, in the case where it is extremely de-
pressed or altogether flat, and then it has really many relations
with one valve of a bivalve shell. It is altogether the reverse
in the tubular or tubiform shells, which much resemble the
calcareous tubes of certain setipodes.

But before proceeding farther, it may not be superfluous to
explain the position in which conchologists place the univalve

ON MOLLUSCA. 257

shells, for the purpose of studying and naming their different
parts. Linneus, Bruguiéres, Da Costa, Lamarck, &c. place
the shell which they study standing on the extremity opposite
to the head, and the aperture in front of the observer. M.de
Blainville, on the contrary, imitating Draparnaud, and many
other authors, supposes it placed obliquely on the back of the
animal, or what comes pretty nearly to the same thing, applied
on a table, on the side of the aperture, and consequently the
head, or highest point, being backwards, and upmost, while
the opposite extremity is in front,and below. From this it re-
sults, that the names of right and /eft are applied to the same
sides, according to the two different points of view ; but those
of ¢nferior and superior, in the description of the aperture and
its edges, are replaced by the words anterior for the first, and
by that of posterior for the second.

The summit or head (apex), which is the part where the
shell has begun, may be altogether flat or very projecting,
straight or vertical, or inclined directly backwards, to right, or
left, but it does not appear to be ever directed forwards. It
may be pointed or nippled, entire or carious, and even some-
times hollow, as in the bulle.

The base (basis), or the part usually opposed to the summit,
is that in which the aperture, of which we shall presently
speak, is invariably pierced. Under this name, however (for
we follow the system of M. de Blainville), we do not under-
stand what Linnzus and the majority of conchologists so desig-
nate. In fact, with them it is the extremity, pointed or not,
opposite the head, and they name it thus, because, in their
manner of designating the different parts of a shell, they placed
it vertically, the head being above, and the aperture in front; but
in the system which we follow, the base is all that part which
rests more or less obliquely on the back of the animal. Some-
times this base is very broad and round, as in the trochi,
which gives them the form of an inverted top; at other times

VOL. XII. S

258 SUPPLEMENT

it is small, asin the vis, &c. It may be very much elongated,
as for example in the cypreade. It is formed entirely by the
aperture in the patella and some others, and at other times by
a portion of the last turn of the spire.

Its direction, which is usually that of the aperture, also pre-
sents some considerations which ought not to be neglected :
thus, it is altogether perpendicular to the axis of the shell in
the patella, &c.; and it is almost entirely in its direction in
the cypree and olivi. The other shells are more or less inter-
mediate.

The body of the shell is all that portion which is between
the basis and the head. Most frequently it is hollow in the
interior, and serves not only to cover the body of the animal
on its upper part, but also to contain a greater or less portion
of it.

Sometimes it receives the name of discus, as in the halio-
tides; but then only the last turn of the spire is comprehended
under this name.

In a certain number of shells or teste, the body is curved in
no direction, neither to the right, nor to the left, nor in front,
nor in rear, and is even in no wise excavated. These are
named flat shells, symmetrical in the bone of the sepia and
the calamary, non-symmetrical in the patella Sinensis.

Pretty often the base and summit are united by a body
which is not recurved in any way, but which is more or less
excavated. This constitutes the covering or sheathing shell,
as in the patella, the emarginule, and especially in the den-
talia.

Finally, in many cases the body of the shell is formed by its
enrolment in different ways. Such it is in the true coch-
lide or spirivalves. ,

To form a just idea of this, we may conceive that every uni-
valve shell was a cone more or less elongated, but flexible.

If it be rolled from rear to front, and from top to bottom,

a ee ee

a

ON MOLLUSCA. 259

absolutely in the same vertical plane, there results a discoid
shell, compressed from right to left, the summit of which can-
not be visible but in the same direction, and the axis of which
is altogether equally transverse. These sorts of shells the
French name enroulées, and we volute (revolute). A rigorous
example may be taken from the argonaute and neighbouring
genera, but not in the planorbes, which are really subvolute.

The principal differences presented by this sort of voluta-
tion, or rolling, consist in its greater or less perfection; we
name arched, the shell which only presents an arching more
or less considerable, as in certain species of belemnites.

Curved, that in which the body begins to be much more
curved, as ammonoceros.

Semi-volute, that in which the turns of the spire, which we
call whorls, do not touch, as in spirula.

Volute, when the whorls touch, as in the true ammonacea.

And finally, very much voluted, the species in which the
whorls penetrate each other reciprocally, so as that the last
whorl or circumvolution conceals all the others, and the
aperture is modified by it, as in some nautili.

If, on the contrary, the rolling of the spiral cone is made
transversely, or from left to right, this constitutes what are
called énvolute shells. |

In these species the base of the shell is almost as long as
the latter, as well as its aperture, and the axis of volution is
longitudinal. There are in reality scarcely ever any shells
completely involuted; those which approach the most to
being so are the cypreade and the ovule. Sometimes the
shell does not make a complete whorl, as in the bullez, and
then the aperture is as broad and as long as the shell itself.

Finally, the great majority of univalve shells are interme-
diate to both these arrangements; that is to say, that the body
of the shell is the result of an oblique volutation from right to
left, and from bottom to top, if we consider it from the base

$2

260 SUPPLEMENT

to the head, or exactly the reverse if we follow the growth of
the shell. Those are the true spirivalve shells which we
name turbinated.

The name of spire (clavicula) is given to all that part of a
spirivalve shell which is formed by the revolution of the
spiral cone.

That of circumvolution or whorl to a complete revolution
of the spiral cone.

Sometimes we distinguish from the totality of the spire the
last whorl, which is usually the biggest, and where the aper-
ture is found; and it is designated under the name of the
body of the shell. The face, which is found to correspond
to the aperture, is the Jelly, that which is opposed to it the
back ; but Bruguiéres will have it that the belly is only that
part of the last whorl which forms the left portion of the —
aperture, and on which the internal lip is attached. Be this
as it may, the name of clavicle is reserved for all the rest of
the spire.

The direction according to which the rolling of the spiral
cone is made serves to distinguish the shells into right and.
left. In general the actual termination of the shell is at the
right of the animal, and consequently proceeding from this
point, the volutation or torsion seems to be made from right
to left, going from base to head: such are the normal spiral
shells. But it happens pretty often, that the animal being
anomalous in this respect, is, as it were inverted, that is,
what is usually at the right is found at the left, and vice
versa, and then the shell is equally anomalous by having its
terminal edge at the left. These shells are called left, or
sinistre, or heterostrophes.

The consideration of the spire, properly so called, but taken
as a whole, gives rise to some technical terms, which to a
certain point are involved in those used to designate the
general form of the shells. The spire is called

ON MOLLUSCA. 261

Flatted when the united whorls form a surface altogether
flat, as in conus cardinalis.

Crushed when the progress in a vertical direction is but
little rapid compared with that in an opposite direction.
These are the shells which approach a little to those named
above, discoid ; for example, the solaria.

Moderate when the progress in both directions is pretty
nearly equal, as in the buccina, &c.

Elevate when the spiral cone advances more in height than
in breadth.

Elongate when this disposition is still more marked.

Turreted, or turriculate when with a similar disposition
the whorls are very exactly separated by their different divi-
sions of thickness, as in mitra.

Decollated when in consequence of age their extremity is
broken.

Coronate when the edges of each whorl are armed with
projecting points, with tubercles or spires, as in a great num-
ber of coni, and in the Ethiopian voluta.

The whorls, or turns of the spire, also give rise to many
characters, which are expressed by determinate words.

As to their number, they are reckoned either in proceeding
from the summit or from the end of the spiral cone.

Their proportion one to another is expressed in ordinary
terms. It often happens that the last whorl but one is bigger
than the rest altogether; sometimes the last is smaller than
the last but one, &c.

The whorls themselves may sometimes be quite flat, to
which the name of ribboned has been given, as in terebra.
Sometimes they are distinguished with difficulty, and may be
considered as almost confounded ; finally, they may be sepa-
rated from each other by a pretty deep furrow, as in the
olives: this line of separation between thé whorls is named
sulure (sutura).

262 SUPPLEMENT |

The superficies of the whorls is also to be regarded. They
may be designated under the name of carinated when in the
direction of their length they present an angle or fold more
or less marked; smooth when they have no projections or
anfractuosities; rugose, tuberculous, when their surface is
charged with rugosities or tubercles; striated when they are
striped in breadth or length; trellised when this takes place
in both directions ; corded when they are bordered by a pro-
jecting and knotty side; costate when the pad of the left lip
holds on the whorls, as in lyra; varicose when the continuous
pads of the right lip are more or less tuberculous and de-
sected, as in murex generally.

According to the notion which we have given above of the
formation of a spiral shell, we shall see that if the whorls
touch not transversely, i. e. from right to left, nor from top to
bottom, there will be perceptible in the middle of the shell a
conical depression extending from summit to base (which is
named wmbilicus in Latin), and at the same time a vacancy
more or less considerable between each whorl, as in the ver-
metus of Adanson, and in the true scalaria. ‘These shells are
named disjuncte (disjointed.) Tf, in rolling, the convolutions
of the cone touch each other from top to bottom, but not
transversely, we have a shell strongly umbilicated, as in the
scalaria; and finally, if the whorls of the spire touch in all
directions, without encroaching, or more especially if they
should encroach upon each other, constituting in the first case
a complete spiral cone, or in the next an incomplete one, it
follows that the fictitious axis is no longer free, no longer
hollow, except sometimes at the base, and that it is replaced
by a sort of small twisted pillar, resulting from the contact,
and interfusion of the internal edge of the cone, on which it
is rolled. In fact, in examining a shell of this nature from
base to summit, we see in its interior a solid part more or less
tortuous, to which is given the name columella, pillar in

ON MOLLUSCA. 263

English ; and as this sort of pillar, when the base of the shell
is very oblique, is often lengthened to its anterior extremity,
it is it which in this case forms entirely the left edge of the
aperture, in consequence of which that sometimes receives
the name of columellaria.

This column or pillar is called pointed when it is termi-
nated anteriorly in a point, as in lyra; truncated when it ap-
pears to have been cut, as inthe agathini ; salient or project-
ing when it forms an elongation in front of the shell, as in
the terebellz ; spiral when the part thus extended is twisted
like a gimblet ; folded when a greater or less number of ob-
lique folds are perceptible there proceeding from its torsion,
as in the volute; and it is said to be provided with a pad
when towards its extremity it presents a swelling more or less
considerable, and transverse, as in some cerithia.

Externally, or to the left of the termination of the pillar, is
often seen a hole, or rather a cleft, more or less deep, of a
form somewhat variable, and which especially exists in young
subjects. ‘This is the umbilicus, whose formation we have
explained above. From the presence or absence of this hole
proceeds the distinction of shells into wmbilical or non-umbi-
lical. We call the wmbilicus, consolidated, or subconsolidated
when in the full-grown shell it is covered by a sort of calca-
reous deposition, called a callosity, but this likewise exists
underneath. If it exhibits grains projecting in its circum-
ference it is called crenulated ; dentated if it is accompanied
with one or many teeth, as in the turbo pica; canaliculated
when at the interior it presents a spiral gutter, as in some
turbines and many cerithia.

After having thus successively viewed the univalve shells
in their ensemble, and at their external surface, we will now
consider their interior and orifice. ‘

The cavity of a shell may be entirely Patines by the
animal, or the part which -is occupied may be separated from

264 SUPPLEMENT

that which is not by one or many partitions, which divide it
into several cavities named chambers, concamerations, lodges,
or cells.

The shells which have but a single cavity are called wni-
locular or monothalamous, as is the case with by far the
greater portion of the univalves.

Those which, on the contrary, have their cavity separated
into a great number of lodges are named, in opposition, mul-
tilocular, polythalamous, chambered, celled, &c.

The form of the partitions, which may be very different, has
determined the names of partitions.

Even when they are simple.

Sinuous when they present, and especially on their edges
at the point of junction with the shell, certain sinuosities or
sections, which have been compared to those on the edges of
a leaf of parsley ; from the same cause they are also named
by French conchologists decoupées, persillées, words for which
our less flexible language furnishes no equivalent.

It is from this disposition that in fossil conchology have
been formed the names of articulated shells, of articulation
derived from the disposition which the pieces of foreign sub-
stance which have been moulded into these anfractuous
cavities, preserve among themselves, and which are observed,
after the shell itself has been destroyed. These articulations
may be compressed, cylindrical, ventruous, &c.

These different chambers, or particular lodges, communi-
cate more or less completely between themselves by means of
a hole in the form of a canal, which traverses the partitions.
This hole is named siphon, and has been studied, 1. accord-
ing to the number, which is never above two, as in tae oisy-
phytes, but in most cases there is but one; 2. as to position,
it may either be in the middle of the partition or approached
to one of its extremities, from whence the names of

Medial, when it is at the middle.

ON MOLLUSCA., 265

Dorsal, or external, when it is pierced near the external
edge.

Internal, ventral, or against the spire, when it is towards
the internal edge.

3. As to its form, which may be round, oval, or triangular.
In the unilocular shells the cavity is rarely divided into two
only, and incompletely, by a straight lamina, more or less
extended, which is named diaphragm, as in the septaria.
At other times this lamina is more or less curved, thus forming
a little tongue or horn, ex. crepidula, calyptrex, &c.

The aperture, or mouth of the univalve shells, is the en-
trance of their cavity. It is really formed or circumscribed
by the edges, which are only the union of the interior surface
of the shell with the exterior. Linnzus gives the name of
faux, or throat, to all that part as far as we can see into the
interior of the shell, that is, pretty nearly to the last semi-
whorl.

Some authors give the name peristoma to the entire thick-
ness of the shell at its aperture, but most generally it is di-
vided into two parts, designated as edges or lips, distin-
guished into the internal and external, or the right and left, or
columellary lip.

Considered in totality, and along with a portion of the last
whorl, which it terminates, the aperture is said to be falling,
or inclined, when, not following the direction of the spire, it
falls suddenly; inverted, when, on the contrary, it curves to-
wards the spire.

If we consider the aperture as to its regularity or irregu-
larity, it is symmetrical when it can be divided into two parts
perfectly equal and similar, and mon-symmetrical in the con-
trary case ; thus it may be formed by the excavation, more or
less considerable, of one of its edges, which ought to be taken
into consideration.

As to its proportional size to the rest of the shell, it may

266 SUPPLEMENT

be very large, as in the haliotides, which, in consequence of
this, have received the names of megastomata and macrosto-
mata; or it may be middling, small, &c.

The last whorl of the spire may penetrate more or Jess into
its interior, and modify it. In that case it is said to be so
modified, as in the argonauts, helices, &c. Then, according
to the observation of M. de Férussac, the spiral cone is always
incomplete, but in the contrary case it is complete. It is to
this part that Bruguiéres exclusively applies the name of
left lip.

But above all it may be more or less deeply emarginated
or entire. This explains the term entomastomata, which
indicates that the aperture is entire.

It may show a simple inclination to be emarginated, and
then it is termed versant. 'This means, that if the shell were
on its back, and filled with a fluid, the fluid would run out
through a part of the circumference a little widened. Many
coni are in this state. ;

Finally, we may mention the form which has caused it to
be named siphonostomatous or canaliferous, i. e. when it is
terminated anteriorly by a canal or siphon, more or less
elongated ; this form is in relation with a similar disposition
of the animal itself.

In the relation of form, which is very variable, the aperture
of univalve shells may be round, oval, transverse, having
more breadth than length, angular, semicircular, narrow, or
linear. .

The edges of the aperture are sometimes called lips. It is
divided by a fictitious line, supposed to proceed from one
extremity to the other of the shell; all which is found to
correspond to the right side of the animal is properly termed
labium, and on the other labrum.

In fine, this aperture of univalve shells may be always
open, or more or less completely closed by a piece either

ON MOLLUSCA. 267

calcareous or corneous, flat or slightly concave, formed of
concentric elements, and attached to the posterior part of the
foot of the animal. This is named operculum, cover or lid.
Its form and size are taken into consideration, but give rise
to no peculiar appellations. It is not so with the manner in
which itis joined to the aperture. Those opercles are simple
which have no other relation than that of their form with the
aperture of the shell; composite, which are articulated by
means of eminences and of corresponding cavities.

The bivalve shells, which we must very briefly dispatch,
may be considered pretty nearly under the same relations as
the univalve, and a few peculiar to themselves. As to the
relation of the places where they are found, they are divided
into fluviatile and marine. No terrestrial bivalves have as
yet been discovered.

The fluviatile are not very numerous, and perhaps are still
more difficult to distinguish from the marine than the uni-
valves. It may be remarked, however, that usually nacreous
in the interior, they are covered with a thick epidermis of a
green more or less deep, and that the summits are worn, or
what is technically termed decorticated. None are yet
known but among the species with a double muscular impres-
sion, and altogether closed or short.

The next relation under which the bivalves are considered
is that of their fixity, or that of their mobility ; but of this we
have already spoken sufficiently in another place.

A third relation under which the bivalves may be consi-
dered is whether they are free or concealed in a tube more or
less developed. In this last case the valves are altogether
contained and concealed in a tube of the same nature as them-
selves, and open only at one of its extremities. ‘They may be
called tubicole. ;

Another point of view is that of the substance in which
they may be found: but this has been already treated of.

268 SUPPLEMENT

In considering, for the present, a bivalve shell composed
of a single piece as forming a whole, it may be termed long,
elongated, cylindrical, transverse, &c.; but the application
of these epithets entirely depends on the position in which
the shell is placed for study, which, with M. de Blainville, is
the same as for the univalves. The shell is considered as
covering the animal, and the latter walking before the ob-
server, head in front, though in reality few of them change
place, and they are sometimes in a determinate position on
the side, or even with the head under. On this depends the
name given to their forms and proportions, to enter into a
detail of which in this slight sketch would be quite beyond
our purpose, and we should but merely repeat what has been
already said.

Under the name of multivalve shells we do not understand
those in which the two valves are covered with a tube, which
we mentioned above, but only those which are completely
discovered.

They constantly appertain to animals which may be said
to be intermediate between the malacozoaria and the ento-
mozoaria, or in other words, between the true mollusca and
the articulated animals. They are so few in number that it
has been considered nearly useless to establish peculiar terms
to indicate each of their parts, or such terms enter for the
most part into those which have been already indicated.

These parts may be divided, however, into three sections:

1. The serial, or articulated, so named because they are
placed in a series one after the other in a symmetrical manner,
in the middle and dorsal line of the animal. In a great
number of cases they touch, and even overlap each other more
or less. ‘This is easy to be recognized, because their anterior
edge is attenuated, and the posterior the reverse, except the
first and last, which are rounded, one in front and the other
behind ; their exterior surface may be smooth or rugous, &c.

ON MOLLUSCA. 269

In a certain number of species the pieces are extremely
small, and do not touch; in this case they might easily be
taken for the imperfect shells of univalves, especially the
first and last of the series.

2. The lateral when they are in a greater or less number
placed symmetrical on each side of the envelope of the ani-
mal, a single one occupying the dorsal line. They may touch
or exist only in a rudimentary state, but they never articulate.
They may also vary considerably in form and size, and be
more or less smooth or striated.

These two groups of multivalve shells have been named
dissivalves.

3. The coronals or sub-coronals, first established by M. de
Lamarck, when being disposed in a manner more or less re-
gular round a common axis, they are solidly dovetailed toge-
ther by the edges, so as to form a complete cavity, close or
open inferiorly, and closed above by a small number of pieces
of a form not very variable, the ensemble of which is termed
operculum.

The form, the number of the principal pieces, as well as
that of the operculum vary, but the differences which they
present do not require to be designated by peculiar terms.

We shall now close this imperfect yet we fear tedious
sketch, by a very brief account of the history of conchology.

Aristotle, the first in this branch of the sciences, as in so
many others, presents us, if not a systematic arrangement of
shells, which was not his object, at least the basis of several
divisions, which have been subsequently established. ‘Thus
we find in his principal work that he has considered shells
with a view to the principal relations under which we study
them at present; that is to say, according to the number of
the pieces of the shell, he divides them into monothyra or
univalves, and into dithyra or bivalves. He then takes
among the first the consideration of their turbinated or

270 SUPPLEMENT

non-turbinated form ; their living on land or in the water;
their habits of frequenting the shores or the depths of
the sea; and even their capability of motion or fixedness,
according to which he names them cimetica or acine-
tica. |

Pliny, Appian, &c. added nothing, or almost nothing, to
what Aristotle had done, even in the way of simple facts,
and most assuredly nothing to their classification. We must
therefore pass to the writers at the period of the restoration
of letters.

The first author who really occupied himself in the distri-
bution of shells, or in establishing a true conchological sys-
tem, was, as every one agrees, Daniel Major, in a sort of
appendix which he placed at the end of a German edition of
the treatise respecting the Purpura of F. Columna, under the
title of Ostracologia in ordinem redacta, printed at Kiel, in
1675. This consists of synoptical tables which conduct to
genera tolerably natural, but few in number, and established
only on the species‘observed by Columna. It is to him that
we are indebted for the division into univalves and multi-
valves, among which he places the bivalves.

In 1681, Grew, in his Musewm Regium, or description of
the collection of the Royal Society, of which he was se-
cretary, published a systematic and synoptic table of the
genera of shells, in which he includes all the testa or testa-
ceous envelopes, and in which, without employing the terms
at present received, he establishes the division of shells into
simple, double, and multiple, which corresponds to our uni-
valves, bivalves, and multivalves. Among the first he sepa-
rates those which are not voluted from those which are, and
among the latter those in which the whorls are apparent from
those in which they are not so, as in the nautili, the cypree.
Could we have presented this synoptic table it would have —
been evident that Grew had arrived at the majority of genera

ON MOLLUSCA. 271

admitted at the present day, and that many authors have de-
rived excellent hints from his performances.

Sibbald, in 1684, in his Scotia Illustrata, returned pretty
nearly to the division of Aristotle, that is, he took into chief
consideration the abode, from which he deduced the division
of shells into terrestrial and aquatic, and these last into fluvi-
atile and marine.

This was also done by Lister, who, living at a period when
commerce had brought a great number of shells into this
country, published a treatise necessarily much more complete,
under the title of Historie sive Synopsis Methodice Conchy-
liorum libri Quatuor, &c., in numbers, from 1685 to 1688.
We find in this work, besides some very excellent figures
designed and engraved by his daughter, and characters rather
more rigorously circumscribed, the introduction of the dis-
tinction of shells according to the equality or inequality of the
valves. A greater degree of attention is also paid there to
the hinge of the bivalve shells.

Tournefort, the celebrated French botanist, who died in
1708, also endeavoured to facilitate the study of shells, which
he designated under the general name of testacea, and which
he defined to be the envelopes of certain animals, which have
the hardness of a tile or of a vessel made of baked clay ; but
his method was not known for the first time but by the work
of Gualtieri, in 1748. This clever botanist substituted the
names of monotoma, ditoma, and polytoma for those of uni-
valves, bivalves, and multivalves. Among the monotomes he
established the distinction of univalves, properly so called,
spirivalves, and fistulivalves; and in the generic characters
he paid sufficient attention to the form of the aperture. In
the class of ditoma he seems to have been the first who estab-
lished the divisions of bivalves close or open (clause et hi-

antes). He also gave some attention to the position of the
hinge.

272 SUPPLEMENT

In his polytoma, or multivalves, he places at once the echini
and balani.

In 1711 Rumph made known a tolerably great number of
shells from the Indian seas; but he made no great addition
to conchology, properly so called. He did not even separate
the bivalves from the multivalves. As for the rest, in his
work the univalves are simple or turbinated, as in Aristotle.
It must not be forgotten, however, that he has pointed out
some generic sections tolerably good, as the strombi, porce-
laines, volute, &c.

A little later, in 1722, Langeius proposed a new concholo-
gical arrangement, but a partial one, as he treated only of
marine testacea, in a work in 4to., published at Lucerne,
under the title of Methodus nova et facilis Testacea Marina
pleraque, que hue usque nobis nota sunt, in suas debitas et
distinctas classes, genera et species distribuendi, nomini-
busque suis propriis, structure potissimim accommodatis,
nuncupandi, &c. But it is certain, notwithstanding this
pompous announcement, that he has added no very new con-
siderations to those which had been already employed by
Lister, unless perhaps that which is derived from the equality
or inequality of each valve, or from the relative position of
the summit or head. He also pays a little more attention to
the form of the aperture in the univalves, and to that of the
head in the bivalves. He also establishes among these last a
division of anomalous species.

It is to J. Philip Breynius, in 1730, that we owe the
employment of a new character, hitherto unobserved, namely,
that derived from the number of chambers in the univalve
shells, from whence the names of polythalamous and mono-
thalamous. ‘This he performed in a work published at
Dantzic.

A little before him, in 1728, J. Ermest Hebenstreit pub-
lished at Leipsic a dissertation, De Ordinibus Conchyliorum

13

———— ee

ON MOLLUSCGA. ots

Methodica ratione instituendis, in which we find but few im-
portant innovations. He paid, especially in the univalves, more
attention to the spire than perhaps had been given before his
time; and in the bivalves, his first division is founded:on the
presence or absence of a hinge.

In 1742, Gualtieri, an Italian author, whose work is still
often cited, from the great number of mediocre figures which
it contains, published a method, in which he has employed all
the combinations which his predecessors made use of, without
introducing any thing new. Thus his first division equally
rests on the habitation of the shells. He names exothalassi-
bie those which are not marine, and divides them as usual
into fluviatile and terrestrial: as to the marine, thalas-
sibie, they are turbinated or not, and the latter are vascular
or tubular; he admits the polythalami. He pays atten-
tion to the equality or inequality of the valves, and of their
sides. Finally, he considers the presence or absence of the
hinge. In general, though in this work we find a considera-
ble number of generic sections indicated, they are not solidly
established.

In the same year was published, in France, the first edition
of a work, which for a long time enjoyed a degree of reputa-
tion which it little merited. It was by d’Argenville, entitled
U Histoire Naturelle eclaircie dans deux de ses parties prin-
cipales, la Lithologie, et la Conchyliologie, in 4to. Although
this work was very successful, especially in France, in conse-
quence of the figures which it contains, its merit is of a very
inferior order. In fact, the author has introduced absolutely
no new consideration in the manner of observing shells, which
he again divides, according to their habitation, into marine
and fluviatile, but nevertheless places the helices among
the latter. Each section or subdivision is divided, according
to the number of pieces, into univalves, bivalves, and multi-
valves, for the first, and into univalves and bivalves only for

VOL. XII. T

Q74 SUPPLEMENT

the second. We should also observe that the class of multi-
valves is still worse handled than in any other system. As to
the genera, those of the univalves, though very few in num-
ber, are pretty well characterized by the form of the aperture ;
but it is not so with those of the bivalves, in which there is no
reference made to the hinge. In fact, d’Argenville has almost
always followed Lister; and when he has not, he has done
mischief. He has often strongly criticised him, and always
erroneously.

Immediately after d’Argenville comes another entirely sys-
tematic writer, who has not the advantage of having given
good figures. This is Klein, who has almost invariably
attached himself to changing every thing which Linnzus
attempted to establish. He published, in 1753, a new system
of conchology. He comprehends them all in the teste, which
he divides into cochlides, conche, niduli testacet, echnioder-
mata, and finally into tubuli, or marine tubes. Under the
name of cochlides he understands the turbinated shells, which
he divides into two sections: simple cochlides, which he de-
fines to be a spiral canal, resulting from a single circumvolu-
tion of the shell, and composite cochlides, which are those in
which the circumvolutions of the shell appear double ; so that
the testa seems to be composed of two cochlides. Although
his definitions are bad enough, we can see that the first sec-
tion comprehends the spirivalve shells which have not their
aperture terminated by a siphon, or rather the last whorl of
which is not terminated in a point like the spire; and that he
understands, on the contrary, by his composite cochlides, those
which are pointed in front as well as behind. Although this
consideration is evidently new, it is clear that it conduced but
little to a good division. Another innovation of Klein is his
having separated, one cannot well tell why, the conchs,
conche, into monoconchs, which are the patelle and. the
neighbouring genera; and into diconchs, diconche, which

13

ON MOLLUSCA. 975

are the ordinary bivalves, an innovation which, to a cer-
tain point, has been adopted even by later writers. Not ad-
mitting multivalves, he places the anatifee among the conchs,
under the name of polyconche, while the balani form a divi-
sion under the name of néduwli testacet. The bivalves are then
divided according to the consideration of the resemblance or
dissimilarity of the valves, and their more or less complete
closure. He has, besides, proposed, rather than established, a
great number of genera, which have since been adopted; but
the characters which he assigns to them are so vague and so
ill defined, that it is not wonderful that this writer should have
remained in partial oblivion.

We shall yet place before Linnzus, although the first
editions of the Systema Nature had already appeared, the
celebrated French traveller Adanson, because it appears
almost indubitable, that it was from the latter’s “ Voyage to
Senegal,” published in 1757, that Linneus has taken the most
considerable part of his fixed general principles of conchology.
Adanson, as we have already noticed in treating of the mol-
lusca, took into consideration at once both the animal and the
shell; he has nevertheless carried some innovations into con-
chology, properly so called. Thus, beside a profound study of
each of the parts of shells, and an exposition of the characters
which may be drawn from them, he has, as it were, established
upon each of them a particular system. He has, among other
matters, divided the bivalve shells according to the number of
the muscles, or of their attachments; and above all, he has
introduced the consideration of the opercula, which before his
time had been almost entirely neglected, or merely separately
viewed under the name of marine wmbilici, without any refer-
ence to the shells to which they had belonged. It was
according to this character that he established, in the family
of the helices, two sections, the first the univalve helices, and
the second the operculated helices, which he considers as

v2

276 SUPPLEMENT

forming the passage to the conchs or bivalves, but erroneously.
We should also observe, that he appears to have been the first
who arranged the oscabriones with the patella, the section of
his multivalve conchs containing only the pholades and
teredo. Linnzus, who in the first edition of his Systema Na-
ture had not proved that he was really aw fait at this part of
the natural sciences, showed in that which followed the publi-
cation of Adanson’s work, that the same vrinciples might be
applied to it, which he had so happily imagined and success-
fully employed in botany. He nevertheless created no very new
characteristic distinction in the primary sections, nor even in
the secondary, since he divides the teste into multivalves, with
which he commences, and in which he ranges the oscabriones
into bivalves and into univalves, which he subsequently divides
into turbinated and non-turbinated. But he has introduced in
the exposition of the characters, in their circumscription, and
in the creation of conchological language, that precision and
that clearness, which must ever cause him to be regarded as
the model and the master of all systematic naturalists.

Pretty nearly about this period, viz. in 1769, began to be
published the great work of Martini, continued and terminated
by Chemnitz in 1788. As we must regard it rather as a col-
lection of figures of shells, than a true system of conchology,
we shall content ourselves with mentioning that the order
which has been adopted by the last, partakes at once of that
of Gesner and Lister, the primary divisions being still derived
from the habitation of the animals. In other points he follows
Linneus closely; and it may be said that his sections are
tolerably simple, and tolerably consonant with natural rela-
tions.

In 1776, Da Costa published, in our own language, some
true elements of conchology, in a work entitled “ Elements of
Conchology.” His system evidently differs but little from
that of Linnzus; nevertheless, he appears to have insisted

ON MOLLUSCA. AE |

more on the predominance of the characters drawn from the
form of the aperture in turbinated univalve shells, and of the
hinge in the bivalves. He was the first too, as it would
appear, who proposed to change the terms, which in reality
are somewhat obscene, especially when translated into any
modern language, which were imagined by Linnieus to desig-
nate certain parts of the bivalve shells. He has, besides,
sufficiently augmented the number of the genera of the
Swedish naturalist, and has constantly united a very passable
figure of one species of each. In general, his work is very
instructive, although he has not introduced any very new con-
sideration into the science.

We shall pass over in silence a tolerable number of authors,
such as Miiller, de Born, &c. who have added scarcely any
thing to conchology, except some new species, and proceed to
speak of some French naturalists, who have done more for
this art than any of their predecessors: we particularly mean
de Bruguiéres and de Lamarck.

Bruguiéres, in 1792, almost entirely followed Linnzus; but
we must do him the justice to say, that he has much more
clearly circumscribed and characterized the genera, which
obliged him considerably to augment their number. The
descriptions of the species, in the small number of genera
which he was able to treat of in detail (death having cut him
off long before he could terminate his work), are well done,
and complete. In a word, he should be regarded as the con-
chologist who first began to introduce into the science that
exactitude and those details which have enabled us to employ
it in paleozoology, or in the comparison of fossil remains.
We must nevertheless observe, that he has introduced no new
consideration.

M. de Lamarck brought to still greater perfection the method
or mode of view of Bruguiéres, his friend, not only in not con-
fining himself to the mere consideration of the shell, and in

278 SUPPLEMENT

viewing it as a part of the animal, but also in conchology
properly so called, by a great number of new generic sections;
by the employment of a terminology still more rigorous; and,
finally, by the introduction, as the basis of a principal divi-
sion of the bivalve shells, of the number of the muscular
impressions, in 1807, which was adopted in 1810 by M.
Oken. He was of opinion, however, that the oscabriones
should be placed with the patella, contrary to the felicitous
conjecture of Linneus. In general, as one might easily be
convinced, by a complete exposition of his new system (for
which, however, we have no room here), he has entirely
abandoned the division of shells, established by the majority of
the conchologists his predecessors, on the number of pieces
of which the testa is composed, and has rather chosen the
general form of the shells on which to establish his first four
divisions into subspiral, cardiniferous, subcoronal, and ver-
micular; in fact, he could no longer admit the division of
univalves, bivalves, and multivalves, since he places the osca-
briones among the subspirals, which certainly no one would
do, who proposed merely to make an arrangement of shells.
In general, it would appear that M. de Lamarck, in this sys-
tematic arrangement of shells, was too anxious to place it in
a direct relation with that of the animals, which unquestion-
ably must render it more difficult, but at the same time,
perhaps, also more interesting as regards true science.

Since, and during the publication of the method successively
brought to perfection by M. de Lamarck, other conchologists
adhered almost rigorously to the system of Linnzeus, extended
by Bruguiéres, such as M. Bosc, Montagu, &c., or carried to
excess the generic sections or subdivisions, as did M. Denys
de Montfort, in his Systematic Conchology, printed in 1808,
but which contains only the univalve shells. This author,
absolutely paying no attention to any thing but the testa, has
necessarily considerably multiplied the genera, by desiring too

ON MOLLUSCA. 279

much to specialize or render rigorous their characters. But we
must not deny that a considerable number of them ought to
be, and have been, already adopted, and that he was the first
to call the attention of conchologists to those extremely minute
shells termed microscopic ; and that, although this part of his
labour ought certainly to be considerably modified, conchology
is not the less indebted to him for a real service. He has also
separated from the multivalves the shells or teste of the ana-
tifee, under the name of fissivalves.

A few years afterwards, M. Megerle proposed a new distri-
bution of shells, but none of it we believe has been published,
except the part which treats of the bivalves, in the Berlin
Magazine for 1811; and although he has entitled it a new
system of conchology, it is evident that he follows Linneus
almost scrupulously, with this difference, that he has esta-
blished a tolerably great number of new genera, which have
since been proposed and admitted by others.

Finally, M. de Blainville (to whom, as we have already said,
we are indebted for the principal part of this essay), in the
Memoire read at the Philomathic Society, and inserted in its
bulletin, although his classification referred essentially to the
animals, and not simply to their envelopes, has introduced
some new considerations into conchology, by shewing that the
shell, especially in the univalves, is essentially the protecting
body of the organs of respiration, of which it follows, to a cer-
tain point, the general form and position.

He has also called attention to the employment of a new
character, drawn from the symmetry or non-symmetry of the
univalve shells, in relation with the organs of respiration, and
has replaced the oscabriones among the multivalves.

We might very considerably lengthen this critical analysis
of the works of authors who have written on conchology pro-
perly socalled. Butit would be superfluous to speak of those
who have added almost nothing to the art of classifying sheils,

280 SUPPLEMENT

although they have frequently proved more useful to real
science, by making known a great number of new species.
Those zoologists who have considered, the shells only as
making a part of the animal, and who in general have
diminished rather than augmented the number of genera of
shells, we of course pass over in silence.

As we have inserted four plates in explanation of the terms
made use of in conchology, it becomes necessary to advert
here to such of the references as could not be engraved on the
coppers.

The figures of wnivalve spiral shells include,

1, An involute shell, with the spiral horns separate, and
the siphon ventral. Spirula Australis (Peronii, Lam.,) Nau-
tilis spirula, Gm.

2. A multilocular shell, the spire invisible, siphon medial.

3. A monolocular shell, subinvolute, columella plaited.
Voluta musice.

4. An involute shell, emarginated or notched, narrow
mouthed. Oliva littorata, Lam.

4. a. Shell without columella. Jd.

4. b. Shell with sulcated suture. Jd.

5. A globular shell, aperture semicircular, left edge septi-

form. Nerita peloronta.

6. A turriculated siphonostomatous shell; a. anterior ex-
tremity (inf. Lin.)—b. the canal—c. right or external edge—
d. emargination, or notch—e. posterior sinus—f. umbilical
cleft—g. left or inner edge. Plewrotoma (Murex, Lin.) Ba-
bylonia.

7. A turriculated shell, columella smooth and truncated.
Helix (Bulimus) zebra.

8. A monolocular ampullaceous entomostomatous shell;
a. emargination, or notch. Buccinum doliwm, Lin. (Dolium
maculatum, Lam.)

a a i i i i i ae

Wellusca: Pi. 15.

Univalve spiral shells.

vide Pidlished by Whittaker & C Ave Marta, Lene i835

oMcz. LIBRARY
MARD) tea

Ucllusca Pl

Vnivalve nen-spital shells and Cpercidla.

London, Published. by Whittaker & C2 Ave Maria. Lune 1853

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ON MOLLUSCA. 281

9. An heterostomatous shell, lip subcontinuous and folded
back. Gen. Pupa, Lam.

10. A cricostomatous shell, lip continuous. Cyclostoma
elegans.

11. A tubular cricostomatous shell, fissure subspiral. S¢dc-
quaria anguina ; Serpula anguina, Gm.

12. A tubular shell, cricostomous and subspiral. Vermetus
(Serpula) Adansonii.

The figures of univalve non-spiral shells and opercula in-
clude,

1. A symmetrical tubular non-spiral shell. Dentaliwm
entalis.

2. A symmetrical shell, with the beak or apex posterior ;
a. posterior—b. anterior.

3. A symmetrical shell, with the beak or apex anterior.
Patella cymbalaria, Lam.

4, A non-symmetrical shell. Siphonaria radiata.

5. A non-symmetrical shell, with the apex or beak posterior.
Hipponiz.

5, a. It’s foot.

6. A subspiral shell with a perforated disk. Hadvotvs.

The following are opercula:

7. Multispiral operculum. Genus Trochus.

8. Paucispiral op. Gen. Turbo.

9. Unispiral op. Gen. Nerita.

10. Subspiral op. Gen. Phasianella.

11. Unguiculated op. Gen. Murex.

12. Unispiral inarticulate op. Gen. Natica.

13. Subunguiculated op. Gen. Purpura.

14, Squamous op. Gen. Helicina.

15. Lamellateous op. Gen. Buccinum.

16. Radiated op. Gen. Navicella.

282 SUPPLEMENT ON MOLLUSCA.

The figures of bivalve shells include,

1. Cytherea lutea (Venus chione, Lin.) i a normal or per-
pendicular position.

2. Back view of the same in the same position.

3. Interior view of the right valve of the same, in the same
position.

4, Exterior view of the left valve of the same, in the posi-
tion of Linnzus and Lamarck.

The letters A and P in each figure indicate the anterior
and posterior parts of the shell, L and R the left and right.

The figures of multivalve shells include,
. Interior of the right valve of Pholas dactylus.
. Left view of Pholadidoides Anglicanus.
. Teredo nigra, De Blain., with a portion of the animal.
. Posterior extremity of Teredo navalis.
. Articulated palette of a Teredo.
6. Balanus (Lepas, lin.) tintinnabulum. U.S. V. upper
side valve, L.S. V. lower side valve.
7. Operculum of Balanus squamosus.
8. Left view of Polylepe vulgaris, Blainy. D. back, or
dorsal valve; V. belly, or ventral valve.
9. Upper view of Lepas diadema.
10. Valves of Chiton squamosus.
11. Valves of Chiton raripilosus.

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Miullivalver Shells.

Tondonw, Published’ by Whittalcer & C? Ave Marva Lane 1833.

‘MCZ MBRARY
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Mollusca’ Pl. 18

Upper Edge

Beak or apex

Lunule
or antertor edge

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Borders of Lozenge (Vulva Lin:)
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Borders of Lozeng
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Fidcrum

Bivalve Shells.

Fondom, Fublished by Whattater& C’ Ave Marta Lane 1833

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SUPPLEMENT

ON THE

CLASS CEPHALOPODA.

THE division of molluscous animals, however numerous in
species, is so concisely arranged by the Baron, that it has
been deemed inexpedient to separate his text by inserting
our own supplementary observations at the end of each class.
Having translated this portion of the Régne Animal unin-
terruptedly, we shall proceed in like manner with the supple-
ments.

It would be repetition to speak of the class cephalopoda in
general after our long preliminary article on the division. We
begin with the genus SEPIA.

We are chiefly indebted to the ancient writers for all we
know respecting the natural history of those remarkable mol-
lusca. Although the species of this genus appear to have
been rather neglected by zoologists, it would seem that sepize
are to be found in all parts of the world, and alike in the
different zones, frigid, temperate, and torrid.

It is only in the sea that the sepiz exist, but at some dis-
tance from the coasts, and probably at all depths. They are,
in fact, along with the calamary, or Joligo, the only animals
of the molluscous type which may be regarded as not littoral.

284 SUPPLEMENT

We may be assured that they never come out of the water,
which cannot be averred with equal certainty respecting the
octopi.

Their movements are rapid and in all directions, pretty
nearly like those of fish, and performed by the aid of the
branchial sac, and of the circular fin which surrounds the
body, the tentacular appendages being pressed close one
against the other into a packet pointed in front, and the
branchial appendages retracted within their cavity. The first
do not separate except when the animal attempts to seize any
prey within reach, and they especially serve to retain it, and
submit it to the action of the powerful teeth with which the
mouth is armed. As to the branchial appendages, it is pro-
bable that the sepia can put them forth with rapidity from
their cavity, and, as it were, shoot them upon an animal at
some distance from itself, to bring it back within reach of the
_ tentacular appendages. We may also equally conceive that
they answer the purpose of hooking the animal to the rocks
at the bottom of the sea, and thus sheltering it from the
storms and tempests with which that element is frequently
agitated ; but this, though probable, can hardly be considered
as more than conjecture.

The sepiz are evidently carnivorous. They probably feed
upon fishes, and especially on the swimming crustacea, which
live at some distance from the coasts, and which they overtake
and seize after a pursuit of longer or shorter continuance, like
the loligo, and not by placing themselves in ambuscade, like
the octopi. We must nevertheless add, that Aristotle re-
gards the sepia as a very cunning animal: he says that it not
only casts forth its ink when it is afraid, as do the octopi and
loligines, but that it also makes use of this liquor, which it is
true is more abundant and more coloured than in the former,
to create around it ‘a thick cloud, in which it envelopes itself,
either to escape the pursuit of the fishes, or to attract the fish

ON CEPHALOPODA. 285

by rendering itself invisible. He adds that it will then seize
very large fish, and even mullets. Unfortunately, this ob-
servation, although many authors have adopted it, which has
rendered the sepia yet more celebrated than its congeners, has
no other foundation than the authority of the Greek philoso-
pher, and has not been confirmed by any modern naturalist.

The animals of this genus do not probably live in troops,
and still less ina social state. But it appears that this is not
the case as regards individuals of different sexes; and Aris-
totle attributes to the male a sentiment of friendship for its
female sufficiently strong to induce it to come with courage
to her assistance if she has had the misfortune to be har-
pooned. But as this sentiment is not reciprocal, it is pro-
bable that Aristotle alludes to the means of procuring a
number of male sepiz, still employed in the Mediterranean,
and of which we shall presently speak.

The internal differences which characterize the sexes we
have explained in our general article, and many of them had
been already noticed by Aristotle. We must add here, that
the males are more brightly coloured, and the spots, or zebra-
like stripes of the back, are much blacker and more numerous
than in the females.

It would appear that it is at the end of the spring or the
commencement of summer that the season of love takes place
with these animals, and that they fecundate, if we may judge
at least by the period in which eggs are found containing
young ones; this most usually happens in August or September.
Aristotle, however, in one place says that the sepiz reproduce
at all seasons of the year, though he adds a little further on,
that they are full in the spring.

We are ignorant of the generative relations of these ani-
mals, or even if there be any true sexual intercourse pre-
viously to the female laying her eggs. No modern observer
appears to have afforded any information on this subject; and

286 SUPPLEMENT

it would seem that the text of Aristotle which speaks of this

particularity in the natural history of the sepie has been

interpreted in a different manner by translators and com-
mentators. Most of them, however, are inclined to believe
that there is no intercourse, since they say that the male be-
dews the eggs with the seminal fluid when they have been
deposited by the female, and that it is this fluid which, being
viscous, attaches them one to another, and forms them into a
cluster. This appears to be more than doubtful. Be that,
however, as it may, the following is what Aristotle says re-
specting the female. “ Fifteen days after she has been full
she throws out her eggs, near land, among the alge, the reeds,
and other bodies which may be found upon the shore, in its
anfractuosities, and even around the sticks which fishermen
have placed there for the very purpose. She does not lay
them all at once, but at several attempts, as if she were in a
state of suffering. This operation lasts fifteen days. After
the laying, the female herself sheds her ink upon her eggs,
which turns them from white to black, and causes them to
increase in bulk. It is then that the male bedews them with
the seminal liquor; a fact,” he adds, “ which, though not
having been observed but with regard to the sepia, ought,
however, very probably be extended to the loligo and oc-
topus.”

We have just said, that according to the same author, it is
this fluid which unites the eggs, and gives to them the appear-
ance of a cluster of grapes. In fact, on our coasts these heaps
of the sepia’s eggs, more or less considerable, are designated
by the name of sea-grape, in consequence of their form and
colour, which is most usually black; some, however, have
been observed which were altogether white, and which con-
tained young sepiz as much advanced as those which were
in eggs of the finest black. Accordingly we cannot be assured
to what the coloration of these eggs is attributable; but it is

ON CEPHALOPODA. 287

not probable that the cause which Aristotle assigns for it
should be the true one. Neither do we think that their ag-
elutination, which is extremely irregular, and which takes
place by the pedicle that terminates them, is owing to the
viscous quality of the semen of the male, which would be
shed on their upper part, but rather to the viscosity of the
adventitious membrane of each egg; and it really seems pro-
bable that an actual intercourse takes place between these
animals in the same manner as in all the cephalous malaco-
zoaria. Aristotle also tells us that the female sepia, after
having totally got rid of her eggs, hatches them in the place
where she has deposited them. She is often to be seen, he
avers, with the body resting against the ground and over her
eggs.

The eggs of the sepia have an oval form, attenuated at the
two extremities, one of which is free, and the other prolonged
into a pedicle of greater or less length, and twisted round
some foreign body, or even joined to a greater or less number
of other eggs, in a manner completely inextricable. It is thus
that the clusters are produced. Their bulk and the number of
the eggs which compose them are extremely variable ; though
most frequently, as we have observed, of a black colour, they
are sometimes of a yellowish white, a little transparent. In
studying their organization we easily perceive that the en-
velope of the egg is nothing but a gelatinous matter, more or
less thick, which may be divided into an indefinite number of
laminz, but which is not really organized. In the interior is
the egg, properly so called, composed of the germ and of the
vitelline mass, in an inverse ratio of development, according
to the period at which it has been laid. ‘The vitelline mass
is almost of a white colour. Contained in its egg, the little
animal has the head and eyes much bigger than they are
subsequently to be, as Aristotle has most justly observed. In

288 SUPPLEMENT

proportion as it is nourished by the vitellus it acquires more’
and more resemblance to the mother, and, while it resembles.
her completely, it continues for some time to swim in the
interior of the fluid which fills the egg, and which has taken
place of the vitellus. Accordingly, when accidentally at this
period the envelope of the egg is broken, the little animal issues
forth, and swims with as much facility and elegance as the
mother. Its eyes perceive obstacles in the same manner; in
a word, it is in full possession of all its faculties. In the or-
dinary state it is probable that the parietes of the envelope,
distended by the fluid, which is doubtless introduced there
by transudation from the exterior to the interior, conclude by
bursting, which gives issue to the young sepia. We are igno-
rant how much time is necessary for its complete develop-
ment from the period when the egg is laid, but it is probable
that it cannot be very long, since the eggs of the sepia are
often found on the coast at the end of July, the little ones in
which, extracted artificially, are altogether complete.

This little sepia is then scarcely five or six lines in length,
though destined to arrive at neatly a foot long, with a propor-
tional breadth. We are altogether ignorant of the time which
is necessary for this growth; nevertheless, if we give credit to
what Aristotle again affirms, that the sepiz, like the loligines,
live but a short time, and rarely attain to their second year,
we must admit that their growth must be extremely rapid,
which appears by no means probable.

The sepiz exert no great influence on the external world, if
it be not upon the animal kingdom, in consequence of the
species of fish and crustacea on which they feed, and because
they themselves are food for a great number of marine ani-
mals, for fish, cetacea, &c.

Even man employs them sometimes as food, as well as the
calamary (loligo), at least on the coasts of the Mediterranean

ON CEPHALOPODA. 289

and Atlantic, where they constitute a portion of the aliment
of the poor. The ancients likewise ate of them, according to
Atheneus.

Nevertheless these animals are but little sought after now
by fishers, but for their bone, which has been called sepzosta-
rium, and their ink.

The first, or the bone of the sepia, is employed to be put in
the cages of those little granivorous birds which are reared in
a domestic state, probably to replace the little grains of silex,
or lime, which they are in the habit of swallowing when at li-
berty, or to wear the extremity of their bill, which without that
might grow to an injuriouslength. But more frequently it enters
into the composition of those decorating powders under the
name of coral powder, which is used for the purpose of clean-
ing teeth, and removing the ealcareo-animal substance called
tartar, which is deposited on their surface during the night.

As to the ink of this animal, it composes almost by itself
alone that colour so agreeable from the equality of its tone,
its warmth, and even its tint, called sep¢a. But it is more
than probable, notwithstanding all that has been said on the-
subject, that it does not enter into the composition of the
China-ink, or as we more generally call it, Indian-ink, which,
as it is now understood, is formed of lamp-black, extremely
divided, and mixed with a certain quantity of gum, and aro-
matized with some substance with which we are not precisely
acquainted.

The genus OcToPUS closely approximates to sepia, and,
indeed, was considered but as one of its species by Linnzus ;
the ancients gave it the name of polypus, a name now exclu-
sively consecrated to a tribe of the radiata.

From the organization of the octopi it is easy to perceive that
they are animals whose sensations must be pretty nearly similar
to those of others of this class, but their mode of locomotion
differs from that of the majority; in fact, they do not swim

VOL. XII. U

290 SUPPLEMENT

with the swiftness and elegance of the sepia and the calamary ;
they perform this movement rather by whirling in an irregular
manner enough, the head usually downwards, and by rowing
with the assistance of their long tentacular appendages. On
the other hand, they can walk, or to speak more correctly,
draw themselves along over a resisting ground at the bottom
of the water, or even on the shores, in the anfractuosities of
the rocks. For this purpose they attach one of their arms,
previously considerably extended, to a solid body, and then
make use of it to draw towards this point the rest of their
body. It has also been supposed that these animals can walk
with the head downwards, and by means of their eight ten-
tacula; but this is less probable. Aristotle, nevertheless,
declares positively enough that this is the only molluscous
animal which makes use of its arms for walking. According
to this notion hé admits, as do Pliny and all the ancient
writers, that this animal issues from the water, and that it
sometimes visits the land, avoiding however all the smooth
places. lian and Atheneus add that it can also mount on
trees, which is much more doubtful ; for, in truth, what should
it go in search of there? They suppose that it must be fruits!

Most generally the long arms of the octopi serve the pur-
pose of enlacing their prey, and of attaching themselves to it
by means of the numerous suckers with which they are
armed, and the action of which it is easy to conceive. In
fact, beside the trifling adherence which may be owing to the
viscosity produced by these organs, each nipple acts abso-
lutely like a cupping-glass, its edge being fixed, and a capa-
bility given of producing a vacuum by the contraction of the
longitudinal fibres of its bottom. Now, as the number of
these cuppers, or suckers, may amount to several hundreds,
we may easily conceive that the adherence of the octopi to a
body is so strong that it is almost impossible to tear them
from it otherwise than by cutting off the arms, and that they

;
,
2

ON CEPHALOPODA. 291

will even adhere to it for some time after death. This ad-
herence will produce a pretty strong redness in the part
affected by it, but it does not seem probable that this ever
amounts to inflammation.

The octopi are animals eminently carnivorous, and particu-
larly live in the anfractuosities of rocks, where they place
themselves in ambuscade, concealing their body, properly so
called, in the cavern which they inhabit,.and letting nothing
come forth but their arms, which they make use of to reach,
enlace, and draw in their prey. They sometimes, however,
do this more openly; in fact, Belon informs us that he saw
an octopus fighting for more than an hour with a crab, in the
port of Corcyra. Aristotle says that this animal has the
faculty of changing colour, and assuming that of the bodies
which surround it, and this for the purpose of more easily
catching fish: he adds, that it does so likewise when under
the influence of fear, and at the same time it darts its ink,
the colour of which is rather red than black.

It appears that the octopi make their principal food of
crustacea, as Aristotle observed long ago. M. de Blainville
informs us that he has many times heard the fishermen com-
plain of the injury done them by these voracious animals, not
only from the quantity of crustacea which they destroy, but
chiefly by frightening those of which they are unable to gain
possession, and forcing them to quit the localities which they
had previously inhabited. The octopi also feed on conchyli-
ferous mollusca; and Pliny relates concerning them the trick
which has also been attributed to apes, of placing a little
stone between the two valves of oysters, of which they are
extremely fond, so as to prevent them from closing, and that
then they extract the flesh: on this Pliny cries out, “ Such is
the wonderful intelligence of animals, even the most stupid !”
But how could an octopus take up a little stone and place it
so adroitly, even supposing that the semi-hiatus of the oyster,

U2

292 SUPPLEMENT

continually filled by the tentacular cirrhi of the edges of its
mantle, would permit it?

The habitation of an octopus is discernible by the debris of
‘shells and of fish, the flesh of which it has eaten. It has also
been asserted, absurdly enough, that when pushed by hunger
it will gnaw its arms, which possess the singular property of
shooting forth again. But Aristotle and Pliny, more justly,
attribute the fact of octopi being often found which have some
few appendages less than usual, to their having been eaten by
the conger eels. Belon, in fact, informs us that he saw, near
Epidaurus, some murenez whose stomach contained arms, or
tentacula of the octopus. These fish, indeed, inhabit rocky
places, as well as the octopi. Rondelet tells us that the
octopi are very fond of the branches of the olive, and also of
the fig-tree, and that these substances may be made use of as

a bait to catch them. Whether this observation be peculiar

to Rondelet or no, it appears to be very doubtful.

The moderns do not appear to have completely observed
the mode of sexual intercourse among the octopi; neverthe-
less Rondelet assures us that it takes place, as among the
sepiz, mouth to mouth, and interlacing with their arms.
Aristotle says that the male is distinguished from the female
by the form of one of the arms, where fishermen aver that the
male organ is situated. But nothing appears to confirm this
popular report, and indubitably there is no sort of excitatory
organ in the anus of the octopus. He adds, that their inter-
course takes place like that of the other mollusca, by which
we essentially understand the sepia and calamary; while
Pliny affirms that they unite by means of their pointed and
forked tail, an organ with which undoubtedly no species of
octopus is provided. -He probably means the foot, which is
more pointed in these than in others of the class, whitish, and
cleft at its extremity. This, according to Aristotle, is placed
upon the spine, a part which has no more pretensions to ex-

ON CEPHALOPODA. 293

istence than the aforesaid tail. It has been said by observers
that the males are much more numerous than the females, and
that in intercourse there is a very strong adherence between
the two individuals; in fact, the fishermen of the French
coast have a peculiar mode of fishing for the octopi, as for the
sepiz, by attaching a living female individual to the end of a
cord and letting it go, tne male then approaches, and on
drawing the cord two individuals are brought up, interlaced
together. It is only necessary to repeat this operation to
get possession of all the male individuals in the district.
This fishery takes place towards the middle of spring, and
nevertheless, according to Aristotle, it is in winter that the
intercourse of the sexes takes place, so that the female de-
posits her eggs in spring. They forma mass, more or less
considerable, according to the age of the individual, which
mass the Greek philosopher compares to the fruits of the
alder, or of the wild vine. Their number is considerable, and
the united mass which they form is much greater than the
part of the body from which it issued. This shows that these
eggs are like those of many other aquatic animals, which
swell considerably after they have been ejected. It is always
in some hole or cleft of the rocks that the octopus deposits its
eggs: Aristotle had already made this observation when he
said that the octopus seeks a convenient place for the deposi-
tion of her eggs, such as the interior of a shell, the bottom of
a vessel, or of some other cavity, to the sides of which it sus-
pends them. He adds, that this animal hatches its eggs, that
is to say, that it sometimes places itself upon them, and that
sometimes it fixes itself at the entrance of the hole where it
has placed them, disposing its arms in such a way as to cover
them more securely. During this time the animal grows thin,
for it eats nothing. He says also that fifty days must elapse
before the little octopi come forth from their eggs. It is pro-
bable that, as these eggs are conformed altogether like those

294 SUPPLEMENT

of the sepiz, the young ones are in possession of all their
faculties on issuing forth from the egg.

We are not precisely acquainted with the duration of the
life of the octopi. Aristotle says in a general manner that it
is not long, and that the major part of them only live two
years ; that then they grow soft, become decomposed, and are,
as it were, annihilated. But it seems by no means probable
that an octopus, whose egg is of such small dimensions, can,
in two years, attain to the size at which it eventually arrives.
As for the reason which lian assigns for this shortness of
life, namely, the exhaustion occasioned in the male by sexual
intercourse, and the number of births in the female, it lends
but little support to the pretended fact.

It appears nearly certain that the octopi remain concealed
during the winter; the fishermen never meet with them
during this season. The ancients tell us that this hyberna-
tion lasts two months; how then is it possible that the
winter can be the period of their sexual intercourse ?

We are ignorant respecting the full size to which the octopi
may attain. We find in the recitals of certain travellers, and
even of some naturalists, that a species exists to which the
name of kraken has been given, which arrives at an immea-
surable bulk, so as to resemble an island when it approaches
to the surface of the water, and to overset the largest vessel
under full sail when it becomes entangled in their cordage.
But we may be assured, without any fear of deceiving our-
selves, that this is but an exaggeration of what has been said
by the ancients, especially Pliny, concerning an octopus, which,
according to Trebius, had a head of the size of a barrel con-
taining fifteen amphorz, and whose tentacular appendages,
which, as well as the head, were presented to Lucullus, were
thirty feet im length, knotted like clubs, and so thick that
a man could scarcely embrace them round; the suckers re-
sembled basins,‘and the teeth were proportional. All that

ON CEPHALOPODA. 295

was preserved of the body weighed seven hundred pounds.
There are other traits still more curious in the history of this
most marvellous octopus. It was observed at Castera, in
Beetica, in Spain, and was accustomed to come forth from the
sea into the reservoirs or depots for salted fish, &c. and de-
vour those provisions. The pertinacity of its robberies at
Jength aroused the indignation of the keepers; they built
very lofty palisades, but all in vain, this persevering polypus
succeeded in getting over them by taking advantage of a
neighbouring tree, so that it could not be taken but by the
sagacity of the dogs, which, having marked it one night as it
was returning to the sea, intimated the affair to the keepers,
who were struck with terror and astonishment at the novelty
of this tremendous spectacle: in truth, the animal was of an
immeasurable bulk; its colour was changed by the action of
the brine, and it exhaled a most intolerable odour. Never-
theless, after a desperate combat with the dogs, which Pliny
depicts with all the vigour of his poetical style, and by the
efforts of men armed with tridents, it was at last killed, and
the head was brought to Lucullus.

flian also tells us that in the course of time these animals,
which he, in common with all the ancients, calls polypi, arrive
at a most extraordinary bulk, so as to equal in size the largest
cetacea. On this subject he favours us with a story pretty
nearly similar to that of Trebius, of an octopus which, having
devastated the magazines of the Iberian merchants, was Je-
sieged by a great number of persons, and cut in pieces with
hatchets, just in the same style that wood-men cut down the
thick branches of trees.

Aristotle, indeed, tells us that there are polypi whose arms
are as much as five cubits in length, which would make about
six feet. But this is a long way behind the narrations of
Trebius and lian, and falls still shorter of the wonders of

13

296 . SUPPLEMENT

the northern romancers concerning their kraken. Denys de
Montfort, in his history of the mollusca, has thought proper to
collect all that was written before his time upon this subject,
but he has not limited himself there. Thanks to the usual
fertility of his imagination, he has arrived to such a point of
exaggeration, that although he boasted of having made na-
turalists believe whatever he pleased, he has failed in per-
suading any body to adopt the history of the kraken. It was
about the same time when this author wrote, that they began
to speak in the United States with so much assurance con-
cerning the colossal sea-serpent, which turned out after all to
be nothing but a tunny of ten or twelve feet long.

The ancients tell us that the octopi are the enemies of the
locusts and of the lobsters, which dread them, while they are
themselves pursued by the murznz, which devour their arms.
They likewise inform us that their bite is stronger than that
of the sepiz, but not so venomous. -#lian adds, that it is
said by fishermen that the octopi are attracted to the land by
the fruit of the olive-tree.

The octopi do not seem to be very hurtful to the human
species, except by the destruction of such crustacea as serve
for our nutriment. The mode in which these animals twist
themselves, with the assistance of their arms, provided with
suckers, and the force with which they do this, is the cause of
the horror which a man experiences, who, at the moment in
which he is swimming in the sea, finds himself thus enlaced
and in peril of drowning.

In many countries some species of octopi are eaten. The
ancients appear to have held them in request; and even at
the present day, in the Mediterranean, and particularly the
isles of Greece, sailors eat a considerable quantity of them.
But it appears that their flesh is always much harder than

that of the calamary or loligo, and that it even requires to be

ON CEPHALOPODA. 297

beaten with sticks to render it digestible. ‘This is done by
the Greek sailors for more than half an hour before they
cook the octopus.

Octopi are found in all parts of the globe, but perhaps more
particularly in the seas of warm climates. Peron and Le-
sueur have observed them in the seas of New Holland. The
common octopus seems to extend even as far as Greenland,
though it is but rarely found there.

The distinction of species is not easy, and has not perhaps
hitherto sufficiently occupied the attention of naturalists.
The ancients, and Aristotle in particular, had, however, dis-
tinguished four at least, but Linnzus confounded them all
under the name of sepia octopus. M. de Lamarck very pro-
perly separated octopus from sepia, and has characterized
three species.

Some octopi form a second division, called OCYTHOE by
M. Rafinesque, and which are placed with the argonauts in
the text. Among these is the polypus of the ancients, ocy-
thoé antiquorum.

This species, common in the Mediterranean, has never been
observed but in a shell of the argonaut genus, so that a great
number of authors have admitted that this shell belonged to
and was formed by the octopus; while others, on the con-
trary, think that it is only parasitical. ‘The Baron, as may be
seen by the text, leans to the former opinion ; and though the
latter is discussed and defended by M. de Blainville at great
length, we shall not follow him into the controversy.

One of the species, however, which compose this division
being, as it would appear, pretty common in the Mediter-
ranean, was observed long ago by the ancients, who have re-
lated how these animals navigate on the surface of the sea, in
the shell, which serves them as a bark, and by the assistance
of the oars and sails, which their simple and palmated arms
conduce to form. They are all pretty nearly agreed in affirming

298 SUPPLEMENT

that it is only at the moments of a calm that these octopi or
argonauts navigate thus, and that as soon as any danger me-
naces them they sink their skiff, overset it, and fall to the
bottom of the water. But they do not agree respecting the
manner in which their organization allows of this kind of na-
vigation, or even the mode of it, so that in fact they appear to
be in the same predicament as most of the moderns, who
never themselves have had the good fortune to behold this
elegant method of sailing on the surface of the waters. In
fact, though M. L’Abbé Ranzani has proposed a rectification
of the text of Aristotle, a little after the manner of the ancient
commentators, who, by adding, retrenching, or modifying the
words of which they have need, necessarily arrive at the sense
which they desire, it is evident that this celebrated philo-
sopher speaks of a fine membrane, like a spider’s web, which
is found between the arms, like the membrane which unites
the toes of ducks. This is exactly what is found in the com-
mon octopi. Pliny also mentions the thing too clearly to
admit of a doubt: he says, however, that the membrane exists
between two of the arms only. He adds a tail, so that the
animal is completely equipped with sails, oars, and helm.
félian, Athenzus, and Oppian, though they have a little mo-
dified what Aristotle has said respecting this navigating oc-
topus, rather follow him than Pliny, since they say nothing
about the tail. Belon, Rondelet, Gesner, Aldrovandus, and
his abridger Jonston, although most of them lived on the coast
of the Mediterranean, did never themselves observe these na-
vigating animals; accordingly, all that they say concerning
them is drawn from Aristotle and other ancient writers. They
have done the same as to the mode of navigation. As to the
figure which they have given, it is exact as far as the shell
goes; but that of the animal which inhabits it, is either solely
the product of their own imagination or taken from an animal
altogether different from the one that is usually found there.

, eed. SP. ..

oe Meet

i i i i i i i

ON CEPHALOPODA. 299

The Dutch naturalist, Rumph, appears to be the only one
among modern authors who has really given us the description
of this argonaut, or navigating octopus. “ One individual,”
says he, “had the body soft, fleshy, furnished with eight feet,
six of which, shorter than the remaining two, were provided
with suckers, asin the other sepiz. The two longer, or the hinder
ones, double the length of the others, were smooth, rounded,
and furnished with suckers likewise, but they were widened to-
wards the end, in the form of oars. Between these tentacula
there was no membrane, such as is described in the octopi
of the Mediterranean. In another individual, taken in 1693,
in a Shell of seven inches long and six in height, the six or-
dinary arms, from twelve to fourteen inches in length, were
very slender, and attenuated at the end, while the upper two
were much stronger and thicker, their bulk equalling that of
the finger. They were furnished at their anterior extremity —
with a thin and broad membrane, more narrow behind than
in front. ‘This molluscous animal,” he adds, “ on the skin
of which there were spots of a reddish brown, similar to those
remarked in the octopi, and like them varying in shade, is
free in its shell, not being attached there by any thread, as is the
case with the chambered nautilus; accordingly it issues forth
from it with facility, and comes to float upon the surface of
the waters.” Notwithstanding this, the Dutch observer says
that it is very uncertain if it can live without its shell, be-
cause some individuals which he had by him, recently taken
from the sea, died immediately, though they were put into
water. At the bottom of the sea this animal walks by the
assistance of its arms, the keel of the shell being uppermost.
It is also in this position that it re-ascends, but the instant it
is arrived at the surface, it throws out the water which its
shell contained, sets it floating, and spreads its arms around;
sometimes it fastens itself by means of its arms to large leaves
of trees, or pieces of floating wood, transported by the waters,

300 SUPPLEMENT

and lets itself be carried along. It is frequently seen, as the
same author tells us, in this position. But he also admits
that-it can swim, and in this case its shorter feet spread out
like arose; the hinder feet, palmated, and much longer, issue
forth from the shell, the animal suffers them to drag along in
the water, and thus, by their means, directs its fragile bark.
Finally, he also describes its navigation by the aid of the
wind, but differently from his predecessors, since he says, that
in this case it derives the principal assistance from the raised
edges of its vessel, which it presents to the gale; then it
withdraws its body very much back into the shell, and steers
its bark with two arms, which serve to direct it. He adds,
however, that the palmations of the two long arms might be
of as much use to it in sailing as in rowing, though his own
opinion is, that this molluscum effects its navigation without
sail, and with the raised edge of its shell.

It is never met with but at sea, and always solitary, shoot-
ing the water with force through its excretory conduit. Its
ink is of a bluish brown. Rumph says that he found in the
belly of some individuals some round white eggs, united in a
mass, and marked at the upper edge with a black point,
while, in the volutation of the shell itself, there was at the
same time another small mass of eggs or spawn, resembling
in form and colour the spawn of fishes, contained in a com-
mon envelope, extremely fine. He adds, that even when the
shell is not bigger than one’s finger, an ovary is nevertheless
found there, which reposes on the shell in the form of a
cushion. All this, however, is by no means clear, and more
especially, as he says a little farther on, that new observations
have proved to him that the eggs are found out of the body,
in the hollow of the keel, but attached to the animal. ~

Notwithstanding all these observations, which prove that
Rumph really saw an octopus with dilated tentacula, he has
left no figure of it but one done by his son; nor has the sub-

ee

ON CEPHALOPODA. 301

ject been renewed by any author, not even by Halma, the
editor of his great work.

With respect to the argonauts it is unnecessary to add any
thing further, as all that we have now said entirely refers to
them.

We now come to speak of the CALAMARY, which was
called revfoc by the Greeks, and LoLiIego by the Latins.
The word calamary itself is derived from that of calamarium,
which in low Latinity signifies a portable writing-desk, or
escritoire, with ink, pens, and a pen-knife. It has been
given to these animals because their body has a little of the
cylindrical form of these sorts of escritoires, and contains a
sort of pen in the back and ink in the interior.

The organization of the calamary is very like that of the
sepia, but the body is usually more elongated, and almost
cylindrical. ‘The product of the female is a very considerable
mass of oval eggs, disposed in series round an axis in the
form of a cord; this cylindrical mass is about three feet in
length and two in diameter. Bohadsch, who observed one of
these dimensions, having counted the number of series, and
that of the eggs in each, found that it contained 39,760 eggs.
They are at first of a yellowish colour, but afterwards they
become limpid, and finally blue.

The calamaries appear to possess both general and parti-
cular sensibility, still more developed than in the sepiz and
octopi. Their sight especially seems to be very fine; their
muscular activity is not less great : they move with the greatest
rapidity in the deep sea, which they never quit unless driven
from it by some violent impulse, as is the case with the flying-
fish; for this they employ the fins with which their sac is
furnished, or rather the contractions of the sac itself, in ex-
pelling the water which it contains. In their general move-
ments from place to place they hold their tentacular append-
ages motionless, and crowded into a point one against the

302 SUPPLEMENT

other, in front of the head ; nor does it seem that the branchial
appendages are developed. It appears that they do not
separate or move the first but to retain their prey, and the
second only when they await it at a distance, or employ them
to attach themselves to marine bodies in tempests and violent
currents. ‘They more especially inhabit the high sea, and die
in a few minutes after they have been taken out of the water,
in a sort of convulsion. They cannot even be preserved alive
in a vessel filled with sea-water, except when it is very large,
and the water very frequently renewed.

They pursue and destroy their prey by main force; it con-
sists principally of crustacea and fish. These they seize with
their tentacula, retain by the assistance of their suckers, which
are often armed with hooks, and break and triturate to a cer-
tain point with their jaws.

We are entirely ignorant of the duration of life in these ani-
mals, and whether their growth be rapid or no; nor have we
much more certain notions respecting the mode of intercourse
between the sexes. The two individuals differ in size, the
female being a little smaller than the male, accordingly the
dorsal cartilage is always more narrow in one than in the
other.

We do not know whether any actual coupling takes
place. Belon asserts the affirmative, which does not how-
ever seem to be probable. It is more likely that the mode
of generation is the same as in fishes. The singular me-
chanism of the tubes containing the seminal fluid is per-
haps destined for the purpose of acting upon the eggs. The
foetus enclosed in the egg undergoes its development pre-
cisely like that of the sepia; at first it is imperceptible in the
fluid by which the egg is filled, afterwards a sort of vitelline
mass may be observed, then the young animal, which makes
its appearance in one point, grows by little and little, appear-
ing to embrace this mass with its long tentacula. These, in

fete

ON CEPHALOPODA. 303

fact, exist some time before the ordinary tentacula make their
appearance. Finally, when on the point of issuing forth, the
young calamary differs very little from what it is afterwards
to be. Its back is already spotted with red.

The calamary is very generally used as food, and especially
in Greece ; it is rather an insipid sort of aliment, Fishermen
employ these animals as baits, cutting them into strips.

The calamaries are found in all seas, and even in great
abundance at rather small distances from the shore. Many
species, however, forming distinct groups, may appertain only
to certain countries. But the study of the species is not as
much advanced as might be wished. Molina, in his natural
history of Chili, defines after his fashion those which exist on
the shores of this country, in the South Sea. ‘Though it is
probable that they are new species, it is impossible to be as-
sured of it, and particularly to insert them with any certainty
in the catalogue. The first is his sepea unguiculata ; query
if it be acalamary? the second is sepia hexapus, which would
be very singular if it were true that the body, which he says
is of the size of the index finger, is fractured into four or five
articulations, which decrease in bulk towards the tail, and
that, on touching it with the hand, one experiences a sort of
electric commotion; his third species is called tanicata, and
has the whole body over the ordinary skin enveloped in a black
and pellucid covering. It is very large, for he adds that some
were brought to him weighing five hundred pounds.

NAUTILUS is a denomination employed by the ancient
naturalists, both Greeks and Romans, and among others by
Aristotle and Pliny, to designate two animals which can make
use of their shell as a little boat, to float upon the surface of
the water. This observation, which perhaps was derived
from the form of the shell, was afterwards confirmed, at least
in appearance, by circumstantial details, added by Pliny,
Alian, Oppian, and Philo, on the mode of navigation of

304 SUPPLEMENT

these animals. Be this however as it may, Aristotle says,
upon the subject, after having previously spoken of the po-
lypi, or naked octopi, “there are yet two genera of polypi,
but they inhabit shells; the first is named nautilus by
some, and nauticus by others. The animal is similar to a
polypus (octopus), and its shell has a concave cochlea, but
the animal is not attached to it. This animal, which is
small, usually seeks its food along the coasts; sometimes the
waves cast it ashore, and the shell falling, it is surprized and
dies on land. The second, which has a shell, is like the snail ;
it does not come forth, but remains there, like the helix,
though it sometimes stretches forth its arms out of the shell.”
A little further he says, ‘‘ the polypus nautilus is of the nature
of those animals which may pass for extraordinary, for it can
float upon the sea; it rises from the bottom of the water, the
shell being reversed, so that it may do this the more easily,
and that the shell may be empty. But when arrived at the
surface it turns it round again. It has between the arms a
kind of tissue, similar to that which unites the fingers of pal-
mipede birds, and which only differs in being much more
slender, and of the consistence of a spider’s web. The animal
makes use of this tissue where there is a little wind, at the
same time letting fall, by way of helm, the arms on each side.
On the least appearance of danger it dives into the sea, by
filling its shell with water. As to the origin and growth of
this shell there is nothing certain. It does not appear to be
engendered by sexual intercourse, but to be produced like
other shells; but yet even this is not evident, any more than
whether the animal can live without it.”

Pliny, at the end of his 29th chapter, book the ninth, de-
voted to aquatic animals, speaks only of Aristotle’s first species
of nautilus, which he says was called pompylos by some per-
sons. That Pliny speaks of the same animal, rests, however,
on the supposition of Gaza, that we must read in Aristotle

ON CEPHALOPODA. 305

as Pliny gives none of the details which are furnished by
Aristotle; he confines himself solely to mentioning the mode
in which it navigates, by raising its first two arms, between
which it extends a membrane of extreme tenuity, rowing
with the others, and steering with its medial tail, an organ
which never existed in any species of octopus.

Oppian, in his Halieticon, also speaks only of the first
species of Aristotle’s nautilus, but, like a poet, he considers
only its mode of navigation, which he believes to have served
as a model to the man or the god who first dared to open for
himself a path upon the waters.

“‘ Concealing itself,” continues Oppian, ‘in a concave shell, it
can come to land, but it can also raise itself to the surface of
the waters, the back of its shell being upwards, lest it should
fill with water: as soon as it has arrived at the surface it
turns its shell, and navigates like the most skilful sailor. For
this purpose it extends like sail-yards two of its feet, between
which there is a thin membrane, stretched like a sail by the
wind, while the other two, which touch the water, direct, as
with a helm, the house, the vessel, and the fish. If it per-
ceives any danger it furls its sail, draws in the helms, and
plunges into the deep, being rendered more heavy by the
water which it has caused to enter into its shell.”

AMlian, under the denomination of polypus nautilus, like-
wise speaks only of the first species of Aristotle, without even
adding the second name given by Pliny. He also tells us of
the mode of navigation, with some little variety: to come to
the surface the animal ascends, the back of the shell being
upwards, to prevent it from filling with water ; but once arrived
there it turns it. Ifthe sea be calm it then navigates as in a
small boat, rowing with two of its arms, which it has extended
one on one side and the other on the other side of its znnate
or connate shell; but if there should be a little wind it pro-
ceeds by converting its oars into a strong helm, at first ex-

VOL. XII. X

306 SUPPLEMENT

tended in front, and it raises the other limbs, which are united
by avery slender membrane, which it half opens, and it thus
navigates as long as it perceives no danger: on any alarm,
however, it sinks to the bottom, by its own proper weight,
and by that of the shell, which it has filled with water, con-
ceals itself, and escapes its enemy. As soon as the danger is
past it reascends, and navigates afresh. It is from this
operation that it has received its name. Thus lian has
imitated Pliny in mentioning nothing concerning what was
certain in Aristotle, and he cuts the difficulty by adding the
epithet of znnate to the shell.

Philo, a Greek writer, much more modern than those now
cited, in his treatise on the nature of animals, and which is
only a pure compilation, or rather an abridgment of Aristotle,
has added nothing to what the latter has given us concerning
the nautili.

Belon, the most ancient of the naturalists, who wrote at the
era of the revival of learning, appears to have been the first
who considered the handsome partitioned shell which we re-
ceive from India as another species of nautilus, and we shall
presently see that it is the only one to which the name should
remain. Nevertheless he has not referred it to the second
species mentioned by Aristotle, but to a shell which is evi-
dently but a large species of doliwm, and which, presenting
the character of being very slender and light, might in truth
belong to aswimming animal. It is unfortunate, however, that
this is a true gasteropod, and that Aristotle has positively
declared that the animal of his second species is a polypus or
octopus. Belon adds nothing to the description of Aristotle’s
first species but a bad figure, evidently designed from ima-
gination.

Rondelet manifestly copies Aristotle, and likewise gives a
figure of the shell, which is supposed to be that of the first
species; but the animal which he represents as belonging to

13

ON CEPHALOPODA. 307

if is certainly an octopus, with simple arms and a single
range of suckers. He speaks of the shell which now consti-
tutes the genus nautilus only as a cochleid, vulgarly called
margaritiferous, and blames Belon strongly, and in a very
unsuitable manner, for having supposed that this could be a
species of nautilus.

Gesner, in his article nautilus, compares, according to his
custom, with much care, all that has been said by the ancient
Greek and Latin authors, adding what he found in Belon and
Rondelet, as well as their figures. But he also mentions, in
his corollary, that he had received from an English physician
named Falconer, the figure of a molluscous animal, the shell
of which was evidently that of Belon’s second species.

Aldrovandus copies Gesner very closely, and his abridger,
Jonston, of course does the same.

Bonnani (Recreatio mentis, p. 88.) adopts the opinion of
Belon with less hesitation, and gives two good figures, the
one of Aristotle’s first species, and the other of that which
Belon thinks to be the second. The first, he tells us, has the
name of polpo moscardine or moscarolo in Italy, and that it is
found in the Adriatic sea, on the Italian coast, where the
fishermen catch it along with the sepiz, near the rocks upon
the shore, where it frequently seeks its food.

Rumphius, the only author, except the physician cited by
Gesner, who has seen the animals of both shells regarded
hitherto as nautili, again confounds under this name the
species without partitions or chambers and those which have
them. But his denominations were not derived from this
character, which was never properly marked until after the
dissertation of Breynius, de Polythalamis, and he distin-
guishes three or four species, in only one of which, belonging
to his second section, does he describe the animal.

The majority of authors on conchology at this period did
the same as the foregoing, until Gualtieri, enlightened doubt-

br

308 SUPPLEMENT

less by the labours of Breynius, divided the nautili into two
genera, and with a singular sort of caprice reserved this
name of nautilus to the species with which Aristotle was
certainly not acquainted, although Belon had considered it —
his second species, and gave the name of cymbium to that
which this celebrated philosopher had regarded as the type
of the nautili. -

Nevertheless this mode of consideration was not adopted
by every body. Thus D’Argenville always comprized under
the same name the nautili without chambers and those with
them, indicating many species in each group. Davila did so
likewise, and many other authors. But at length Linnzus,
having admitted the division proposed by Gualtieri into two
genera, restricted the appellation of nautilus to the polythala-
mous species, and that of cymbium, which the Italian con-
chologist had proposed for the monothalamous, was changed
into the denomination of argonaut.

From this it is evident, that under the name of nautilus the
modern zoologists can by no means employ the observations
which the ancients have left us on the octopi which navigate
in a shell, but merely what Rumphius has given us in his
Curiosities of Amboyna. This is the nautilus of the text, to
which we refer for characters. The animal, though very
common in the Indian seas, is known to us only by the unsa-
tisfactory figure and incomplete description of Rumphius; for —
it appears evident that the details added by Denys de Mont- é
fort are the product of his own imagination, or mere con- |
jectures founded on the description of the Dutch writer. The —
description, of course, we will not follow here. Rumphius
tells us that this animal, when it is desirous of sailing, is —
always alone. It puts forth its head, all its tentacular ap-
pendages, and extends them with the membrane it has be- —
hind. Often it draws itself along with the body upwards, .
the head and tentacula under, and more frequently still it is

ON CEPHALOPODA. 309

at land, or in some muddy cavity where fish occasionally
retire ; in fine weather it remains but little upon the water.

He concludes that this animal is but slightly attached to
its shell, from the quantity of empty teste which are found
either floating on the surface of the water or cast upon the
shore. But this circumstance is more probably attributable
to another cause; namely, that being without cover, or de-
fence, the nautilus is an easy prey to the voracious crustacea.
This appears to be fully proved by the empty shells being
damaged on the edges.

This animal is in no great request for the table, because its
flesh is extremely hard ; but its shell serves for the purpose of
making drinking-vessels. According to the Dutch author just
quoted the savages make spoons of it, which they call papeda
in the eastern islands. .

From his time no person has described from observation
this singular molluscum, which in all probability exhibits
‘numerous relations with the octopi, but which likewise must
differ considerably from them. . The form and number of the
tentacula are very different. It appears even that these ani-
mals are not provided with those singular suckers which are
found in all the species of cryptobranchia that are known,
unless we believe that the digitations about the size of a straw
supply their place. The disposition of the mantle is also
altogether different ; it forms, in fact, a large advancing piece,
which lines the whole cavity of the shell, and which, very
probably, even out-edges it, or contains a portion of it in its
interior. But more especially, this animal is provided with
a shell which resembles nothing that we are at present ac-
quainted with in the living state, if it be not that of the
spirula. It is tolerably thick, particularly if we compare it
with that of the first nautilus of Aristotle, to which the name
of papyraceous has been given, in consequence of its tenuity.
Its mode of growth is altogether similar to that of other shells,

310 SUPPLEMENT

but the manner in which it is rolled, from front to rear in one
and the same vertical plane, so that it may be cut into two
completely similar parts, is a character without any parallel
in the living state, except in the spirula. Itis the same with
its concameration, or the division of the posterior part of its
cavity into a great number of lodges, formed by simple or
smooth partitions, convex behind, concave in front, and at
the middle of each is an orifice, which is prolonged into the
internal of the following partition. These partitions, and the
chambers which they form, are evidently produced by the ad-
vance of the animal, determined by its growth, during the
whole active duration of its life: something of the same sort
takes place in ‘certain spiral shells. The siphon is evidently
the point of attachment of the terminal muscle of the body,
analogous to the columellary muscle of the same spiral shells,
and which necessarily follows the progress of the entire ani-
mal. The animal itself is only enclosed in the first lodge,
whose size and even form have no resemblance with those of
the other abandoned lodges. From all this it may be con-
ceived that the number of the chambers and their proportional
extent vary in each individual. In regarding the composition
of this shell we find it to be of two parts, one exterior, of but
little thickness, of the usual nature, coloured by irregular
bands, transverse, reddish or ochreous on a white ground,
which becomes more and more predominant as we approach
the aperture, and of an internal stratum, thicker, and nacreous.
This stratum spreads even over the back, from the return of
the spire to the interior, and more or less externally, so as to
close more or less completely the two lateral umbilici situated
at the two extremities of the transverse pillar. It is upon
this nacreous part that may be easily seen, both to right and
left, and pretty deeply, two broad muscular impressions,
rounded, and which tend to unite together.

We have said above that this shell has evidently many re-

ON CEPHALOPODA. sll

lations with the spirula, with these differences, however, that
the latter must be still more interior or more concealed by the
mantle or its lobes, since it is constantly colourless, that the
cavity occupied by the posterior part of the animal is much
less large, and particularly that its circumvolutions are much
less close. ‘The partitions are of the same form, the siphon
being only almost marginal. Nevertheless, if we should trust
to the notes taken on the animal of the spirula by MM. La-
marck and de Roissy, who examined it when in the posses-
sion of Peron and Lesueur, and even the figure given by the
latter, it would differ considerably from what we find in
Rumphius on the animal of the nautilus.

We find a similar approximation between the partitioned
or chambered nautilus and a great number of those fossil
shells which are called ammonites. These shells are likewise
partitioned, and rolled regularly in the same vertical plane
from front to rear. The cavity which contained the hinder part
of the animal appears proportionally less large than in the
nautilus, and its orifice dilates a little into a trumpet form.
The siphon, besides, is much more frequently dorsal; but
more especially the circumvolutions are less close, holding a
sort of intermediate relation between those of the spirula and
those of the nautili, so that all the turns of the spire are vi-
sible, and the aperture is not modified by the last but one.
Finally, the partitions are more or less sinuous, which doubt-
less is occasioned by the form of the posterior part of the body
of the animal. As to the extreme thinness of the shell, that
appears to have been somewhat exaggerated, and judged of
only by a few remaining lamine of the nacreous part, which
is never exterior in any of those shells, nor even in that of the
nautilus.

We have much pleasure in referring to a most excellent
memoir on Naut. Pompilius of Lin., by Mr. Owen, with
elaborate figures of the animal, its shell, and various parts,

312 SUPPLEMENT

published by direction of the council of the College of
Surgeons. The reader will find the most satisfactory infor-
mation on the subject, and the scientific public will earnestly
hope that the present memoir will be the first of a similar
series.

The shell of this chambered nautilus (nautilus pompilius,
L.), which is nearly eight inches in its highest part, is very
common in the East Indian seas, and especially towards the
Molucca islands. This is the one which was the subject of
the observations of Rumphius, which we have cited a little
farther back. It is usually brought into Europe in conse-
quence of its fine mother-of-pearl, much in request with ca-
binet-makers and jewellers. The smallest and most exca-
vated partitions are used to make pendants for the ear. ' The
orientals, by removing the stratum of this shell, which is not
nacreous, form drinking-vessels of great brilliancy, on which
they engrave divers figures. Formerly the same use was made
of them in Europe, and such vessels were found only in the
houses of great men and princes. At present they are chiefly
confined to the cabinets of the curious.

This SPIRULA is a true cephalopod, provided with a sac
which envelopes the posterior part of the body. The anterior
is external, and the head, which terminates it, supports ten
arms, arranged like a crown around the mouth, two of which
are longer than the others. M. de Lamarck adds, that at the
posterior extremity of the sac is seen a shell encased, pre-
senting externally only a single discovered portion of its last
circumyvolution. It was even this resemblance of the animal
of the spirula with the sepiz that first induced M. de Roissy,
in his “ General History of the Mollusca,” and subsequently
M. de Lamarck, to conclude, in a more rigorous manner than
had been done before, that all the polythalamous shells had
belonged to cephalopods. Unfortunately, the only individual
which had served for observation to the zoologists now cited,

ee ee

ON CEPHALOPODA. ols

and which had been found by Peron and Lesueur dead, and
floating on the surface of the sea, in their passage from the
Moluccas to the Isle of France, was lost or mislaid in the
collections of the museum in the Jardin du Roi, so that it was
impossible to confirm by an attentive observation that which
probably had only been the result of a rapid and superficial
examination. What seems to prove this is, that the figure
given in the French Encyclopedia corresponds very incom-
pletely to that given by Lesueur in his “ Voyage in the Austral
Ocean,” and in which (singular enough) the animal, which had
only been seen dead, is yet coloured of a lively carnation red.
It would not, therefore, be at all surprising if the similitude
of the animal of the spirula to the sepiz were exaggerated.
We find, indeed, that M. de Freminville, a judicious observer,
has declared that this animal, which he saw in the living
state, is totally different from what we would be led to believe
from the descriptions of others. So that it appears that this
subject yet remains in considerable doubt; still it seems pro-
bable, even from the incomplete figure given by Rumphius of
the nautilus Pompilius, that the resemblance is not so great
as the French naturalists and travellers just mentioned would
lead us to believe. As for the shell, it is equally likely that it
is altogether interior, which may be presumed from its slender-
ness, its fragility, and the total absence of coloration.

As yet but one species of spirula is known, spirula Aus-
tralis, or Peronii ; itis the nautilus spirula of Linneus. This
is a handsome and very slender shell, altogether white, and
nacreous in the interior, and appears to be very common in the
Atlantic Ocean, in its intertropical parts, but probably it is
chiefly to be found in the high seas. In St. Domingo, how-
ever, and in the other islands of the American archipelago,
the shells of the spirula are so common on certain coasts that
the soil over which one walks is completely strewed with

314 SUPPLEMENT ON CEPHALOPODA.

them; we may therefore indulge a hope that before long zoo-
logists will be in possession of more certain data respecting
the true characters of the animal which produces this hand-
some shell.

SUPPLEMENT

ON THE

SECOND CLASS OF THE MOLLUSCA.

THE PTEROPODA.

To the text on this small class we must add proportionally
little.

The first genus (CL10) was established in 1774, by Pallas.
Brown, some years previously, had given the name to some
other little animals, tolerably approximating, but which are
contained in a gelatinous case. Pallas gave to this genus the
name of Clione. But as Linneus and others had united all
the pteropods under the general name of clio, MM. Peron and
Lesueur thought fit to separate this genus anew, in their labours
on the family, and to give the name of Cleodora to the true
clio of Brown, and leave that of clio to the animal so called by
Pallas. The characters of the genus clio thus circumscribed,
are a free and naked body, more or less elongated, a little de-
pressed, pointed behind, and without any other fins than the
lateral appendages, considered as being branchiferous. The
head is very distinct, provided with six tentacula, conical,
retractile, separated into two groups of three each, capable of
being entirely concealed in a sort of prepuce, which itself has

316 SUPPLEMENT

a kind of small tentaculum at its external side. The mouth is
altogether terminal and vertical; the eyes almost superior ;
and there is a sort of sucker under the neck. These characters
are established upon the most common species of the genus,
namely, the clio borealis of Linneus, a very small animal,
almost entirely gelatinous, which is found in great abundance
in the northern seas, where it is said to be known under the
denomination of food for the whale, because it is allowed to
constitute a considerable portion of the nourishment of that
vast animal.

With regard to the habits and manners of the next two
genera of pteropods (Cymbulia and pneumodermon), we know
nothing whatsoever. The same may be said of the limacine,
except that the species which is known (clio helicina, Gm.)
is scarcely less abundant than the clio borealis in the northern
seas, and is also considered to constitute one of the principal
aliments of the whale.

There are certain peculiarities in the organization of the
HyALZ#A, which, as they have been so briefly touched on in
the text, it may be necessary concisely to notice here.

M. de Lamarck was the first who established under this
denomination a very distinct genus of the mollusca, though
little was then known concerning it, except the shell, which
Forskahl, and subsequently Gmelin ranged in the section of
the terebratule. The first of these authors, indeed, has men-
tioned something concerning the animal, which he observed
in the living state. But he has spoken of it in a manner so
obscure as to place it, as we have seen, among the bivalves,
in which he was imitated by MM. Cuvier and de Lamarck,
in their earlier works. Lamartiniere, who was the naturalist
on the expedition of La Peyrouse, as well as Forster, who
belonged to that of Captain Cook, was disposed to place it
with clio. After M. Cuvier had published the comparative
anatomy of this animal, no other variations took place, and

ON PTEROPODA. 317

all subsequent zoologists have placed it where it should be,
namely, in the neighbourhood of the Clio, as it stands in the
text.

The body of the most common hyalza, of the size of a
tolerably middling nut, at least when it is contracted, is
formed of two parts, separated by a very well marked
contraction. One anterior, containing the head and a sort
of thorax ; and the other posterior, which might be named
abdomen. ‘The latter is always covered by a sort of shell
of a rather singular form, and which might, and has been
taken for a bivalve, the valves of which were united closely,
or continued to the place of the hinge. The fact is, that
it is rather a kind of sheath, very symmetrical, very much de-
pressed, and in which the anterior aperture is prolonged into
a very narrow emargination on each side. This sheath, very
thin, although hard, of the colour of horn, and translucent,
is pretty nearly square. The posterior edge, on which the
two lamin are confounded, is divided more or less deeply
into three points, the middle one of which, always longer, is
pierced at its extremity. The lateral edges are straight and
cleft, for a greater or less part of their length. As for the
anterior edge, it presents the aperture of the sheath or shell,
_ which is rather narrow and transverse. The upper part ad-
vances much more than the lower, because the upper lamina,
which is almost plane, with four sorts of keels, radiating from
the middle point, is prolonged, forming in front, a sort of
blunt apophysis. The under plate, on the contrary, is much
more hollow, considerably more gibbous, and as it were
hemispherical, and its anterior edge is rounded.

This shell is completely uncovered, and is attached to the
animal only by its middle or pierced point, to which the
dorsal muscles, or those of the pillar are attached, and by the
edges of its aperture, to which those of the mantle adhere.

Although it really appertains only to the abdomen, it ap-

318 SUPPLEMENT

pears that the animal can shelter the anterior part of its body
under the advancement of the upper lamina over the lower,
but it can never draw back into the shell itself. Perhaps even
in a state of repose, the animal envelopes its shell with the lobes
of its mantle, as is the case with some other mollusca.

When this shell has been removed, (which cannot be done
but by breaking it, if we wish to preserve the animal, because
the entrance of the shell is much more narrow than its cavity,)
we see more evidently the separation of the body into two
parts. Both one and the other are perfectly symmetrical.
The posterior or abdomen presents the very form of the
sheath or shell, which it fills exactly. Accordingly, itis much
more plane above, and, on the contrary, considerably more
curved underneath. It is entirely enveloped by a mantle
very thin in the middle parts, where it is adherent, and, on
the contrary, more thick in the whole circumference which
borders the cleft of the shell, and which is more or less free.
Above it is prolonged like the upper plate of the shell; un-
derneath it equally edges the inferior lamina, but there it is
thicker. It becomes more especially so on the sides, where
it edges the cleft of the shell, and where it is divided into two
lips, but which, nevertheless, are not cleft in their length.
At the posterior extremity of their union, there seems to exist
a sort of strip, which is only their prolongation, and which
may sometimes be much longer than the shell.

In the space which separates the two united lips from this
lateral part of the mantle, is formed a sort of fold, or projecting
plate, equally muscular.

From what Forskal says of the edges of the mantle, it ap-
pears that in a living state they have the capacity of extend-
ing very considerably, and become very thin, and even trans-
lucent.

From this description of the mantle, it follows, that it is
really open only in all its anterior part, especially above and

ee

ON PTEROPODA. 319

on each side, and by no means on its lateral parts, which cor-
respond to the lateral parts of the sheath, neither does it pre-
sent any trace of the arrangement of gills. Those which
Cuvier has described and figured as such, are really only
the muscular fibres of the lateral prolongations of the mantle.
As in its central parts, this envelope is very thin, one may
perceive, transversely, above, the true gill on the right side,
and the ovary forming a much more considerable mass to the
left. All the lower part is occupied by the liver, and the
second portion of the oviductus.

The anterior or cephalo-thoracic part of the hyalxa is
much more complicated. It is separated from the posterior
by a very sensible contraction, which has been named
erroneously a neck, from whence it has followed that the
divers organs which are found there have been mistaken.
The fact is that we must distinguish there the trunk properly
so called, terminated anteriorly by the head, which is not
separated from the foot, or from the locomotive appendages,
which are enormously developed on its sides.

The trunk consists in a very narrow band, but little distinct,
and especially so underneath ; for above it forms perceptibly
enough, an oval, elongated, plane projection, between the
locomotive appendages, and is terminated by the head. The
extremity of the male apparatus of generation, is even seen a
little behind, through the skin, which is very thin. On this
part, and at its anterior extremity, are the tentacula. They
are rather small, but very visible, cylindrical, and formed by
a sort of sheath, in which are contained the true tentacula, a
little swelled at their summit.

The existence of eyes in this animal has not been precisely
ascertained, but it appears very probable.

More in front, and a little to the right, at the root of the
tentaculum on that side, is an orifice a little infundibuliform.

320 SUPPLEMENT

It is that of the male apparatus of generation. We cannot
say that it is really central.

Underneath, the middle projection of the trunk, which is
always of avery deep colour, and which can only be well
seen in front, is terminated by a small inferior cleft, disposed
in the direction of the axis of the body. This is the mouth.
It is placed in the summit of the angle formed by two small
labial decurrent bands, and which, separating considerably,
are lost under the locomotive appendages.

These appendages, which remain to be described, are
nothing but what is called the foot, in the gasteropods, and
which assumes its development, not in the middle and inferior
part, but especially on the sides, and in front, so as to pass
considerably beyond the head; and as these two lateral parts
to proceed thus forward, must approximate to each other, a
sort of deep emargination has been the result on the lateral
parts of the head. From this character is derived the name
of the class pteropods. Behind, however, there is no trace
of separation, and there the external edge, after having formed
a fold in front of the lateral aperture of the mantle, is con-
tinued without interruption, and is curved in front of its in-
ferior edge, forming a sort of bulky transverse fold, from
which it results that this foot, much thicker at the root, and
at the middle of its dilatation, and rather thin in its circum-
ference, may not only serve for swimming, by acting like
sorts of wings, but that it can very probably creep a little on
the surface of submarine bodies, and particularly form a sort
of sucker when the animal is in a state of repose.

To complete the external description of the hyalea, we
have only to speak of the orifice which terminates the diges-
tive apparatus, and of that of the apparatus of generation.
The one is formed at the posterior extremity of the furrow
which separates the two lateral lips of the mantle, on the

a ee

ON PTEROPODA. 321

right side, and the other exists also at the right, but is
situated much more forward, and in the emargination which
separates the two parts of the body, in front of the orifice of
the branchial cavity of this side.

We have already viewed the exterior envelope of the hyalza,
in the relation of its disposition and form, let us now consider
the mantle in its uses.

It would appear that it is not of a very mucous texture, for
the shell is very thin; but it is evidently very contractile, and
probably very sensible in its exsertile parts. The local, or
special sensibility is carried on by the tentacula, of which we
have spoken above, and which are but little developed, and
probably by the eyes.

The exsertile parts of the mantle, are, moreover, capable of
great extension. They have particular muscles which draw
them inwards, and they may easily be seen on the back, and
under the belly. These white fibres, which are evidently
muscular, proceed transversely, and in directions almost
parallel to each lip of the lateral lobes. These our author
considers as branchial vessels.

The foot of the hyalea being the principal, if not the only
- organ of locomotion, the muscular arrangement there becomes
more complicated. ‘These animals belong to the ocean, and
are seldom found near the shore. ‘Their manners and habits
are little known with the exception, that they swim with
great swiftness. On the rest of this class we have nothing to

add.

VOL. XII. Y

SUPPLEMENT

ON THE

THIRD CLASS OF THE MOLLUSCA.

THE GASTEROPODA.

THIS class, though numerous, and divided into eight orders,
we must embrace in a single supplement, as our object is now
to confine ourselves as much as possible to popular matter.

The first order is that of the PULMONARLA&, the first genus
of which, LIMAX, we shall consider in a general manner,
without attending to the subdivisions.

The limaces in general, to which we give the name of
slugs vulgarly, are naked mollusca, or at all events have no
apparent shell. ‘Their organization exhibits a very great
analogy with that of the helices or snails. 'The dermo-muscu-
lar envelope, very thick, and especially in the under part,
forms a long and simple cavity, in which the viscera are
contained. ‘The dermis, which cannot be separated from the
contractile stratum underneath, has a greater or less number
of tubercles at its superficies. The colouring pigment at its
surface is often very: thick, whereas the epidermis is very thin.
A great number of pores are there distinguishable, which send
forth a great quantity of mucosity to its surface. This ap-

pears particularly to issue in greater abundance from a sort |

re

SUPPLEMENT ON GASTEROPODA. azo

of white sinus of no great depth, surrounded with tubercles,
and which exists at the posterior part of the back of the red
limaces. Into the thickness of this skin, it appears from
desiccation, that there enters a great number of calcareous
molecules; but they exist in much greater quantity in the
anterior part of the body, sometimes called the shield, so as to
form, especially in the grey limaces, the rudiment of a shell,
which it is true, is very thin.

The viscous matter just mentioned serves to attach the
limaces to the bodies over which they move. By means of
this sort of spittle, become friable and shining, a limax may
be traced, frequently many days after it has passed. To-
bacco, common salt, and in general all irritants, produce so
great an ejection of this matter, that the animal swells, stiffens,
and dies, when a pinch of them is put upon its head.

These animals have four tentacula. The extremity of the
anterior is swelled, translucent, and as it were gelatinous.
That of the posterior tentacula presents a small disk, alto-
gether black, which forms the organ of vision. The eye, very
small, is nearly spherical. It has evidently a fibrous enve-
lope, very thin, and allowing the black colour of the choroid
to be seen through. Behind, the sclerotica is applied against
the nervous ganglion; in front itis continued with the trans-
parent cornea, which appears also to be the continuation of
the skin. ‘The choroid, very much coloured, is pierced by a
pupil extremely small.

The organ of locomotion, as in all animals of the molluscous
type, is in a great measure cutaneous, that is, the muscular
fibres which compose it, are very adherent to the skin, con-
founded with the dermis, and disposed in all directions.
Under the belly, however, where the locomotive disk exists,
they are much thicker, and directed according to the length
of the animal.

The tentacula are hollow in all their length, and formed by

¥ 2

324 SUPPLEMENT

an elongation of the dermoid envelope, consequently some
muscular fibres line the internal face of this hollow cylinder.
These fibres are in a great measure annular, and of course
their contraction suffices to elongate the organ.

The mouth is armed above with a small arched tooth,
adapted for cutting the leaves of the plants on which they
feed.

The limaces possess the sense of touch in more perfection
probably than the helices, and especially in the anterior
parts, and on the edges of the mantle. In taste, smell, and
sight, there must be a strong resemblance. That they both
taste and smell is certain, since they seek out and prefer cer-
tain substances to others. ‘They donot seem, in reality, to
perceive bodies, although they are provided with an organ of
vision, and they are certainly deaf.

Their locomotion is performed pretty nearly like that of
snails, by the successive contraction of the muscular fibres of
the foot, and especially of those of its middle band. But it is
more lively and more rapid, particularly when they are en-
deavouring to escape from a place where they have been
detained.

Their food essentially consists of vegetable substances.
These are, particularly young plants, paper, rotten wood,
fruits, mushrooms, &c. They will also feed upon some
animal substances, as cheese, meat, and other matter of this
kind in a state of putrefaction. They are evidently most
voracious animals, and eat more in the evening than any
other part of the day. Their mode of eating is a sort of
mastication, the lingual plate being opposed to the upperjaw,
and then pushing the substance towards the cesophagus. As
in all the molluscous animals, digestion appears to be very
slow in the limaces, and accordingly they can support a very
long fast. ‘hey are less capable of this, however, than the
helices, unless they are in very favourable circumstances for

a a a

ON GASTEROPODA. 3290

it, in consequence of the nudity of their skin, which causes
the dryness of the air, as well as the solar action, to be very
pernicious to them.

They are animals, in fact, which never issue forth from the
holes of old walls, from under stones, or half-rotten leaves,
cracks in the barks of trees, mushrooms, and even from the
interior of the earth, where they retire habitually, except at
that period of the day when there is generally more humidity
in the air, that is in the evening, and early in the morning.
They are particularly to be seen in greater abundance after
warm and gentle showers in spring and summer.

Like the helices, or snails, the limaces are afraid of cold ;
but although they can shelter themselves but very incom-
pletely under their buckler, they appear to dread it less than
the latter. Accordingly they are found to enter later into the
state of hybernation. Nevertheless, for the purpose of passing
the winter, they sink into the hollows of the ground. They
appear, on this occasion, more particularly to prefer the
humus or mould which is formed in the trunks of rotten trees.
Individuals have been found at more than the depth of a foot
in this substance. In this state of torpor, the limaces con-
tract themselves as much as possible in length, so that they
become almost hemispherical.

Their general activity increases according to the tempera-
ture. It is generally about the end of spring, and in summer,
that they seek each other for the purpose of reproduction.
We know but little respecting the particulars of their inte1-
course. ‘They are hermaphrodites, and give and receive im-
pregnation at the same time. The organs of generation are
situated near the neck.

A very short time after intercourse, and generally in the
month of May or June, the limaces lay eggs, more or less
globular, and the size of which varies according to the
species. They are deposited isolatedly in little heaps, more

326 SUPPLEMENT

or less numerous, in humid places, and sheltered from the
sun’s rays, under stones, in dung, in the holes of walls, &c.
At first perfectly transparent, they become by degrees, ‘from
the thickening of their envelope, opake, and of a yellowish
colour. Finally, they disclose at the end of a period which
seems to vary a little according to the external temperature.
The young limaces are then extremely soft, and almost
mucous. But they crawl with their tentacula, or horns, ex-
tended, as soon as they have come forth naturally, or even
have been extracted artificially from the egg. We are not
yet sufficiently informed as to the time when they become
adult, nor as to the duration of their existence.

They are fond of rainy seasons. When they are forced to
remain exposed to the rays of the summer sun, as they have
not the resource of the helices of enclosing themselves in a
shell, they begin by transuding from their bodies a greater
quantity of the viscous matter, and end by perishing. Ina
very few hours after their death they are decomposed, and.
melt into a viscous matter, which deserves to be analysed
with a greater degree of attention than, perhaps, has as yet
been bestowed upon it.

The limaces are scarcely in any manner useful to the
humanrace. Formerly many imaginary virtues were ascribed
to the little shell of the grey slug (L. griseus), and to the
mucosity which issues from all parts of their skin. But those
sorts of fantasies, like many others, have had their day, and
will go down no longer. They are still, however, ‘in some
eases considered to be cooling, humectant, and pectoral.
They are consequently sometimes ordered in consumptions,
coughs, and spitting of blood. These properties are common
to them with the helices, which are employed in preference,
as being more easy to collect and preserve. i

The limaces, as unfortunately is too well known, are very
mischievous in our gardens, kitchen gardens especially, and

ON GASTEROPODA. S27

in our orchards and fields. ‘These animals principally seek
out for their food the young shoots of esculent plants. They
attack without distinction, like the snails, fruits, the young
buds of trees, and vegetables of all kinds, when they are
young and tender. They constitute a real scourge ; for when
circumstances are favourable to them, 7. e. when the soil is
rich and humid, planted with herbs of which they are fond,
and exempt from the visits of animals which devour them,
they multiply to excess. They have been known completely
to devastate in asingle night a very large seed plat, the plants
of which had just begun to shoot forth. This evil is always
to be apprehended in gardens infested by these animals. ‘To
prevent its happening, it is necessary to cover the earth,
or the edges of the plants, with ashes, slacked lime, or
simply with fine sand. These substances act mechanically
upon the animal, and hinder it from walking, by attach-
ing themselves to its body. But care must be taken to keep
them constantly in a pulverized state.

Various methods have been devised to destroy these
noxious animals, but we shall not describe them here; suffice
it to say, that to prevent them from coming to any circum-
scribed spot, it is sufficient, as we have said before, to sur-
round it with sand or dust, or some very agglutinating sub-
stances which they cannot pass.

The limaces appear to be found in all the northern zone of
both continents, as well as in the temperate zone. Accord-
ingly we find them in Norway, Sweden, Lapland, in all
Russia, Denmark, and Britain, in all parts of Germany, in
Greece, in Italy, in France, and in all the southern parts of
the Mediterranean on the African coasts ; whether they are to
be found in the rest of Africa is doubtful. It appears certain
that true limaces exist in North America; at least such is
the assertion of M. Raffinesque. It does not seem so likely
that the limaciform terrestrial mollusca, that are found on the

13

328 SUPPLEMENT

coasts of the Mexican Gulf,in the American Archipelago, and
in all the rest of South America, are true limaces. Perhaps
they may be species of veronicella. It would also seem that
the true limax does not exist on the Indian coasts, nor in
Polynesia, nor even in Australasia. This would be a very
curious subject of research.

It appears that the grey limaces, or slugs, seek human habi-
tations in preference, more than the others do, from which
Swammerdam has thought proper to separate the genus into
domestic and rural slugs. The ZL. agrestis, though a very
small species, is, nevertheless, the one that is most hurtful to
agriculture, in consequence of its great multiplication. It has
been observed that two individuals, after coupling, have laid
seven hundred and seventy-six eggs, and that these eggs may
be dried eight times in succession on a stone, without losing
their property of disclosing the young.

A very curious species is the phosphorescent slug, L.
noctiluca, which is only known after a description and
figure, incomplete enough, given by M. d’Orbigny to the

Baron de Férussac, and which the latter has published in his.

work on the mollusca. It appears particularly remarkable,
because towards the posterior extremity of the shield, there is
a small disk, or pore, covered with a matter which is luminous
in darkness. This limax, which is fifteen lines long, and
seven thick, was found under stones, in the Island of Tene-
riffe.

The limaces and terrestrial helices, for many years, have
greatly occupied the attention of physiologists, and even of
all persons who take any interest in scientific researches.
Curiosity was excited to ascertain if, as Spallanzani had
advanced, the head of these animals could be reproduced, after
having been cut off. Observers were then busily engaged in
various parts of Europe, in immolating to their (shall we not
call it) cruel thirst for knowledge, myriads of these poor ani-

ee ee

ON GASTEROPODA. 329

mals, and in spite of this sacrifice, many among them deny the
reality of the fact, which others assert to have taken place.
It is, in fact, impossible for any one who has not convinced
himself of it by personal experiment, to believe in the repro-
duction of a part so important as the head. Nevertheless;
even now, at the present day, many persons believe it, though
it seems to be proved that it never takes place but when the
horns, or that part of the head which is in front of the brain,
alone has been removed. The animal infallibly dies, when
the first ganglion, which essentially constitutes the head, has
been taken away.

The motion of the limaces is in general very slow. It has
even passed into a proverb. They have a great number of
enemies among the birds, quadrupeds, and reptiles. Accord-
ingly an immense quantity of them is destroyed every year,
but the following spring amply makes up for the deficiency.

In treating of the HELICES, or snaz/s, an interesting and
well known genus of mollusca, we shall enlarge a little on
the text.

The organization of these animals has many relations with
that of the limaces, or slugs. ‘To form an idea of it we may
conceive one of the latter, 7.e. an ovaliform, elongated body,
convex above, plane underneath, in which the mass of the
viscera of digestion, and a part of those of generation, should
have formed a sort of hernia, for the extent of the middle third
of ‘the back, or rather in the space formed by the shield, and
have drawn along with them the skin, considerably attenu-
ated. This mass, in the front of which is the apparatus of
respiration, is turned spirally, and is contained in a shell of the
same form.

The body is pretty nearly cylindrical in all its anterior
parts, and, behind, terminates in a sort of tongue, entirely
muscular, which is only the elongation of the foot. This last
name is given to a flatted and very thick portion of the under

330 SUPPLEMENT

part of the body, by means of which the animal crawls. All
the lower surface of the body is smooth, but the upper is
rugose. The head, especially on the upper part, is not really
distinguished from the body, except by the organs with
which it is provided. There are two pairs of the tentacula, or
horns, the posterior of which are the largest, and have a small
black point at the extremity which has been considered as an
eye. They differ much from those of other mollusca, by
being retractile. At the anterior extremity of the head, is a
folded aperture which forms the mouth. In this anterior
part, at the root of the right horn, is a small cleft, where the
apparatus of generation terminates. The visceral mass is
entirely concealed by the shell. Of the latter, a description
would be superfluous. It is attached to the rest of the body
by the retractor muscles of the head and foot. Some of these
shells are variegated, and very beautiful, but in general they
are plain enough.

The skin of the snail, where it is uncovered by the shell, is
of an extreme degree of sensibility, and accordingly it re-
ceives a great number of nerves. It must have a very con-
siderable number of mucous pores, if we may judge by the
great quantity of viscous or mucous matter which it ejects.
This quantity, however, is less than in the slugs. That por-
tion called the col/ar, which is a muscular ring, bordering
the visceral mass, and which answers to the mantle of the
other mollusca, has the greatest number of these pores.

Thus the general sense of touch, must be, and is, in fact,
extremely delicate in those animals. We must add, that the
skin which envelopes the tentacula appears to possess still
greater sensibility than that of the rest of the body. It is
more fine, less viscous, perhaps, but in particular more
nervous. .

With respect to the function of the tentacula, it is ques-
tionable if it be confined to this general sensibility, and

ON GASTEROPODA. Som

whether they have not a peculiar office. The latter appears
probable. Some writers are of opinion that the anterior pair
may serve as olfactory organs. Others have imagined that
the entire skin of these mollusca, was, as it were, pituitary,
z.e. that it could transmit the sensation of odours, but from
analogy, this appears to be extremely improbable. Be this,
however, as it may, it is certain that snails can smell extremely
well, for they are easily attracted by many plants, the odour
of which pleases them.

The black points at the extremities of the last pair of ten-
tacula already mentioned, all authors have agreed to consider
as eyes, and very probably, with great justice. Swammer-
dam has even anatomized them, and declares that he has
found there all the parts which compose a true eye. It must,
however, be very imperfect, since, when we oppose a body to
the first or second pair of the tentacula of these animals, they
do not seem to perceive it more with one than the other.

There is no trace of any special organ of hearing in the
snails, and in fact these animals do not seem to perceive noise,
unless it be so considerable and so near them as to produce
a sensible agitation in the circumambient air.

The apparatus of locomotion in the helices is general or
partial. It is general in so much as the muscular or con-
tractile fibre is not distinct from the skin of which it forms
the internal stratum, directed in all ways. This is only
more thick, and takes a more determined direction, when it
belongs to the foot, where the muscular fibres are divided into
little bundles, and disposed lengthwise. It is by means of
this foot the animal moves, and very promptly, contracting
and elongating successively each of these little bundles.
There is a muscle which penetrates from one of the muscular
bundles of the pillar, (another of these serves to retract the
foot within the shell) into the interior of the tube of each

332 SUPPLEMENT

tentaculum, and proceeds to fix itself at the extremity. This
muscle, by its contraction, draws in the horn, turning it inside
out, like the finger of a glove.. These organs, on the contrary,
are unfolded by the action of the annular fibres of the skin
which forms them. The mouth and its appendages are
drawn back by another muscular bundle from the pillar of
the shell; and they are put forth by some small muscles,
much shorter, which, from the circumference of the lip, ter-
minate on the anterior edges of the mouth.

Of the interior anatomy, we shall merely notice the organ
of respiration. This is situated in a large cavity, placed
above the general mass of the viscera, occupying the last
whorl of the shell. It communicates with the external air
by an orifice formed in the right side of the thick edge of the
mantle, or in the collar. All the inferior part of this cavity
is smooth, and formed by a membrane evidently muscular ;
but the superior is almost entirely vascular.

Thus the snail, like all the mollusca of the same family,
respires directly the atmospheric air in a cavity evidently
pulmonary. The mechanism of this function is simple
enough. The animal causes the air to enter, by drawing
back the respiratory cavity into the last whorl, which is the
broadest, at the same time putting forth from the shell, all
the parts that can come out, and strongly dilating the pulmo-
nary orifice; it expels the air, on the contrary, by withdraw-
ing its body into a more narrow part of the shell, and by so
much the more completely, as it draws in the head, foot, &c.
But these movements of respiration are never regular. The
fluid elaborated in the respiratory organ, or the blood, which
is of a slightly bluish white, arrives to the heart, by means of
the pulmonary vein. |

These animals, like the slugs, are hermaphrodite, giving
and receiving fecundation at the same time. The organs of

ON GASTEROPODA. oon

generation are extremely complicated. Each individual has
an ovary, two oviducts and a bladder; a testicle, an epi-
dydimis, a deferential canal, and an excitatory organ.

The nervous system of the helices is very considerable.
There is a central part above the intestinal canal, composed of
two very thick ganglia. The nerves which it furnishes from
all its external edge are very numerous and very considerable.
There is a peculiar ganglion for the generative apparatus,
which receives a thick thread of communication from the
cerebral ganglion, and furnishes threads to the different parts
of the apparatus.

The helices are found, as it would appear, in all parts of
the earth. They are known in Europe, in Africa, in the two
Americas, in Asia, and in Australasia. It is generally in
humid situations that they are principally to be found; but
they are also to be met with in warm and dry places, which is
never the case with the limaces or slugs. They usually with-
draw into the excavations of old walls, of rocks, under the
bark of old trees, and even under ground. ‘They sink more
deeply during the winter season, at least in our part of the
world; for in climates where vegetation is continual, it is
probable that the snails do not hybernate, or if they do retire,
it is during the intense heat, and especially at- the season
when no rain is falling. Before they enter into the torpid
state, the helices of our climates withdraw their body entirely
into the shell, and produce at its entrance a sort of momen-
taneous opercle, or lid, to which the name of epiphragma
has been given. It is evidently composed of calcareous
molecules, not very abundant, united by an animal gluten,
and exuded in strata from the parts of the body which enter
last into the shell, namely, from the external swelling of the
collar. There are, however, a certain number of species,
which, even in our climates, do not produce this epiphragma.
Probably, at this period, they bury themselves deeper in

334 SUPPLEMENT

the earth. It is at the end of autumn that the snails thus
retire. During the whole of the fine season, they do not
re-enter into the excavations which conceal them, except
during the heat of the day, and particularly in dry weather ;
for as soon as rain falls, and especially in fine and gentle
showers, they may be seen to issue forth from all parts, as
they commonly do during the night. ‘Their mode of locomo-
tion, which may easily be observed by placing one of these
animals in a transparent body, is a peculiar kind of reptation,
in which the animal seems to glide on the plane which sup-
ports it, and to follow all its irregularities. But on closer
examination, we find that this reptation is executed by means
of the successive action of all the ranks of little muscular
fibres of which the inferior face of the body is composed,
something the same as in certain articulated animals, in
which the number of articulations is very considerable. Al-
though this mode of locomotion is very slow, yet the snails
do not fail to advance more than one would imagine at first
sight. As their resting point is always taken in front, it is
always in this direction that they draw themselves along, and
never backwards. ‘The mucous matter which issues from all
the parts of these animals, but especially from the foot, and
which enables them to adhere more strongly even to the
smoothest bodies, remains on the surface of these bodies, and
through desiccation, which is very prompt, leaves a sort of
silvery trace, which always betrays the route which these
animals have taken. It is this matter which forms the
epiphragma, as it is that which exudes from all parts of the
skin, covering the visceral mass, and especially from the edges
of the mantle, or collar, that produces the shell. No helices
have been seen able to swim, or even crawl in an inverted
posture on the surface of the water, as the lymnez, and some
neighbouring genera can do. It is generally in search of their
food, or of some individual of their own species, during the

——_——- se

ON GASTEROPODA. 335

season of reproduction, that the helices issue from their
retreats. ‘They are advertised of the presence of external
bodies only by means of the fineness of their touch. In fact,
at the slightest contact with any part of their body, but
especially of their tentacula, they withdraw themselves more
or less completely within their shell, and do not come forth
again but by degrees, and with the greatest possible precau-
tion. ‘The choice which the snails make of certain herbs, does
not permit us to doubt of their being provided with the sense
of taste. It would appear that they do not perceive bodies
at a distance, but by the assistance of the sense of smell, the
seat of which is probably in the first pair of tentacula, and
that in a manner complete enough, since it is known that
these animals are attracted a good way by the odour of the
plants which they prefer. It is not probable that the organ
of vision found at the extremity of the large tentacula is of
any great use to them. In the first place, it is by night that
they are most active; then it is evident that the structure of
the organ is very incomplete, and experiment proves, besides,
that on approaching a body to these tentacula, the snail does
not perceive it any sooner than when it is approached in the
same manner to the first pair. Moreover, their extreme
timidity, the precautions which they take in walking, to ex-
tend as much as possible the two pairs of tentacula in front of
their body, to explore all obstacles, evidently indicate an
animal pretty nearly blind.

The snails are nourished essentially with vegetable sub-
stances, with tender succulent herbs, and fruits of the same
nature. But it seems that they also eat animal substances,
such as cheese. They gnaw the leaves and fruits by means of
their jaw, which is opposed to the tongue, and that with very
considerable strength, and sometimes quickly enough to cause
great devastation in our gardens. But it is especially in fine
weather, and when they come forth from their hybernating

336 SUPPLEMENT

state, that they eat more, and consequently occasion more
mischief. In proportion as the autumn approaches they eat
less and less, until at last they bury themselves in some exca-
vation, and fall into a state of torpor.

Towards the end of spring these animals seek each othe
for the purposes of reproduction. The duration of the inter-
course is almost two hours.

The rut of these animals continues for a very long time,
and it is said that they can reproduce again at the end of six
weeks. It appears that even fecundation does not take place
until the third time of intercourse.

The helix has one organ peculiar to itself, which must not
be passed over here. It would be difficult to say to what
apparatus it properly belongs. It is formed by a purse or
pouch, more or less elongated, obtuse, rounded at its pos-
terior extremity, and the parietes of which are very thick
and muscular. Its interior is a cavity of no great extent,
with four furrows, and at the bottom is a nipple. It ter-
minates in the cloaca by a narrow orifice above the origin
of the female apparatus. The interior of this pouch, espe-
cially the nipple, excretes a cretaceous matter, which being
disposed in strata in the cavity of the pouch, assumes its
form and produces a sort of pointed and quadrangular dart,
with a very narrow canal in its interior. The animal has the
power of shooting forth this dart, which is an invariable pre-
liminary to sexual intercourse.

If a helix be opened a little time after this intercourse, the
male organ will be found diminished in volume, the multifid
vesicles empty, and the pouch no longer containing the dart
above mentioned, which, according to the observation of
Swammerdam, is sometimes contained in the canal of the
bladder. The ramifications of the oviduct in the interior of
the ovary contain a fluid in which are swimming some little
round membranes marked with a black point, which are eggs.

ON GASTEROPODA. aaa

The first part of the oviduct, properly so called, presents
some unequal dilatations, which seem filled with a calcareous
matter. Its second part is manifestly augmented in all its
dimensions, and contains a great quantity of white matter
resembling the spawn of fish. This matter afterwards be-
comes gelatinous, and swells considerably in water. The
testicle appears to be still filled with a tolerable quantity of
fluid.

Some time after this, the embryos, detached from the ovary,
come into this second or swelled portion of the oviduct.
They are enveloped there in a considerable quantity of the
matter of which we have been speaking, and which forms for
the little animal the fluid, by the absorption of which it is
nourished. Later, or in another part of this oviduct, is de-
- posited an external membrane, sometimes rather calcareous,
and then the egg is complete. After the end of about fifteen
days these eggs are expelled. Duvernoy makes a curious
observation respecting the manner in which these eggs are
formed. “If we open asnail,” says he, “alittle before the
eges are laid, we find no eggs, but some little embryos
swimming in a very clear fluid, and exhibiting very lively
motions. They become eggs on the road which they are
obliged to pursue to get out.”

The eggs of the helices are usually rounded, tolerably big,
and of a white colour. They are at first a little glutinous,
and especially so in the species which deposit them serzatim,
one after another, and in the form of a chaplet. Most fre-
quently they are deposited one by one, or in an irregular
mass, in holes which the animal excavates in a soft earth, but
much more usually in natural excavations, fractures more or
less deep in the ground, in the holes of trees, rocks, or old
walls ; in general in places where drought cannot reach them,
and where moisture is permanent. The number of these eggs
does not appear to be extremely considerable.

von, I. Z,

308 SUPPLEMENT

At the end of a time, which varies more or less according
to the species, and, perhaps, also according to circumstances,
the eggs disclose, and a young snail issues forth, which is
already invested with a shell, extremely thin, it is true, and
almost membranaceous. Accordingly at this time they are very
much afraid of the drying action of the air, and especially of
that of the sun, and do not issue from the holes in which they
have been born, except during the night. Their growth at
first is tolerably quick, but afterwards it becomes much slower,
so that judging by the striz of the shell, which mark the
growth, these animals ought to live along time. But with
regard to this point we possess no certain information. ‘The
erowth of their body, in fact, necessitates a proportional
erowth in the shell. When it is necessary that this shell
should be increased, the helices assemble in troops. ‘The
animal remains in a state of repose, sinks into some cavity,
and there issues from all the parts of the mantle, and espe-
cially from its thick edge, a stratum of calcareo-glutinous
matter, which is applied within the preceding, out-edging
it a little. It is this part of the junction of this new
stratum which forms the stria that marks the growth; it is
so much broader in proportion as the animal is_ better
nourished and more vigorous. When the shell is arrived at
the completest growth which it can attain, it merely becomes
thicker, and forms, in most of the species, a sort of pad, more
or less thick ; and there is deposited on that part of the spire
which modifies the aperture, a calcareous matter, generally
not very thick, which can join the two edges. This is named
a callosity. ‘Though all this constitutes the complete or ter-
minated shell, yet the animal was adult before, that is to say,
was capable of reproducing its species. But it is very im-
portant to observe, that the shell of the same individual
differs much according to the period of life of the animal
which is examined. In general the spire is so much the less

ON GASTEROPODA. 339

raised as the animal is younger, and consequently the last
whorl is larger in proportion; the wmbilicus is more un-
covered; the aperture is wider, the edge more trenchant, and
the shell is thinner. Accordingly, when it is terminated, the
last whorl comes out from the line of the spiral, and becomes
falling, which renders the aperture more narrow. ‘These dif-
ferences are important to be known, otherwise we might be
liable to consider individuals of different ages as different
species. We find also, in these animals, and especially in
their shells, some anomalies. ‘Thus we find some that are
entirely deft, that is, all the parts are reverted from right to
left, and then the shell has its free edge at the left, and the
columellary one at the right. We also find some in which
‘that part of the body, which is in spiral, instead of being very
compact, is twisted in a very loose manner, or merely a little
recurved. ‘The shell then assumes the form of a sort of cork-
screw, and is termed scalaria. ‘The cause of these irregulari-
ties is unknown.

The uses of the helices, or snails, are not very numerous.
It appears, however, that the larger species, and especially
the garden snails (H. pomatia, L.) serve for the aliment of
man in many countries. ‘The Romans, according to Pliny,
consumed great quantities of them ; and they must have been
in great estimation for the table, since that author has thought
it necessary to give, in his Natural History, the name of
him who first thought of rearing these animals in sorts of
parks, or depots, and fattening them with particular sub-
stances. The best came from the island of Astypalza, one of
the Cyclades, the smallest from Reate, in the Sabine terri-
tory, and the largest from Illyria. The Romans also greatly
esteemed the snails of Sicily, of the Balearic Isles, and of the
Island of Caprea. They shut them up in sorts of warrens, and
fattened them there with cooked meat, flour, &c. It was
Fulvius Harpinus who first conceived the idea of this pre-

Z2

340 SUPPLEMENT

viously to the civil war between Cesar and Pompey. He
carefully separated each species, and succeeded in obtaining
individuals whose shell contained octoginta quadrantes,
about ten quarts. All this history is taken from Pliny; but
there would appear to be some confusion in it, especially
with respect to the size produced by education ; for Varro,
after whom he writes, says the same only concerning the

Mauritanian species, which naturally attained to these dimen- -

sions. It does not appear that this mode of educating snails
was practised for any great length of time, for Macrobius says
nothing about it. Some authors tell us that these animals
are still eaten in different countries, and among others, in
Silesia, Brabant, Liege, Switzerland, Italy, and many de-
partments of France. It is said that in the environs of
Rochelle, they form depots of them, putting them one above
the other in layers, between each of which moss and other
plants are spread. It is allowed that the individuals which
live in elevated situations are the best, and that they acquire,
in some measure, the flavour of the plants on which they feed.
In general, it is very probable that their flesh must be rather
hard, in consequence of the proportional size of the foot. It
is certain that many half-civilized nations eat them dried in
the smoke.

In Paris, and many other continental cities, a great quantity
of snails is to be found in the market. But it is not as an
article of food that they are employed. Mucilaginous broths
are made of them for persons afflicted with maladies of the
chest and lungs, and in such cases they have been found
efficacious. It appears less certain that they may be em-
ployed with advantage in incipient hernia, and that they
exercise an astringent effect upon the inguinal ring. Of this,
however, we are assured by a French medical writer, M.
Georges Tarenne. He employs for this purpose the blood of
the animal, obtained by pricking it with a sharp instrument,

a a ia il Ht Bl gO he

ON GASTEROPODA. 341

and placing it in the form of a sort of cataplasm on the
cushion of the bandage used in such cases. In a few months,
he says, two or three hundred of these animals thus applied
will work acomplete cure. It appears much more likely that
the cure, if effected at all, is effected by mechanical means.
It is not necessary to detain our readers by enumerating all
the properties which have been attributed to these animals,
which for the most part have been conceived @ priori, from
the viscosity of the blood, and the calcareous matter which
their humours contain. Those who are curious on this sub-
ject may find enough to gratify them in Gesner, and the older
writers on the medical science. |

We must, however, dwell a little more on the employment
which physiologists have made of these animals, and which
we have already glanced at in our notice of the slugs, to
prove that reproduction is not confined to less essential parts,
and to animals but little raised in the scale of being, but that
it may equally take place as to the composition of numerous
and very important organs, and even in the head itself.
Spallanzani positively affirms the fact, grounded upon nume-
rous experiments on the helices; but, as takes place in all
such cases, many other authors have denied it, and founded
their opinion equally on the basis of experiment.

The experiments of Trembley on the green hydrz, or fresh-
water polypi, have established beyond a doubt, that in this
degree of organization, an animal can reproduce not only the
different parts of its body, but that when the latter is cut in
pieces, each piece can become a perfect animal. He even
succeeded in causing six or seven heads to sprout from a
single body, by dividing the latter longitudinally into so many
strips.

Bonnet, desirous of repeating the experiments of Trembley,
and not being able to procure any of these green hydre, tried
whether some fresh-water worms, a species of nais, could not

342 SUPPLEMENT

also reproduce the parts which should be cut off, and as he
could make no experiment on the appendages, he only tried
upon the body, and found that it might be cut into twenty-
six parts, and that each part reproduced a complete animal,
so that by a very simple calculation he showed that from a
single individual of two inches long, which might be cut into
eight parts, and those successively into the same number, in
proportion as they became perfect, there would be produced
at the end of the fourth year 32,768 individuals.

This faculty which the worms possess of reproduction, when
mutilated, was equally demonstrated in animals apparently
more complicated, that is, in the actinie, by the Abbé Dicque-
mare. He proved, in fact, that their body might be divided
into a sufficiently great number of parts, provided that in the
strip which was cut off, a portion of the mouth should be
preserved.

Up to this time, although these facts appeared sufficiently
extraordinary, nevertheless, as they had not been observed,
except in animals but little elevated in the living scale, and
all the parts of which, to a certain point, were similar, a small
number of persons remained incredulous, or rather, as the
experiments were made upon animals not very common, nor
easily to be procured, perhaps less attention was paid to them.
But when, in 1764, Father Boscovich, in a letter to M. de la
Condamine, announced that snails whose head was cut off,
reproduced another altogether similar, as was proved by the
experiments of the Abbe Spallanzani, a great number of per-
sons massacred an immense quantity of snails with the idea of
verifying these experiments. Voltaire himself, as may be seen
in his questions in the Encyclopedia, article Colimacon, com-
menced experimentalist. But he showed as little skill as a
physiologist, as, on another occasion, he did in geology. In
1769, the celebrated Adanson, after having made trial on more
than 1500 snails, denied that the individuals from which he

ON GASTEROPODA. 343

had cut, not the entire head, but merely the tentacula and the
jaw, but without leaving their roots, reproduced these organs,
and he concludes that Spallanzani, in his amputations, only
removed the cap or bonnet.

M. Cotti, an eminent meteorologist, declared, that after
numerous experiments made from 1768 to 1774, he was also
obliged to conclude, that the snail whose head was completely
amputated, did not renew it, but perished. Valmont de
Bomare tried similar experiments about the same time, and
with similar success.

Nevertheless some persons were more fortunate, and among
others, the celebrated Madame Bassi de Bologne, M. La-
voisier, Scheeffer, &c. But the memoir which seemed to put
the result of Spallanzani’s experiments out of doubt, was one
inserted by Bonnet, in the “‘ Journal de Physique.” He in-
sisted on the precautions which were necessary to be taken
that the experiment might succeed. He accompanied his
memoir with figures, to show the parts retrenched, and the
manner in which they are reproduced by a sort of vegetation.
We there find that he never cut any part but tentacula as far
as their base, as well as the entire cap of the head and the
jaw, and that the reproduction, which has some variations
both with respect to time, and the order in which the organs
are reproduced, does, nevertheless, really take place. Un-
happily, he has not given us the anatomy of the organs
which he retrenched, nor that of those which were reproduced,
so that his experiments can scarcely yet be considered as
conclusive.

In 1788, M. O. Miiller published some experiments con-
firmatory of those of Bonnet. He made use of very sharp
scissors, and placed them obliquely, so as also to take away
only the upper half of the head, that is, the four tentacula, the
upper lip, the jaw, and sometimes a small part of the foot.

Finally, some experiments on the same subject, and much

344 SUPPLEMENT

more conclusive, were made by M. G. Tarenne, of whom we
have spoken before, in 1803. If we admit the testimony of
this gentleman, we cannot refuse to believe that snails can
reproduce the entire head, since he assures us that the piece
which he suddenly cut off, with very sharp-edged scissors,
placing them perpendicularly, a little behind the large ten-
tacula, and under the foot, contained not only the tentacula,
the jaw, and the upper lip, but also the buccal mass altogether,
the brain, and the anterior part of the foot. He continues
even to assure us that snails thus mutilated, at the end of a
year and more have reproduced a complete head; but a fact
so extraordinary, with reference to so great a length of time,
requires much more evidence before it can be generally re-
ceived. Nevertheless, Spallanzani says very positively that
the head is regenerated, whether the section be made above
or below the brain. ‘Thus we find, that whatever re-
pugnance we may feel in admitting this fact of the regenera-
tion of the entire head in the helices, it is exceedingly
difficult to deny it altogether. It took place in about two
years after decollation, and the new head did not differ
from the old, but in the circumstance of the skin which
covered it being whiter and smoother. Sometimes also, there
is a sort of furrow at its junction with the trunk. According
to Spallanzani, it appears that the manner in which this re-
production takes place is rather variable, and that sometimes
it even remains incomplete. But M. Tarenne says, that
having cut the heads off of two hundred helices, and having
put them into a humid thicket at the extremity of a garden,
so that they might more easily find the nutriment which was
suitable to them, he perceived on all the individuals that he
could find again at the end of the fine season, a new head
somewhat resembling a coffee-berry. It had four small horns,
a mouth, and lips. At the end of the following summer the
heads were perfectly reproduced, except that the skin was

ON GASTEROPODA. 345

smooth, or cicatrized, in the same way as it is in partial am-
putations. How they could avail themselves of the nutriment
which Tarenne placed at their disposal, till the new head ap-
peared, does not appear. Although Spallanzani has given
fewer details respecting the operatory process which he pur-
sued, than M. Tarenne, we find that he had already really ob-
tained the same results, as the latter is candid enough to avow.
From all this, it would certainly appear established, that the
entire head of the helices can be regenerated when cut off, and
yet, notwithstanding, we cannot quite get rid ofa certain degree
of repugnance to admit this assertion as an indubitable fact.
It is with difficulty that we conceive how the nervous threads,
the muscles, the vessels which have been cut through the
middle of their length, can re-accord with the portions which
sprout from the head, now become a sort of germ; or, ad-
mitting that the regeneration should proceed from the nervous
and muscular threads themselves, how should the nervous
threads shoot forth and give birth to the brain. To render
our conviction complete, it would be necessary that the re-
produced head should be carefully dissected, and compared
with the one which was cut off.

If the advantages which we derive from the helices are but
inconsiderable, it is otherwise with regard to the detriment, or
at least the inconvenience which they occasion us. All per-
sons occupied in gardening regard them as a sort of plague.
In fact, when these animals are abundant, they can lay waste
ina single night an entire plantation of oleraceous herbs, a
little time after they have sprouted from the earth, and are
yet extremely tender. ‘They also attack the finest, and espe-
cially the most succulent fruits, as they approach to maturity,
and so produce their destruction, either of themselves, or by
facilitating the destructive operation of other frugivorous
animals, such as wasps and hornets, or that of rain, by which

346 SUPPLEMENT

rottenness is produced. Many modes have therefore been
thought of to destroy them as well as the slugs, or to hinder
them from getting at the fruit. The best way of destroying
them is, certainly, to hunt them morning and evening, or after
a small rain, and crush them. But their propagation may
also be hindered, by taking care always to avoid tufted borders,
and especially those made with box, close hedges, and all
those ancient ornaments of gardens, formed of yew and haw-
thorn. In general every arrangement must be avoided which
can present humidity and shelter to the snail, unless it be used
as a sort of snare in which they may be found collected in
greater or less numbers, and destroyed at once. Their hurt-
ful effects upon the fruits of isolated trees may be prevented
by investing a part of the trunk with any very viscous matter,
and among others with a sort of pitch or tar, the residue of
distillation from coal or charcoal. The same effect may be
produced by ashes, or any pulverulent substance, strewed at
the foot of the tree, but the pitch is better, because it stops
the progress of many other pernicious animals.

We now come to the aquatic pulmonaceous mollusca,
which will not detain us long. The ONCHIDIA are without
shells. The species called O. typhe, by Buchanan, has an
oblong body, and is about an inch and three quarters long
in a state of repose, but when it walks it becomes linear,
obtuse at the two ends, and its length extends to two inches.
The foot is formed by a great number of transverse wrinkles,
by means of which the animal walks, and adheres pretty
nearly after the manner of an earth-worm. The head changes
form considerably when the animal walks, becoming extended,
flat and oval. From the upper part of the head arise two
tentacula entirely similar to those of the snails, and having
the appearance of eyes at the extremity.

This animal, says Buchanan, is not hermaphrodite, like

13

ON GASTEROPODA. 347

many other zorms, but the sexes are separated in different
individuals. 'This, however, is indicated by no external dis-
similarity. The anus and sexual organs are placed in a com-
mon cloaca at the hinder extremity of the tail, and during in-
tercourse the distinction of sex is very evident. This animal
lives on the leaves of the typha elephantina, common on the
banks of the Ganges.

The manners and habits of the PLANORBES are nearly the
same with those of the next genus, (Limnee) with which they
are constantly found. Thus they are fresh-water animals,
altogether aquatic, perhaps more so than the limnee. In fact
they are very seldom indeed to be met with out of the water.
They crawl, like them, on the surface of bodies as well as on
that of the water, with the foot upwards, and the shell down-
wards. They equally feed upon vegetable substances, which
they eat in the same manner. Their mode of sexual inter-
course is exactly similar: the individuals form long lines, be-
ginning with a male, and ending with a female; but they are
hermaphrodite. The eggs which they lay are in a gelatinous
mass, applied against submerged bodies. In our temperate
climates, and in cold climates, the planorbes, at the approach
of winter, sink into the mud, and fall into a lethargic state, so
that it is impossible to find an individual in a place where,
some months before, there were myriads.

The species of this genus appear rather to belong to the
temperate and boreal zones, than to the other parts of the
world. They are very common in Europe and North America.
Few are known in the Austral regions ; many are found in the
fossil state.

A viscous matter issues from the collar of these animals,
when it is irritated.

The Limna appear to possess a greater degree of sensi -
bility than most other mollusca, which is doubtless owing to
their skin being more gelatinous and less tuberculous. ‘They

348 SUPPLEMENT

creep sufficiently fast by the assistance of the very broad
muscular disk with which they are provided, not only over
solid bodies, immerged or not, but also at the surface of the
water. In this case they are inverted, the shell beimg below
and the foot above. It appears that the contraction of the
foot takes its hold of a very light stratum of the water, which
they leave above them. Their strength, however, cannot be
very great, and in fact the slightest wind is often sufficient to
accumulate the limnee, thus floating towards the opposite
side from which it blows. On the least danger, they with-
draw all their parts into the shell, become of a greater specific
weight, and fall to the bottom. To return to the surface they
are obliged to crawl along the bottom, as far as the bank, or
to follow the stem of some aquatic plant. It is only in the
water, and in the fresh water especially, that the limnee are
to be found, and as this fluid cannot serve them for respiration,
they are obliged to come from time to time to the surface to
respire the atmospheric air. Sometimes they are found alto-
gether out of the water, but on some aquatic plant, and never
even at the slightest distance from the element. They feed on
vegetable substances alone, and especially on the leaves of
aquatic plants, which they cut, like the slugs, with the tooth
with which their mouth is armed. During winter, at least in
our climates, they fall into a sort of torpor, and sink more or
less deeply into the mud which is at the bottom of the ponds,
marshes, rivers, or streams, that they inhabit. It is at the
end of spring, when their activity becoms greater, that they
engage in the grand work of reproduction. Although her-
maphrodites, their mode of intercourse differs from that of
the limaces and helices ; for with the limnzz the concourse of
three individuals is necessary, and as others come up, they
thus form long cordons. At the end of a certain time after
this, of the duration of which we are ignorant, the fecundated
individuals deposit upon dead or living bodies in the water,

2
5

d
4

ON GASTEROPODA. 349

small masses, glairy, translucent, and ovaliform, composed
of a greater or less quantity of eggs. These eggs, at first, by
no means distinct, become so by degrees. In each of them
the little animal provided with its shell, is very distinguish-
able, and in a little time it separates from the others and
proceeds in search of its food.

We are ignorant of the duration of the life of these animals,
and of the time which they take to become adult. In certain
localities they are accumulated in great abundance.

The limnee are of no direct utility to the human species.
They serve as food to aquatic birds, and particularly to fishes,
which consume great quantities of them.

The species of this genus appear, along with the physe,
planorbes, &c. to be found in the fresh waters of all parts of
the earth. ‘They are known in the Northern Zone, in Europe,
in Asia, and in America. ‘The temperate zone assuredly con-
tains them in the three quarters of the world. They are found
in the tropical regions of America, Africa, and Asia. Finally,
if we are not acquainted with them in the antarctic, or
southern zone, it is probably owing to the want of direct
observations.

We have nothing to add on the rest of this order.

The second order of this class is the NUDIBRANCHIA. In
this DoRIs constitutes a very numerous genus. Bohadsch
first established this genus under the name of Argo, derived
from this curious reason, that he thought the upper tentacula
of many species, which are formed as it were of an aggrega-
tion of small rounded tubercles, were an agglomeration of
eyes. ‘The details of the organization are curious, but our
limits oblige us to omit them, and rest contented with the
brief description in the text.

The Dorides are hermaphrodites, the two sexes being united
in each individual. The dorides are all marine, and live at
variable depths, in rocky situations, where alge, and marine

350 SUPPLEMENT

plants in general abound. ‘Their motion is slow; they creep
along with their tentacula and gills very much spread out, by

means of the broad disk, which occupies their entire abdomen, -

either on submarine bodies, or at the surface of the water in
an inverted position. On the slightest contact they draw in
their tentacula, and even in a great measure their gills, which
have many relations of structure with the former organs, and
gather up their bodies, much after the manner of the slugs.
It was generally believed that they fed on living animal sub-
stances, and among others upon oysters, and other fixed
conchyliferous mollusca, whose shells they pierced by means
of their sort of tongue. But M. Dupont de Nemours assures
us that their nutriment consists in sea-weed. ‘Their mode of
sexual intercourse is altogether unknown. ‘Their spawn is in
the form of gelly, adherent to submarine bodies.

As to the subsequent genera, down to scyllee, their
habits are either utterly unknown, or may be presumed to be
analogous to those of doris.

The Scyllez, like the preceding, are hermaphrodites ; they
are little pelagian animals, which seldom visit our coasts, but
are not rare upon the masses of fucus in the Atlantic Ocean.
They live, as it would seem, in the depth of the waters, where
they creep upon the stems of fucus, as the canaliculated form
of their foot would indicate. It is probable, however, that
they can swim with equal facility, by means of the foliaceous
appendages with which their body is provided, and especially
the two branchial pairs. ‘Their other manners and habits are
altogether unknown, but, in all probability, they differ little
from those of doris and other neighbouring genera.

Very little is known respecting the manners and habits of
GLAUCUS, and the remaining genera of this order. We
merely learn from Dupont and other observers, that they are
found only in the high seas at a considerable distance from
the shore, and that they often remain at the surface of the

~

ON GASTEROPODA. 351

water, where they swim in an inverted position, like the
planorbes, the limnzz, and many other mollusca, with the
assistance of their small foot. André Dupont says that the
middle line of what he names the back, but which in fact is the
belly, appeared like a leaf of silver, and was in a continual
undulatory movement. ‘This little animal, little more than
an inch in length, in consequence of its fine blue colour,
silvery under the foot and at the extremity of the digi-
tations, and especially from its form, appears extremely
elegant when it is swimming in calm weather at the surface
of the sea.

The little order of the INFEROBRANCHIA we must entirely
pass over here, as nothing whatever is known concerning
their habits or manners.

Of the first two genera of the order TECTIBRANCHIA, we
know nothing, except what regards structure. The genus
APLYSIA, by a typographical error, in the second edition of
Linneus, was called Laplysia, which misnomer, ridiculously
enough, has been preserved. Pliny and Dioscorides speak
of a species of this genus under the name of sea-hare, and
depict it as a venomous animal, which not only should not be
touched, but not even looked at. Following them, Rondelet
has spoken in the same manner.

The Aplysia are supposed to possess the property of
causing the hairs to fall from those parts of the body to which
they are applied, and of causing strangury to those who are
so foolish as to swallow a little of the sanies which flows from
their bodies. But M. Cuvier has proved this opinion to be
erroneous, at least as far as the first of these properties is
concerned. But they exhale an odour so nauseous and fetid,
that one would be more disposed to avoid than approach
them.

The best known of the species resembles, when in a state of
repose, a mass of unformed flesh. When it is in motion its

352 SUPPLEMENT

figure approaches to that of the slugs. Its colour is a reddish
brown; it has four horns in the head; and the eyes, which are
very small, are situated between the two hinder ones.

This aplysia has a reservoir of ink like the sepia, and em-
ploys it for the same purpose, that is, it ejects it for the pur-
pose of escaping the pursuit of its enemies. It inhabits, in
preference, the muddy bottom of the water, and lives on small
crabs, small mollusca, &c.

Draparnaud thinks we should not regard the two anterior
prolongations of the head as tentacula or horns; if such then
be the case, this genus in reality will have but two.

The remarkable molluscous animal, called OMBRELLA by
Lamarck, and Gastroplax by de Blainville, exhibits many
relations in its interior structure with aplysia. We know
nothing respecting the manners of this animal, which lives
in the Chinese seas. It is sometimes called the Chinese
parasol. From the extremely anomalous position of the
shell, it is not easy to conceive how it can crawl. Accord-
ingly, M. de Blainville, considering that the back covered
with a skin extremely thin, has need of being sheltered from
the action of external bodies, has supposed that this mol-
luscum was, as it were, compressed between two protecting
bodies, one inferior, or the shell, and the other superior,
which might be a sort of valve, extremely thin, and adherent,
like the anomia, or even some rock. An hypothesis which
may be yet further supported by a consideration of the cavity,
at the bottom of which is the mouth, and towards which the
pedicled tentacula might, by their movement, determine the
arrival of nutritive substances.

In the order of HETEROPODA, we must pass the first two
genera, and come to the FIROLZ, of which we can say but
little. Their manners and habits are but little known. They
are found, as it would seem, pretty commonly in all the seas
of warm regions, and even in the Mediterranean, where they

ee

ON GASTEROPODA. oo

swim with peculiar elegance, by means of their fin and tail.
It often happens that they are mutilated, a circumstance
which has occasioned some confusion in the distinction of
species.

In the order PECTINIBRANCHIA, the animals of the first
genus TURBO, are marine; they live on the sea-coasts, in the
midst of rocks beaten by the waves, and consequently at no
great depth of water. At low water, when the rocks are un-
covered, these animals often remain fixed in the same place,
but they are also sometimes seen to move, endeavouring with-
out doubt to regain the sea. On the least touch they suffer
themselves to fall, and thus easily escape from their enemies.
Their locomotion is not rapid, which is certainly owing to the
shortness of their disk. ‘Their nutriment should be vegetable,
if we may judge by the apparatus of their mouth; but of this
we are not perfectly assured.

Weare ignorant of all the particulars of their reproduction ;
we merely know that the sexes are distinct, and not combined
in the same individual. The small species with corneous
operculum are ovo-viviparous. ‘Thus these animals do not
deposit corneous eggs like the siphonobranchia. It yet re-
mains a question whether there are any true turbines with
calcareous operculum.

The animals of this genus are of some utility to the human
species. In fact the inhabitants of the sea-coasts feed upon
the smaller species, and from the larger a very fine nacre, or
mother-of-pearl, is derived. Formerly, ornaments were made
for cupboards of the shell of the ZT. marmoratus, completely
stripped of its non-nacreous stratum.

The animal of the SCALARIA is but very incompletely
known. From the figures given by some authors, we conclude
that it does not differ much from the animals which inhabit
other operculated shells of the same order. From a figure
communicated by Dr. Leach to M. de Blainville, it would

VOL, XII. Aa

354 SUPPLEMENT

appear that the proboscis, or more probably the labrum, is,
as it were, laciniated, or divided into little tongues swelled
at the extremity, a disposition, which if true, is exceedingly
anomalous. We also learn from Bianchi, that this molluscous
animal suffers to escape from its body a great quantity of fluid
which stains the fingers, and paper, of a fine purple colour,
which suggested to him the idea that this might be one of
the conchyliferous mollusca, which furnished to the ancients
the purple with which they tinted the most precious stuffs.
Linnzus, and some other writers, have adopted this opinion.

The scalariz, like the turbines, appear to prefer the sea-
coasts, where there are numerous anfractuosities and rocks.
It is probable that some of them are to be found in all seas.

In the animals of the genus CYCLOSTOMA, the sexes are
separate. They live on land, in somewhat humid places,
under rotten leaves, or in the trunks of rotten trees, where
they are sometimes found in great abundance, the common
species especially, cyclostoma elegans. Its tentacula appear
to be contractile, though M. de Férussac has asserted that
they are retractile, which is contrary to all analogy, for ten-
tacula of this kind are not known, except in the limacine.
This little mollusca is remarkable for the mode in which it
moves, making sorts of steps or strides, as M. de Férussac
has observed, though this seems to be done by means of its
foot, and its proboscidiform mass, and not by raising the two
lateral parts of the foot alternately.

The females of the PALUDIN&, which are always bigger
than the males, present, in the apparatus of generation, a
disposition which has been erroneously thought to be peculiar
to these animals in the great development of the second part
of the oviduct, to which the name of matrix has been given,
and where the eggs are accumulated, until they are sufficiently
developed to disclose the young, so that the little paludine
come forth from the body of the mother in the living state.

SO ns ee

ON GASTEROPODA. 395

This has occasioned the species most common in great rivers
to be called vivipara. This singularity was observed long
ago among many species of ‘Turbo.

There is nothing very peculiar in the manners and habits
of the paludine. They generally live at the bottom of rivers,
on the aquatic plants which are found there. They appear
to feed on substances of all kinds, but more especially
vegetable. Their mode of sexual intercourse offers nothing
very worthy of remark. We have said that the young issue
forth in a living state from the interior of the mother ; but they
do not all come forth at once. The females of the paludinz
appear to lay during the entire of the fine season. The little
ones, on issuing forth, place themselves on the shell of the
mother, and appear to remain there for some time. They
crawl pretty fast on a resisting ground, and sometimes come to
the surface of the water, where they can also float after the
manner of the limnxz. ‘This, however, appears to take place
very rarely.

The species of paludine appear to exist only in our
northern hemisphere, and not in the torrid zone, where they
are replaced by the ampullarie. They seem to be very
common in the rivers of North America.

The JANTHIN constitute a very distinct genus, established
by M. de Lamarck on a molluscous animal, which Linneus
had classed with Henix. The name of Janthina indicates
the colour of the handsome shell, which is a fine violet. ‘This
genus has now been adopted by the generality of modern
zoologists.

The body of the animal is globular, as the form of the shell
would indicate, and the visceral part is very small, compara-
tively with the head, chest, and foot. The foot itself is not
remarkably large, but it is very thick and muscular, and is dis-
tinguished by a vesicular mass, which forms the principal
characteristic of this animal. It is said to be a sort of sub-

Aa2

356 SUPPLEMENT

cartilaginous froth, composed of small cells or utricles, which
can swell or contract at the will of the animal. M. de Blain-
ville, however, tells us that this mass, in an individual a long
time preserved in spirits of wine, bore a strong resemblance to
the cellular tissue, a little gelatinous, and did not present the
least indication of being cartilaginous. Observers are doubt-
ful as to its point of attachment. Forskal says that it is at-
tached to the mantle of the animal, but M. Bosc that it
issues from the anterior part of the foot, and is extended in
length beyond that organ. M. Cuvier, as we see in the text,
describes it as being situated under the foot.

The janthine inhabit the deep parts of the sea in all warm
latitudes. When the water is calm they may be seen floating
on its surface, with the shell underneath, and the foot and its
vesicle just mentioned, upwards, and are sometimes in pretty
numerous bodies. It is probable that they have no need of
any muscular effort to maintain themselves thus on the surface
of the water, and that the vesicles of their feet produce the
effect of an hydrostatic bladder ; but then they must of neces-
sity be the sport of the lightest wind or the least current,
which is not the case with the other mollusca, which can
swim in this manner on the water, unless we admit that the
foot should possess some action, or at all events that its lateral
appendages should act as fins. Be this, however, as it may,
on the slightest appearance of danger, or cessation of calm,
the little animal withdraws its head into its shell, contracts
its vesicles, either by forcing them to re-enter the testa with
its foot, if they be attached to its posterior part, or by acting
directly upon them, if their attachment be under the foot
itself, and in the hollow which it forms; but in whatsoever
manner this may be done, the air of these vesicles can neither
be absorbed nor rejected. By the diminution of its volume
the weight of the animal is increased, and it sinks more or
less towards the bottom of the water. Whether it can creep

|

ON GASTEROPODA. 3507

on the ground, or fasten itself thereto, is doubtful. The first
position does not seem at all probable; but the second is
more likely to be founded in truth, from the peculiar form of
the foot, in the style of a sucker.

The janthine, in all probability, feed upon animal sub-
stances, though we possess no certain information on this
subject. Neither are we much better acquainted with their
mode of propagation. According to Forskal it would appear
that the female preserves her eggs in a sort of matrix, or in-
flated portion of the oviduct; at least he has several times
seen young individuals issue from the body not larger than
grains of sand, and which in the microscope, have appeared
to him provided with a shell similar to that of the mother,
with the exception of colour. According to the same ob-
server, it would appear that the young animal presents some
differences more considerable, by having towards the aper-
ture of the shell two transverse laminz, rounded, and ciliated
in their circumference, which it might use as fins for loco-
motion.

Notwithstanding the probability of what we have just
advanced respecting the ovo-viviparous character of the
janthine, Sir Everard Home has published a contrary ob-
servation, that around a shell which he examined, there
was a glairy and oviferous band, which he supposes to come
from the body of the animal. His opinion too, founded
on this observation, is that the animal never touches the
ground, and that nature has thus given it the faculty of
rolling its eggs around the shell.

According to M. Bosc, who has had occasion to observe
many of these animals, the janthine are eminently phosphoric.
They serve as food to fish and birds. The violet liquid which
they produce might be employed with equal success as that
of the purpura, with which doubtless it has much analogy.

Ina supplement necessarily confined to such limits as ours,

358 SUPPLEMENT

we are forced to pass in silence many subdivisions of the
mollusca, even when some degree of popular interest may
attach to them; but it would be unpardonable to omit all
mention of the animal supposed to have produced the cele-
brated purple of the ancients.

M. de Lamarck was the first who established under the
name of PURPURA, a distinct genus composed of several
species of shells, previously classed by Linneus and his fol-
lowers, in the genera buccinum and murex. The name,
however, was applied before by various authors, not only to
the species of the last mentioned genera, but to many others,
owing doubtless to this circumstance, that all these animals
furnish in greater or less abundance, the materials which the
ancients employed in dyeing. In fact, we must not even sup-
pose that it is in the species of this genus that the purple is
principally found. It exists equally in murex and buccinum,
and it is even probable that the species of shell-fish, from
which the ancients extracted the purple, did not belong to
the present genus; this, however, is a convenient place for
treating on the subject.

The purpure are marine animals, living in the fractures of
rocks, in places covered with fucus, and also sometimes bury-
ing themselves in the sand. ‘They creep, by the aid of their
foot, like the other gasteropods. Their nutriment appears to
be constantly animal, and obtained by piercing the shell,
principally of the bivalve mollusca.

The mode of sexual intercourse is not known. The eggs are
spheroid, a little elongated, corneous, of a yellowish colour,
and not deposited until towards autumn. They adhere to the
rocks, and other submerged bodies, by means of a sort of
paste. Their other extremity is closed by a sort of opercle,
small, oval, thick, and transverse. In their interior, a thicker
matter is found in the middle of one more fluid.

The species of this genus are found in all seas; but the |

ON GASTEROPODA. 359

greater number and the largest come from the warmer lati-
tudes, and more especially from the Austral seas. But with-
out considering this genus more minutely, we shall seize the
present opportunity of treating concerning the purple of the
ancients.

The words zoo¢tea, or purpura, were indifferently em-
ployed by the Greeks and Romans, to designate the colour
itself, and the animal which furnished it. Aristotle is the
first writer who has spoken of the purpura. He tells us that
“‘ with the exception of the head, all its other parts are con-
tained in the shell; it is provided with a very firm proboscis,
by means of which it pierces the testa of the animal on which
it feeds. In the turbinated part of the shell lie the stomach,
liver, and intestines; between the neck and the liver is the
organ which furnishes the colouring matter; it has the form
of a vein. The substance which fills the rest of the interval
resembles alum.” Here it is probable that Aristotle alludes
to the cretaceous matter frequently found in the rectum of
many of the mollusca. He continues:

“The purpure move but little; they remain concealed
during the great heats of the dog-days. Fresh-water is posi-
tively injurious to them; but they can live as long as fifty
days out of water altogether. They can perceive. their
prey from a very great distance. ‘They assemble in spring in
the same place, and there make what is named their wax,
which is a production resembling a cake of wax, except that
it is not smooth, or rather a multitude of white pease-cods
joined together; no aperture is ever perceived in it. When
the purpurz, like the other testacea, commence to form this
production, they produce a gluey mucosity, which serves to
connect these sorts of pods. It is in this united mass that
the young purpure are born, and that they are found attached,
sometimes as yet imperfectly formed, to the shells of the old
ones, when the latter are fished up. If the purpure be taken

360 SUPPLEMENT

before they have cast this spawn, they do so in the baskets in
which they are put, and the narrow space in which they are
enclosed merely gives to the mass of the wax the form of a
cluster of grapes.”

Although Aristotle has pretended that in these animals,
there is no generation, properly so called, but that they spring
from the earth, it is evident that the,above description agrees
to the eggs of the purpurz, which consequently resemble
greatly those of the buccinum undatum in buccinum proper.

““ We distinguish,” continues the Stagyrite, “ many species
of purpure ; accordingly there are some large, as those of
the promontory of Sigetum, and small, as those of the Kuripus
and the coasts of Caria. In general those which are fished
for in gulfs are large and of unequal surface; some of them
weigh as much as a mina.” The colour which they furnish,
named by Aristotle flower, (avoc) is most generally black,
though sometimes red, and small in quantity. On shores, and
around promontories, they are small, and their liquor is red.
In places exposed to the north, it is generally black, and red
in southern aspects. It is never of less value than when the
purpure have cast their spawn, accordingly they are fished
for in spring, at the very moment when they are getting rid of
it. They are otherwise taken by means of baits composed of
tainted flesh, or of small fishes, and without a net; but as they
often fall back into the water, after having been drawn out of
it, to avoid this inconvenience the fishermen place drag-nets
underneath and around the bait, so that if they should happen
to fall, which they do easily, when satiated, (and it is difficult
to pluck them away) they are not lost. They then leave them
in the drag-nets, with which they continue to take others
until there is a sufficient quantity for use. To extract the
fluid from them, they remove, at least in the larger species, the
animal from its shell, and then take the part situated between
the neck and the liver or vein; but as for the smaller indivi-

ON GASTEROPODA. 361

duals, they break them up with their shell, because it would’
be too difficult to separate them from it. But,” adds Aris-
totle, “ care is taken to do all this when they are living,
without which, if they died naturally, they would shed their
fluid in expiring.”

Pliny considerably abridges what Aristotle says concerning
the purpura, and even modifies it in a manner nearly unin-
telligible, which proves that he did not comprehend the text
of Aristotle. He adds, “that they generally live seven years,
though they grow much more quickly than other shell-fish,
and attain their full size in about a year. They can live fifty
days without eating. They remain concealed for thirty days
during the dog-star heats; and it is especially on the coasts
of Tyre in Asia, of Meninx, and Gitulor in Africa, and of
Laconia in Europe, that the finest purple is to be found.”
But he gives many interesting details respecting the species
of shell-fish from which different colouring matters are
derived.

“There are two genera of shells which produce the purple
colours, and the conchylian colours, colours which differ only
in shade. The smallest is a buccinum, so called because it
somewhat resembles that from which the sound of the horn is
produced. Its aperture is round, and its edge emarginate.
It is only found attached to stones, and in the neighbourhood
of rocks. ‘The other is named purpura ; it is in the form of a
club, and composed of seven whorls, which indicate its years,
as in buccinum. But it is bristled with sharp points like
needles, which do not exist in the latter. It is, moreover,
provided with a projecting beak, (70strwm) and on the sides
with small tuberculous spines, into which the animal can
introduce its tongue.”

“‘ The purpure are also distinguished by the denomination
of pelagian, among which many varieties are established
according to the places which they inhabit and the sub-

362 SUPPLEMENT

stances on which they feed. Those which live in mud, or
among the alge, and feed thereon, are in very little estima-
tion. Those of the coasts, which are gathered by the sea-side,
are better, though the colour which they furnish is lighter and
more clear. Another variety, which is called gravelly, from
the gravel-beds of the sea, where it is found, is extremely
proper for the conchylian colours ; but the best for the purple
colours is the dialutensis, that is, the one which finds its sub-
sistence on different kinds of soil or strata.

“ The purpure are taken with small nets, which are cast
into the deep sea. Bivalve shell-fish are used by way of
bait, which can open and close, or mussels, which, half-dead,
are reanimated as soon as they are restored to the sea, and
half open their shell. The purpure, eager to devour these,
attack and thrust their tongue into them. But soon stimu-
lated by this sting, the mussels close their shell, and retain
the purpurz, so that, victims of their avidity, the latter are
carried off still suspended to their prey. The most advan-
tageous season for this fishing, is after the rising of the lesser
dog-star, or before the spring, because when the purpure
have spawned, their juices are too liquid. But the workmen
are ignorant of this, although it is very essential.

** In employing the purpure for dying, the artists begin by
removing the vein already mentioned, and adding to one
hundred pounds of this substance, twenty ounces of salt.
The whole is allowed to macerate for three days exactly. Itis
boiled in a leaden cauldron, until greatly reduced. A moderate
heat is then kept up by means of a long stove; after which,
the flesh which necessarily remained attached to the veins,
being skinned off, and the tincture being completely liquified
on the tenth day, and afterwards strained, the wool is plunged
into it. They continue to keep it warm until the desired
point has been ascertained. A lively red tint is less valued
than a blackish red. The wool is left to steep for five hour?

ON GASTEROPODA. 363

for after being carded it is replunged into the bath, until it
has imbibed as much of the liquid as possible. The buccinum
is never employed by itself, because it produces a dye which
will not hold, or rather, perhaps, because it does not preserve
the lively red ; but by mixing it with the purpura, it gives to
the too dark tint of the latter the solidity and brilliancy of the
scarlet, which is sought for. By this mixture, these colours
mutually heighten or darken each other. The best proportion
is for fifty pounds of wool, two hundred pounds of buccinum,
and one hundred and eleven pounds of the purpura. ‘Thus
that superb colour is obtained, which is named amethyst. -
To obtain the Tyrian colour, the wool is saturated in a bath of
the liquor of the purpura, still green and not black, and then
it is transferred into one of the buccinum. Thus is produced
the finest purple, the colour of coagulated blood, blackish
when viewed in front, and of a brilliant hue when seen side-
ways. From this Homer applies the epithet of purple to the
blood.

“The conchylian colour is obtained by similar processes,
excepting that no buccinum is used, and half the bath is
composed of equal portions of water and wine. Thus a palish
colour is obtained, (aptly termed conchylian, from its resem-
blance to the usual colour of sea-shells), which is in high
estimation, and more extensive, as the wool is less saturated.

“ Another tint is yet obtained, which has been named
tyriamethyst, by saturating a stuff which was at first
amethystine, in a bath of the Tyrian purple, as its name in-
dicates, so that they tint at first conchylian, to facilitate the
Tyrian tincture, which then becomes, as is said, more agree-
able and softer. Just as to obtain the deep poppy-colour,
they retint in Tyrian purple what had been first tinted in
Kermes.”

The price of these colours varied according to the supply
of animals; but, nevertheless, in consequence of the small

a2

15

364 SUPPLEMENT

quantity of juice extracted, and the length of the operation of
dyeing, the purple was so dear, that in the time of Augustus,
one pound of wool dyed with the Tyrian purple, could not
be bought for thirty pounds. Itis supposed that the opulence
of the city of Tyre was much increased by the commerce of
this precious dye. The purple decorated the magistrates of
Rome ; but as it grew scarcer, its use was reserved, under pain
of death, to the emperors alone. The priests, when it -was
first known, assumed it as a colour agreeable to the divinity,
and employed it in the public solemnities of religion.

For a long period nothing was known respecting the two
juices which formed the Tyrian dye, excepting what we de-
rive from the ancients, and, indeed, we may say more espe-
cially from Aristotle and Pliny, for no additional information
can be said to have been communicated by other ancient
writers ; so that, although Aristotle and Pliny had given some
intimations of their being primitively white, and Pliny had
mentioned one of the intermediate colours, as we have already
seen, a green, yet the other colours which they undergo on
exposure to the sun, were not distinctly noticed, until the
animals themselves were discovered at the end of the last
century, and the beginning of the present; until then, no
adequate conceptions could be formed of the changes they
underwent before they became purple.

The buccinum was found in 1686, by Cole, in great plenty
on some of the Irish shores, on the shore of Somersetshire, and
the opposite shores of South Wales. Its juice was profitably
employed to mark linen of a fine durable crimson. A small
species of the buccinum was likewise found by Jussieu on the
French coast. Cole found the juice of the buccinum, when
taken out of the vein or reservoir, to be white and clammy ;
and if this viscid juice be then squeezed on linen or silk, it
immediately, on being exposed to the sun, acquires a pale
yellowish-green hue, then changes to a blue, and lastly to a

ee

ON GASTEROPODA. 365

deep purple red. These changes, though very rapid, are
quicker or slower in proportion to the heat of the sun.

On washing the cloth with scalding water and soap, and
again exposing it to the sun, the colour changes to a beautiful
crimson, and then no further alteration takes place from sun
or air, or any of the agents usually employed to try colours.
The linen marked with the white juice, while drying, always
yielded, for the first time, a strong fetid smell, resembling a
mixture of garlic and assafoetida. A similar scent was attached
to the purple of the ancients.

Duhamel informs us, with regard to the purpura, that its
juice neither receives nor communicates colour without ex-
posure to the sun, and that this colour is evolved, not by the
heat, but by the light of the sun’s rays; for when the silk or
linen which is stained, is covered with thin opake bodies,
which transmit heat without light, no colour is produced,
which is not the case when transparent bodies are employed.
Also the light of a fire, though concentrated by convex
glasses, and concave mirrors, has no effect upon it.

Duhamel gives the colours which it assumed, on exposure
to the sun, in the following order ; 1. a pale green, or yellow ;
2. an emerald green ; 3. a dark blueish-green ; 4. a blue, with
an incipient redness; 5. a purple. These colours appeared
in less than five minutes; but it only became green when it
was not exposed to the light. ‘This succession of colours is
best observed when the sun is low; in the light of noon in
summer, they come on so quickly as not to be easily dis-
tinguished.

Observers, however, are far from being perfectly agreed re-
specting the circumstances which cause the colouring matter
to pass from the pale-green, or greenish-white to the purple-
red. Respecting the permanence of this tincture, however,
there is no dispute. Cole, Reaumur, Templeman, and par-
ticularly Duhamel, have proved, that when the stuff has been

366 SUPPLEMENT

perfectly saturated, and all its parts completely exposed to
the solar action, that the strongest lixivia, and most active
_ tests, have no influence on the colour, except that when
there remain many layers at the surface, the last having im-
peded the solar action upon the others, and its combination
with the tissue not having taken place, the colour then grows
very clear, so that Duhamel concludes, from his experiments
on the subject, that the ancients must have had a peculiar
process for extending the colouring matter, which is always
pretty thick and viscous in the animals, and thus making it
penetrate into all parts of the tissue. Perhaps it was for this
purpose that water, urine, and salt, were employed by the
ancient dyers. ‘Templeman tells us, however, from his own
experience, that the addition of salt has no effect. This is a
subject for the analysis of chemists, who, nevertheless, appear
to have bestowed but little attention upon it. It deserves
investigation, not as regards the art of dyeing, for the purple
of the moderns is as beautiful and as fixed as that of the
ancients, more easy to be obtained, and consequently less ex-
pensive—but it is important to the science of animal chemistry.
Duhamel thinks that the action of the sun in purpurification
is somewhat analogous to what passes in the coloration of
fruits which remain whitish, yellow, or green, in shady places,
and are coloured only where the action of the sun is received.
Here, however, the change is slow and gradual, but in the
purple it takes place instantaneously.

From all that has been investigated respecting this subject,
M. de Blainville draws the following conclusions.

1. That it is probable, that the molluscum from which the
ancients principally derived their purple, is an animal toler-
ably large, known in the Mediterranean, perfectly described
by Columna, and of which Linneus, and the modern concho-
logists make their murex trunculus, or perhaps the murex
brandaris.

ee eee ee oe

_ —_——— .

ON GASTEROPODA. 367

2. That they also employed a species of buccinum, which
was smaller, to obtain an analogous, though a little different
colour, and this species is probably the B. lapillus of
Linneus.

3. That it is certain that a great number of species of this
family furnish an analogous liquor; but it is probable that
they do not all do so.

4, That it is even probable that all the individuals of the
same species do not produce it. It is a query whether this
depend on sex, or age, or the epoch of reproduction ?

5. That we do not precisely know in what part of the
animal this matter is found. Is it in the depurating organ, or
in the generative apparatus? We might be induced to believe
in the latter, as the eggs of the B. lapillus contain the same
liquor in abundance.

6. That the process employed by the ancients in dyeing
purple is as yet unknown.

7. That the chemical phenomena of the purpurification are
as yet but very incompletely known.

We shall now pass at once to the last order of the gastero-
pods, the Cyclobranchia, on which we can afford but very
little space.

The PATELL#& are animals much more simply organized
than the preceding mollusca. They live upon the shores of
the sea, and constantly on those parts which are alternately
covered and left dry by the waters. None are yet known
belonging to the fresh water, nor have any been observed even
in the mouths of large rivers. They are almost constantly
fixed upon rocks and submerged bodies, and sometimes in
excavations tolerably deep, which they have hollowed in the
substance of the rock. They do not, however, always remain
in the same place, as some persons have supposed. It is
now a long time since Reaumur published his observations on
their mode of locomotion. It takes place in the same way as

368 SUPPLEMENT ON GASTEROPODA.

in the other gasteropods ; but, in spite of the size of their foot,
their movements are extremely slow, which is occasioned by
the thinness of the layer, composed of longitudinal fibres,
which is the seat of locomotion. But, on the other hand, the
patellz can adhere to the plane of position in a manner truly
astonishing. In fact, if previously to removing a patella from
its rock, it has been first touched, and thus, as it were, ad-
vertised of the intent, it is impossible to get it away, and the
shell might sooner be broken, unless a plate of iron be passed
between the foot of the animal and the rock. It has been
proved by experiment that a patella will thus support a weight
of many pounds without falling. This faculty is owing to the
great quantity of the vertical fibres of the foot, which, by
raising the middle part form a hollow in the centre, and con-
sequently a sort of sucker.

Patella may frequently be observed sunk two or three lines
in depth in chalky rock, which is singular, considering that
they do possess, though in a very small degree, the faculty of
changing place. M. d’Orbigny, however, tells us that each
individual constantly returns to the same place. From the
dental apparatus of the patella, and their great abundance
in places covered with marine plants, it is probable that they
feed on vegetables. Concerning their reproduction nothing
is known. ‘They are eaten by some of the poor inhabitants of
the sea coasts, but their flesh, though savory, is coriaceous
and indigestible.

With respect to the OSCABRIONS (CHITON) though their
organization is very remarkable, we know little or nothing of
their manners.

SUPPLEMENT

ON THE

FOURTH CLASS OF THE MOLLUSCA.

THE ACEPHALA.

WE shall begin our review of this class with that well known
animal the OYSTER, (OsTREA, L.)

Oysters have been pretty generally regarded as almost in
the last rank of animality, but most erroneously so, since there
are a great number of animals below them, most certainly their
inferiors in point of organization, and consequently in its
results. What has caused them to be so considered is, that
they live, for the most part, fixed to submarine bodies, or to
individuals of their own species, and that it is thought that
they are not capable of changing place. This, however, is
an error; certain species can move, if not by means of a foot,
of which they have no trace, at least by abruptly opening and
closing their shell, as many other bivalves do, so as to turn
themselves, when by any chance they happen to be upside
down. If their sensibility is nothing, or at least extremely
obtuse in the greater part of their body, it is not so with the
papillary edge of their mantle or cloak. At the slightest con-
tact of an external body on the tentacular threads, at the
slightest rough motion of the water, it contracts, and the

VOL. XII. Bb

370 SUPPLEMENT

animal closes its shell. It must be confessed, however, that
the majority, being fixed more or less completely, according
to age, and always by their inferior valve, they are obliged
to live in the places where they are born. Some species form,
by a successive accumulation of individuals, strata, or banks,
often very much extended and very thick, while others re-
main more or less free and solitary.

They are found, as it would seem, in all seas, but never at
very great depths, nor at a great distance from the shore.
The gulfs formed by the mouths of great rivers, or those in
which the waters are more tranquil, constitute their usual
habitation. But it does not appear that oysters ever live
entirely in fresh water, or delight in it, as Pliny is pleased to
inform us. Certain species, it is true, live in those parts of
rivers where the sea comes up, so that they remain dry during
low-water. 'This especially takes place with the Ostrea para-
sitica, which attaches itself to certain shrubs and trees in the
torrid zone, vulgarly called Mangliers in the French Antilles,
Conocarpus of Linneus. 'Then they close their shell ex-
actly ; but in their ordinary state, z.e. in the water, they
leave it half open, the marginal line of their tentacular papillze
edging almost the entire of the cleft. On the slightest contact
of a foreign body, with these tentacula only, they close the
shell more or less completely, and can also enclose there some
of the smaller crustacea, especially of the genus Pinnothera,
but which do not serve them as food. In fact, the nutriment
of oysters, is, in all probability, composed of animals much
smaller, of infusoria, of animated molecules, and even of ani-
mal matters so abundantly spread in the waters of the sea;
for, in spite of the size of their buccal aperture, the softness

of its edges, and its position, will not allow us to believe that —

oysters can feed upon substances at all resisting ; and the con-

fidence with which we ourselves eat these animals, must in- —

duce the belief that their stomach contains no hard sub-

ON ACEPHALA. re!

stances. Accordingly, it is generally admitted, that the
water of the sea in which they live, continually attracted and
rejected by the mantle, brings at once both the matter of
respiration and that of nutrition,

The oysters having, like the other bivalve mollusca, only
the female sex evident, they must be genuine hermaphrodites ;
and, in fact, it appears quite certain that a single individual
can reproduce and continue the species. The eggs are ex-
pelled in the form of spawn, or white fluid, very similar
to a drop of grease, in which may be perceived with the
microscope, innumerable little oysters. This is called spats
by our fishermen. This matter, in which they swim, doubt-
less serves to agglutinate them to the submarine bodies, or to
individuals of their own species ; then the new ones, in being
developed, smother, as it were, the old ones, not permitting
the water to reach them, or hindering them from opening
their shel]. It is thus are formed those immense banks of
oysters which are found upon our coasts, and which, in spite
of the constant destruction wrought amongst them for cen-
turies, never appear to be exhausted. The species which are
not fixed, or are not so in a flat position, not being circum-
stanced so favourably for the adherence of the spawn, appear,
in general, to be less multiplied.

We are entirely ignorant of the manner of growth in the
oysters, and of the duration of their life. It would seem,
however, that as the growth is rather slow, if an individual
be placed in favourable circumstances, that is, without risk
of being smothered by its progeny, it would live a very long
time. But we have no certain data to go on here. However,
if we give credit to what is asserted by the inhabitants of
Marennes, on the coasts of the Atlantic, oysters do not live
more than ten years. In three days after the deposition of
the spawn, the shell of the little oyster is already three lines
in breadth ; in three months, or six, it is nearly the size of a

Bb2

o12 SUPPLEMENT

half crown piece ; and at the end ofa year, as large as a dollar.
The fishermen on the coast just mentioned, distinguish the
age of the oysters by the strie of the shell. When they ap-
proach the term of their growth, the shell is very large in
proportion to the animal, which grows thin, and diminishes
more and more. As the oysters can completely shut their
shell, and thus enclose a large quantity of water in their in-
terior, they can live a sufficiently long time out of this fluid,
especially if the drying action of the air on their testa be pre-
vented, and they be placed in their natural position. ‘This
faculty, which allows of their being transported to consider-
able distances, facilitates the extensive commerce to which
they give rise.

The oysters which never cause us any injury, except it
may be in occasionally contracting or diminishing the depth
of a bay, are of very considerable utility, inasmuch as from
time immemorial they have constituted the food of man,
fresh, dried, or cooked, but particularly in their fresh state.
The Greeks, and more especially the Romans, when they
levied contributions upon land and sea, throughout the then
known world, to cover the table of a Lucullus, or an Apicius,
held them in very high estimation, and attached no small
importance to the localities from which they were imported.
Those of the Dardanelles, of Venice, of the bay of Cumez, and
of England, were those which they preferred ; but they espe-
cially attached a very great value to those which, brought
from these different places, and perhaps from places still
more remote, were transported in large boats (lacubus ligneis)
and deposited in the Lucrine lake, where they grew remark-
ably fat. The first Roman who entertained the notion of
establishing this sort of park, or oyster-bed, was Sergius
Orata, at Baie, in the time of the Marsian war. It appears
that the Romans preferred those oysters which have the
edges of the mouth a deep brown, almost black, and that they

ON ACEPHALA. ole

gave them a particular name, that of culliblephara, a word
which is nevertheless supposed to be corrupted. Those are
they which vulgarly, but most erroneously, are called males,
because the oysters are all hermaphrodites. ‘The Romans ate
oysters raw, and also cooked, with various seasonings, into
which entered pepper, the yolks of eggs, vinegar, oil, wine, &c.
But it is not probable that they made so great a consumption
of them as do the modern Europeans. Accordingly oysters,
at the present day, constitute a very considerable article of
commerce.

The best oysters in Europe are our own. ‘The most
esteemed in France are found upon the coasts of Bretagne,
and the largest on those of Normandy, whence they are
brought at great expense to Paris in the autumn and winter
seasons. The places where oysters are chiefly caught in
England, are the Pont Burnham, Malden, and Colne waters,
near Chester. This brood, and other oysters, are carried to
the creeks of the sea, especially on the coasts of Kent and
Essex, near the mouth of the Thames, and then thrown into
the channels which are called oyster-beds, or layers, where
they grow and fatten for the supply of the London market.
In two or three years the smallest will become oysters of full
size.

The mode in which oysters are parked, as they call it in
France, affords some curious details that may not prove unin-
teresting to our readers.

The oysters, which form a considerable object of commerce
in the north of Europe, and especially at Paris, come from
the bay of Cancale, in the British Channel, between the
village of that name, Mount St. Michel, and St. Malo. The
bottom of this bay appears even, solid, and without current,
all favourable circumstances for the reproduction of these
animals. It must be, therefore, very considerable, and the
bank which the oysters have produced must be very much

374 SUPPLEMENT

extended, to suffice for the continual fishing which has taken
place there for so long a time, without any sign of diminution.
Nevertheless, from 1774, to 1777, we carried off so great a
number, with the intent of forming a bank upon our own
coasts, that some diminution was perceived in the bay ; but
it was very speedily supplied. Although the French may
certainly be said alone to possess the right of fishing in this
bay, it is yet open to all nations, but not at all periods of the
year. The fishing usually commences at the end of Septem
ber, and finishes in April; during the other months it is se-
verely interdicted, because then is the time of spawning, and
the oyster is supposed to be of an injurious quality. This
idea, which is probably erroneous, is nevertheless a useful
prejudice ; for, otherwise, the continual fishing would soon
destroy the bank, not only by subtracting the adult indivi-
duals, but also by destroying the sources of reproduction.
The mode of fishing is very simple. Itis performed by means
of what is called the drag, which is a sort of iron rake or har-
row, behind which is attached a leathern pouch, and which is
drawn along by a boat in full sail. By thus raking the sur-
face of the bank, sometimes as many as eleven or twelve
hundred are taken at a single haul. These oysters, shipped
in the ports of Granville and Cancale, are then transported to
the different places where parks or depots have been esta-
blished for them. ‘These parks not only answer the purpose
of preserving the oysters and facilitating the sale, but also of
ameliorating them, as the ancient Romans well knew long
ago. In fact, the oyster when it first comes from the sea, has
a strong taste of the muddy bottom, is more or less hard, and
of an indifferent flavour altogether. It acquires the desired
qualities in those parks, or beds, which we have mentioned.
They are simply reservoirs, more or less extensive, excavated
in the soil, or even in the rock, as at Etretat, and into which,
at will, the sea-water may be permitted to enter at full tide,

ON ACEPHALA. 375

and from which it may be suffered to run out. In general,
these excavations, which are in the form of parallelograms,
are only a few feet in depth, and their walls are sloping.
They communicate with the sea by means of a canal, more or
less long, and furnished with a small flood-gate. When the
water is to be changed, the flood-gate is opened at the end of
the low tide, and the reservoir is filled at high water. The
bottom and sides of these passes are covered with pebbles, or
very coarse sand, for mud must be carefully avoided, which is
always very hurtful to oysters. Care must also be taken that
the motion of the water be not considerable enough to cause
any grains of sand to enter the shells. When the park is thus
disposed, the oysters are placed there in their natural position,
that is, horizontally, the gibbous valve underneath, on a part
of the elevation of the slope, so deep, that it will be difficult
for robbers to get at them, but not too deep, that we may avoid
as much as possible the deposition of the mud. The more
suitably the oysters are fixed, the more cautiously they are
moved, and the more the deposition of mud is prevented,
which may be done by washing the walls of the park, and
frequently throwing water on the oysters, when left uncovered,
the sooner will these animals become good and marketable.
Those also which happen to be dead should be carefully
thrown away, and they are easily recognized, as they remain
half open when the water has retired. There are some doubts
as to the preference which should be given to these parks, or
depots, according as the water which they contain is received
every tide, or only twice a month. In the first case the
oyster may be, perhaps, a little harder, and more coriaceous
that in the second. But the water should always be very
clear and limpid.

Fresh water is not good for oysters, at least when the
quantity which is introduced into the parks, either by great
rains or inundations, becomes too considerable. Experience

376 SUPPLEMENT

has settled this question, beyond all doubt, in the case of the
parks of the Courseulois, which are liable to be filled with the
fresh water by the inundations of the Seule. This proves the
necessity of more frequently renewing the water of the parks
during great rains. As cold is equally injurious to oysters, it
would be desirable to have them placed at a sufficient dis-
tance from the surface of the water; but another inconvenience
would result from this, that they would be less easily in-
spected.

From all these considerations it appears, that to establish
a park of oysters properly, it should be in places sheltered
from the wind, to prevent the agitation of the water, and con-
sequently the entrance of grains of sand into the shells. The
bottom should not be muddy, or it should be well covered
with pebbles and coarse sand, so that the animal may lose
the muddy flavour, and not resume it. The mass of water
should be pretty considerable, especially if not changed at
each tide, to escape too great a proportion of fresh water from
rains. The oysters should be placed sufficiently deep to
escape cold, but not deep enough to prevent them from being
easily viewed by the inspector, as in that case he could not
throw out the dead individuals. Finally, the more it is in our
power to renew, or not to renew the water at pleasure, the
more influence can be exerted in modifying the oysters. If it
be desired that the oysters should be very white, clear, and
even bigger, the water should be changed at every tide, as is
done at Etretat, and different points on the Atlantic. If, on
the contrary, it is wished to have them more tender, smaller,

and particularly to make them green, they must be left in the’

water a longer or shorter time, according to the season, and
some other circumstances, iin, | atmospheric, of which
not much is known.

Tt is quite certain that the green oysters are absolutely of
the same species with the white, and come from the same

Ee

ON ACEPHALA. 5 ii!

places, and that the latter may be greened at pleasure. For
this purpose a park is chosen, in general rather small, and
sea-water is introduced into it, which is preserved for a longer
or shorter time without being changed. When the pebbles
with which the wells have been lined, commence to grow
green, the oysters are putin. But they are obliged to be
placed with much more precaution than the other oysters, so
that they shall not be one upon the other. From this, it
happens that in any given space, where oysters are placed
for this purpose, a third of the quantity used in ordinary
cases, cannot be placed. Sometimes three days are sufficient
to give the oysters a light green tint; but a month is neces-
sary to render it of a deeper colour. The oysters will not
green either in winter, or during very hot weather. A mode-
rate heat is necessary for this purpose, as in March, April,
September, and October. Rainy and stormy weather is said
to be unfavourable, as is the agitation of the water, especially
by the north winds. Generally speaking, there are some
years in which the oysters green easily, while in others they
will scarcely do so at all. What can be the cause of this
coloration, which other mollusca may equally experience ?
Certainly it is not that these animals feed upon fucus, nor
even upon green matter. It might be a state of malady, and
to a certain point this is probable, as the green oysters are in
general smaller. But M. Gaillon thinks that it is owing to
the penetration throughout their entire tissue of an animalcule
of a fine green colour, which he terms the wbrio of the oyster.
This penetration of the animalcule may be owing to a state of
‘atony in the animal, arising from unfavourable circumstances.
The great precaution which is required in greening oysters,
causes them to be very dear.

What we have now said on the art of greening oysters, is
drawn from the observations of M. Lair, and other French
gentlemen, on the coasts of Normandy ; but it seems that this

378 SUPPLEMENT

art is carried to much greater perfection on the coasts of
Aunis, whence come the excellent green oysters of Marennes.
The men who employ themselves in this sort of business do
not take the oysters indiscriminately. They choose individuals
only a year old, and especially those which come from oysters
already greened. They catch them with the hand upon the
rocks, or they detach some large individuals fished up with
the drag, and more deeply; they also choose the best con-
formed individuals. The parks in which they place them are
named Claires. These are situated on the banks, at the
mouth of the river Seudre, and particularly on the right bank.
Each park is enclosed by walls of three feet high at most, and
can communicate with the river, or rather with the sea, at
high tide twice a month only, by means of a small canal,
with a flood-gate. All around, and within the enclosure, is a
canal of three feet in depth, for the deposition of the mud.
The middle is as smooth and level as the alley of a garden,
and care is taken that no plant is left there. It is in this
place, about a year after its arrangement, that the oysters are
placed, very flat, and carefully insulated from each other; then
the water is introduced, which is kept only six inches high,
except during great heat, or great cold, when it is raised as
much as possible. The oysters remain thus for more than
two years, sometimes without being brought to market, and
much care is necessary on the part of the superintendents, to
change their places, and even to transport them into other
parks, which accelerates their greenness. To prevent the
deposition of mud, there must be a suitable mixture of salt
and fresh water; crabs must not be allowed to introduce
themselves into the park. With all these precautions, the
green oysters which are obtained are of a very superior
quality. As to the cause of this greenness, the people attri-
bute it to a variety of circumstances, to the nature of the soil,
to that of the waters, and particularly to the mixture of fresh

‘eT ele

<a oe

ON ACEPHALA. 379

and salt water; to the influence of the solar action, of the
north-east wind, of a moderate temperature, but by no means
to any single immediate cause. They are not at all disposed
to coincide with the theory of M. Gaillon, above mentioned,
against which they have many objections; but it would be
too long to enumerate them.

The transportation of the oysters, thus become marketable,
still demands some precautions. ‘They must always be placed
in their natural position, that is to say, horizontally, the
hollow valve underneath, so that they may lose less of the
water which bathes their gills. It is equally advantageous
that they should be enveloped in fucus, or marine plants, to
avoid the drying action of the air. The quicker this trans-
portation takes place the better, especially when the weather
is a little warm. But as this mode by land is very expensive,
during the winter oysters are brought to Paris in rather large
boats, which come from St. Vast, by the Somme. Then they
are very cheap at Paris. Some years back, a notion was en-
tertained of no longer sending oysters dry, but in a boat full
of sea-water, after the manner of the Romans. But the at-
tempt did not succeed, for so small a quantity of water, con-
taining so many animals, not being capable of being renewed,
soon putrified, as sea-water easily does, and caused the death
of so great a number of oysters, that the police were forced
to order the whole to be thrown into the river.

Oysters of good quality, are in general easy of digestion,
but not very nutritious, especially when they are eaten raw.
They rather act as a provocative to appetite, which is occa-
sioned by the agreeably subsaline water which they contain.
Persons have been known to eat fifteen or twenty dozen at a
meal, without experiencing any inconvenience. It would not
have been the same if they had been cooked; they then be-
come harder, more coriaceous, and consequently more indi-
gestible. They are also eaten pickled with vinegar and fine

13

380 SUPPLEMENT

herbs. In this state they are sent into places far remote from
the sea, heaped on each other in small barrels without their
shells.

If oysters almost always present a nutriment light and
agreeable, it sometimes happens, though but rarely, that they
produce grievous accidents. It is generally supposed that
such accidents are more serious when they are eaten in
certain months of the year, when they deposit their spawn, as
in June, July, and August, but this is now considered
erroneous.

The species of oyster most commonly eaten, is that which,
from this very circumstance, has been justly named Ostrea
edulis, and the one which is found in the greatest abundance.
But there are also many others which serve for the nutriment
of man. It appears, generally, that the oysters of hot climates
are less agreeable than ours, whether this be attributable or no
to the species or to the climate.

The oysters have a great number of enemies. It is reported
that the crabs, to eat them with security, clap a small stone
between their valves when they are partly open, to hinder
them from closing. Credat Judeus. Among their enemies,
there are many that introduce themselves furtively, and suffer
themselves to be enclosed in the cavity of the valves. Others
pierce them slowly, and all finish by killing the animal and
living on it. It has been observed, that the oyster, to defend
itself against the first, possesses the faculty of shooting forth
very strongly the water which it holds in reserve in its body,
and it can retard, and even hinder the action of the second by
augmenting, at will, the thickness of the shell, in the place
exposed to danger.

Some persons have, proceeding gradually, succeeded in
making certain species of the oyster live in fresh-water.

It is not necessary to dwell upon the therapeutic qualities
which have been attributed to oysters, because none of them

ON ACEPHALA. 381

will stand the test of an attentive examination. We shall
only mention, that in some places, where limestone is scarce,
their shells are employed with great advantage to make, by
calcination, a most excellent lime.

The PECTINES are so called from the form of the canali-
culations of their shell resembling a little the arrangement of
the teeth of acomb. They evidently differ from the oysters
in all their anatomical relations. ‘Their habits are pretty
similar to those of mussels, with this difference, that they are
in general more free. They never sink in the sand, and, on
the contrary, are always at the surface of the bottom of the
sea, resting partly on the side, like oysters, and, as it would
appear, at rather a small distance from the shore. The species
which have a byssus, must, doubtless, never quit the place
where they were born, and deposited in the egg-state ; but the
others are said to be susceptible of a very singular species of
locomotion, since they can raise themselves in the water, and
even at its surface, by agitating the two valves of their shell,
pretty nearly as birds do with their wings, and fishes with
their fins. The small length of the ligament, its position, its
great elasticity, and consequently the trifling separation of
the valves, allow us to believe, that these animals can really
move by contracting them suddenly on the fluid which they
contain, and pushing themselves on in an opposite direction.
But it appears by no means probable that a sort of flight can
result from this operation. We know, indeed, but little re-
specting the habits of the pectines. On some sea-coasts the
larger species are eaten ; but few, except the poor, have re-
course to this kind of food, which is hard and indigestible.
For a long time the hollow valve of the larger species of
pectines was used in some places by the poor asadish. It is
capable of bearing the fire, and is sometimes adopted as a
culinary vessel. The species of this genus are found in all
seas, and pretty equally divided.

382 SUPPLEMENT

Passing over the intervening subdivisions as affording little
or nothing of popular interest, we come to the genus AVICULA,
a species of which the mytilus margaritiferus of Linnzus is
celebrated as principally producing the fine “ Orient pearl.”
A few short details on this subject cannot fail to be interesting
to our readers.

The pearl is a body of a variable volume, and of different
forms, composed of layers of the nacreous substance, ex-
tremely numerous and compact, which constitute a more or
less considerable part of certain species of univalve, or bivalve
shells, and which appears to be constantly accidental, and is
supposed to be caused by a malady of the animal or its shell.
This, however, is far from being an ascertained fact, as, were
it so, the disease must extend to the far greater majority of
individuals, so much so indeed, that every one is found to be
accompanied by a certain proportion of minute particles,
which are evidently the pearl in the first stages of formation;
hence it may be fairly supposed that they are in some essential
degree useful rather than prejudicial to the inhabitant of the
shell.

When we treated of the structure of the coquillaceous en-
velope of the mollusca, we observed how it is produced and
thickened by little and little, showing that the whole surface
of the skin, which clothes the body, properly so called, is
exhaled excessively from thin strata of calcareous molecules,
dissolved in an animal mucus, and applied one within another,
always outedging a little, from which results the augmenta-
tion of the shell, not only in thickness, but in breadth and
length. We have likewise seen that the necessary modifica-
tion in this formation, to produce the nacre, or mother-of-
pearl, seems to consist in the calcareous molecules being placed
so as to leave very small spaces between them, in which the
light is decomposed before it is reflected back to us. Thus
the pearls are an animal production, in which chemists re-

ee

ON ACEPHALA. 383

cognize a great quantity of carbonate of lime united to an
animal matter or mucus. They are capable of being dissolved
in all acids stronger than carbonic acid. ‘They are also
necessarily formed of strata, which envelop one the other,
at least when they are perfect. It has been suggested,
moreover, that they always contain a little foreign body,
around which the layers are deposited. Athenzus would
have it that they are produced in the body of the animal, and
compares this production to that of the hydatids in the flesh
of a leprous pig. We certainly cannot admit the opinion of
Pliny and Dioscorides, that they are a production of dew ; nor
without hesitation, that of Valentine, who thinks that they
are the eggs of the females, an hypothesis, however, much
more probable than that of Pliny.

In carefully studying a great number of shells, the interior
of which is nacreous, we can easily see that at the places
where the movements are most irregular, for instance, in the
places where the fibres of the muscles of attachment are in-
serted in a univalve or bivalve, the nacreous substance is
much less smooth, than at the places where the mantle only
executes its ordinary movements of retraction and extension.
Sometimes they even form pretty well marked swellings, and
even sorts of irregular tubercles, as is very obvious in the
haliotides. When a shell has received an external shock,
considerable enough to cause it to lose substance, or even
merely to occasion a depression of no great depth, we find in
its interior that the nacreous matter, in depositing at first, has
followed the inflexion produced by the depression, and after-
wards was necessarily accumulated in this place in a greater
quantity than if there had been no iritation, so as to form an
irregular tubercle, more or less considerable. ‘This is evi-
dently the origin of at least one genus of pearls; for, once
that the parallelism is lost in the deposition of the forming
layers, the irritation produced by this sort of foreign or

384 SUPPLEMENT

anomalous body, continues and determines this part of the
mantle to deposit more nacreous matter, from which results
a tubercle more and more thick, and even more and more re-
gular. The original inequalities being necessarily effaced
more and more in proportion as the new layers are deposited,
the consequence is the production of a pearly mass ; but, that
this should form a pearl, properly so called, that is, that the
mass should assume a form more or less regular, either globu-
lar, oval, or pyriform, is a matter entirely owing to chance.
Moreover, in this species of pearl, it is impossible to conceive
that there should not always remain, at some part of the pearl,
a pedicle more or less narrow, in proportion to the bigness
of the swelling, and which is the place where the disturbing
cause commences to act. A pearl of this kind cannot, there-
fore, by any means, be compared to an animal or vegetable
excrescence ; for in the latter, the growth, the augmentation,
takes place within, whereas the contrary is the case with the
pearls.

Another genus of pearls is that, the observation of which we
owe to Redi. On opening many pearls, he has:constantly found
in their interior a foreign body, like a little grain of sand, and
in this case the formation is very easily conceived. Neverthe-
less, considering that itis only the mantle itself which produces
the coquillaceous matter, nacreous or not, we must suppose
that this grain of sand, which has penetrated by accident into
the interior of the shell, being a foreign body, and in relation
with a part of the mantle, has produced a point of irritation,
and subsequently a continual deposition of layers of nacreous
matter, somewhat like calculi in the bladder. Then we per-
ceive why, in this genus of pearls, there should be no pedicle
of insertion. They must be equally smooth in their whole
circumference, and it is more conceivable why they should be
spherical. As to their form, bulk, and even the beauty of their
nacre, (water, as it is sometimes termed) these are matters

ON ACEPHALA. 385

pretty nearly inexplicable, although, in a certain degree, the
first may be referred to the figure of the determining body,
the second and third to the vigour and duration of life in the
animal. M. de Blainville says on this subject,

“ T have attempted several times, in the small pearls which
merchants name seed-pearls, to find this little kernel in their
interior, in which I succeeded, though the trial took several
days, and I was obliged to employ an acid much stronger
than the acetic, namely the sulphuric acid. I can even say
that it cost mea good deal of trouble, so that we may entertain
some doubts respecting the celebrated anecdote of Cleopatra,
who, with the intent of expending a sum much greater than
Antony had done in his most sumptuous repasts, where he
had lavished the riches, and exhausted the Juxuries of the
East, took a pearl from her ear, of considerable bulk and
value, put it into vinegar, where it was supposed to be dis-
solved, and swallowed it. To effect such a purpose, vinegar
must be very strong, and many weeks, perhaps months,
would be necessary to complete the dissolution. Some of
these small pearls, in which, nevertheless, I could trace no
pedicles of attachment, were equally formed of layers, al-
though often not exactly concentric, but without any interior
kernel; so that we must necessarily admit a third genus of
pearls, which is formed independently of the shell, indepen-
dently of a foreign body, and which would be but a sort of
extravasation of the shelly matter, without doubt, in the
mantle, perhaps even in its edge, that is to say, in the part
which forms the greatest quantity of calcareous matter. The
origin of this, however, may be in some accidental or external
irritation produced on the edge of the mantle, or, in fine, in
some internal malady of the animal, and in that case, it would
be nearly impossible to determine the formation of these
pearls. It is not so with the first two genera. We know, in
fact, that certain shells may be brought to produce pearls by

VOL. Xt. ce

386 SUPPLEMENT

artificial means. Linneus has effected this in the shells of
the genus Unio, in the rivers of Sweden. By piercing the
shell while the animal is living, the formation is induced, at
the corresponding part of the interior, of a pearly mass, which
will present the desired size and form. 'The Swedish govern-
ment at first made a secret of this invention, and established
artificial pearleries; but at the end of a few years it was
obliged to abandon them, the advantages of the undertaking
being very far from counterpoising the expence ; because, in
the number of pearls which were formed, it was very rare to
find any of the slightest value.”

The inhabitants of India appear to pursue a system pretty
nearly analogous to this. We find sometimes in collections,
though not often, the large shell which produces the most
numerous and the finest pearls, crossed by a thread of brass-
wire, in a part of its length, and we see in the interior,
some crumplings, or blisters of the nacre, which indicate
that pearls might be found there. A fluviatile shell, from
China, has been seen penetrated by a brass-wire, rivetted
externally like a nail-head, while the part which penetrated
inside had a very well formed pearl, soldered, as it were, to
its extremity.

Pearls are also said to be obtained by depositing in a living
shell, a very small piece of spherical nacre, in a place where
the mantle is raised up, and the nacreous paries scratched.
This mode is reported to have been tried with success in
Finland. It has been even said, that certain Asiatics intro-
duced into shells little works of handicraft, which, in the
course of time, are invested with the substance which forms
the pearls.

We have already observed, that it is easy to imagine that
all the nacreous shells may produce pearls. Thus we find
them sometimes in the patelle, the haliotides, and the pinne ;
but in general, they are more especially produced by the

“oe

ON ACEPHALA. 387

thick bivalve shells, such as the wniones, and more particu-
larly by the pearl-mussel, vulgarly called the pearl-oyster,
M. margaritaceus of Linneus, and the old conchologists,
avicula margaritacea of Bruguiéres, and finally, the pinta-
dina margaritacea of Lamarck. In all the countries in which
it exists, as in the Gulf of Mexico, (if indeed it be the same
species) in the Red Sea, in the Persian Gulf, on the coasts
of Japan, and especially in the Indian ocean on the coast of
Ceylon, it has given rise to regulated fisheries, and to a very
considerable commerce, as it would appear, from time imme-
morial.

This fine species of shell exists in considerable banks, at-
tached by its byssws, or beard, to the submarine rocks, some-
what like the mussels, and as it would appear, constantly at
considerable depths. ‘There are many such banks in the
Gulf Manaar, island of Ceylon, at Arippo, Condatchy, and
Pomparippo. The most considerable is said to occupy a
space of twenty miles opposite Condatchy. To prevent the
useless destruction of a great number of individuals, the bank
is divided, as it were, into regular cuts, pretty nearly like the
banks of coral on the coast of Sicily, that is to say, it is di-
vided into seven parts, which are worked successively every
year, because it is supposed that these animals, in that space
of time, attain the full size of which they are capable, and that
if they were left longer, the pearls would become troublesome
to the animal, and that it would finally expel them from the
shell. Be this as it may, in the commencement of February,
when the fishing begins, to end in April, all the boats which
are to be employed in it, assemble in the bay of Condatchy,
whither they come from different parts of the continent, and
from the isle of Manaar. At ten o’clock at night, on a signal
given by cannon, the boats set out together, so as to be upon
the bank where the fishery takes place, at break of day, which
is the hour of commencement. Each bark is manned by

cc 2

388 SUPPLEMENT

twenty men, besides the master, ten of whom are rowers, and
ten divers. The latter, who are from infancy habituated to
this trade, and the most skilful of whom come from Colang,
on the coast of Malabar, and from the island of Manaar,
divide themselves into two bands, of five each, which dive
and rest alternately. Each man is provided with a net, in the
form of a sack, to put the pearl animals in, with a cord, to
which a stone is attached to facilitate his descent, and finally
with another cord, one extremity of which remains in the bark,
and of which he makes use to give notice that he wishes to
come up. At the moment when he is about to dive, he takes
between the toes of his right foot the cord with the stone,
between the others, the net, and seizes the cord of call with
his right hand, at the same time that he stops his nostrils with
the left. Arriving quickly at the bottom of the water, some-
times to the depth of from four to ten fathoms, he hooks the
net to his neck, and works with the right hand in plucking
away the shells, with which he fills the net. At the end of
two, and sometimes of four, five, or six minutes, which last,
however, is very rare, and depends upon the skill of the diver,
he gives the signal for ascent, with his cord of call, and is
drawn up by the men who remain in the bark. Each diver
can repeat this operation fifty times in the same day, bringing
up about fifty shells each time, but sometimes the blood will
stream from his nose and ears. The fishery continues thus
until noon, when a second discharge of cannon recals the
barks to the point of departure. There the proprietors of the
fishery, or the government, if it has reserved to itself the right,
cause the shells to be deposited in pits of one or two feet in
depth, or on mats, in square places, surrounded by palisades.
At the end of some time, when the animals are dead, which is
judged of by the opening of the shell, they search attentively
in the latter, and in the animal itself, that is, in the lobes
the mantle, sometimes even by boiling, for the free pearls,

;
©
&

\

ON ACEPHALA. 389

which may be found there. They choose, moreover, the finest
shells, most proper for the production of nacre, and leave the
rest. In spite of the pestilential exhalations which result
from such a considerable mass of dead mollusca, the poor of
the country come afterwards to glean what the rich by chance
may have left behind.

The free pearls thus obtained are then sifted and selected
carefully, and even drilled, and strung by negro workmen,
who are extremely adroit in this sort of operation. As to the
adherent pearls, they must be first detached and then rounded>
and polished at the place of their adherence, which is like-
wise done in the same country, by means of a powder, fur-
nished by the pearls themselves.

The commerce of pearls appears to be of the highest anti-
quity. History, in fact, apprizes us, that from time imme-
morial, the princes and princesses of the East have sought
after this kind of ornament with a sort of passion, and em-
ployed it in all parts of their dress, and even in instruments,
furniture, &c. The Persians, according to the report of
Athenzus, paid for pearls with their weight in gold. The
pearl mussels, therefore, must be like our common mussels,
which, in spite of the prodigious quantity which have been
eaten for so many ages, do not appear to suffer any sensible
diminution. It is, nevertheless, said that the Dutch having
fished too often on the coasts of Ceylon, the pearl fishery is
not now so lucrative in the hands of our government as it was
formerly.

We should hope that the facility for this business, given by
the invention of the diving bell, may not contribute to hasten
the destruction of those pearl-banks, but that it will be rather
employed to regulate the fishery still better than has hitherto
been done.

In Europe also a certain number of pearls are derived from
the Unio margaritifera, a large species, which is found in

390 SUPPLEMENT

the great rivers of the north, and in many lakes. Those of the
Tay, in Scotland, are in tolerable estimation.

From what we have said concerning the origin and nature
of pearls, it is evident that it must be very rare to find any
which possess all the requisite qualities, that is, great regu-
larity in form, whether that be round, oval, or pear-shaped ;
a fine water, or a tint white, lively, with brilliant reflections,
similar to those of the opal, which is called a fine Orient, and
finally, a considerable bulk. Accordingly, those which combine
all these qualities are of an excessive price, and it requires
some art in the jeweller to unite, in the formation of a neck-
lace, or any other ornament, pearls which are well matched
in size, and still more in tint or colour.

The irregular pearls are termed, in commercial language,
uneven, and those which are extremely small, and seldom
very regular, are called seed pearls.

The pearls of Europe, or the Union pearls, are sometimes
very fine and rather large. But the majority have little or no
brilliancy. They are found of all forms.

Pearls are of different colours; most generally they are
white and nacreous, but sometimes they are yellowish, or
greenish, or even livid or lead-coloured. Tavernier informs
us that he had six in his possession that were jet-black. It
is supposed that these colours are owing either to the pearl
having remained too long in the putrified animal, or perhaps
to the latter having lived in mud which was more or less
fetid. :

The jewellers sometimes make very large ones, but which
are composed of two knobs of pearl applied one upon the
other; these are only hemispherical tubercles, rounded, and
which have been taken from the interior of a pearly shell.

Pearls have the great disadvantage of changing, and being
deteriorated by time. They more especially alter quickly
when worn immediately upon the skin. They tarnish and

ON ACEPHALA. 391

lose their brilliancy. It has been proposed, for the purpose
of restoring them, to cause them to be swallowed by pigeons.
Supposing that the art of jewellery possessed no other means
than this, attention should be paid to prevent them from re-
maining too long in the crop of these birds, otherwise they
would soon diminish in bulk. Redi, who made this experi-
ment, informs us, that having caused a pigeon to swallow
twelve grains of pearl, they diminished one third in weight.
This author also relates, that on the opening of the tomb,
where the daughters of Stilicho had been interred, with all
their ornaments, eleven hundred and eighteen years before,
every thing was found in high preservation, except the pearls,
which were so brittle as to be very easily crushed with the
finger.

The genus PINNA approximates very much to that of the
mussels, the only difference of any import being in the thick-
ness and fineness of the byssus. In manners and habits they
are also very similar. ‘They live, as it would appear, con-
stantly fixed by their byssus, in a vertical position, the
summit of the shell being undermost, and the base, or pos-
terior extremity, uppermost. But it is particularly in a sandy,
or even muddy bottom, that they fix themselves in consider--
able troops, and by attaching the filaments of the byssus to
surrounding bodies, and even to grains of sand, so as easily
to resist the movements of the sea. ‘The ancients relate many
things respecting these animals, which have not been con-
firmed by modern observations ; among others, they tell us
that these mollusca have many enemies, the presence of which
is indicated to them by a small crustaceous animal, thence
named pinnothera, and which shelters itself in their shell.
The most common species exists in certain places in the
Mediterranean, at the depth of from five to six fathoms. The
inhabitants of Sicily and Calabria seek after them, not merely
for eating, like the mussels, but also to gather their byssus, of

13

392 SUPPLEMENT

which is manufactured in certain places, stuffs remarkable
for their suppleness and warmth. 'The fishermen, to procure
these pinnz, make use of a large kind of iron rake, called a
cramp, the teeth of which are a foot long, and the handle pro-
portioned to the depth of the water, where the shell-fish are
found. By dragging the rake strongly along, either by force of
arm, or with the assistance of the motion of the bark, which
carries the fishers, the pinna is tom away, the filaments of the
byssus breaking in some point of their length, nothing then
remains but to cut at their origin such as are long enough,
and to spin them when they have been dried, to form tissues
of different kinds, such as gloves, stockings, caps, and even
larger clothing. The filaments of this byssus being extremely
fine, of a perfect equality of diameter through their whole
extent, of very great strength, and of a very brilliant and un-
alterable reddish brown colour, they produce a stuff extremely
supple, smooth, warm, and solid, the colour of which never
changes. The ancients were acquainted with this sort of
stuff, and it is still made in certain parts of Calabria and
Sicily ; but its great dearness, resulting from the number of
pinne marine which are necessary to make even a pair of
‘gloves for example, has caused it to be scarcely any thing
more than an object of curiosity, and the number of families
that devote themselves to this sort of industry is diminishing
every day. Were it an object to continue this manufacture,
the best mode, perhaps, (and it has been proposed) would
be to form depots for the pinne, as has been done both for
oysters and mussels. By placing them in favourable cir-
cumstances, they might be made to multiply prodigiously,
and they might be gathered when they had attained the
requisite size.

The pinne are found in all the seas of warm climates, and

in the Mediterranean ; one alone has been found in the British
Channel.

— eC

ON ACEPHALA. 393

We now come to those well known animals the MUSSELs,
MyYTILvs, L.

The mussels do not appear to possess a greater general
or special sensibility than the other testaceous acephala ;
perhaps, indeed, their sense of touch may be less fine, in con-
sequence of the absence of tentacular filaments at the edges
of the mantle.

Their locomotion is nothing, or very trifling, according to
some observers, who even assert that the mussel never totally
changes place, and that the linguiform appendage of their ab-
dominal mass serves only to spin the different threads of the
byssus, or to place or fix these threads on submerged bodies.
According to Reaumur, on the contrary, the mussel can
change place when it has been accidentally detached by the
cutting of the fibres of the byssus. He tells us, that in the
saline marshes on the coasts of the ocean, where the fisher-
men throw the mussels at hazard, they are found at the end
of some time, united in packets. By putting them into glass
vessels, he observed that their mode of locomotion consisted in
drawing their linguiform appendage out of the shell, curving
it, hooking it to some bodies, and thus drawing themselves
towards the point of attachment. It is certain, that in ordi-
nary circumstances, the mussel does not change place, fixed
as itis by means of a greater or less number of its fibres, to
all the surrounding bodies of whatsoever nature they may be.
When we examine how this fixedness takes place, we find
that it is by agglutination, each fibre being often a little
widened at its extremity. The linguiform appendage of the
foot may also conduce to a similar purpose, and this organ,
(as has been ascertained by experiment) when cut off, will
sprout again.

The mussels undoubtedly feed upon very small animals,
or their spawn, as is proved by the property which they ac-

394 SUPPLEMENT

quire of being poisonous, when they have eaten that of the
asteriz.

It is certain that the mussels are hermaphrodites, like the
others of the same tribe; that is, all the individuals are
similar, or a single one constitutes the species.

The female product of generation does not come from the
mother in a perfect state. It is rejected in the form of a
gelatinous substance, in which are contained the germs of the
young mussels. The latter, no larger as yet than a grain of
millet, already have their byssus, which, most likely, is born
with them, and which, probably, serves to attach them, with
the assistance of the linguiform appendage of the mother.

The species of this genus live in assemblages, more or less
numerous, usually placed in a compact manner, one against
the other, fixed more or less solidly by their byssus, in an
oblique situation, the top of the shell being undermost and
behind ; the base, or broadest part of the shell, is uppermost,
the two valves being a little open. ‘Through this semi-aper-
ture, the fringe which edges the mantle comes out behind,
and the filaments of the byssus pass through the emargination
of the ventral edge.

Some species are thus placed at the superficies of bodies ;
others, in preference, seek the excavations which may exist
in such bodies. Finally, some species excavate a lodge for
themselves, like the other lithophagous bivalves. It also ap-
pears that some live sunk in mud, like the pinne. It is pro-
bable that they have a thicker byssus, contrary to the litho-
domous species, in which it is very small, and even does not
exist except in youth. As their shell closes exactly, they can
very well support the alternation of the flux and reflux upon
our coasts, and thus live during six hours out of the water,
but in general they are more constantly submerged.

Mussels are almost always found in salt, or at least in

~

ON ACEPHALA. 395

brackish waters. According to the observations of Adanson,
some species can remain six months of the year in salt water,
and the other six months in fresh. Moreover, it appears
certain that there are true mussels constantly existing in river
waters. One species, in fact, belongs to the Danube, and
another to the lakes of North America. M. Beudant suc-
ceeded in causing the common mussel to live in water alto-
gether fresh, by taking suitable precautions.

Mussels are to be found in all the zones of the earth,
whether frigid, temperate, or torrid. The identity of our
mussel with the mus of Aristotle, is allowed by all naturalists
and commentators.

The flesh of mussels, which is a sufficiently agreeable
food, though less so than that of oysters and certain species
of Venus, very often produces, not only serious, but even
very alarming symptoms of illness. ‘This would appear to
take place more in certain places, and at certain times of the
year than others. The symptoms produced by the hurtful
qualities of cooked mussels, are said to be an uneasiness, and
universal numbness which seize the body in about three or
four hours after the repast. ‘These are followed by a constric-
tion in the throat, a sensation of heat and swelling in the
whole head, and especially in the eyes, an inextinguishable
thirst, nausea, and sometimes vomiting. If the patient has
not the good fortune to vomit up altogether, or in part, the
mussels, the constriction of the throat, the swelling of the
face, of the lips, of the eyes, and of the tongue, increase to
such a degree as to render speech difficult. The colour of
these parts becomes so red, that they seem to be excoriated ;
it extends externally, first to the face, then to the neck, the
breast, the belly, and in fine, over the whole body. This
eruption is the most characteristic symptom of the malady.
It is constantly accompanied with delirium, a singular degree
of inquietude, an insupportable itching, and sometimes with a

396 SUPPLEMENT

great difficulty of respiration, as well as an extreme stiffness,
as in catalepsy. It cannot be compared to any other cutaneous
eruption. Although the skin is redder than in cutaneous
complaints generally, it is thickly sown with points of a still
deeper red, which are infinitely smaller than a grain of millet,
and which, viewed with the microscope, appear distinctly to
be the apertures, or pores of the skin, leaving the subjacent
tissue quite uncovered.

Sometimes, this malady is accompanied with nervous
phenomena, such as convulsions, spasms, and insupportable
pain. At other times the inflammation of the throat is so
great that gangrene supervenes.

Notwithstanding the alarming character of these symp-
toms, they are not so formidable as might be supposed, and if
suitable remedies are administered, the cure will be effected
in about three or four hours, though the numbness will some-
times last for several days. There have been instances of
persons who have suffered horribly for three or four days, and
even of some patients who died of this malady.

The cause of this singular disorder has been attributed to
the orange colour of the mussels, to their putrefaction, to their
leanness, to the phases of the moon, to a particular disease
of the animal, to the little animals which introduce them-
selves between its valves, and particularly to a small species
of crab of the genus pinnothera. But it would seem that
all these suppositions are erroneous; at least we are told
by M. de Beunie that the mussel never produces this effect
but when it feeds upon the spawn of the asterie. This
spawn, observed in the microscope, appears at first to be
nothing but a dead and formless mass of jelly; but after a
few days of hot weather, it appears living, and filled with
animalcules, which become developed and metamorphosed
into little asteriz. Itis from the end of April, or the beginning
of May, to the middle of July, or the commencement of

ON ACEPHALA. 397

August, that the asteriz spawn, which explains sufficiently a
vulgar opinion, that mussels are poisonous only during the
months into the name of which an 7 does not enter. This
spawn is so poisonous, so caustic, that, according to M. de
Beunie, it immediately causes swelling and inflammation,
with insupportable itching in the hand of the person who
touches it, and stiffens this part to such a degree, that it
appears ready to fall into a gangrene. But this accident is
followed by no evil consequences, especially if the part be
rubbed with vinegar.

It is not merely to man and quadrupeds that this spawn is
deleterious, it is also hurtful to some fishes, and among others,
to sturgeon, salmon, &c. ‘The little star-fish themselves are
equally poisonous, according to the experiments of M. de
Beunie. Several of these animals, raw, were wrapped up in
meat, and given to dogs and cats; these animals either died
in consequence, or were seriously ill, except when they were
made to swallow a quantity of vinegar, or when the star-fish
were cooked. ;

From all these considerations, M. de Beunie thinks that
the mussels owe their injurious quality to the spawn of the
asteriz, which is very abundant during the months of May,
June, July, and August, on the mussel-banks which are on
the coasts of Flanders, and, in fact, it was at this period
alone, that he witnessed the malady in question, especially at
Antwerp, where it appears more frequent, since every person
there, even down to infants of three years old, eats raw mussels.
He thinks, indeed, that cooking will remove this dangerous
property of these mollusca, which, however, unhappily, does
not appear to be the fact; at least M. Durondeau, a physician
of the same country, relates that he has seen this malady
constantly produced at Brussels by feeding on these animals.
He even cites examples of it in the months of April and
September, and in fact, in all the rest of the year; so that the

a

398 SUPPLEMENT

opinion of M. de Beunie does not appear to be divested of all
shade of doubt. It appears that this accident is more com-
mon in cold and humid countries, than in dry and warm
climates, and more prevalent in Flanders than elsewhere. We
know of no example of it reported by travellers on the coasts
of the Mediterranean. This may certainly be referrible to the
mussel-banks of Flanders being more in relation with the
asterie and their spawn, as being less deeply situated in the
sea. It must also depend a little on the idiosyncrasy, or
individual constitution, since, among many individuals who
have eaten of the same dish of mussels, and pretty nearly in
the same quantity, some experienced very serious effects,
while others suffered no inconvenience whatever. The cura-
tive means, however, are very simple. They consist in
making the patient vomit, with the assistance of ipecacuanha,
and then, after having recourse to a general bleeding, to make
him drink plentifully of some refreshing diluent, and three
ounces of vinegar, a little diluted with water, every hour.
Vinegar appears to be essentially the antidote to this poison.
Accordingly, all persons who have observed the effect, agree
that raw mussels are more dangerous than cooked, but that
they seldom cause any accidents, when, in either of those
states, they are seasoned with vinegar alone, or vinegar mixed
with pepper.

The mussels being a source of nutriment to the human
species, means have been sought to cause them to multiply,
and impart to them some qualities which they do not possess
habitually.

The fishing of mussels presents no great difficulty. Women
and children are usually employed in it, on the north coasts
of France. An indifferent knife is sufficient for the purpose,
and they gather the mussels, breaking the filaments of the
byssus, which attach them to submerged bodies, or to one
another. In places where the banks of mussels are open to

ON ACEPHALA. 399

sea, they are seldom very fine. They are much larger, and
even of a more delicate taste, when they come from banks
which are not uncovered, except at the great monthly or
annual tides. Notwithstanding the great destruction which
is made of them, the multiplication of mussels is so consider-
able, that no sensible diminution is observable on the coasts
above mentioned, and especially none in those which are not
continually explored.

On the coasts of the ocean more art and industry are exer-
cised than on those of the British Channel. There the
mussels are parked pretty nearly in the same manner as we
have already described the oysters to be. As it happens
with the latter genus of mollusca, it appears that the mussels
are rendered more tender, and the quality of their flesh is im-
proved, by putting them in places where the saltness of the
sea-water is tempered by rain or river-water. Pliny has made
the same observation respecting that species of bivalve which
he names myas, in saying that it was better in autumn, be-
cause a greater quantity of rain is then mingled with the sea-
water. Accordingly, on the coasts of the Atlantic, the fisher-
men throw into the saline marshes the mussels which they
have taken in the sea. In the port of Tarentum, in the
kingdom of Naples, in the month of March, long poles are
sunk into the mud, on which the spawn of the mussels is
fixed. In the month of August, a period at which they are
as large as almonds, the poles are transported to the mouth of
those streams, which fall into the gulf. In October, they are
replaced in the port, and it is only in spring that they are
eaten, although they have not yet arrived at their full growth.
In the neighbourhood of Rochelle, the mussels fished in the
sea, are deposited in sorts of ditches or ponds, to which they
give the name of bouchots *, and in which the salt-water is

* The literal meaning of the word bouchot, is a fishing-hurdle, or crawl.

400 SUPPLEMENT

stagnant, and where a greater or less quantity of fresh-water
can be introduced. These bouchots are formed with two
ranks of stakes, intertwisted with poles, and united so as to
form an angle, the summit of which is opposite to the sea.
They are placed on a muddy bottom of great depth at the
mouth of the Seine, and to the west of Aunis. The mussels
which are there attached, deposit their spawn, which is shel-
tered in the branches ofa sort of coralline which abounds
very much on the wood of the bouchots. At the end of some
months, part of the mussels are detached from among those
which are too much accumulated, and they are distributed in
such places as were unfurnished with them. To facilitate
their adherence, they are carefully engaged in the hurdle-
work, and even, for greater precaution, they are enveloped
with a net, without which they would be soon carried off by
the waves. The mussels multiply in these bouchots in the
proportion of ten to one in the same year. They are gathered
from the end of July, for more than six months, either at low
water, or by the assistance of a machine named acon*. The
product of these bouchots would be considerable, were it not
for the expense of repairing the wood, which has been gnawed
by the teredo since 1720, at which time this species of mol-
lusca was introduced by a vessel wrecked upon the coast.

Besides the human species, mussels have a great number of
other enemies ; many sea-birds detach them from their situa-
tion, by breaking the shell, and then feeding on them. Many
cephalous mollusca, and among others the turbo littoralis,
according to the observation of Reaumur, pierce the shell
with their proboscis, and suck the soft parts.

The fresh-water mussels, (ANODONTES) are, some of them,
very large, particularly the species called mytilus cygneus.
The heart of this animal is remarkably large, and the foot

* Acon, or accon, signifies a sort of flat-bottomed boat.

ON ACEPHALA. 401

composed of three layers of fibres, directed according to
length, breadth, and depth, imparts to the animal the faculty
of changing form in these three dimensions. The anodontes
are viviparous. ‘Thousands of young ones are frequently
found, in winter only, between the plates of each gill. They
may be seen distinctly with a good microscope, opening and
closing their shell. All the anodontes are fluviatile. When
they want to walk, they place their shell level, put out their
foot, and crawl something like snails. It has been said that
they swim by striking the water with their valves. They are
most commonly found sunk in mud, the aperture of the valves,
and the obtuse extremity which corresponds to the mouth,
directed upwards. They may serve as food, but are in no
kind of estimation.

There is nothing to induce us to mention the UNIO here,
except the circumstance of some of the species producing
pearls, on which we have already sufficiently enlarged. The
species are very numerous.

The mollusca of the genus CHAMA live attached to rocks,
like the oysters, by one of their valves, also to corals, and
even to other shell-animals. This often injures their develop-
ment, and renders it more or less irregular. They are fre-
quently found in numerous groups, pressed one upon the
other. They are thus cemented so strongly, that they cannot
_ be detached without breaking the shell. The adherent valve
assumes, like that of the anouriz, and oysters, to a certain
point the form of the bodies on which it reposes. It is
usually rather irregular, and much less coloured than the
other. From this mode of existence, we may easily conceive
that the chamz make but little use of their foot.

Almost all the CARDIA, to which we now pass, live in the
sea; a very small number of species inhabit the fresh-water.
Some of them remain remote from the coasts: but the majority
prefer sandy shores, where they remain concealed in the sand

von. XI. pd

402 SUPPLEMENT

at the depth of three or four inches. They come forth from
this retreat, re-enter it, raise themselves briskly, advance or
recede, by means of their long fleshy pedicle, which is move-
able in all ways, and capable of contraction and elongation,
in a variety of directions. If they are desirous of sinking in
the sand or mud, they elongate it, and make it penetrate as
much forward as they can, hook themselves by its extremity,
which they curve, then shorten it, and force the shell to ap-
proach its point, cutting the sand with the edge. To cause
it to spring back, they curve it into an arch, then straighten
it quickly, and thus raise the whole body with agility. The
same manceuvre enables them to raise themselves above the
soil with a sort of jump. It is easy, therefore, to conceive
how they can advance or recede by similar operations.

The cardia are found in all known seas. The species are
numerous, and the individuals exceedingly multiplied and
spread in very different latitudes. In many countries of
Europe, such as Italy, England, Holland, and the coasts of
France, a very great quantity of them are consumed. Their
flesh may not be very delicate, but it is, nevertheless, whole-
some and agreeable enough. Their abundance causes them
to be very cheap.

The Cardium rusticum is frequent on the maritime coasts
of the two Sicilies, where it lives sunk in sand, covered by
about fifteen feet of water. The fishery, which is prohibited
in summer, is made with an iron rake, with which the sand is
worked to discover these animals. But, though the flesh is
pretty good, none but the common people eat it. It is
dressed with oil, crumbs of bread, pepper, and aromatic
herbs. This species is equally found in the European At-
Jantic.

The Cardium edule, which is our common cockle, is fished
up in immense quantities during winter, on the coasts of
England, Ireland, and Holland, where they are used as food,

13

EEE

ON ACEPHALA. 403

during that season. According to Pali, those which are
consumed in Naples, are found in great abundance, sunk
in the mud of the lake Fusoza, which is partly fed by the
waters of the sea. Their flesh is good, but not very savoury.
The foot, if we are to believe Pali, is not of the same colour
all months of the year. In October it is whitish, in Decem-
ber and January it grows yellow, and afterwards becomes a
fine vermillion.

The CYCLADES are constantly found in fresh-water, and
have the habits and manners of Venus, of which we shall
treat presently. ‘They walk by means of the abdominal ap-
pendage, which is sometimes formed of a widened base, from
which arises an elongated, flagelliform appendage. They
live in mud, but not in a vertical position, and put forth their
tubes through the posterior part of the shell, a little open.

The mollusca of the genus VENUS are animals found in all
parts of the world. They constantly live on the sea coasts,
sunk in the sand, but at no great depth, so that they issue
forth easily, and can walk very well with the assistance of
their foot. Itis even said that they can jump, and as it were
vault, striking the interior of the water repeatedly with their
valves. ‘This same faculty has caused Palito name the whole
class of the bivalves, swbsilientia; but all are very far from
possessing it.

Very little is known concerning the habits and manners of
the venus, which cannot differ much from those of other
bivalves.

At different sea-ports these animals are eaten, and esteemed
a delicacy, instead of, and indeed preferably to, oysters.
The taste is stronger than that of oysters, and one must be
habituated to it to relish it.

The mollusca called SOLEN, all live at but small distances
from the shore, sunk vertically in the sand, the mouth under-
neath, and the anus upwards. The holes which they make

pd2

404 SUPPLEMENT -

there are never lined with a calcareous deposit, as in certain
neighbouring genera, the reason of which may be very well
conceived, as the mantle is entirely covered by the shell. The
movements of the solens are usually confined to an ascent or
descent in their hole, which is sometimes two feet in depth.
This movement is doubtless produced by the action of the
foot, which becomes attenuated at its extremity for the pur-
pose of descending, or being widened, assumes a resting point
from which to ascend, and cause the tube, and even a part of
the shell, to pass the orifice of the hole, at the surface of the
sand, and to rise more or less in the water which covers it.
It does not seem probable that the animal ever comes forth
altogether from this retreat of its own accord, though we can
very well conceive it possible that it should do so. But it is
certain, according to the observations of Reaumur and Adan-
son, that if by any cause it has been drawn out of it, it can
enter there again. The first of these observers has described
the mode in which the animal proceeds for this purpose.
Curving and sinking the extremity of its foot, it commences
by raising its shell more or less obliquely to the horizon;
then a new impulse, by straightening the foot, begins the
sinking of the shell, at the same time that it makes a still
shorter angle with the horizon. The same action renders it
vertical and alittle sunk. Then it extends its foot as directly
as possible, and giving it. the form of an angle, by then draw-
ing it back, the shell to which it is attached descends. By
repeating these motions, it sinks very quickly. The ascent,
on the contrary, is made by drawing back the foot strongly,
and widening it much; the resisting point is on the swell of
the foot, and the motion takes place in the shell upwards.
We know little more concerning the natural history of the
solens. Aristotle, however, tells us, that these animals seem
to hear, when a noise is made near them. The only ground
for this opinlon is, that if a sudden and somewhat loud noise

ON ACEPHALA, 4.05

be made near them, they will sink down into their holes. But
this may proceed simply from the immediate shock upon the
water, and on the cirri which terminate their tubes.

We are ignorant as to how the solens reproduce, and how
their germs, or eggs, are placed by the mother. Aristotle
maintains that they reproduce in the sand, which is conceiv-
able, if he means that the eggs are deposited, at a very small
depth, in the sand itself. The distinction found in Pliny,
and subsequently in Rondelet, and other writers of the same
era, of male and female solens, does not rest upon any thing
positive.

The ancient authors, and Pliny among others, tell us, that
the solens are essentially phosphoric. But this was, doubt-
less, because they comprehended under this name, animals of
the genera Pholas and Lithodoma, for Reaumur does not say
that the true solens possess this property.

The inhabitants of the coasts where the species of this
genus are to be found, proceed in search of them, either for
food, which, however, is only the case with the poorest sort of
people, or to use them as baits for the catching of certain
fish. It is when the sea is considerably withdrawn, especially
after high tides, that they are able to procure them in great
abundance, and with more facility. They recognize the
place where any are to be found, by a transverse aperture,
widened at each extremity in the form of a key-hole, above
the hole which they inhabit. To draw them out, which is
often rather difficult, the animal being sometimes sunk very
deeply, they throw some pinches of salt into the hole. The
salt produces such an irritating effect on the extremity of the
tube of the animal, that it immediately ascends out of the
hole to get rid of it; then it is seized, but still some address,
and quickness, more especially, are necessary, without which
the animal would re-enter as rapidly as it came forth, and
fresh pinches of salt would no longer produce the same effect

406 SUPPLEMENT

as the first. The animal, warned by the danger it had escaped,
would prefer suffering the irritating action of the salt, to the
certainty of being taken. Then the fisherman is obliged to
have recourse to a long iron crook, which he sinks pretty
deeply, and drawing it out obliquely, carries away the sand
and the solen contained in it. In some places an iron rod is
employed for the same purpose, terminated by a conical
button. The solens are the inhabitants of almost all known
seas.

The organization of the PHOLADES has scarcely any
thing to distinguish it from that of others of the same family,
but the particular disposition of the mantle, which is closed
in almost its entire extent, except in front, and underneath,
where it presents a very small and oval cleft, for the passage
of the foot. ‘They are all marine, and inhabitants of the
shores. It appears, however, that they can live in fresh-
water, for Adanson tells. us that he has found them in the
Niger, at a height to which the sea does not ascend. ‘They
live constantly buried, with the mouth and foot under, and
the tubes upwards, in argillaceous soils, or in calcareous stone,
so that all their locomotion consists in mounting or descend-
ing in their hole, that their tube may reach the water in which
they are immersed, a little above the bottom. They probably,
too, excavate their lodge. They are of the number of tere-
brant, or ithophagous mollusca, which last expression, though
almost consecrated by the usage of naturalists, is, nevertheless,
erroneous.

This is a convenient place to notice the opinions of writers,
in explanation of the modes by which these animals perforate
the substances in which they lodge. The complex denomina-
tion of Mthophagous, which signifies stone-eating, is em-
ployed in the natural history of several molluscous animals,
to designate the habit which they have of living more or less
deeply in the interior of stones and rocks, and not because

i

ON ACEPHALA. 407

they actually feed upon them. Lithophagous species are
found in almost all the families of the bivalves. The majority
live in our European seas, and especially in the waters
of the Mediterranean; yet, notwithstanding the facility of
observation, we are still ignorant of the process pursued by
these lithophagous animals, to penetrate thus into the interior
of the stones. Some persons have thought that it was only
when the stones were soft that this could be done, because, in
fact, the pholades are found in a sort of white soft argile,
which has been regarded as a sort of incipient stone. But
they are also found in the true lime-stone, more yielding and
softer, no doubt under the water, than when it is exposed to
the air. This opinion was supported by Reaumur, and by
Lafaille, of the Academy of Rochelle. M. Fleurian de Belle-
vue, who made his observations in the same places as the
last mentioned naturalist, was convinced that the pholades,
however small they may be, pierce the calcareous stone itself;
and M. de Blainville has seen, on the coasts of Normandy,
the same species of pholas in the clayey depositions of the
mouth of the Seine, and in the tolerably hard calcareous mass
of the chalk formation, which borders the sea for a great
portion of its extent. Moreover, pholades and lithophagous
mussels are sometimes found in marble on the coasts of the
Mediterranean. ‘The direction which the lithophagous mol-
lusca take, in the substance where they conceal themselves,
varies according to the genera. The pholades place them-
selves vertically ; but not so the Saxicava, and some approxi-
mating genera ; these animals pierce the stone in all directions,
so as sometimes to meet one another. If we should admit
that the pholades, whose shell is pretty thick, and furnished
with asperities at its anterior extremity, can excavate their
stony lodge, by mechanical means, in turning on themselves,
the thing is conceivable enough, because they are free. But
this can hardly be the case with others, which fill the cavity

4.08 : SUPPLEMENT

almost completely, so as to be unable to move there, an im-
possibility which is often augmented by a ridge of the stone,
which fills the furrow, formed by the crooks of the two valves.
When we add that these shells are often very smooth, and
that one species is so thin as to be merely membranaceous,
we are led to reject every idea of the possibility of motion,
whether of rotation or vibration, by means of which these
animals could file the stone to introduce themselves. We
must, therefore, have recourse to the theory of a corrosive, or
solvent fluid, which would act upon the stone, soften it, and
convert it into a sort of liquid, which the movement of the
foot of the animal would subsequently expel from the cavity.
But what is the organ of the animal producing this sort of
humour, and what is its nature? It is probable, according to
the opinion of M. de Bellevue, that it is the foot, or abdominal
appendage, which furnishes the greatest quantity. In the
pholades, this part constantly passes the coquillaceous enve-
lope. As to the nature of this liquid, the same observer is
induced to think that it must be an acid strong enough to
decompose the calcareous salt, of which the shell is formed,
but not sufficiently so to attack the animal matter, which also
enters into its composition. He has, in fact, observed that
when the rupellarie, which pierce the stone in all directions,
come to meet, they make an irregular wound, one in the shell
of the other, but without destroying the membranaceous part.
He has also observed that the pholades in their cavity are
bathed in a sort of black slime, tolerably abundant, which
even penetrates some distance into the substance of the stone,
when the latter is somewhat soft. He has made the same
observation on the other lithophagous mollusca, and even on
certain worms which also lodge in stones. This black slime
appears to be the result of the corrosive humour of the animal
mingled with the earthy matter of the stone. M. Fleurian
having, besides, observed that the pholades and modioli pos-

ON ACEPHALA. 409

sess the property of shedding a phosphoric light, appears in-
clined to believe that the fluid which serves the lithophagous
mollusca to soften and dissolve the calcareous stone in which
they lodge, contains a greater or less quantity of phosphoric
acid. Whatever probability may attach to this view of the
subject, it is far from being beyond the reach of doubt, the
more so, as it would seem, from Spallanzani, that pholades
are also lodged in rocks which are not calcareous, as, for in-
stance, in lava. A chemical analysis of this black liquor of
the pholades would be highly desirable, to ascertain whether
itis acid or not. That it is so, is not very probable, as the
patella, which excavate pretty deeply the calcareous stone
of the coasts of the Channel, where they live, have no trace of
acid in the humour which issues from their foot; so that it
appears a tenable opinion, that the excavations, more or less
deep, formed by the mollusca in stones, are owing to a simple,
constant maceration, produced by the mucous fluid which
issues from the foot. It is probable that it is the same way
with worms, which possess the same faculty; for though, un-
fortunately, we are as yet but very insufficiently acquainted
with them, we may nevertheless presume that their mouth
is not armed with organs or instruments by means of which
they could act mechanically upon the stone; were it so, they
would be no longer worms properly so called, but species of
the family of the mereides, and the problem would be less
difficult to solve.

The pholades present another singularity still more inex-
plicable than their mode of lodging in the stone. This is
their phosphorescence. It appears that there are few mol-
lusca which are so luminous; and it is said that persons who
eat them raw, and in an obscure or dark place, seem to be
swallowing phosphorus. No one appears to have attempted
any explanation of this phenomenon. The pholades feed,
probably, like others of the family, on small animals, which

410 SUPPLEMENT

the water brings to them by penetrating to the mantle.
Their reproduction, in all probability, is similar to that of
other bivalves. Their eggs, however, must be agglutinated
pretty near the parents, if not placed by the parents them-
selves; for the place occupied by the pholas candida, in
the horizontal banks of clay, appears to augment in every
direction.

Mankind use many species of this genus as food, and par-
ticularly on the coasts of the Mediterranean, where the largest
are found. It is even probable that the ancient Romans were
fonder of them than the moderns, which explains why the
columns of the temple of Jupiter Serapis, at Puzzuoli, are
pierced by phalades at a level, much superior to the actual
level of the sea; and in fact, it appears that it served as a
piscina, or reservoir for sea-fish, as was first remarked by M.
Desmarest, the elder. This goes fairly to overturn all the
hypotheses of geologists on this subject, for it seems very
probable that the pholades were placed there artificially.

Though the pholades are not considerably numerous in
species, it appears, nevertheless, that some exist in all seas.
It does not seem, though, that the Australasian expeditions
have brought any from that part of the world.

The manners and habits of the TEREDINES (vulgo ship-
worm) have been studied with considerable care, particu-
larly by the inhabitants of the sea-coasts, who have been
forced to construct dykes, to resist the invasions of these
animals. It is generally known that they live constantly
buried, pretty nearly vertically, with the head down, and the
anus upwards, in such pieces of wood as are constantly im-
merged most frequently in salt-water, but sometimes also in
brackish, and even in fresh-water, according to the observa-
tions of Adanson. The highest point at which they commence
to bury themselves, is always some feet below the lowest
waters, so as to be constantly immerged. By means of one

ON ACEPHALA. 411

of the tubes of their mantle, they let in, as far as the mouth,
and traversing the branchial cavity, the fluid which is to serve
at once for the purposes of nutrition and respiration, while,
through the other come the excrements, and the product of
generation. ‘This double movement is produced by the action
of certain organs, to which the name of palettes, or palmule,
has been given. ‘They vary in form in each species, but are
always similar to each other, and symmetrically placed, one
at each side of the extremity of the mantle. In the common
teredo, each is composed of a calcareous piece in the midst of
a membranaceous part. These palettes are opposed to each
other at their internal face, and, by being applied together,
can close the orifice of the hole which the animal inhabits,
after it has withdrawn the tubes of its mantle. These parts
therefore serve as kinds of opercula, but they cannot be better
compared than to the antenne of certain male insects. They
are, in fact, composed of a considerable number of calcareous
articulations. ‘The hole inhabited by the teredo commences
with an orifice extremely small, which is often even difficult
to perceive. Its beginning is always a little horizontal or
oblique, but beyond that point it curves, and becomes more or
less vertical or straight. The nature of the wood has a great
influence on the regularity, and the flexions of the canal, which
is hollowed in its interior. The neighbourhood of other
teredines exercises a still more manifest effect upon it. In
fact, they seem to endeavour to avoid each other, which some-
times produces very considerable flexions. The depth of the
holes is necessarily proportioned to the size of the teredo, and
to the duration of its life, which appears to be rather short
and rapid. But by what process does this animal, which,
very probably, is ovo-viviparous, and rejects the product of
generation, already provided with the shell, thus excavate
the hardest woods, and that in so very prompt a manner?
The form of the shell, so well adapted for boring and filing,

412 SUPPLEMENT

its solidity, the nature of the ligneous body, and the perfectly
smooth state of the hole which is excavated, will not permit
us to doubt that it is done by mechanical action, aided, how-
ever, by the maceration of the wood. It appears that the
thick adductor muscle, which passes from one valve to the
other, is in reality the power which puts the shell in play,
supports it at the bottom of the hole, and causes it to turn in
the wood like a real gimlet. ‘There is here no necessity to
have recourse to the presence of a solvent acid, which we
have already observed is so doubtful as to the other terebrat-
ing shells. The relation of cause and effect is too evident.
In proportion as the little animal grows, it excavates its hole,
which it also carpets in proportion as it goes on, with the
cretaceous exhalation of the parts of its body not covered by
the shell, and there buries itself until it has arrived at its full
size.

From the singular habits of the teredines, it is evident that
they must be very formidable animals to the human species,
for they very considerably hasten the ruin of all constructions
in wood, established in or near the sea, such as piles, dykes,
moles, barricades, and even vessels. Piles are in general
completely untouched by them, as far as they are discoverable
at the lowest sea; but from a certain point which is constantly
immerged, to a very considerable depth, the holes of the
teredines are so numerous, that the thickest piles give way to
the slightest efforts. Holland is the country where the results
of this are most fatal. Vessels have been known to spring
leaks in consequence of the holes made in them by teredines.
Means have been devised to obviate such serious accidents,
either in the selection of the wood, or in securing it from the
attacks of these animals. No European wood is certainly
secure against the terebrating action of these mollusca. It
has been asserted that there are some American timbers which
they will not attack, either in consequence of their hardness,

ON ACEPHALA. 413

or of some resinous gum which they contain; but what these
woods are, and even whether the assertion itself be true, are
points not ascertained. It is said that the previous carboniza-
tion of piles, to the depth of a few lines, will be sufficient to
protect them completely; but for vessels, the best method
undoubtedly is coppering the bottoms.

For the great injury done us by the teredines, there appears
to be some slight compensation. They are said to constitute
an article of food with some of the inhabitants of the coasts
of the Atlantic, and their flesh is reported to be very
delicate, and of a more agreeable flavour than that of the
oysters. It is probable, also, that they may have their use in
removing decayed vegetable matter, serving to somewhat the
same end at sea, as the éermites, and many other insects, do
by land.

According to Seba, who made his observations in Holland,
certain species of nereides are mortal enemies to the teredines,
penetrating into their tube and devouring them. ‘The species
of teredo appear to exist in all parts of the globe.

We now proceed to the second order of Acephala, or those
without shells.

The BIPHORES of the text, THALIA SALPA, &c., are
curiously constructed animals. ‘These gelatinous, transparent
mollusca, sometimes free, and sometimes united in long lines,
or cordons, like fire in consequence of their phosphorescent
quality, must long ago have attracted the attention of naviga-
tors. But it must have been somewhat difficult to form an
exact idea of them, in consequence of their remoteness from
ordinary conformation. Had they come under the inspection
of some ancient naturalist, which is very probable, they
would have been placed among the purgamenta maris, that
is, in the very numerous section, where old writers placed all
animals that do not come under the ordinary forms.

The Salpze float constantly immerged at variable depths in

414 SUPPLEMENT

the interior of the sea; but it appears that whether free or
aggregated, they can move, probably, without any determined
direction, by means of the water which they cause to enter
into their mantle for respiration and nutrition. ‘This water
penetrates through an aperture provided with lips and valvules,
and issues forth by an opposite one. ‘This alternative action
has been sometimes called systole, and diastole, and its result
is, that the body is carried in an inverse direction to that of
the rejected water.

We have no knowledge respecting the digestion of these
singular animals. Itis probable that it must be easy, in con-
sequence of the fluid form in which their nutriment is con-
veyed. It is not likely that some foreign bodies which are
often found in the cavity of their mantle are digested there ;
for this does not constitute their stomach. The function of
respiration takes place by the introduction of water into the
cavity of the mantle.

Circulation appears to be somewhat singular. The motions
of the heart are made spirally ; they take place by a twisting
of its parietes, and always begin from one of its extremities.
If it be that which touches the nucleus, a name given to the
little mass of the digestive apparatus, the motion of the blood
is made into the aorta, and into its principal ramifications ;
if it be the other, the march of the fluid proceeds in an oppo-
site direction. These motions of the heart are easily per-
ceived, first pushing the blood in one direction, stopping, con-
tracting, and then impelling it in an opposite direction. We
then see this fluid fall back, as it were, by its own proper
weight, and assuming a direction opposite to what it had at
first. But as the two systems of vessels which issue from the
heart communicate together, it happens, after a certain time,
that these sorts of oscillations send the blood into all parts of
the body.

These motions of the blood are more perceptible, as it is

ON ACEPHALA. 415

composed of small whitish lumps, visible through the parietes
of the vessels, sometimes of a reddish brown, and transparent.
These observations may be still more assisted, by holding the
animal vertically, with the nucleus downwards; then, as the
blood pushed into the aorta, is forced to ascend against its
own Weight, its march is much less rapid, and the movement
of the globules can be very well followed.

These animals are essentially marine, and are seldom found,
except in the high sea. It appears that they exist in all the
seas of warm climates, and even in the Mediterranean, on the
African coast. Farther northward they do not seem to be
found, or if so, they have been driven thither by currents or
tempests. They are sometimes found in great abundance in
the deep water, at a great distance from the shore, either
solitary, or united according to a particular method for each
Species, so as to form long cords or ribands, which float in a
serpentine manner at no great distance from the surface. It
is especially during the night that they are most perceptible,
in consequence of the phosphoric property with which they
are endowed to so high a degree. All navigators are agreed
upon this subject, and say that the salpze, when chained
together, produce the effect of long ribands of fire, drawn
along by the currents.

Although they really possess the locomotive faculty, it is
extremely probable that they are the sport of the waves and
winds, which drive them along in their own direction. ‘This
appears most likely with regard to the individuals which are
linked together.

Their nutriment, without doubt, is entirely animal, and
composed of animalcule, and even of the amorphous matter
which is found in such great abundance in the sea-water,
which traversing the cavity of their mantle, serves at once for
locomotion, nutrition, and respiration. The salpz are true
hermaphrodites. .

416 SUPPLEMENT

There are very great singularities in the product of genera-
tion, or the offspring of the salpez. It may be solitary, or
united with a great number of individuals similar to itself, the
union of which takes place in a constant manner by means of
those organs to which the name of suckers, or spiracula, has
been given.

The single or solitary foetuses appear considerably to differ
from the individual from which they come; so much so,
that according to Messrs. Quoy and Gaimard, without being
apprized of the fact, one might be disposed to set them down
as distinct species. They are suspended in the cavity of the
mantle by a sort of cord, which M. Chamisso names the um-
bilical cord. MM. Quoy and Gaimard also speak of a pedicle
attached to a sort of placenta, filled with mucous matter.

M. Chamisso informs us that the species of this genus pre-
sent themselves under a double form, a race entirely dissimilar
to the mother, during the whole course of its life, nevertheless.
producing young ones all similar to her, so that a salpa
which differs equally from its parent, and its own children,
resembles its grand-parent, its grand-children, and its own
brethren. In both states, the salpa is androgynous, or to
speak more correctly, female, and equally viviparous ; but in
one the product of generation is a solitary animal, and mul-
tiparous ; in the other, it is a stérps composed of individuals
united together in a determined manner, and oviparous.
Thus each species presents a solitary, and an aggregated
race, equally capable of reproduction.

Many animals of this genus produce eggs enchained toge-
ther, and from each egg comes an animal entirely similar to
its parents. But the solitary race, instead of eggs, produce
animals thus enchained, from each of which, as from an egg,
issues a solitary salpa, similar to the first mother; so that
we might say, that the solitary race is an animal, and the
enchained race is nothing but a mass of aggregated and living

ON ACEPHALA. 417

eggs. M. Chamisso discovers some analogy between this
singular disposition of the salpz, and the metamorphoses of
batracian reptiles and insects. What seems to confirm this
opinion is, that there are extremely important differences be-
tween the two forms of the same species of salpa, not only
in external conformation, but also in the disposition of the
muscles, and the position of the viscera.

In the solitary, and consequently multiparous individuals,
the body presents none of the appendages, or protuberances
which are proper to produce a junction. ‘The orifices are
terminal, the first bilabiate, with unequal lips, and the second
truncated. In the aggregated or uniparous races, there are in
different parts of the body appendages, protuberances, or
spines, by the assistance of which the individuals are linked
together in a determined order. All the individuals of one
and the same group are perfectly similar in bulk and length,
though they may differ much in these respects, in different
groups.

The mode of life in the ascidiz, very much resembles that
of oysters, to which they approximate also in internal organi-
zation. Most of the species have the habit of grouping to-
gether in numbers on the same body, where they remain fixed
all their lives. Sometimes the young are fixed and grow on
the body of the mother.

The ascidiz furnish an abundant nutriment to fish, and
even man feeds on several species. It is thought that they
place themselves, in preference, at a certain elevation on the
coasts, to escape becoming the prey of the former. Their
only mode of defence consists in shooting out the water con-
tained in their sac, through its two apertures, which is done
whenever they are touched. Some of them can squirt this
fluid to the height of three feet.

The little animals called BOTRYLLI, were for a long time
very imperfectly known. They were considered as belonging

VOL. XII. Ee

418 SUPPLEMENT ON ACEPHALA.

to the division of Zoophytes. They are most generally
grouped, either in a circle or ellipsis, sometimes pretty regu-
larly; but some are also found which may be said to be
scattered, two or three only being together. They have much
of the exterior of radiated animals.

In the curious compound genus called Pyrosoma, the
organization of each little animal composing the whole, has a
very great analogy with that of the salpz. In fact, we can
scarcely be assured even yet, that the pyrosomata may not be
young salpz, not yet adult, and which disunite themselves
later. According to the actual state of our information, the
pyrosomata form cylindrical masses, more or less elongated,
soft, gelatinous and bristling at their surface, with a great —
number of sorts of spines, or pointed tubercles, a little more
hard, or more cartilaginous than the rest. ‘These masses,
which float horizontally in the interior of the sea, are, doubt-
less, abandoned to its movements, and cannot resist them, nor
direct themselves. Accordingly, they are never to be met
with but in the open sea, and often in troops, composed of a
great number of these masses. Nothing can be more brilliant,
sparkling, and lively, than the phosphoric light which these
animals emit. They often form long trains of fire, from the
manner in which the masses are disposed in cordons. But a
more singular phenomenon attached to this phosphorescence,
is, that the colours vary instantaneously, passing rapidly from
the most lively red to the principal tints of the solar spectrum,
to the crimson of the morning, to orange, to greenish, to
azure-blue, and finally to an opaline yellow, when the mass
is, to all appearance, in a state of absolute repose.

SUPPLEMENT

ON THE

FIFTH CLASS OF THE MOLLUSCA.

THE BRACHIOPODA.

In the first genus of these bivalve mollusca, the animal has
altogether the form of the shell; that is, it resembles pretty
nearly a large claw, pointed at one extremity, widened at the
other, which is nearly straight, with a short, obtuse, and
middle point. The shell is moderately hollow, and is only
curved in the direction of its breadth. It is formed, like all
other shells, by imbricated strata from point to base. The
two valves are not completely similar. The upper differs
from the lower in having a sort of internal pad tolerably long
and projecting, which corresponds to an excavation of the
latter. At its base are two muscularimpressions. ‘The lower
is a little larger, and more pointed behind. It gives an at-
tachment to the tube, or ligament, in a small fossette, hollowed
at its external face.

The tube is very elastic, transparent, and striated trans-
versely through its entire extent. It adheres to the lower
valve by a thinner part. It is hollow in its entire length, and

Ee2

420 SUPPLEMENT

contains in its interior a soft pulpous body of the same form
as itself. ‘This does not appear to be contractile.

There is a considerable byssus of the same structure as that
of the mussels. It appears to proceed from the adductor
muscles, and not from the tube.

The body of the animal exactly fills the two valves of the
shell, and is so placed that one valve corresponds to the back,
and the other to the belly. °

Seen from above, the body presents a posterior or visceral
cavity, covered with a very thin, transparent membrane. In
raising this from the back, a sort of regular figure is per-
ceptible, anterior and surrounded with branchial lamine.
One altogether similar is on the other side.

The body, properly so called, is comprized between two
cutaneous laminz forming the mantle, whose whole circum-
ference, thicker and more evidently muscular, presents no
trace of papille or tentacula. This membrane is very thin,
and altogether adherent on the mass of the viscera, which it
allows to be seen in almost the entire posterior half of the
body. In all this half are the fasciculi of muscular fibres,
which pass from one valve to the other, and which are five
in number. From one of these seems to spring the byssus
just mentioned.

Beyond the first pair of muscles, the lobes of the mantle
are entirely free, as far as their adherence tothe trunk. Their
form is altogether that of the extremity of the shell. On their
internal face is a disposition evidently branchial.

On raising this part of the mantle from front to back, we
find the mouth and tentacular apparatus. The mouth is
very small, but quite visible, transverse, and at the extremity
of a sort of point or flatted nipple. There are really four ten-
tacula, to the first pair of which organs the name of arms has
been given, whence the denomination brachiopoda for the
class.

ON BRACHIOPODA. 491

In the anterior cavity are two orifices placed symmetrically
at the lower face of the upper lobe, in front of the mouth, and —
even of the tentacula. These two orifices appear similar,
one at the right, and the other at the left of a medial canal.
It seems not improbable that they are the termination of the
organs of generation. :

In the visceral cavity, on each side, externally to a granular
mass, which occupies all the interval of the muscles, is seen
from the point of the shell to the termination of the external
pair of muscles, a gelatinous body, pretty large, and thick.
This, in all probability, constitutes the ovaria. Another organ,
much smaller, is placed at the right side, and formed by kinds
of little leaves, joined by a common and longitudinal pedicle.
This may or may not belong to the generative system.

The rest of the visceral cavity is filled by a mass subdivided
into two, and as if composed of grains, which very probably
is the liver, and at one of the sides of which is a part of the
intestinal canal, which may be the rectum.

The heart seems to be placed at the middle of the anterior
part of the anterior visceral mass immediately behind the
middle pair of muscles.

This description of the anatomy of the lingula is taken
from M. de Blainville. The Baron’s view of its anatomy
differs in some points; but it is proper to observe that the
animal is but imperfectly known. There is but a single
species, which comes from the Indian Ocean, near the
Molucca Islands.

The TEREBRATULZ constitute a genus of mollusca, esta-
blished, and perfectly defined by Linnzus, under the name
of Anomia, but into which many unsuitable species were in-
troduced. The shell may be considered horizontal. The
valves are equilateral, but the under one is always the smallest.
The upper is generally more gibbous, and its constant cha-
racter is to have its top more or less elongated into a sort of

4.22 SUPPLEMENT

hook. ‘This hook is always perforated by a trench or furrow,
proportional to its length, and whose edges, in touching, ter-
minate the canal, which produces at the extremity a hole of
a form somewhat variable, whence this genus of shells has
received its name of Terebratula.

The shell appears to be doubled in extent by a mantle,
which must be very thin, as Pallas describes it under the
name of periosteum, As to the body itself of the animal, it
is contained altogether in a small part of the shell, pressed
against the summits, and sustained by the double forks, when
there are any. It appears that the belly is applied upon the
complex valve, and the back upwards; for it is not placed in
its shell, as is the body of the bivalves generally, one valve on
each side. The body of the terebratule is depressed or flatted
from bottom to top, and perfectly similar on the right and
left. What constitutes its greatest part is what is now named
its arm, and what were termed gills by Pallas. The mouth
is medial, and very large. The intestinal canal, which is
probably the stomach, of a compressed and conical form, re-
poses in the angular sac of the plane valve, where it receives
the esophagus. It is entirely surrounded be a certain black
matter, which is the liver.

The gills, or arms, (for authors differ on this point) form a
considerable fasciculus on each side, almost altogether behind
the abdominal mass. Each is composed, not only of a single
triangular ligula, very narrow, pinnate in its entire extent,
which, attached by its base on the sides of the mouth, would
turn and be free at its extremity, but also of a ligula longi-
tudinally pinnate, wider in the middle, and attenuated at the
extremities. This, attached by one extremity on each side, in
front of the mouth, after having gone backwards and under-
neath, reascends upwards, convoluting, directs itself anew
towards its origin, and, uniting itself in the middle line with
its fellow of the opposite side, forms a vaulted mass. All its

1 Mesodesma: solencides. 4Mescdesma sublriangutala.

2 Mes. denticulata: 5 Meara Chinensis.
3 Annatina eliplica. 6 Mesodesma’ ornata.

London: Published. by Whittaker &C° Ave Maria’ Lanes 1253

Vo fh MCZ LISRARY ere cate
4, | HARVARD Peden |

ON BRACHIOPODA. 4.23

external edge is furnished with flatted, triangular, and flexible
filaments, longer in the middle, and diminishing as they ap-
proach more to each extremity. Thus each branchial mass
forms in reality two planes placed one above the other, and
which, commencing at the mouth, finish very probably at the
anus. ‘These singular organs are very firm and solid, and
probably capable, by their movements, of partly opening the
shell, and coming out to a certain extent, not, however, in the
way of arms, which the animal would agitate externally to
attract the water for the purposes of nutrition and respiration.

The muscular apparatus of the terebratulz is not less re-
markable than their respiratory system. All the muscles sur-
round the visceral mass. Some even appear to belong to it,
and it is in their interstices that the intestines are situated,
while the largest proceed from one valve to another. Pallas
describes three pairs, but M. de Blainville could distinguish
clearly only two. The first, or most considerable, proceeds
from the bottom of the most convex valve, and is inserted
near the middle of the anterior edge of the flatted valve. The
other two, conical, proceed obliquely into the sinus of the
former. They are very probably the fibres of one of the more
internal muscles, which issue forth through the orifice of the
pierced valve, or rather attach themselves to the membrane
which closes its orifice; for it seems probable that the ad-
herence of the terebratule takes place by means of this mem-
brane, and not immediately through the muscular fibres.

We may observe, that, though the anatomy of these animals
is not completely known, yet, from all that we have now said
touching their organization, they seem to hold an intermediate
place between the lingula and the ordinary bivalves, perhaps
nearer to the latter. In fact, the gills are certainly not attached
to the mantle, and the mouth is not provided with extensible
labial appendages, as in the former ; but also, the gills are not
distinct from the labial appendages, and are, moreover, solid,

424 SUPPLEMENT

resisting, and perhaps even altogether mobile, instead of
being soft and flexible, as in the ordinary bivalves. All this
might lead us to form a distinct order or perhaps even a par-
ticular class of the terebratule.

The definition of this genus may be thus summed up.
Body oval, or rounded, compressed, horizontal, provided with
a double pair of gills, free, resistent, extensible, turned in the
form of a double comb, contained in a regular, dorso-ventral,
equilateral, and inequivalve shell ; the upper valve in general
longer, more gibbous, and lengthened into a top pierced with
a hole, or emarginated ; the lower, shorter, more flat, provided
internally with a system of support, or a very diversiform
apophysis; the hinge ginglymoid, composed of two tubercles,
or teeth, more or less separated, for each valve; no ligament ;
muscular impressions not apparent.

The terebratule, which are so extremely abundant in the

fossil state, have as yet been found but in a small number in
the living, probably because they remain fixed at tolerable
depths, to immoveable bodies, and more especially to rocks
that are always submerged. Accordingly, we know scarcely
any thing concerning their manners, and their organization,
but very imperfectly. We know, however, that some species
of them exist in all seas. They are, in fact, to be found at
the most remote points of the two hemispheres; that is, in the
Norwegian seas, and those of New Holland, as well as in the
seas of the warmest latitudes. Their habit of living fixed to
rocks, and as it would seem, to other bodies, will account for
the number of fossils to be found in this group of organized
bodies.

The last tribe of this class which we shall notice is that of
ORBICULA. ‘This was established by M. de Lamarck, on a
small shell of the northern seas, of which Miiller, and subse-
quently Gmelin, made a patella ; because, not having observed
the adherent valve, they took it for a univalve shell. The

ON BRACHIOPODA,. 425

genus may be thus characterized. Body very much com-
pressed, rounded ; the mantle open in its entire circumference ;
two tentacular ciliated appendages, as in lingula; shell orbi-
cular, very much compressed, inequilateral, or a little irre-
gular, very inequivalve, and without hinge properly so called ;
one very thin valve, more or less perforated by a fissure ; the
other patelloid, with a top more or less inclining towards the
posterior side; four muscular impressions on each valve, two
of which are larger, and more approximating to the centre ;
the others more separate, and more anterior.

These animals live in the northern seas, contained in the
excavations of rocks, whence they often assume rather an
irregular form, or they are often rooted by some fibres of the

central pair of adductor muscles, which traverse a fissure of
the flat valve.

SUPPLEMENT

ON THE

SIXTH CLASS OF THE MOLLUSCA.

THE CIRROPODA.

THE ANATIFA is a genus distinguished, as well as the
Balani, from all the other animals of this division, by articu-
lated and ciliated tentacula, ranged by pairs, to the number of
twenty or more, on each side of their body. ‘They were the
more deserving of forming a separate order, or class, as they
now stand, inasmuch as they approximate in many respects
to the articulated animals.

The name of anatifa is an abridgment of anatifera, and
owes its origin to a strange fable. Believing some analogy
to exist between the most extended species of the anatifa,
and the numerous wild ducks, or bernacles, which abound on
the maritime shores of the west and north of Europe, their
inhabitants imagined that it gave birth to these birds, and it
therefore received the name of anatifera, or bernacle.

The shell of the anatifera has the form of a flatted cone.
It is usually composed of five or seven principal valves, and
sometimes of a great number of small ones, for the most part
triangular, or trapezoid. These valves are not joined by
means of any hinge. ‘They hold together by means of the

SUPPLEMENT ON CIRROPODA. 427

mantle of the animal, which lines their interior, and opens
anteriorly by a longitudinal cleft, as in the bivalves. The
base of the shell is united to a fleshy tube more or less long,
fixed by its other extremity to the rocks, to the timber
of vessels, to fuci, to gorgons, and even to the sandy
bottom of maritime coasts. ‘This tube is composed of three
strata of fibres, of a circular form in the two external strata,
and much harder, and more consistent than in the internal
stratum. ‘The fibres of which this last is formed extend in a
parallel manner, from one extremity of the tube to the other.
It is by its base, or its posterior and inferior part, that the
body of the anatifa adheres to the tube. The mouth, placed
towards the middle of the belly, is directed forward, when the
animal extends itself out of its shell, and upwards when it is
folded back. It presents a very remarkable apparatus of
organs. Six parallel thin leaflets, of a form almost triangular,
denticulated at their lower edge, which is free, surround it
superiorly, and on a part of the sides. The two external
leaflets are attached a little to another organ, situated at the
inferior part of the mouth, hard, very projecting, of a triangular
form, and which much resembles a lower jaw. A pointed
proboscis, at the base of which a small aperture may be ob-
served, protected on each side by two triangular lamelle,
terminates the upper extremity. Between it and the mouth,
are, on each side, five or six trunks, which support an equal
number of pairs of tentacula, of a corneous substance, whose
length augments in proportion as they are removed from the
mouth, composed of numerous articulations, ciliated and
curved forwards. ‘The animal puts them forth from its shell
and agitates them at every instant. It cannot be doubted,
that it endeavours by this manceuvre to attract towards its
mouth the alimentary corpuscula. It has an intestinal canal,
which runs along the back, and ascends towards the pro-
boscis, and two tubes winding at its sides, which hold the

428 SUPPLEMENT

place of testicles. 'The ovaries are towards the base of the
body. We sometimes find between this base and the mantle,
an immense quantity of eggs, forming a thick stratum of
yellowish matter, which covers the back of the animal. The
gills are little conical leaflets, of a soft substance, attached to
the base of the tentacula in such a manner, that there are as
many pairs of threads as there are pairs of tentacula. But
these threads are directed in a contrary way, that is, towards
the back, and inclined against the body under the mantle.
The nervous system likewise presents some peculiarities.
The brain is situated cross-wise on the mouth. Four nerves
repair to the muscles which border this organ, and to the
stomach. ‘Two other cords embrace the cesophagus, approxi-
mate to form a ganglion, and then rise, pressed one against
the other between the tentacula, each pair of which receives
a nervous filament detached from the principal cord, without
forming any enlargement.

We have purposely entered into some detail respecting
the organization of the anatife, because it presents many
peculiarities, when compared with that of the other mollusca.
Those concerning the nervous system, and the gills, are taken
from the Comparative Anatomy of M. Cuvier.

Fixed by its fleshy tube, and unable to move but by the
elongation and contraction of this tube, and by its flexion in
all directions, the anatifa presents but little that is remarkable
in the history of its manners. The medium in which it is
immersed, is filled with substances, which serve it as aliment.
This was necessary for its preservation, since it is incapaci-
tated to go in search of food. To obtainit, it is sufficient that
the animal should determine towards its mouth, a current of
the surrounding fluid, by means of its multiplied arms.

Most of the species live in groups of fifteen or twenty, more
or less. They prefer such situations as are beaten by the
waves, and when attached to the keel of a vessel they

ON CIRROPODA. 429

place themselves at some inches from the line of water, and
especially near the helm.

The PoLLIcIPEs, which now forms a subgenus of anatifa,
derives its name, as is said, from the resemblance which the
ancients imagined they could perceive between it and the
nail of the thumb, or the great toe. A strong, thick, and short
tube, of a conical form, shagreened, as it were, by a great
number of little valves which cover it, and five large valves,
constitute the character of the species on which this sub-
genus is founded. Its individuals are found united in groups
of twenty, or more, of different size, in the Mediterranean, on
the coasts of Spain, Normandy, Brittany, &c. They serve
for food in many countries, after having been boiled in water.
A notion has even been entertained that they are aphrodisiac.
Their flesh, according to Rondelet, becomes red by boiling,
like that of the lobster.

The lepas aurita, or leporina, is our author’s subgenus
Otton. This species has a very remarkable conformation.
The tube is dilated into a coriaceous sac, which contains the
animal. Five very small valves are, as it were, dispersed
over the surface of this sac, which has two appendages
formed like an ear at the superior and posterior part. It has
been found in several of the European seas.

The BALANI have also been named sea-acorns, from some
sort of resemblance to the fruit of the oak. They are mol-
lusca which have the greatest analogy with the anatifee ; ac-
cordingly Linneus united them together under the same
generic name, notwithstanding the great differences existing
in their envelope. We observe in the balani, as in the
anatifee, twelve pairs of articulated tentacule, a transparent
tube between the bases of the two most elevated pairs; a
mouth similarly placed both in one and the other, and also
surrounded by analogous organs; and an internal organiza-
tion absolutely similar in all that is essential. The eggs, as

430 SUPPLEMENT

in anatifse, are placed at certain periods in the folds of the
mantle. The latter is formed of an extremely thin membrane,
which lines the interior of the shell, and in which wind in-
numerable vessels. 'Two appendages of this membrane,
placed on each side of the animal, in which is remarked a
wide canal, filled with a lacteal humour, which ramifies into
a body fringed with a purple colour, form, according to Poli,
the gills of the balani. We have some difficulty in believing
that they differ so much from those of anatifee, which we have
just described after the Baron Cuvier. Four teeth arranged
in pairs, one above the other, and surrounded by an equal
number of crustaceous palpi, bristling with sete, arm the
mouth externally. The intestinal canal makes the circum-
ference of the body, reascends behind towards the base of the
proboscis, and terminates in this place, by an oval aperture, at
the bottom of which the heart may be seen to beat. It is also
towards the proboscis that we discover the small end of the
testicles, which are two claviform sacs placed on each side of
the body. They are continued with a canal which winds into
the proboscis, which Poli has observed filled with a whitish
and opake fluid, similar to that contained in the testicles, and
from which the same fluid trickled, when he compressed the
latter. The same author thinks that the fecundation of the
eggs takes place out of the body, by means of the proboscis,
which inclines downwards, to shed on them the spermatic
fluid.

The shell of the balani has, in the majority of species, an
oval or rounded form, which gives it some resemblance to an
acorn. From thence the generic denomination under which
they are described. Six valves, which touch each other by

their base, and separate towards their summit, essentially

compose this shell. But a single species is known in which

there are but three valves. The interval which they leave

between these and their summit, is filled with testaceous
13

ON CIRROPODA. 431

laminz, of which the furrows, canaliculations or striz, are
usually in a direction opposite to those of the first. They hold
together by the teeth of their edge, which are fastened one in
the other, or by a scaly suture. Their structure is sometimes
tubular, and very remarkable. ‘They rest, in the greater num-
ber of species, on a base of the same nature, more or less
thick, flatted, or hollowed, which holds strongly to the bodies
on which the animal has the habit of fixing. This base is of
a coriaceous nature in a small number; sometimes it appears
to be wanting altogether. Finally, an operculum, usually
pyramidal, and formed of two or four valves, closes the
superior aperture. It is raised, or lowered, by five different
muscles, and holds to the valves by a tendinous membrane,
ample enough to permit the play of the muscles. The form
of the valves, that of the operculum, and of the base itself,
vary in the different species. The majority of the balani
unite, like the anatifee, in groups more or less numerous, in
which individuals of all sizes are to be met with. Frequently
this agglomeration does not allow all of them to be equally
developed, and hinders the sheli from assuming its natural
figure. The lepas testudinaria, or balanus of the tortoise,
and that which lives parasitically on the whale, are the only
species which are isolated. Some of them are to be found in
all the known seas, and many are extended through very re-
mote latitudes. ‘Their fecundity is almost beyond what ima-
gination can conceive. They lay their eggs in summer, and
the little ones which issue from them are filled at the end of
four months, according to the observation of Poli, with similar
eggs ready to disclose. Their manceuvres to draw to them
their nutriment are the same as those of the anatife. They
raise their operculum at every moment, put forth their arms,
move them with great swiftness, and draw them in with equal
velocity. This is always done on the approach of the
slightest danger. The ancients were of opinion that they

432 SUPPLEMENT

hooked themselves more firmly to the rocks when it was at-
tempted to pluck them away; and the difficulty thus ex-
perienced, has served Aristophanes as a comparison to express
that of detaching an old woman from a young man, with
whom she is in love. The balani serve as food in many
places.

We shall conclude by briefly noticing a few of the principal
species, just premising, that they constitute subgenera in the
text, and will be found named in the notes.

The lepas balanus has a conical shell, with six valves,
furrowed longitudinally, and marked transversely with fine
strie. The operculum terminates in a curved point. It is of
a yellow colour, the valves of a pale rose, and the furrows
whitish. These last are united by teeth, which are fastened
one in the other; and a similar mode of articulation unites
them to the base, which is very thick, and pierced with
several ranks of quadrangular cells, which communicate to-
gether. Some canals hollowed longitudinally on the internal
face of the valves abound with the most superficial of the
cells which surround the base. This remarkable structure,
which is far from being the same in all the species, has been
described with much detail by Poli. The animal presents no
particularity. It lives in numerous groups, fixed to rocks, to
shells, and other marine bodies, in the Mediterranean and
the Atlantic, on the coasts of England, Holland, and Green-
land.

The lepas balanoides has a truncated shell, with six smooth
valves, rose-colour, marked in their length with purple lines.
This species is more rare, says Poli, in the Mediterranean,
than the preceding. Fabricius has found it much more fre-
quently on the coasts of Greenland. It is also to be found on —
our coasts, and those of Holland, united in groups intermixed
with those of the preceding species.

The lepas tintinnabulum has a shell with six valves, rose

ON CIRROPODA. 433

coloured, and spotted with white ; the aperture is quadran-
gular, and the operculum prismatic. The largest individuals
are usually an inch and a quarter in height. They are found
agglomerated in great numbers on the rocks, on shells, zoo-
phytes, and other marine bodies in the Mediterranean, the
European Atlantic, the coasts of the Island of Amboyna, and
those of Jamaica. Rumphius relates that the Chinese make
of these animals a delicate viand, prepared with salt and
vinegar. ‘They are red, and grow white by boiling. ‘Their
taste is similar to that of our lobster. This species attaches
itself, in preference, to vessels, the course of which it some-
times slackens, by accumulating there in innumerable quan-
tities.

The lepas spongites, has a base hollowed in the form ofa
chalice, the structure of which is spongy. It is pierced with
many longitudinal series of pores, and embraced by six
triangular valves, of a purple colour, and wrinkled trans-
versely. The least effort is sufficient to disunite them. This
balanus remains fixed by its base in the cellules of the softest
sponges. It is found in the common sponge of the Medi-
terranean.

The lepas diadema (not the subgenus DIADEMA of the
text), is vulgarly termed the whale-louse. The shell is almost
conical, with six valves marked externally, with three or four
raised ribs forming a sort of cone, in relief, on each valve.
The membranous operculum opens anteriorly, and is provided
at its posterior part with two small testaceous teeth. A hori-
zontal partition, pierced in the centre, divides the shell into
two cavities, one superior, which contains the animal; the
other, inferior, divided into eighteen principal cellules, by
testaceous lamella, which are fixed, as well as the circum-
ference of the valves, on the skin of the whale. Fabricius
has seen, in the largest individuals of this species, some small
membranous sacs come out through the orifice of the cellules.

VOL. XII. Ff

434 SUPPLEMENT ON CIRROPODA.

Each of these little sacs enclosed an embryo, which per-
fectly resembled the adult animal. ‘The latter does not ap-
pear to differ from other species of balani. It fixes itself, in
preference, in the furrows of the chest, and near the pectoral
fins of the balena boops, L. Its whiteness, similar to that of
ivory, causes it to be easily recognized by the whale-fishers.
It withdraws promptly into its shell when it perceives the
harpoon, and produces on the skin of the whale a sensation,
which, in the opinion of Fabricius, may serve to give it timely
warning of the danger with which it is menaced. If this
observation, made by an eye witness, be exact, we cannot
help thinking it somewhat singular, that an animal provided
with good eyes should be warned more tardily of the approach
of a body, than one which possesses no means of information
but from the touch alone.

FOURTH AND LAST GRAND DIVISION

OF

ANIMALS.

THE ZOOPHYTES, OR ANIMALIA RADIATA,

COMPREHEND a considerable number of beings whose or-
ganization, always manifestly more simple than that of the
three preceding divisions, also exhibits more gradations, and
seems to be constant only in this point, that the parts are
disposed round an axis, and on two or several radii, or on two
or several lines, proceeding from one pole to the other. ‘The
intestinal worms themselves, have at least two tendinous
lines, or two nervous filaments, proceeding from a collar
around their mouth. Several among them have four suckers
round a prominence, in the form of a proboscis ; in a word, in
spite of some irregularities, and with very few exceptions,
(such as the planaria, and most of the infusoria) we always
discover some traces of the radiating form, very much marked
in the great majority of these animals, and especially in the
asteriz, the echini, the acalephe, and the innumerable polypi.

The nervous system is never very evident; when any
traces of it have been at all discoverable, they were also dis-
posed in radii; but most frequently there is not the slightest
appearance of it.

Nor is there ever any true system of circulation. The

a

436 FOURTH GRAND DIVISION.

holothuriz have two vascular apparatus ; one attached to the
intestines, and corresponding to the organs of respiration ;
the other serving only to fill the organs which occupy the
place of feet. This last alone is distinctly seen in the echini
and asteriz. We can see through the gelatinous substance of
the medusz, some canals, more or less complicated, which pro-
ceed from the intestinal cavity. All this indicates no possi-
bility of a general circulation ; and in the great majority of
zoophytes, it is easy to convince one’s self that there are no
vessels of any kind.

Some genera, such as the holothurie, the echini, and seve-
ral intestinal worms, have a mouth, and an anus, with a dis-
tinct intestinal canal; others have an intestinal sac, but with
only a single opening, representing both mouth and anus.
In the greater number, there is nothing but a cavity, hollowed
in the substance itself of the body, which sometimes opens by
several suckers. Finally, there are many in which no mouth
is perceptible, and which can only be, nourished by the
absorption of their pores.

The distinction of sex is observable in several intestinal
worms. ‘The greater number of the other zoophytes are her-
maphrodite and oviparous; many have no genital organs, and
are reproduced by buds, or by division.

The composite animals, of which we have already observed
some traces among the last of the mollusca, are greatly mul-
tiplied in certain orders of the zoophytes, and their aggrega-
tions form trunks and expansions of every sort of figure. This
circumstance, united to the simplicity of organization in the
majority of species, and to that radiating disposition of the
organs, which reminds us of the petals of plants, has obtained
for them the name of zoophytes or animal plants, by which
these apparent relations only are meant to be indicated ; for
the zoophytes, possessing sensibility, voluntary motion, and
nourished for the most part, on matters which they swallow,

THE ZOOPHYTES, OR ANIMALIA RADIATA. 437

or suck, and digest in an interior cavity, are assuredly animals
in every sense of the word.

The greater or less degree of complication of the zoophytes
has given occasion to their division into classes; but as we
are not yet perfectly acquainted with all the parts of their
organization, these classes cannot be characterized with as
much precision as those of the preceding divisions.

The echini, and asteriz, to which the spines that they are
usually furnished with, have caused Bruguiéres to apply the
name of ECHINODERMATA, have a distinct intestine, floating
in a large cavity, and accompanied with several other organs
for generation, for respiration, and for a partial circulation,
It has been found necessary to unite to them the holothuriz,
which have an analogous internal organization, perhaps even
still more complicated, although they have no moveable spines
on the skin.

The INTESTINAL WoRMsS, which form the second class,
have no very evident vessels in which a distinct circulation
might be carried on, nor separate organs of respiration ; their
body is, in general, elongated or depressed, and their organs
disposed longitudinally. ‘The differences in their nutritive
system will probably cause them one day to be divided into
two classes, which we already indicate by establishing two
orders. In fact, in some there is an alimentary canal sus-
pended in a true abdominal cavity, which is wanting in the
others.

The third class comprehends the ACALEPH2, or sea-nettles.
They also have neither true circulating vessels, nor organs of
respiration. Their form is generally circular, and radiating,
and the mouth almost always serves as anus. They differ
from the polypi only in a greater development in the tissue
of their organs. The hydrostatic acalephe, which we leave
at the end of this class, may, probably, at some future
time, constitute a separate one when they shall be better

438 CLASS ECHINODERMATA.

known; but it is only by conjecture that we can judge of the
functions of their singular organs.

The Potyrt, which compose the fourth class, are all those
little gelatinous animals, whose mouth, surrounded with ten-
tacula, conducts into a stomach, sometimes simple, sometimes
followed by intestines in the form of vessels. It is in this
class that those innumerable composite animals are found,
with a fixed and solid stem, which for a long time were re-
garded as marine plants.

It is customary to place subsequently to them the thethyz,
and sponges, although no polypi have yet been discovered in
them.

Finally, the INFUSORIA, or fifth and last class of the
zoophytes, are those little beings which have been discovered
only by the microscope, and which swarm in stagnant waters.
The majority of them present nothing but a gelatinous body,
without viscera. Nevertheless, we have at their head some
more complex species, possessing visible organs of motion,
and a stomach. Of these, too, in all probability, at some
future day, a separate class will be formed.

THIRD CLASS OF THE ZOOPHYTES.

THE ECHINODERMATA.

THE Echinodermata are as yet the most complicated animals
of this division. Invested with a well organized skin, often
supported by a sort of skeleton, and armed with points, or
with articulated and mobile spines, they have an interior

ORDER PEDICELLATA. 439

cavity, in which distinct viscera are floating. A sort of vascu-
lar system, which, in truth, does not extend to the whole
body, keeps up a communication with divers parts of the
intestine, and with the organs of respiration, which, most
generally, are also very distinct. We even observe in several
species, some filaments which might perform the nervous
functions, but which are never distributed with the regularity,
and in the fixed order, which exists in the other two divisions
of invertebrata.

We divide the echinodermata into two orders: those which
have feet, or at least vesicular organs, to which this name has
been given, and those which are destitute of them.

FIRST ORDER OF ECHINODERMATA.

THE PEDICELLATA

ARE distinguished by organs of motions altogether peculiar.
Their envelope is pierced by a great number of small holes,
placed in very regular series, through which pass some cylin-
drical, membranaceous tentacula, terminated each by a small
disk, which performs the office of a cupper. ‘The part of
these tentacula which remains in the interior of the body is
vesicular. A fluid is spread through all their cavity, and is
carried, at the will of the animal, into the external cylindrical
part, which it extends, or it re-enters into the internal vesi-
cular part, and then the external part sinks in. It is by
elongating and contracting in this manner, their hundreds of
little feet, or tentacula, and fixing them by the cuppers, which

440 CLASS ECHINODERMATA.

terminate them, that these animals execute their progressive
movements. Some vessels proceeding from these little feet,
repair to the trunks, which correspond to their ranges, and
which end at the mouth. ‘They form a system distinct from
that of the intestinal vessels which are observed in some
species,

Linnzus makes of these animals three genera, very natural,
but sufficiently numerous, and comprehending species suffi-
ciently varied to be considered as three families.

ASTERIAS, L. Vulg6, Sea-stars, or Star-fish.

Have received this name, because their body is divided into
radii, most frequently five in number, at the centre of which,
underneath, is the mouth, which at the same time serves
as anus.

The frame-work of their body is composed of small osseous
pieces, variously combined, the arrangement of which would
merit investigation, They have a very great power of repro-
duction, and not only reproduce the radii, which have been
taken away separately, but a single ray with the centre being
preserved can reproduce the others, which is the cause that
we so frequently find them irregular.

In the

ASTERIAS, Lam.,

Or Asterias, properly so called, each ray has, underneath, a
longitudinal furrow, on the sides of which are pierced all the
little holes which allow the feet to pass. The rest of the in-
ferior surface is provided with small mobile spines; the entire
surface is also pierced with pores, which allow some tubes
much smaller than the feet to pass, which probably serve to
absorb the water, and to introduce it into the general cavity
for a kind of respiration. On the middle of the body, a little
towards the side, is a small stony plate, to which corresponds

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internally, a canal filled with calcareous matter, which is
believed to contribute to the growth of the solid parts. In-
ternally, is seen a large stomach immediately upon the mouth,
from which proceed, for each ray, two cceca, ramified like
trees, and each suspended to a sort of mesentery. There are
also two ovaries in each ray, and it appears that the asterie
fecundate themselves. A peculiar vascular system corres-
ponds to their intestine, and there is another for the feet.

M. Tiedemann considers as their nervous system, a very
fine filament which surrounds the mouth, and sends a branch
to each arm, which proceeds externally between the feet, and
gives forth two ramuscula internally.

Their osseous frame-work consists principally, for each
branch, in a sort of column predominating along the inferior
face, composed of vertebre, articulated one with the other,
and from which proceed the cartilaginous branches, which
support the external envelope. Between the roots of these
branches are the holes through which the feet pass. Other
osseous pieces, to which mobile spines are frequently attached,
furnish, in many species, the lateral edges of the branches.

Certain asteriz have the form of a pentagon, with rectili-
near sides, rather than that of astar. The radiation is marked
externally only by the sulcus of the feet. (Asterias dis-
coidea, Lam.)

Others have, on each side of the pentagon, a slight re-
entrant angle. (Asterias membranacea, Link.)

In others, the sides are concave, which begins to give them
the figure of a star. (Asterias tessalata, Lam., &c.)

In these different species, the coeca and the ovaries are not
as much elongated as in the majority of the others, which
have their radii elongated, and separated by well marked
re-entrant angles.

Such are

Ast. rubens, L. Encyc. cxili. 1, 2. which is exceedingly

4.4.2 CLASS ECHINODERMATA.

common on all our coasts, so much so, that in some places it
is employed to manure the grounds.

Ast. glacialis, L. Link. xxxviii. 69. Encyc. cvii. and cviii.
is frequently more than a foot in diameter; the spines which
invest the upper part of its body are surrounded with a mul-
titude of little fleshy tubes, which form sorts of cushions
around their bases.

Ast. aurantiaca, L. Link. vi. vii. xxiii. Encyc. cx. Echin.
pl. iv. 1., is our largest species. The edges of its branches
are furnished with pieces, like mosaic work, on which some
strong mobile spines are articulated. All the upper part is
covered with some other small spines, terminating in truncated
and bristling heads.

Some have a number of rays above five. Their ceca and
ovaries are very short. (Ast. paposa, Link.)

We must separate from the other asteriz, the species in
which the rays have no longitudinal furrows underneath, for
the purpose of lodging the feet; in general, these rays are
not hollow, and the stomach is not prolonged into cceca, but
its prominences remain in their intervals. Locomotion is
effected principally by the curving and the movement of the
radii, and not by the feet, which are too few in number.

M. de Lamarck names Ophiures those which have round
a central disk five radii not branched. But we should still
distinguish

Those in which these radii are furnished on each side, with
mobile spines. The small fleshy feet also issue forth on each
side from between the basis of these spines. (Ast. nigra,
Miill., &c.)

And those in which the radii, having no lateral spines, but
being furnished with imbricated scales, resemble the tails of
serpents. The central disk, has, in each interval of the rays,
on the side where the mouth is, four holes which penetrate
into the interior, and serve, perhaps, for respiration, or, ac-

ORDER PEDICELLATA. 443

cording to others for the issue of the eggs. There are no feet,
except in five short furrows, which form a star around the
mouth. (Ast. ophiwra, Lin., &c.)

The GORGONOCEPHALA, Leach, named Euryale, by M.
de Lamarck, are those in which the radii are divided into a
double point. There are some in which this division com-
mences from the base of the radii, and which present the
appearance of a parcel of serpents. They have been vulgarly
named heads of Medusa. The base of each ray has two
penetrating holes. (Asterias caput Meduse, &c.)

But there are also some in which the division commences
only at the end of the ray, and is but little repeated. (Huryale
palmiferum, Lam.)

We should still separate from the other asteriz

The ALEcTO of Leach, which M. de Lamarck calls Coma-
tula. ‘They have five large articulated radii, divided each
into two or three, which support two ranges of articulated
filaments. These five radii are attached to a stony disk
which again supports, on the side opposite to the mouth, one,
two, or three ranges of other articulated filaments without
branches, shorter and thinner than the large radii, and which,
it is said, enable them to hook themselves to bodies. The
sac which contains the viscera is at the centre of the large
radii, opened by a star-formed mouth, and another tubular
orifice, which may be the anus. (Asterias multiradiata, &c.)

It is near the comatule that we should place

ENCRINUS, Guett.,

Which may be defined to be comatule, with a disk prolonged
into a stem divided into a great number of articulations.
Their branches themselves are articulated, and divided into
pairs of branches, supporting a range of filaments, all articu-
lated, and the stem itself supports some smaller ones, at

444 CLASS ECHINODERMATA.

various heights. In the centre of the radii is the mouth, and
the anus on one side.

There is in the seas of Europe but one very small species,
Pentacrinus Europeus, Thomson, Monogr., which is attached
to divers lithophytes.

The seas of the warmer climates produce larger and more
complex species, such as Hncr. asterias, Blum., Isis aster.,
Linn.

But the fossil encrini are very numerous, and vary suffi-
ciently in detail to be divided into several subgenera, ac-
cording to the composition of the central body, placed at
the summit of the stem, and from which the large radii
proceed.

This body may be formed of pieces articulated with the
stem, and supporting radii by similar articulations. Then if
the stem is round and enlarged at the top, these are the
APIOCRINITES, Mill.

If it is round, but not enlarged, the ENCRINITES,

If it is pentagonal, the PENTACRINITES.

Or this body may be formed of angular laminz, joined
together by their edges, and forming several ranges.

Among those 5

The PLATYCRINITES have but two ranges, one of three
lamine, the others of five.

The POTERIOCRINITES have three ranges, each of five
plates.

The CYATHOCRINITES have also three, each of five, but
the last has some intercalary laminz, which may increase it
even up to ten.

The ACTINOCRINITES have several ranges, the first of
three, the second of five, the others more numerous. The
first two have radiated crests.

The RHopocrINITES have also several ranges, the first

ORDER PEDICELLATA. 445

of three, the second of five, the third of ten, all three with
crests; then follow some with more numerous lamine.

Finally, the central body may be all of one piece, but
which appears to be composed of five cemented together.
These are the EUGENIACRINITES.

The fossil productions, known under the name of Entrochi,
are pieces of the stem and of the branches of animals of this
genus.

EcHINUS, Lin. Vulgo Sea urchins.

Have the body clothed with a testa, or calcareous crust, com-
posed of angular pieces, which join exactly, and are pierced
with several very regular ranges of innumerable small holes,
through which pass the membranous feet. The surface of
this crust is armed with spines articulated on little tubercles,
and moveable at the will of the animal, to whose motions they
administer, conjointly with the feet, which are situated be-
tween them. Other membranous tubes, much finer, and
often divided at their extremity, probably serve to introduce
and to expel the water which fills the interior of their shell.
The mouth is furnished with five teeth, enchased in a very
complicated calcareous frame- work, resembling a lantern with
five panes, furnished with divers muscles, and suspended in a
large aperture of the testa. These teeth, in the form of long
bands, grow hard towards their root, in proportion as they
are worn at the point. The intestine is very long, aud at-
tached spirally to the interior parietes of the testa by a mesen-
tery. A double vascular system runs along this canal, and
extends partly over the mesentery, and there are also particu-
lar vessels for the feet. Five ovaries situated around the anus
empty themselves each by a particular orifice. They form
the eatable part of these animals.

The echini subsist more especially on small testacea, which
they seize with their feet. Their motions are very slow.

446 CLASS ECHINODERMATA.

Their teste are preserved in great abundance in ancient
strata, especially those of the chalk formation, when they are
usually filled with silex.
The echini should be divided into regular and irregular.
The regular

ECHINI, (properly so called) Zam. C1pDaRtIs, Klein.

Have the testa generally spheroidal, the mouth at the middle
of their inferior face, and the anus precisely opposite. The
little holes are ranged there on six bands approximated by
pairs, which proceed regularly from the mouth to the anus,
like the meridians of a globe.

Certain species have large and thick prickles of very various
forms, supported on thick tubercles of the testa, and the bases
of which are surrounded with other smaller prickles. (Echinus
mamillatus, L., &c.)

It is among these species that are ranged, as M. de Luc
has discovered, those whose prickles, in the form of olives,
are frequently found petrified in chalk or other ancient forma-
tions, and have received the name of Judaic stones.

The most common species, and especially those of our
coasts, have only slender spines, articulated on small tuber-
cles, much more numerous. Such is

Ecuinus Escuxentus, L., Klein., Lesk., I. A. B,,
Encye. 132.

Of the form and size of an apple, all covered with short,
striped tubercles, usually of a violet colour. Its ovaries are
eaten in spring uncooked, they are reddish, and of a flavour
sufficiently agreeable.

The neighbouring species are difficult enough to dis-
tinguish, being marked by the greater or less approximation
of the bands of holes, by the equality or inequality of the
tubercles, &c. (Heh. miliaris, Kl., &c. &c. &c.)

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ORDER PEDICELLATA. 44.7

Some round and depressed echini lose something of their
regularity by a wide sulcus, with which they are furrowed on
one side. (Ech. sinuatus, KI.)

There are also some of these echini with mouth and anus
opposite, which, instead of having the spheroidal form on a
circular plane, are transversely oval, that is to say, one of
their horizontal diameters is larger than the others. (Ech.
lucunter, K1.)

They also differ among themselves by the equality or in-
equality of the prickles, and by the relative proportions of the
tubercles.

One species should be distinguished,—Echinus atratus,
L. Encyc. 140. 1—4, in which the prickles, widened, trun-
cated, and angular at their extremity, touch each other there,
like pavement. Those of the margin are long and flatted.

We call irregular, all the echini in which the anus is not
opposite to the mouth. It appears that they are furnished only
with short and slender prickles, almost like hairs. Among
them some still have the mouth at the middle of the base.
They may be subdivided, according to the extent of the bands
of holes for the feet. Sometimes these go, as in the preceding,
from the mouth to a point directly opposite, or they unite
after having embraced the entire testa. In the former, the

ECHINONE, Phelsum and Leske,

Have the round or oval form of certain regular echini, the
mouth at the middle of the base, and the anus between the
mouth and the margin, or near the margin, but underneath ;
oval species, Echinus cyclostomus, Miill., &c. ; round species,
Ech. depressus, Walch, &c.

NUCLEOLITES, Lin.,

Have, with these characters, the anus near the margin, but
above.

448 CLASS ECHINODERMATA.

The known species are all fossil. (Spatangus depressus,
Leske.)

Others,

GALERITES, Lam. CONULUS, K1.,

Have a flat base, on which their body is raised like a cone, or
a semi-ellipsoid figure. The mouth is at the middle of the
base, and the anus near its margin.

They are very common in rocky strata, but no living species
are known.

The most extended is Ech. vulgaris, L. Encyc. 153. 6—7.
Klem. Ed. Fr. VII. D. G.

Some have not their bands of holes distributed in the
quinary number. Ech. quadrifasciatus, Walch, &c.

SCUTELLA, Lam.,

Have the anus between the mouth and the margin, the testa
exceedingly depressed, flat underneath, and of a form ap-
proaching to orbicular.

Some have it entire, and without any other holes than the
series of little pores which are seen in all the echini.

Others have the testa equally, without large holes, but
divided by two emarginations. (Hchinus auritus, Seb., &c.)

Others have it entire, and pierced from interval to interval,
by some large holes which do not penetrate into its cavity.
(Echinus hexaporus, Seb., &c.)

Others have it at once emarginated, and pierced with three
large holes. (Echinus tetraporus, Seb.)

There are some, in fine, RoTULH, KJ., in which a part of
the posterior margin is festooned, like a dentated wheel, and
these are divided according as they have large holes. (Kch.
decadactylus, Encyc.;) or according as they want them,
(Echinus orbiculus, Encyc.)

CASSIDULUS, Lam.,
Are oval, and have the anus above the margin, like the

ORDER PEDICELLATA. 449

nucleolites, but they are distinguished by their incomplete
bands of pores, that is to say, not proceeding from one pole
to the other, and figuring a star. (Casstdulus Caribeorum,
Lam.)

Other irregular echini have not the mouth at the centre of
their base, but it is towards one side, often transversely, and
directed obliquely. The anus is towards the other side.
They are subdivided according to the extent of their ranges
of holes.

Thus the ANANCHITES, Lam., GALE, Kl., have a littie
the form of the Galerites, and their complete bands, their
greatest difference, consists in the position of the mouth.
They are only known in the fossil state. Such is

Ecuinus Ovatus, L., Cuv. et Brong.
(Envir. de Paris, 2d. edit. f. v. 7. A. B. C. D.)

A species extended in innumerable quantities in the chalk
formations of our environs.

Some have four bands. (Ech. quadriradiatus, K).)

We may make a particular subgenus of certain species, in
which the four lateral bands are disposed by pairs, and do not
rejoin at the same point. (Kch. bicordatus, K1.)

At other times these irregular echini, with central mouth,
have bands of pores which do not lead to the mouth, but
which form on their back a sort of rose. Such are

CLYPEASTER, Lam. ECHINANTHUS, Klein.,

Which have the anus near the margin, and whose body is
depressed, with oval base concave underneath. They have
sometimes the contour alittle angular. (Hch. rosaceus, and
its varieties, K/.)

Sometimes their back is elevated in the middle. (Hehinus
altus.)

VoL. XU. Gg

450 CLASS ECHINODERMATA.

There are some also whose contour is not angular. (Ech.
oviformis, Seb.)

And even where it is almost orbicular. (LAGANUM, Klein.
Echinus orbiculatus.)

FIBULARIA, Lam. ECHINOCYAMUS, Leske.,

Have, with the rose of the clypeaster, the body almost globu-
lar, and the mouth and anus approximated in the middle of
the under part. They are usually very small. (Hcehinus
nucleus, Kl., &c.)

On the contrary, SPATANGUS, K/., have, with the lateral
mouth of the ananchites, some incomplete bands of pores,
forming a rose on the back. There are usually but four ; that
which is directed from the side of the mouth is obliterated.

Some, BRESSOIDES, Kl., have the testa oval, without
furrows. (Ech. teres, Seb.)

Others have a large sulcus more or less marked, in the
direction of the obliterated band. (Ech. spatangus, Seb., &c.)

When, besides this, they preserve the oval form, they are
Brissus, Kl., but sometimes this sulcus grows deep, and
the testa widening at the same time on this side, assumes

the figure of a heart. (Ech. purpureus, Miill, &c.)
We have some in our seas of the last two forms. Branched
tentacula, like those of the holothurie, have been observed
round the mouth.

HoLoruurRia,, Lin.,

Have the body oblong, coriaceous, and open at the two ends.
At the anterior extremity is the mouth, surrounded by very
complicated branched tentacula, which can be completely
retracted. At the opposite extremity opens a cloaca, where
terminate the rectum and the organ of respiration, in the
form of a hollow tree, very much ramified, which is filled with

ORDER PEDICELLATA. 451

water, or emptied at the will of the animal. ‘The mouth has
no teeth, and is furnished only with a circle of osseous pieces.
Some appendages, in the form of pouches, pour a saliva into
it. The intestine is very long, diversely plicated, and at-
tached to the sides of the body by a mesentery. A sort of
partial circulation takes place in a very complicated double
system of vessels, exclusively relative to the intestinal canal,
and in a part of the meshes of which, is interlaced one of the
two respiratory trees of which we have just spoken. There
also appears to be a nervous cord, but very much attenuated,
around the cesophagus. The ovary is composed of a multi-
tude of blind vessels, partly branched, which all terminate at
the mouth by a small common oviduct. They assume, at
the time of gestation, a prodigious extension, and are then
filled with a red matter, which appears to be the eggs.
Some cords, of an extreme sensibility, attached near the
anus, and which are developed at the same time, appear to
be the male organs. ‘These animals must, then, be herma-
phrodites. When they are disturbed, they frequently contract
themselves with so much force that they tear and vomit up
their intestines’.

The holothuriz may be divided according to the distribu-
tion of their feet.

In some, they are all situated in the middle of the under
part of the body, which forms a softer disk, on which the
animal crawls, elevating the two extremities where the mouth
and anus are placed, which they contract more than the
middle. The anus finishes almost in a point. ‘Their tenta-
cula are very large when developed.

We have one in our seas whose envelope is almost scaly,
Hol. phantapus, L. Miill., Zool., Dan. cxii. cxili. Mem.

1 For the anatomy of Holothuriz, consult M. Tiedemann’s excellent
work already referred to.

G

09

452 ., CLASS ECHINODERMATA.

de Stok., 1767. The feet of its central disk are on three
series.

Others have the inferior face altogether flat and soft, fur-
nished with an infinity of feet, and the superior face gibbous,
supported frequently by osseous scales, and pierced on the
front, with a star-like orifice, which is the mouth, and from
which the tentacula issue; and on the back part with a round
hole, which is the anus.

We have a small one, Hol. squamata, Miill., Zool., Dan.
x. 1,2,3,; but there are some of these of a tolerable size in
the warmer seas.

Others have the body cartilaginous, flatted horizontally ;
trenchant at the edges; the mouth and feet at the inferior
face, and the anus at the posterior extremity.

Such is in the Mediterranean,

Pudendum regale, Fab., Column, Aquat. xxvi. 1. Hol.
regalis, Nob., a species more than a foot in length, three or
four inches broad, and crenulated all round.

Others, again, have the body cylindrical, susceptible of
enlargement in every direction by the absorption of water ;
all the under part furnished with feet, and the rest of the
surface variously bristled.

Our seas, especially the Mediterranean, produce in great
abundance one of blackish colour, which is more than a foot
long in its greatest extension. Its back is bristled with
conical and soft points; its mouth is furnished with twenty
branched tentacula; it is the Holothuria tremula, Gm.,
Bohatch., Anim. mar. vi. and vii.

Some are found in which the feet are distributed in five
series, which extend like the ribs of a melon, from the
mouth to the anus, which has caused them to be called sea-
cucumbers.

Such is in our seas.

Hol. frondosa, L. Gunner, Mem. de Stok. 1767. pl. iv. f. 1,

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2. and cxxiv. The body is brown, and a foot or more in
length.

Finally, there are some whose body is equally furnished
with feet all round. (Hol. papillosa, &c.)

THE SECOND ORDER OF ECHINODERMATA,

OR

ECHINODERMATA APEDICELLATA,

COMPREHEND but a small number of animals, which pre-
sent great relations with the holothuriz, but which want the
small vesicular feet of the preceding order. Their body is
clothed with a coriaceous skin, and without armature. Their
internal organization is not yet cleared up on all points.

MoLpaDIA, Cuv.,

Have, like the holothuriz, a coriaceous body, in the form of a
thick cylinder, open at the two ends, and their internal or-
ganization is pretty similar to that of those animals; but,
besides that they want feet; their mouth has no tentacula,
and is furnished with an apparatus of osseous pieces, less
complicated, however, than that of the echini.

I know but a single species belonging to the Atlantic
Ocean, the extremity of whose anus is finished in a point.
(Molpadia holothurioides, Cuv.)

MINYAS, Cuv.,
Have also the body without feet, and open at the two ends ;

but its form is that of a spheroid depressed at the poles, and
furrowed like amelon. Ican find no armature to the mouth.

4.54. CLASS ECHINODERMATA,

There is a very fine species of a deep blue, in the Atlantic
ocean. (Mynias cyanea, Cuv., Rég., An. iv. pl. xv. f. 8.)

PRIAPULUS, Lam.,

Have a cylindrical body, marked transversely with deep
annular wrinkles, terminated in front by an elliptical mass,
slightly wrinkled longitudinally; pierced with the mouth, and
behind with the anus, from which issues a thick bundle of
filaments, which may be the organs of generation. ‘The in-
terior of the mouth is furnished with a great number of very
sharp corneous teeth, placed like a quincunx, and directed
backwards; the intestine goes straight from the mouth to the
anus ; the muscular system resembles that of the holothurie.

We are acquainted with but a single species from the north
seas, Holothuria priapus, L. Miill., Zool., Dan. xcvi. 1. two
or three inches in length,

LITHODERMIS, Cuv.,

Have the body oval, compressed behind, and the surface is as
it were incrusted with a stratum of small stony grains, which
form a very hard crust. The mouth is surrounded with ten-
tacula, and the intestines appear to have resemblances to those
of the holothuriz. I do not find any anus.

We know but a single species from the Indies, Lithod.
cuneus, Cuv., blackish, two inches in length.

SIPONCULUS, Gm.,

Have a cylindrical elongated body, with a thick skin, wrinkled
in both directions; the mouth at an extremity in the form of
a proboscis, which may be retracted or put forth, by means
of large interior muscles, and the anus more or less near the
base of this proboscis. The intestine originates from the
mouth, proceeds as far as the opposite extremity, and re-
turns, convoluting spirally round its first part. We find
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Zs

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eg
4

1 Minyas cyanea

2 Prapila caudata (7. priapus Mult)
3 Stipunculus edulis.

4 Sip. figrinus.

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ORDER APEDICELLATA. 455

nothing in it but sand and fragments of shells. Numerous
vessels appear to unite it to the external envelope, and there
is, moreover, along one of their sides, a filament which may
be nervous. Two long pouches situated in front, have their
external orifices a little under the anus, and internally, near
this last orifice, is sometimes seen a packet of branched
vessels, which may appertain to the respiratory function.

These animals remain in sand under the sea water, like the
arenicole, thalassema, &c., and they are sought after like
those, for the purpose of being used as bait.

There are several species of them as yet but badly dis-
tinguished.

One of them, Sip. edulis, Nob., Lumbricus edulis, Gm.,
Pall., Spic., Zool. x 1. 7. serves as food for the Chinese who
inhabit Java, and who go to seek for it in the sand, with little
bamboo sticks prepared for the purpose.

Others, sufficiently small, Sip. levis, Sip. verrucosus Cuv.,
pierce the submarine stones, and lodge in their cavities.

BoNELLIA, Rolando,

Have the body oval, a proboscis formed of a plicated lamina,
susceptible of an extreme elongation, and forked at its ex-
tremity. The anus is at the opposite extremity of the body ;
the intestine is very long, replicated several times, and near
the anus are two ramified organs, which may serve for respir-
ation ; the eggs are contained in an oblong sac, which has its
issue near the base of the proboscis.

These animals live deeply in the sand, and protrude their
proboscis as far as the water, and even sometimes into the
air itself, when the water is low.

We have one species in the Mediterranean, Bonellia
viridis, Rol. Ac. de Tur. t. xxvi. pl. xiv.

456 CLASS ECHINODERMATA.

THALASSEMA, Cuwv.,

Have the body oval, or oblong, and the proboscis in the form
of a plicated lamina, or small spoon, but not forked. But one
abdominal filament is discoverable.

We distinguish

THALASSEMA, (properly so called,)

Which have only two hooks placed very much in front, and
the posterior extremity has no sete. (Zhalassema neptunt,
Gertner, &c.)

ECHIURUS,

Whose posterior extremity is furnished with some transverse
ranges of setz.

One is known, lumbricus echiurus, Gm., Pall., miscell. Zool.
xi. 1—6, which inhabits our coasts, on the sandy bottoms. It
serves as bait to fishermen.

STERNASPIS, Otto,

Which, beside the sete of echiurus, have under the anterior
part, a disk, a little corneous, surrounded with ciliz. (Tha-
lassema scutatum, Ranz., &c.)

SECOND CLASS OF ZOOPHYTES.

INTESTINA, ENTOZOA, Rudolphi,

Have, for the most part, this peculiarity, that they are unable
to live, or to propagate, except in the interior of the body of
other animals. There is almost no animal that does not
nourish several kinds of them, and those which are observed

Zoophytes Fl. 1.

1 Bonellia’ viridis.
2 Thalassema’ nepluni |Z. thalassima Fav) i!
3 Echiurus Lallasit. Guer (L.echiurus Gv, i
4 Sternaspis thalasstmoides Olto. Mi

London; Published by Whittaker k& 62 Ave’ MartaLane1933.

ORDER INTESTINA. 457

in one species but rarely extend to many other species. They
are not only found in the alimentary canal, and the canals
which conduct thither, such as the hepatic vessels, but even
in the cellular tissue, and in the parenchyma of the best en-
veloped viscera, such as the liver and the brain.

The difficulty of conceiving how they get into such places,
joined to the observation that they never appear out of living
bodies, has caused some naturalists to imagine that they en-
gender spontaneously. It is now, however, quite certain,
not only that the majority manifestly produce eggs, or living
young ones, but that many of them have separate sexes, and
couple like ordinary animals. We may then believe that
they propagate by germs, sufficiently small to be transmitted
through the narrowest passages, or that frequently the animals
in which they live bring the germs into the world with
them.

We discover in the intestinal worms, neither trachez nor
gills, nor any other organ of respiration, and they must re-
ceive the influence of oxygen through the medium of the
animals which they inhabit. They present no trace of a true
circulation, and only vestiges of nerves, so obscure, that
several naturalists have doubted their existence.

When these characters are found united in an animal, with
a form similar to that of this class, we range it here, although
it does not inhabit the interior of another species.

Every one knows to what an extent the intestinal worms
injure the animals in which they are too much multiplied.
Against those of the alimentary canal many remedies are em-
ployed, of which the most efficacious appears to be animal oil,
&c., mixed with oil of turpentine.

We divide them into two orders, perhaps sufficiently dif-
ferent in organization to form two classes, if adequate obser-
vation could affix their limits.

458 CLASS ECHINODERMATA.

INTESTINA CAVITARIA. (ENTOZOA NEMATOIDEA, Rud.,)

Which have an intestinal canal floating in a distinct abdo-
minal cavity, and a mouth and anus.

INTESTINA PARENCHYMATA,

Whose body encloses, in its parenchyma, some viscera, but
imperfectly terminated, and most frequently resembling vas-
cular ramifications, even sometimes being not at all per-
ceptible.

THE FIRST ORDER OF INTESTINA.

CAVITARIA. NEMATOIDEA, Rudolphi,

COMPREHEND those whose external skin, more or less fur-
nished with muscular fibres, and in general striated trans-
versely, contains an abdominal cavity, in which floats a dis-
tinct intestinal canal, proceeding from the mouth to the anus,
and where also are,generally observed some distinct organs for
the two sexes. The intestine is united to the neighbouring
parts, and to the general envelope by numerous filaments, in
which some have imagined that they discovered nutritive
vessels, others trachez, but without any proof. It is impos-
sible to observe in these animals any true circulation, but
there appears to be in many, one or two nervous cords, pro-
ceeding from a ring which surrounds the mouth, and running
the entire length of the body, on the internal face of the
envelope.

The intestine is generally straight, and tolerably broad ;
the cesophagus is frequently more slender, and in some species
we remark a stomach more ample and more robust. The

ORDER INTESTINA. 459

internal organs of generation consist in very long vessels, con-
taining the semen, or the eggs, and having their issue at dif-
ferent points according to the genera.

FILARIA, L.,

Have the body elongated and slender, in the form of a thread,
pierced in front with a round mouth. Externally they very
much resemble the gordius. They are principally found in
the cavities of animals, which have no external issue in the
cellular substance, and even in the thickness of the muscles,
and the parenchyma of the viscera. They are sometimes in
parcels, and in innumerable quantities, enveloped in sorts of
capsules. ‘They are even found in insects, and in their larve,
and in the visceral cavity of several of the mollusca.

The most celebrated species of this genus is,

Filaria Medinensis, Gm. Encyc. xxix. 3. (Vulg. Guinea-
Worm.) Very common in warm climates, where it insinuates
itself under the human skin, principally in the legs, and is
sometimes developed there, to the length of ten feet and more,
if we may credit the accounts of some writers. It can subsist
there for several years, without causing any very lively sensa-
tions ; but it also sometimes produces very dreadful pains and
convulsions, according to the parts which it attacks. When
it shows itself externally, it is seized, and drawn out very
slowly, for fear of breaking it. It is as thick as the quill of a
pigeon’s feather. Its distinctive character is to have the end
of the tail pointed and hooked.

TRICHOCEPHALUS,

Have the body round, thicker behind, and as slender as a
thread in front. This slender part is terminated by a round
mouth.

The most known is,

Trich. dispar. Rud. Goetz. vi. 1—5. Encyc. xxxiii. 1—4.

460 CLASS ECHINODERMATA.

One or two inches in length, of which the thick part occupies
only one third. In the male this part is convoluted spirally,
and a small penis is visible, which comes out near the tail.
In the female it is straighter, and simply pierced at the ex-
tremity.

It is one of the most common worms in the large intestines
of man, and multiplies beyond measure in certain disorders.

From the trichocephali have been distinguished,

TRICHOSTOMUS, Rus. CAPILLARIA, Zeder.,

The anterior part of which grows slender only by degrees ;
and the

OxyYuRIS, Rud.,

In which it is the posterior part of the body which is atten-
uated in the form of a thread.

A species is known belonging to the ccecum of the horse,
Oxyuris curvula, Rud. Getz. vi. 8. Encyc. xxxiii. 5., from
one to three inches in length.

CUCULLANUS,

Have the body round, more slender behind ; the head blunt,
invested with a sort of little hood, often striated ; the mouth
round.

These have hitherto been found only in fish. The most
common is that of the perch. C. lacustris, Gm. Goetz. ix.
A. 3. Encyc. xxxi. 6., which also infests the pike, &c. It is
viviparous, about an inch in length, of the thickness of a
thread, and appears to be red, in consequence of the blood
with which its intestine is usually filled.

OPHIOSTOMUS,

With the body of the preceding, are distinguished by a mouth

Zoophytes PU. 7.

1 Filaria’ medinensis.
2 Tricecephalus dispar.
o Cryurus curvida:
, 4 Cucullanus teagan.
5 Ophiostema spherocephala.
6 Asca hunbrecandes. '

London, Published by Whittaker &C? Ave Marir Lane, 1834.

MCZEMRARY
HARVARD UMIVERDITY .

ORDER INTESTINA. 461

cut cross-wise, and consequently provided as it were with
two lips.

Some of them are found in the air-bladder of certain fishes,
Ophiost. cystidicola, R. Cystidicola, Fisch. Monogr.

ASCARIS,

Have the body round, slender at both ends, and the mouth
furnished with three fleshy papille, between which projects
from time to time, a very short tube. It is one of the genera
that is most numerous in species. They have been found in
all sorts of animals. Those which have been dissected have
exhibited a straight intestinal canal; and in the females,
which form by far the greater number, an ovary with two
branches has been observed, several times longer than the
body, opening externally by a single oviduct, towards the
interior fourth of the length of the animal. The males have
but a single seminal tube, also much longer than the body,
and which communicates with a penis sometimes double,
which issues forth through the anus. The latter is pierced
under the extremity of the tail.

M. Otto, and M. Cloquet, consider as the nervous system
of these worms, two white filaments which extend, one along
the back, and the other along the belly; two other thicker
threads, extending, one on the right, the other on the left, are
regarded by some as muscular, by others, as vascular, or even
as tracheal.

Some have the head without lateral membranes.

The most known species,

Ascaris lumbricoides, L., is found without any sensible dif-
ference in man, in the horse, the ass, the zebra, the hemionus,
the ox, and the hog. They have been seen more than fifteen
inches in length. Its natural colour is white. It sometimes
multiplies to excess, and may cause mortal maladies, espe-

4.62 CLASS ECHINODERMATA.

cially in infants, to whom it occasions a variety of affections,
particularly when it ascends into the stomach.

Other species have a small membrane on each side of the
head. Such is,

Ascaris vermicularis, L. Goetz. v. 1—6. Encyc. Meth. Vers.
xxx. pl. x. 1. So common with infants, and in certain mala-
dies of adults, in whom it produces an insupportable itching
at the anus. It scarcely exceeds five lines in length, and is
thicker in front.

STRONGYLUS, Miill.,
Have the body round, and the anus enveloped in the male,
by a sort of pouch, variously configured; and from which
issus a small filament, that appears to serve the purpose of
generation. ‘The female is destitute of these latter charac-
ters, which might sometimes cause her to be taken for an
ascaris.

There are some of these strongyli which have ciliz, or den-
ticulations to the mouth. Such is

Strong. Equinus, Gm. Str. armatus, Rud. Mill. Zool.
Dan. ii. xlii. Enc. meth. xxxvi. 7—15. Two inches long,
with a hard spherical head, mouth furnished all round with
small soft spines. The pouch of the male is divided into three
leaflets. It is the most common of all the worms of the
horse. It penetrates even into the arteries, where it occasions
aneurisms. It is also found in the ass and the mule.

Others have round the mouth, only tubercles or papille.

Such is particularly,

Strongylus gigas, Rud. Ascaris visceralis, et Asc. renalis,
Gm. Rud., &c. The largest of the known intestinal worms ;
it is two or three feet long and upwards, and of the thickness
of one’s little finger. What is most singular is, that it is most
frequently developed in one of the kidneys of divers animals;

1 Stongylus gigas. 4 Lierhynchus denticadatus.

2 Spiroplerus stornguiinus. 5 Linguatila/Tentastoma/tenwiles.

3 Physalopterus dausis. 6 Linguatala.

7 Frienederma ascarvides

London; Published by Whittaker & C? Ave Maria Lane; 1834

Zoophytes PY,

10,

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“HARVARD UNIVERSITY
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“J

ORDER INTESTINA. 463

such as the wolf, the dog, the marten, and even man, remain-
ing there convoluted upon itself, causing this organ to swell,
destroying the parenchyma, and, in all probability, occasion-
ing the severest pains to the individual in which it has taken
up its abode. These worms have been sometimes passed in
urine, while they were still small. This species also some-
times inhabits other viscera. It is often of the finest red
colour. It has six papillz around the mouth, the intestine is
straight and wrinkled transversely, the ovary simple and three
or four times longer than the body, communicating externally
by a hole a little behind the mouth, and as it would seem, its
other extremity opening into the anus. A very fine white
filament which extends along the belly, has been thought by
M. Otto to be the nervous system.

From the ascarides and strongyli, have been lately distin-
guished

SPIROPTERA,

Whose body is terminated in a spiral, surrounded with two
wings, from between which the penis issues.

It is said that a species of them is sometimes found in the
human bladder.

There is one in the mole, Sp. strwmosa. Nitsch., which
passes itself into a ring which it pierces in the inmost coat of
the stomach, and retains itself there by a small tubercle.

PHYSALOPTERA,

In which the posterior extremity has a bladder between two
small wings, and a tubercle from which the penis issues.

SCELOROSTOMA. Blain.,

Which have at the mouth six small denticulated scales.
There is one in the horse, and one in the hog.

4.64. CLASS ECHINODERMATA.

LioRHYNCUS, Rud.,

Which have the mouth in the form ofa small proboscis.

LINGUATULA, PENTASTOMA, Rud.,

Have the body depressed and trenchant on the sides; and
the transverse wrinkles are marked by strong and numerous
crenulations. The skin is thin and weak; the head is broad
and flatted; the mouth pierced underneath ; and at each of
its sides are two small longitudinal clefts, from which issue
little hooks. The intestine is straight; the genital vessels
long and contorted. Both have their issue at the posterior
extremity. Near the mouth are two cceeca, as in echinorhyn-
cus. A white filament surrounds the mouth, and gives out
two descending trunks, in which I think I have recognized
some appearance of a nervous system.

This genus connects the intestina cavitaria, with the pa-
renchymata.

One is known. Tenia lanceolé, Chabert. Polystoma teni-
oides. Rud. Hist. ii. xii. 8—12.; Pentastoma tenioides, id.
Syn. 123, which attains to nearly six inches in length. It
remains in the frontal sinuses of the dog and the horse.

It is here that we should place

PRIONODERMA, Rud.,

Whose body and intestines are very similar; but the mouth
is at the anterior extremity; simple, and armed with two
small hooks.

But one is known, which attacks the silurus. Cucullanus
ascarotdes, Goetz. pl. viii. f. 2, 3. Rud. Hist. xii.

I think that we should place at the end of the intestina of
this order, but as a family sufficiently different, and which
should be divided into several genera, when their economy
shall be better understood,

ORDER INTESTINA. 465

LERNAA, L.,

Whose body has pretty nearly the same internal and external
organization as that of the intestina cavitaria; but is pro-
longed in front by a neck of corneous substances, at the end
of which is a mouth variously armed, and surrounded or fol-
lowed by productions of divers forms. This mouth and its
appendages are insinuated into the skin of the gills of fishes,
and fix the animal there. The lernez are further distin-
guished by two cords, sometimes of moderate size, some-
times very long, or even very much folded, which hang from
the two sides of their tail, and which may be their ovaries.
M. Surrirey has found in the cords of a lernza, some eggs,
which have appeared to him to contain an animal analogous
to the crustacea, and very different from the lernea itself.
This fact, compared with what MM. Audouin, and Milne
Edwards have observed, on the nicothoé of the lobster, has
caused those naturalists to think that the lerneez may be, for
the most part, crustacea, grown monstrous after they have
been fixed. The males would remain free, and that, accord-
ing to them, would explain why we never find any but fe-
males. But to establish this opinion, it would be necessary

to find these males.

LERNZA, proper,
Have an oblong body, a long and narrow neck, and sorts of
horns around the head.

The most common is that which attacks the cod and other
gadi. Lernea branchialis, L. Encyc. vers. 1xxvii. 2., from
one to two inches in length; its mouth is surrounded with
three ramous horns, which are, as well as the neck, of a deep
brown. Its body, more enlarged, is bent like an S, and the
two cords are contorted in a thousand ways. Its horns are
rooted, as it were, in the gills of fish.

VOL. XII. wi 3

466 CLASS ECHINODERMATA,

Another ; Z. ocularis, Cuv., is attached to the eyes of her-
rings and other fish. It has only short and simple horns,
two larger, and two smaller. Its body is slender, its cords
long and not folded.

There is one with small horns, unequal, and very numer-
ous. L. multicornis, Cuy., on the gills of a serranus, belong-
ing to the East Indies.

Another group,

PENNELLA, Oken.,

Has the head enlarged, furnished at the nape with two small
horns, the neck corneous, the body long, wrinkled cross-
wise, and furnished behind with small filaments, disposed
like the barbs of feathers. ‘The two very long filaments ori-
ginate at the commencement of this pennated part.

There is a species in the Mediterranean. Pennella filosa,
pennatula filosa, Gm. Boccone mus. 286. Ellis. Trans. Phil.
lxiil. xx. 15., seven or eight inches long, which penetrates into
the flesh of the sword-fish, the tunny, &c. and torments them
horribly.

A third group,

SPHYRIONS, Cuv.

Has the head enlarged on both sides like a hammer, some
small hooks at the mouth, a slender neck, followed by a de-
pressed and heart-formed body, which, beside the two long
cords, supports on each side a thick fasciculus of sete. Chon-
dracanthe lisse, Quoy et Gaim.

A fourth,

ANCHOSELLA, (Cuv.),

Is fixed to the gills only by a single production, which pro-
ceeds from the under part of the body, and is directed back-

a

ORDER INTESTINA. 467

wards. Lernea adunca, Strem. Sondmer. pl.i. f. 7, 8.,

common on many gadi.
A fifth,

BRACHIELLA, Cuv.,

Has two prominences, which form, as it were, two arms, and

which are united in a single corneous part, by which the ani-

mal fixes itself to the gills. Brachiella Thynni, Cuv., &c.
A sixth,

CLAVELLA, Oken.,

Has none of these appendages, and is only fixed by the mouth.
Lernea uncinata, Miiller, &c.

These last three groups have marked hooks to the mouth.
Their cords are but little elongated. There are sometimes
other appendages at the posterior part of the body.

After a fresh examination, I refer to the sequel of the

Lerneza.
CHONDRACANTHUS, Laroch.,

Which also have hooks to the mouth ; and on the sides of the
body some appendages, very various in number and form ; so
much so, that in the course of time, it will be found necessary
to establish many divisions of them.

Thus some have on each side two appendages, like arms,
more or less prolonged. Lernea radiata, Mill., &c.

Others have many pairs of them partly forked. Lernea
cornuta, Id., and many new species.

Or even still more subdivided. Chondracanthus Zet.
Laroche.

There are some which have a slender neck, the body wi-
dened, and very unequally indented at the edges. ern.
trigle, Blainv.

I still place at the sequel of this order, an animal which,

Hh 2

468 CLASS ECHINODERMATA.

in some measure, approximates to it, but which may one day
serve as a type for a new order. It forms a genus which I
name

NEMERTES, Cuv.

It is a worm extremely soft and elongated, smooth, slender,
flatted, and terminated at one extremity by a blunt point,
pierced with a hole; widened, and broadly open at the oppo-
site extremity, by which it fixes itself. Its intestine traverses
the whole length of the body. Another canal, probably con-
nected with generation, winds along its parietes, and finishes
at a tubercle on the margin of the wide aperture. MM. Dor-
bigny, and de Blainville, who have seen this animal living,
assure us that the wide aperture is the mouth.

The only known species, Nemertes Borlasit, Cuv. Borlase.
Cornw. xxvi. 13., is more than four feet long. It remains
sunk in the sand, and, it is said, attacks the anomiz, which it
sucks in their shell.

Near these nemertes should, probably, be placed

TUBULARIA, Renieri,

Equally large, and of a very elongated form; but which have
a small mouth pierced under the anterior extremity.

OPHIOCEPHALUS, Quoy et Gaim.,

With the same forms, have the end of the muzzle cleft.

CEREBRATULA, Renieri,

Appear to differ only by having a shorter body.

ORDER PARENCHYMATA. 469

THE SECOND ORDER OF INTESTINA.

PARENCHYMATA

COMPREHENDS those whose body is filled with a cellular
substance, or even with a continuous parenchyma, in which
we observe at most, instead of all alimentary organs, some
ramified canals which distribute the nutriment, and which, in
the majority, derive their origin from suckers, visible exter-
nally. The ovaries are also enveloped in this parenchyma,
or in this cellular substance. There is no abdominal cavity,
nor intestine, properly so called, nor anus; and if we ex-
cept some doubtful vestiges in the first family, nothing is
distinguishable, which has the appearance of a nervous
system.

This order may be divided into four families.

The first family,

ACANTHOCEPHALA, Rud.,

Is attached to the intestines by a prominence, armed with
recurved spines, which appears at the same time to serve as
a proboscis. It only comprehends the genus

ECHINORHYNCUS, Gm.,

Which has the body round, sometimes elongated, sometimes
in the form of a sac, provided in front with a prominence like
a proboscis, armed with small hooks, bent backwards, which
can be protruded or retracted, by means of particular muscles.

470 CLASS ECHINODERMATA.

We sometimes observe at its extremity, a papilla, or a pore,
which may be an organ of absorption, but it is also certain
that the animal, when plunged in water, swells in every part,
and absorbs the liquid through its entire surface, where, it
has been thought, a net-work of absorbent vessels was ob-
servable. In the interior, no other part is seen comparable
to intestines, except two ceca, but little prolonged, attached
to the base of its prominence. It is tubiform, and on each
side a vessel extends over its entire length. M. de Blainville
considers as a nervous system, a filament which stretches
along the inferior face, but neither M. Rudolphi, nor M.
Cloquet, will have this to be the case. Certain species have
a distinct oviduct. In others, the eggs are extended in the
cellular substance, or the parenchyma of the body. The
males have a small bladder at the end of the tail, and internal
vesicule seminales, very distinct. It is probable that they
fecundate their eggs after they are laid.

These worms attach themselves to the intestines by means
of their proboscis, and frequently pierce them. Accordingly
individuals are to be found in the thickness of the tunics,
and even in the abdomen, adhering to the intestines in-
ternally.

The largest species, Echinorhyncus gigas, Gm., Goetze.
1—6. Encyc. xxxvii. 2—7, inhabits in abundance the in-
testines of the hog and wild boar, where the females some-
times arrive to the length of fifteen inches.

Certain species, besides the hooks of their proboscis, are
armed with the like in some other part of their body.

H#RUwCA, Gm.,

Do not differ from echinorhyncus, except that their pro-
minence is reduced to a single crown of spines, terminated
by double hooks.
One is known which frequents the liver of rats, Heruca
13

a 7

1 Echinorhynchus gigas.

2 Heruca.
3 Amplustoma longieellis.

4 Caryophylleus mutabilis.
5 Menestoma BL.

6 Distoma hepatica.

7 Polystoma ilegerrimian.
6 Lol. pinguicela.

9 Cyelocolyles Bellenes.

10 Tristoma coccineum .

London, fublished hy Whittaker & C° Ave Maria Lane, 54

tp

Cte)

ORDER PARENCHYMATA. 471

muris, Gm., Echinorh. heruca, Rud., Goetz. ix. B. 12. Enc.
Vers. xxxvi. 1.

The second family,

TREMADOTES, Rud.,

Comprehends those which have under the body, or at its
extremities, some organs in the form of cuppers, by which
they are attached to the viscera.

A single genus might be formed of them, to which might
be given in common the name of

FASCIOLA, L.,

But which may be subdivided as follows, according to the
number and position of the cuppers.

FESTUCARIA, Schr. MONOSTOMA, Zeder.,

Have but one cupper, sometimes at the anterior end, some-
times under this same end. They are found in several birds
and fishes.

STRIGEA, Abildg. AMPHISTOMA, Rud.,

Have a cupper at each extremity. Some are found in several
quadrupeds, birds, &c.
We should probably approximate to them

CARYOPHYLLEUS, Bl.
In which he head is dilated, fringed, and has underneath a
sucker furnished with two lips not very easily distinguished.
Another similar sucker is sometimes perceivable under the
tail.
But one is known, taken from divers fresh water fishes, and
particularly common in the Bream.

Distoma, Retz. and Zéder.,

Have a sucker, or mouth, at the anterior extremity, and a

4.72 CLASS ECHINODERMATA.

cupper a little farther behind, under the belly. The species
are extremely numerous ; some are found even in the comb of
the eye of some birds. But it also appears that some are not
intestine, but inhabit at large the fresh and salt water.

The most celebrated is,

Fasciola hepatica, L., Scheef., Monogr., Copied., Encyc.
Vers., pl. Ixxx. i. ii., which is so common in the hepatic
vessels of sheep, but is also found in those of many other
ruminantia, of the hog, of the horse, and even of man. Its
form is that of a small oval leaf, pointed behind, having in
front a small contracted portion, at the end of which is the
first sucker ; this opens into a sort of cesophagus, from which
some canals proceed, ramifying through the entire body, and
carrying thither the bile on which this animal is nourished.
A little backwards is a small retractile tentaculum, which is
the penis ; and immediately behind that is the second sucker.
Some spermatic vessels, very much folded, fill the middle of
the leaf. The ovary, which is found in all the individuals,
is enchased in the intervals of the intestines, and the eggs
issue through a convoluted canal, which ends at a small
hole on the side of the penis. These animals couple reci-
procally.

This worm multiplies greatly in sheep when they pasture in
humid grounds, and occasions dropsy and death.

M. Rudolphi makes a division which he names ECHINOS-
TOMA, of the species which have in front a small enlarge-
ment, armed with hooks.

HoLostoma, Nitzsch.,

Have a moiety of the body concave, and so disposed as to
act altogether as a cupper. Their orifices otherwise appear
similar enough to those of distoma.

Some of them are found in certain birds. ‘There is one in
the fox.

ORDER PARENCHYMATA. 473

PoLysToMA, Zéder., (or more properly) HEXASTOMA,

Have the body depressed, smooth, and six cuppers ranged on
a transverse line, under the posterior edge. Their mouth
appears to be at the opposite extremity.

Some have been found in the urinary bladder of frogs, in
the ovary of the human female, on the gills of some fishes,
and in the nasal cavity of certain tortoise. (Polyst. integer-
rimum, Rud., &c.)

CYCLOCOTYLES, Otto.,

Have eight cuppers forming almost a complete circle under
the hinder part of the body, which is broad, and supports in
front a small proboscis.

But one species is known, very small, taken on the back
of the Bellone, Cyc. bellones, Ott. Nat. ac Eur. xi. part ii.
pl nt 2:

I also approximate to the fasciole, a subgenus which I
name

TRISTOMA, Cuww.

Their body is a broad and flat disk, behind, at its inferior
face, is a large cartilaginous sucker, which is attached to the
body only by a short pedicle, and under its anterior edge are
found two small ones, between which, a little behind, is the
mouth. In the parenchyma of the body is a ramified circular
vessel, the nature of which it is difficult to determine.

A species of an inch and more in breadth, of a lively red-
colour, Tristoma coccineum, Cuvy., is attached to the gills
of many fishes of the Mediterranean, such as the sword-
fish, &c.

One of the most extraordinary genera of this family is
that of

474 CLASS ECHINODERMATA.

HECTOCOTYLES, Cuv.

Long worms, more thick and compressed, at the anterior
extremity where the mouth is situated, whose inferior face is
altogether furnished with suckers, ranged in pairs, and of a
very considerable number, sixty or an hundred, and which
support at the posterior extremity a sac filled with the con-
volutions of the oviduct. —

The Mediterranean possesses a species four and five inches
in length, with four hundred cuppers, which inhabits the
octopus, and penetrates into its flesh. (Hectocotyle octopodis,
Cuv., An. Sc. Nat. xviii. pl. x1.)

And another smaller, with seventy cuppers, which lives on
the argonauta. (H. argonaute, or trichocephalus acetabu-
laris, Delle Chiaie. mem. part ii. pl. xvi. f. 1, 2.)

Perhaps it is here that should come

ASPIDOGASTER, Ber.,

Which has under the belly a lamina, hollowed with four
ranges of small fossettes.
There is a very small one which is a parasite of the mussels.
(Asp. conchicola, Beer. An. Nat. Cur. xiii. part ii. pl. xxviii.)
I cannot avoid thinking that we should still approximate
to Fasciola the greater part of those animals comprehended
under the genus

PLANARIA, Mill.

Although they do not inhabit other animals, but merely the
fresh and salt waters. In fact, their body is depressed,
parenchymatous, without any distinct abdominal cavity ; the
alimentary orifice, placed under the middle of the body, or
more behind, and dilating into a small proboscis, conducts,
as in fasciola, into an intestine, whose numerous ramifications

a

ORDER PARENCHYMATA. 475

are hollowed in the thickness of the entire body. A vascular
net-work occupies the sides ; behind the alimentary orifice is
a double system of genital organs, and the sexual intercourse
is reciprocal. Small black points are discoverable in the
planariz, which are probably eyes.

These animals are very voracious, and do not even spare
their own species. They not only multiply in the ordinary
way, but also very easily by division, and they sometimes
even undergo spontaneous separation. |

We have several of them in our fresh waters. (Planaria
lactea, Zool., Dan., &c.)

Our coasts also abound with them, and especially with
those of the largest size. (Pl. awrantiaca, Nob.)

There are some whose superficies appear to be hairy. (Pl.
brocchit, Risso.)

Several have two tentacula in front. (Pl. cornuta, Miill.)

M. Dugés distinguishes from them

PROSTOMA,

Which have an orifice at the anterior extremity, and another
at the posterior, and

DEROSTOMA,

In which the alimentary orifice is underneath, but nearer the
anterior extremity.

To the first of these I approximate the PH@NICURI, Rud.,
or Vertumnus Otto, which have but one orifice at the anterior
extremity.

But one species is known, V. thethidicola, Otto, Ac. Nat.
Cur. xi. part ii. pl. xli. f. 2. A parasite of the Thethys
Jimbria, of a marked appearance, and often with a forked
tail, which is the effect of laceration.

The third family of Parenchymatous intestina,

476 CLASS ECHINODERMATA,

TENIOIDES,

Embraces those in which the head has two or four pores, or
suckers, placed round its middle, which itself is sometimes
marked by a pore, sometimes provided with a small proboscis,
either naked or armed with spines. Sometimes there are four
small proboscides thus armed.

Its most numerous genus is that of

TENLE.

Their body elongated, often to an excessive degree, flat, com-
posed of articulations, more or less marked, grows narrow in
front, and generally supports there a square head, hollowed
with four small suckers.

It has been thought that canals were perceptible, which
proceed from these suckers, and extend along the margin of
the articulations of the body. These last have each one or
two pores, diversely placed according to the species, and which
appear to be the orifices of the ovaries, which are themselves
situated in the thickness of the articulations, when they some-
times assume a simple figure, and sometimes are divided into
ramifications. The teniz are in the number of the most cruel
enemies of the animals in which they are developed, and
which they appear to exhaust.

Some have no projecting part in the middle of the four
suckers. Such is in man the

Tenia lata, Rud. T. vulgaris. Gm. Goetz. xli. 5—9., whose
articulations are broad and short, and have a double pore in
the middle of each lateral face. It is very commonly of the
length of twenty feet, and it has been seen even more than a
hundred. The large ones are nearly an inch in breadth ; but
the head and the anterior part are always very slender. It is
extremely troublesome and tenacious. It is frequently found
_ difficult of expulsion, by the most violent remedies.

1 Tenia

lata.

2 Te. selium.

3 Head otf Pothryecephalus cerenatius.

4 Dibothrs orhynchus lepidepr .

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ORDER PARENCHYMATA. ATT

Others have the prominence between the suckers armed
with small points, disposed in radii. Such is again in
man,

Tenia Solium, L. Getz. xxi. 1—7. Encyc. xl. 15—22. xli.
1—7, whose articulations, except the anterior, are more long
than broad, and have the pore alternately at one of their mar-
gins. Itis in general from four to ten feet in length, but some
are found much larger. It is by no means the case that but
one of these worms exists in an individual at one time, as is
vulgarly supposed. Its detached articulations are called
cucurbite. It is one of the most dangerous of the intestinal
worms, and the most difficult to be expelled.

From these common teniz, in consequence of the form of
their head, have been distinguished, the

TRICUSPIDARIA, Rud.,

Which M. Rudolphi now calls TRIANOPHORA, whose head
divided, as it were, into two lips or two lobes, has, on each
side, instead of suckers, two stings, with three points.

But one is known which inhabits divers fish, the pike,
perch, &c. Tenia nodulosa, Gm. Getz. xxxiv. 5, 6. Encyc.
xlix. 12—15.

BOTHRYOCEPHALUS, Rud.,

Whose head, instead of suckers, has only two longitudinal
fossettes, placed opposite one to the other.

Some are found in various fish, and in some birds.

Among the Bothryocephali themselves, it is proper to dis-
tinguish

DIBOTHRYORHYNCUS, Blain.,

Which have at the summit two small proboscides, or tenta-
cula, bristling with hooks.

478 CLASS ECHINODERMATA.

But one is known, with a short body ; lives in the lepidopus.
Blainy. App. ad Brems. pl. ii. p. 8.,

FLORICEPS, Cuv.,

Which have four small proboscides, or tentacula, armed with
recurved spines, by means of which they bury themselves in
the viscera.

Certain species,

RHYNCOBOTHRIUM, Blain.,

Have the body long, articulated, and without bladder.

There is one sufficiently common in the rays; Bothryoce-
phalus corollatus, Rud. ix. 12., some inches in length. Its ©
head altogether resembles a flower.

Some others,

FLORICEPS,

Properly so called, have the body terminated by a bladder,
into which it enters and is concealed.

TETRARHYNCUS, Rud.,

Appear to be only floriceps, reduced naturally to the head,
and two articulations, instead of an elongated body, and seve-
ral articulations.

One is found very commonly in the flesh of the tongue
of the turbot, and of several other fishes. Tetr. lingualis,
Cuy.

TENTACULARIA, Bosc.,

Differ only in the tentacula not being armed with spines.
Those have also been distinguished from the ordinary

tenis, which, with a head similar to theirs, that is to say,

with four suckers, have the body terminated behind by a

er
Zoophytes Fi

1 Floriceps corcllatius. 5 Cysieercus Thna.

2 Tetrarhynelius linqualis. 6 Acrestema amniv.
3 Tentacidana Bese. 7 Canurus cerebralis.
4 Cysheercus pisitermis. & Lehinececeus.

9 Ligula simplictssima.

London. Fublished by Whittaker &C° Ave Martar Lane, Jo

ORDER PARENCHYMATA. 479

bladder. Their articulations are not as distinct as in the
preceding.

CYSTICERCUS, Rud. Vulgo. HYDATIDEs,

Are those in which the bladder supports but a single body,
and a single head. They are particularly developed in the
membranes, and the cellular substance of animals.

There is one species which multiplies in a great number of
quadrupeds, especially in the ruminantia. It is the globular
hydatid (Tenia ferarum ; T. caprina ; T. ovilla; T. bovina ;
T. apri; T. globosa, Gm.) Geetz. xvii. A.B. Encyc. xxxix.
6—8.

Another is very common in hares and rabbits; Tenia cor-
data ; T. pisiformis ; T. utricularis, Gm. Goetz. xviii. A.B.
Encyc. xxxix. 6—8.

But the most celebrated is that which remains between
the fibres of the muscles of hogs, and produces what
is called in them measles. Tenia cellulosa, and T. jinna,
Gm. Blum. Abb. 4. Cah. pl. 39. It is small, and multiplies
excessively in this disgusting malady, penetrating even into
the heart, the eyes, &c. It appears that similar ones have
been observed in some apes, and evenin man. But it is said
never to be found in the wild boar.

AcROsTOMA, Le Sauvage. Ann. des Sc. Nat.,
Is very much akin to this genus. It lives in the amnios of

COWS.

C@NuRUS, Rud.,
Have several bodies and several heads, attached to the same
vesicle.

One very celebrated species is known; Tenia cerebralis,
Gm. Getz. xx. A.B. Encyc. xl. 1—8., which is developed

480 CLASS ECHINODERMATA.

in the brain of sheep, destroys a part of its substance, and
occasions a sort of paralysis, called the staggers, because it
causes them to turn round involuntarily as if they were giddy.
Some of these worms have also been seen in oxen, and other
ruminants, in which they produce the same effects. The
vesicle is sometimes as big as an egg. Its parietes are very
slender, fibrous, and exhibit sensible contractions. The small
worms are scarcely half a line in length, and enter the vesicle
by contraction.
Here should, probably, come the genus,

EcHINococcus, Rud.,

But I have not observed it, nor can I form a sufficiently dis-
tinct notion of it, for the purposes of classification.

ScoLex, Miill.,

Have the body round, pointed behind, very contractile, and
terminated in front by a sort of variable head; round which
are two or four suckers, sometimes in the form of ears, or
small tongues.

Only some very small ones are known, taken from some
fish.

I have seen a large one; Scol. gigas, Cuv., which pene-
trates into the flesh of a species of bream, the sparus raz, L.
the middle part of the body of which is inflated into a bladder,
which in the living state contracts or enlarges alternately
in its middle. It is the gymnorynchus reptans, Rud. Syn.
129.

The fourth family,

CESTOIDES,

Comprehends those in which no external suckers are ob-
served.

ee

ORDER ACALEPHA. 431
But a single genus is known.

LIGuLaA, Bloch.,

Are, of all the intestina, those which appear to be the most
simply organized. Their body resembles along riband. It
is flat, obtuse in front, marked with a longitudinal stria, and
finely striated cross-wise. No external organ is distinguish-
able, and in the interior, nothing is seen but eggs, variously
distributed through the length of the parenchyma.

They live in the abdomen of some birds, and more particu-
larly in that of several fresh-water fish, whose intestines they
envelope and press to such a degree, as to cause them to
perish. At certain periods, they even pierce their abdomen
to get out.

There is one in the bream. Lig. abdominalis, Gm. L. cin-
gulum, Rud. Geetz. xvi. 4—6, which attains even to the length
of five feet. These worms, in some parts of Italy, are consi-
dered as an agreeable food.

THE THIRD CLASS OF THE ZOOPHYTES.

ACALEPHE, Vulg. SEA-NETTLES,

Comprehend zoophytes which swim in the waters of the
sea, and in the organization of which some vessels are per-
ceived which, in truth, are most frequently only productions
of the intestines, hollowed in the parenchyma of the body.

VOL. XII. a

482 CLASS ECHINODERMATA.

THE FIRST ORDER OF ACALEPH&,
ACALEPH SIMPLICES,

Float and swim in the waters of the sea, by means of the con-
tractions and dilatations of their body, although their sub-
stance is gelatinous, without any apparent fibres. ‘The sorts
of vessels which are seen in some of them, are hollowed in the
gelatinous substance. ‘They often come from the stomach in
a visible manner, and do not give rise to any true circulation.

Mepusa, L.,

Have a disk more or less convex above, similar to the head of
a mushroom, and to which the name of wmbrella has been
given. Its contractions and dilatations concur in producing
the movements of the animal. ‘The edges of this umbrella,
as well as the mouth, or the suckers, more or less prolonged
into pedicles, which take its place, at the middle of the in-
ferior face, are furnished with tentacula of very various forms
and sizes. These different degrees of complication have given
rise to very numerous divisions.
We shall give the general name of

MEDUSA (proper),

To those which have a mouth under the middle of the inferior
surface, whether simply opening on the surface, or prolonged
into a pedicle. And among the medusa proper

We may unite under the name of

ALQUOREA,

All those in which this mouth is simple and not prolonged or
furnished with arms.

ORDER ACALEPHA SIMPLICES. 483

When they have no tentacula around the umbrella, they
constitute the PHORCYNIA of Lamarck.

When the umbrella is furnished with tentacula all around,
it characterizes the AZQUOREA, more particularly so named,
of Peron, one of the most numerous subgenera, especially in
the seas of hot climates. Medusa equorea, Gm. &c. &c.

Certain species are remarkable for lamin, which furnish
their inferior surface. Others, FovEOLIA, Peron, are signa-
lized by little fossettes, hollowed in the circumference of the
umbrella. Medusa mollicina, Forsk., &c.

We may thus unite under the name of

PELAGIA,

Those in which the mouth is prolonged into a peduncle, or
divided into arms. Pelagia panopyra, Peron.

In all these subgenera, there are no lateral cavities; but a
much greater number of these meduse, with simple mouths,
have in the thickness of the umbrella four organs, formed of
a plaited membrane, filled at certain periods with an opake
substance, and which appear to be ovaries. They are most
frequently lodged in as many cavities, open at the inferior
face, or on the sides of the pedicle; and which, as I think,
have been erroneously taken for mouths, because some little
animals are occasionally caught in them. Some naturalists
take them for organs of respiration ; but it is more probable
that this function is exercised on the margins of the umbrella.
The tentacula, whether of the margin of the umbrella, or the
circumference of the mouth, vary not only according to the
species, but even according to age.

We unite under the name of

CYANEA, Cuv.

All the meduse with central mouth, and four lateral ovaries.
The most extended, Medusa aurita, L. Miill. Zool. Dan.
1i2

484 CLASS ECHINODERMATA.

Ixxvi. and lxxvil., acquires with age four long arms. Its
umbrella is finely ciliated all around. Some reddish vessels
pass from the stomach to the ‘circumference, subdividing in
their course.

Another, Med. chrysaora, Cuv., has the edges furnished
with long tentacula, and some fulvous or brown lines or spots,
disposed in radii in its convexity. It is also very common,
and varies much as to the spots.

We have given the general name of RHIZOSTOMA, to a
portion of the great genus MEDUSA, comprehending the spe-
cies which have no mouth open at the centre, and which ap-
pear to be nourished through the suction of the ramifications
of their pedicle, or of their tentacula. ‘They have four ovaries
or more.

RHIZOSTOMA, (proper) Cuv.,

Are those which have in the middle a pedicle, more or less
ramified, according to the species.

The vessels proceeding from the small ramifications of the
pedicles, unite in a cavity of its base, from which branches
proceed for all the parts of the umbrella.

The most common is the Rhizostome bleu. Cuv. Jour. de
Phys. tom. xlix. p. 436. Reaum. Acad. des Sc. 1710. pl. xi.
f. 27, 28. Itis found every where on the sand of our coasts,
when the sea retires, and its umbrella is sometimes nearly
two feet in breadth. Its pedicle is divided into four pairs of
arms, forked and denticulated almost ad infinitum, furnished
each at the base with two corslets, equally denticulated. The
umbrella has all around, in the thickness of its margins, a fine
‘net-work of vessels.

According to the observations of Messrs. Audouin, and
Milne Edwards, these medusz live in society, or at least are
always to be met with united in great numbers, and swimming
in the same direction, the body being inclined obliquely. —

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ORDER ACALEPHA SIMPLICES. 485

CEPH#ZA, Peron, are distinguished from the other Rhizos-
toma only by some filaments mixed with the denticulations of
their pedicle. Medusa Cephea, Forsk., &c.

The CAssiop# have, properly speaking, no pedicle;
their arms usually eight in number, sometimes branched,
spring immediately from the inferior surface. Med. Frondosa,
Pallas, &c.

Other species, without a central mouth, have none of these
numerous ramifications to the pedicle, nor open cavities to
lodge the ovaries. ‘They may be united under the name of

ASTOMA.

Some, however, have still a large pedicle, furnished on each
side with hairy filaments, which may serve as suckers.
LYMNOREA and FAVonrA, Per.

Others have not even these filaments, but a membrane in
the form of a funnel at the end of the pedicle, and from the
bottom of which the vessels appear to issue, which ascend
into the pedicle, and spread out in the umbrella. Geryonia,
properly so called; Peron. There is one in the Mediterra-
nean ; Med. proboscidalis, Forsk. xxxvi. 1.

This membrane is even wanting in others. ORYTHTIA, id.
Medusa minima, Bart., &c.

There are some without any pedicle, but in which the under
part appears furnished with small suckers along the passage
of the vessels) BERENICE, Peron. Cuvieria eurisochroma,
Peron.

Finally, there are some in which no suckers are perceptible,
the two surfaces being smooth, and without apparent organs.
Eupora, Peron.

The Mediterranean possesses a species of these about the
size of a five-franc piece, and to which the people give the
name of that coin. Hud. moneta, N.

When these very simple animals assume more concavity, their

~

486 CLASS ECHINODERMATA.

inferior surface becomes interior, and may perhaps be regarded
as a true stomach. These are the CARYBDEA, Peron. Those
in whose interior no traces of vessels are perceptible, do not
properly differ from the hydre, but in size. Medusa mar-
suptalis, Gm.

It has been found necessary to separate from the medusz,
some genera united to_them by Linneus, on very slight
grounds of relation, such as

BEROE, Miill.

They have an oval or globular body, furnished with projecting
ribs, bristling with filaments or fringe, proceeding from one
pole to the other, and in which we perceive vascular ramifica-
tions, and a sort of movement of the fluid. ‘The mouth is at
one extremity ; in those which have been examined, it con-
ducts into a stomach which occupies the axis of the body, and
on the sides of which are two organs probably analogous to
those which we have called ovaries in the medusa,

Such is,

Medusa pileus, Gm. (Globular Beroé) Baster. i. iii. xiv.
6—7.Encyc. xc. 3, 4, with a spherical body, furnished with
eight ribs ; two ciliated tentacula, susceptible of a great elon-
gation, issue from its inferior extremity. Itis very common
in the north seas, and even in the channel on our coasts, and
is considered as one of the aliments of the whale.

According to MM. Audouin and Milne Edwards there ex-
ists in the axis of these animals a cavity which goes from one
pole to the other, and which communicates externally by
means of an inferior aperture, which may be considered as the
front mouth. In the superior third of this cavity is contained,
and as it were suspended, a sort of straight and cylindrical
intestinal tube, which has its external aperture immediately
at the superior pole, and which supports on each side two
granular cords (ovaries perhaps). The cavity is filled with a

ORDER ACALEPHA SIMPLICES. 487

fluid in motion, which is seen to pass into two lateral tubes,
that soon subdivide each into four branches, and terminate on
the surface of the body, by opening into longitudinal canals.
Through these canals the fluid is conducted into the cilia,
which are constantly in motion, and appear to be respiratory
organs. Finally, from the sides of each of the eight costal
canals, spring an infinity of small vessels, or transverse sinuses,
which establish a communication between them, and which
sink into the surrounding parenchyma. On each side of the
spheroid, and internally, we perceive two small masses which
occupy each the bottom of a cavity or cul-de-sac, and give
birth to two long contractile filaments, issuing through two
circular apertures, situated towards the inferior third of the
body. ‘These filaments are subsequently divided into a great
number of branches.

To this genus have been referred some more simple species,
which merely resemble a sac, furnished with ciliated ribs, and
open at the two ends. Ipya. Oken. Bere ovatus Brug.
or Medusa infundibulum, Gm.

There are some which are even destitute of ribs, and whose
form represents that of a band without bottoms. DoLIoLuM.
Otto. D. Mediterraneum, Otto.

CALLIANIRA, Peron, do not appear to differ from Beroe,
except in having much more projecting ribs, united two by
two, to form two sorts of wings. Their internal organization
is not sufficiently known. Callianira didiploptera, Peron.

JANIRA, Oken., appear to be akin to the callianire ; but on
each side there are three large ciliated ribs, and two long fila-
ments divided into branches. Beroé hexagone, Brug. Encyc.
vers. pl. 90. f. 6.

ALCINOE, Rang., have the body cylindrical, open at one
extremity, furnished on the other with two large wings, which
by being folded over it, can envelope it altogether. Its cylin-
drical part is flanked with four projecting ribs, each termi-

13

488 CLASS ECHINODERMATA.

nated in a point, and has eight lines of ciliz. Alcinoe ver-
miculata, Rang.

OcyYROE, id., have the same sort of body with four ranges of
cilie, but without ribs; they have also similar wings, each
furnished at the base with two ciliated points. Ocyroé ma-
culata, id., &c.

It is also near Beroe that we should place

CESTUM, Lesueur,

A very long gelatinous ribbon, one of the edges of which is
furnished with a double range of ciliz. The inferior one has
some also, but smaller, and less numerous. It is at the middle
of the inferior margin, that the mouth is situated; a large
aperture which leads into a stomach, pierced through the
breadth of the ribbon, and proceeding to a very small anus.
From the extremity near the anus, proceed some vessels, which
extend to the two extremities of the ribbon. At the sides of
the mouth two sacs open, which are probably the ovaries.
This animal may be compared to a callianira with two ribs,
and whose wings were excessively prolonged.

The only known species,

Cestum veneris, Lesueur. Nouv. Bull. des Sc. June 18138.
pl. v. f. 1., is from the Mediterranean. Its length, or rather
its breadth, is more than five feet; its height, two inches. It
is preserved entire with great difficulty.

The two following genera, which have also been united to
the medusz, might form a small family in this order, in con-
sequence of the internal cartilage which supports the gelati-
nous substance of the body.

PorPITA, Lam.,
Have this circular cartilage, and its surface marked with
concentric striz, crossing with radiating strie. At the
upper face it is clothed only with a slender membrane, which

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ORDER ACALEPHA HYDROSTATICA. ~ 489

out-edges it. ‘The inferior is furnished with a great number
of tentacula, of which the external ones are longer, and fur-
nished with little ciliz, terminated each by a globule. They
sometimes contain air; the middle ones are shorter, more
simple and more fleshy. At the centre of all these tentacula
is the mouth, in the form of a small projecting proboscis. It
conducts to a simple stomach surrounded with a sort of
glandulous substance.

But one species is known of a fine blue, belonging to the
Mediterranean, and to warmer seas. (Medusa wmbella, Miill.)

VELELLA,

Have, like the porpite, at the inferior face, a mouth in the
form of a proboscis, surrounded with innumerable tentacula,
of which the external ones are longer; but the latter are not
ciliated, and what gives a more important character is, that
the cartilage, which is oval, has on its upper face a vertical
crest placed obliquely, and sufficiently raised. This cartilage
is transparent, and has only concentric strie.

One species is also known of the same colour, and living
in the same seas, as the porpita. Itis eaten fried. It is the
Medusa velella, and Holothuria spirans of Gmelin.

THE SECOND ORDER OF ACALEPH..

ACALEPHA HYDROSTATIC,

ARE recognized by one or more vesicles, usually filled with
air, by means of which they are suspended in the water.
Appendages singularly numerous, and varying in form, some

490 CLASS ECHINODERMATA.

of which probably serve as suckers, others perhaps as ovaries,
and others, longer than the rest, as tentacula, unite them-
selves to these vesicular parts, to compose the whole apparent
organization of these animals. ‘There is no mouth that can
properly be recognized as such.

PHYSALIA, Zam.,

Consist of a very large oblong vesicle, raised above into a
projecting crest, oblique and wrinkled, and furnished under-
neath, towards one of its extremities, with a great number of
cylindrical fleshy productions, which communicate with the
vesicle, and terminate variously. ‘Those towards the centre
support groups, more or less numerous, of small filaments ;
those towards the sides are only bifurcated into two filaments,
one of which is often very much prolonged. One of the ex-
tremities of the vesicle appears to have a very small orifice.
But in the interior, we find, instead of intestine, only another
vesicle, with more slender parietes, and which has some ceeca
extending partly into the cavities of the crest. For the rest,
there is neither nervous, nor circulating, nor glandular system.
The animal swims on the surface of the sea when it is calm,
and employs its crest as a sail. It also has, in the living
state, some very long filaments, more slender than the others,
and sown, as it were, with pearls, or little drops. It is re-
ported that their touch stings like that of the nettle.

There are some in all the seas of warm climates. (Holo-
thuria Physalis, L., &c. &c. &c.)

PHYSSOPHORA, Forshk.,

Have sensible relations with the Physalia ; but their bladder
is much smaller in proportion, without a crest, often accom-
panied with lateral vesicles, and their various and numerous
tentacula are suspended vertically under this vesicle, as a
garland or a cluster of grapes.

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ORDER ACALEPHA HYDROSTATICA. 4AD1

In
PHYSSOPHORA, (proper) Peron,

Between the superior vesicle and the tentacula, are found
other vesicles, placed side by side, or one above the other,
and of a form sometimes irregular, sometimes polyhedral, and
forming by their union, prisms or cylinders; the tentacula,
partly conical, partly cylindrical, partly formed of groups of
filaments, or of globules, some in fine filiform, and susceptible
of great elongation, form a cluster, or garland, at the inferior
extremity. (Physsophora hydrostatica, Gm., &c. &c.)

HIpropus, Quoy and Gaive.,

Have only lateral vesicles, almost semicircular, or in the form
of a horse’s hoof, crowded on two ranges, and thus forming
a sort of ear, like that of certain grains, from which also
hangs a garland, which traverses all those pieces. The con-
tractions of those vesicles impress upon the whole a rapid
movement.

CUPULITES,

Have their vesicles attached regularly on both sides of an
axis, often very long.

RACEMIDES, Cuv.,

Have all their vesicles globular, small, furnished each with a
small membrane, and united into an oval mass, which is
moved by their combined contractions,

RHIZOPHYZA, Peron,

Have no lateral vesicles, but only a superior vesicle, and a
long stem, along which the tentacula are suspended ; some
conical, others filiform. (Physsophora filiformis, Forsk.)

492 CLASS ECHINODERMATA.

STEPHANOMIA, Peron,

Appear to be a third combination, in which the lateral
vesicles, which, in the Physsophore proper, adhere to the
top of the stem, above the tentacula, are prolonged over its
length, and mingled with tentacula of various forms. (Ste-
phanomia amphitritis, Peron.)

It is at the end of the hydrostatic acalephe, that may be
placed

DIPHYES, Cww.

A very singular genus, in which two different individuals
are always found together, one being emboxed in a cavity of
the other, which arrangement, however, permits them to
separate without destruction to individual life. They are
gelatinous, transparent, and move pretty nearly like the
meduse. The one which receives the other, produces from
its cavity, a chaplet which traverses a semi-canal of its com-
panion, and appears to be composed of ovaries, of tenta-
cula, and of suckers, like those of the preceding genera. -

MM. Quoy and Gaymard, have established divisions in this
genus, according to the forms and relative proportions of the
two individuals.

Thus, in

DIPHYES, (proper.)

The two individuals are almost similar, pyramidal, with
some points round their aperture, which is at the base of the
pyramid.

In CALPE, the emboxed individual has still the pyraenas
form, but the other is very small and square.

In ABYLE, the emboxed one is oblong, or oval; the other
a little smaller, and in the form of a bell.

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ORDER POLYPI CARNOSI. 493

In the CUBOIDES, it is the emboxed one which is small
and bell-formed. ‘The other is much larger and square.

In NAVICULA, the emboxed one is bell-formed ; the other
is equally large, but shaped like a shoe.

There are also several other combinations.

FOURTH CLASS OF THE ZOOPHYTES.

THE POLYPI

HAVE been thus named, because the tentacula which sur-
round their mouth give them some slight resemblance to the
octopus, which the ancients called polypus. The form and
number of these tentacula vary. The body is always cylindri-
cal, or conical, often without any other viscera than its cavity,
often also with a visible stomach, to which adhere intestines,
or rather vessels, hollowed in the substance of the body, like
those of the medusz. In this case ovaries are also visible.
The majority of these animals are susceptible of forming com-
posite beings, by sprouting forth new individuals, like buds,
nevertheless, they also propagate by eggs.

THE FIRST ORDER OF POLYPI.

POLYPI CARNOSI. (Vulgo. FIXED SEA NETTLES.)

CoMPREHEND some fleshy animals, which have the habit
of fixing themselves by their base, but several of which can

494 CLASS ECHINODERMATA.

also crawl upon this base or detach it altogether, and swim,
or suffer themselves to be carried away by the motion of the
waters. They are most frequently limited to the movement
of expanding more or less the aperture of the mouth, which
also serves the purposes of an anus. It is surrounded with
tentacula more or less numerous, and leads into a stomach
which terminates in a cul-de-sac. Between this interior sac
and the external skin, is an organization tolerably com-
plicated, but still rather obscure, consisting chiefly of vertical
and fibrous leaflets, to which the ovaries adhere, similar to
threads very much contorted. The intervals of these leaflets
communicate with the interior of the tentacula, and it appears
that the water can enter there and come out by little orifices
around the mouth; at least the actinia sometimes ejaculates _
it in this way.

AcTINIA, L.

Their fleshy body, often adorned with lively colours, deve-
loping numerous tentacula, placed round the mouth, on several
ranges like the petals of a double flower, has occasioned the
name of sea anemone to be bestowed upon them. They are
amazingly sensible to light, and open or close according as
the day is more or less fine. When they retract their tenta-
cula, the aperture from which these organs issue, contracts,
and closes upon them like that of a purse.

Their power of reproduction is scarcely less than that of
the armed polypi. They shoot forth again the parts which
have been cut, and multiply by division. Their ordinary
generation is viviparous. ‘The little actiniz pass from the
ovary into the stomach and come out through the mouth.
These zoophytes dilate their mouth considerably when they
are hungry. ‘They devour all sorts of animals, and especially
crustacea, testacea, and small fishes, which they seize with
their tentacula, and digest pretty quickly.

ORDER POLYPI CARNOSI. 495

ACTINIA, (proper)

Are fixed by a broad and flat base. The species most com-
mon on our coasts are

Act. Senilis, L. Three inches broad, with a coriaceous,
unequal, and orange-coloured envelope, and tentacula on two
ranges, of a moderate length, and usually marked with a rose-
coloured ring. It keeps principally in the sand, into which
it instantly sinks back upon the slightest alarm.

Act. Equina, L. With a soft skin, finely striated; the
colour usually of a fine purple, often spotted with green ;
smaller, the tentacula longer, and more numerous than the
preceding. It covers all the rocks of our coasts of the
channel, and ornaments them as though they bore the finest
flowers.

Actinia Plumosa, Cuv. White, four inches and more in
breadth ; the edges ofits mouth expand into lobes, all charged
with innumerable small tentacula. There is an interior rank
of larger ones.

Actinia Effeeta. Rond. Lib. xvii. cap. xviii. Ofa clear
brown, striped longitudinally with whitish; of an elongated
form, often more narrow towards the bottom ; a smooth skin,
and numerous tentacula. When it contracts itself, there often
issue through the mouth some long filaments, which come
from the ovaries. It attaches itself, in preference, on shells,
and is extremely common in the Mediterranean.

THALASSIANTHUS, Ruppel, are actiniz, with ramified ten-
tacula. (Thal. aster. Ruppel.)

His DIscosoMA, are some in which the tentacula are
reduced to nearly nothing by their shortness. (Discos. nummi-
Sorme, Id.)

ZOANTHUS, Cuv.,

Have the same fleshy tissue, the same disposition of mouth,

496 CLASS ECHINODERMATA,

and of tentacula, and an organization pretty nearly similar to
that of the actiniz. But they are united in a more or less
considerable number, on a common base, sometimes in the
form of a creeping stem. (Hydra sociata, Gm.) Sometimes
in the form of a broad surface. (Alcyonium mamillosum, Ell.)

LUCERNARIA, Miill.

It would appear, should be approximated to the actiniz ;
but their substance is softer; they fix themselves to fucus
and other marine substances, by a slender pedicle; their
upper part is dilated like a parasol; the mouth is in the
middle. Numerous tentacula approximated in fasciculi, fur-
nish the edges. Between the mouth and these same edges,
are eight organs, in the form of cceca, which proceed from the
stomach, and contain red and granulated matter.

In Lucernaria quadricornis, Miill., Zool., Dan. xxxi. 1—6,
the edge is divided into four forked branches, each supporting
two groups of tentacula. In the Z. awricula, Ibid. clii. the
eight groups are equally apportioned round an octagon edge.

SECOND ORDER OF POLYPI.

POLYPI GELATINOSI,

ARE not, like the preceding, invested with a hard envelope,
neither do they produce in the interior of their structure an
axis of ligneous, fleshy, or corneous substance. Their body
is gelatinous, of a form more or less conical ; its cavity serves
as a stomach.

ORDER POLYPI GELATINOSI. 497

Hypra, Linn.

Present us the animals of this class reduced to their greatest
possible simplicity. A small gelatinous trumpet-shaped body,
whose edges are furnished with filaments, which serve as ten-
tacula, constitutes their whole apparent organization. The
microscope enables us to discover nothing in their substance
but a transparent parenchyma, filled with grains, a little more
opake. Nevertheless, they swim, they crawl, they even
walk, by fixing alternately their two extremities, like the
leeches, or geometrical caterpillars. ‘They agitate their ten-
tacula, and make use of them to seize their prey, which is
visibly digested in the cavity of their body. They are sen-
sible to light and seek after it. But the most marvellous pro-
perty is that of constantly and indefinitely reproducing the
parts which are taken from them, so that the individuals may
be multiplied at will, by section. Their natural multiplication
takes place by the young shooting forth from different parts of
the body of the adult, and at first resembling branches of it.

Our dormant waters nourish five or six different species of
them, which differ in colour, and the number and proportion
of the tentacula.

The most celebrated, in consequence of the experiments on
reproduction, to which it has first given occasion, is

Hydra viridis, Trembley, Pol. i. 1. Rees. iii. Ixxxviii.
Encyc. Ix. vi., which is, in fact, of a fine clear green colour.
It is particularly found under the water-lentils.

Hydra fusca, 'Tremb. Pol. i. 3, 4. Rees. iii. Ixxxiv. Encyc.
]xix., is more rare ; of a grey colour; its body is not an inch
long, and its arms are more than ten.

CORINE, Geriner,

Have a fixed stem, terminated by an oval body, more con-
sistent than that of the hydre, open at the summit, and brist-
VOL. XII. K k

498 CLASS ECHINODERMATA.

ling on all its surface, with small tentacula. Some carry
heir eggs at the bottom of this body. (Tubularia coryna,
Gm. &c.)

CRISTATELLA,

Have in the mouth a double range of numerous tentacula,
curved into a half-moon, forming a sort of plume of this figure,
and attracting by their regular motion, the nutritive molecules.
These mouths are supported upon short necks attached to a
common gelatinous body, which moves like that of the hydre.
These animals are found in our dormant waters. To the
naked eye they appear like small mouldy spots. (Cristatella
mucedo, Cuv.)

VORTICELLA,

Have a fixed stem, often branched, and very much divided,
each branch of which terminates by a body, in the form of a
trumpet, or a bell. We behold issue from the aperture, in two
opposite groups, some filaments, which maintain a continual
motion, and attract the nutritive molecules. ‘The species are
numerous in our seas, and the majority too small to be well
distinguished but by the microscope. They form bushes,
arbuscula, plumes, and take other shapes, all very agreeable.

PEDICELLARIA

Are found between the spines of the echini, and are con-
sidered by divers authors, as organs of these animals. Never-
theless, it is more probable that they are polypi, which choose
these parts as their asylum. A long slender stem terminates
by a cornet, furnished at its extremity with tentacula, some-
times in the form of filaments, sometimes in that of leaves.

ORDER POLYPI POLYPIFERI. 499

LHIRD ORDER OF POLY Pi.

POLYPIFEROUS POLYPI

Form this numerous series of species, which for a long time
were regarded as marine plants, and whose individuals are, in
fact, united in great numbers, to form composite animals, for
the most part fixed like vegetables, whether they form a stem
or simple expansions, by means of the solid supports which
line them at the interior. The individual animals, more or
less analogous to the actiniz, or hydre, are all connected to-
gether by a common body, and receive their nutriment in
common ; so that what is eaten by one, profits the general
body, and all the other polypi. They have also a community
of volition ; at least, this is certain with respect to the species
not fixed, such as the pennatula, which are seen to swim by
the contractions of their stems, and by the continued move-
ments of their polypi.

The name of polyparia has been given to the common parts
of these composite animals. They are always formed by depo-
sition, and by strata, like the ivory of the teeth ; but sometimes
they are at the surface, sometimes in the interior of the com-
posite animal. These different positions have given rise to
the establishment of the families of this order.

The first family,

POLYPI TUBIFERI,

Inhabit tubes, the common gelatinous body of which traverses
Kk2

500 CLASS ECHINODERMATA.

the axis, like the pith of a tree, and which are open either at
the summit, or at the sides, to allow the polypi to pass.

Their most simple polypi appear principally to resemble the
hydrz, and the cristatellz.

TUBIPORA, L.,
Have simple tubes, of a stony substance, each containing a
polypus. These tubes are parallel, and united together from
space to space, by transverse laminz, which has caused them
to be compared to the tubes of an organ.

The most known species, Tubipora musica, L. Seb. iii. cx.
89, is of a fine red. Its polypi are green, and have the form
of the hydre. It abounds in the Indian Archipelago.

It would seem, that it is to the tubipora that we should ap-
proximate some fossil polyparia, likewise composed of simple
tubes, such as the CATENIPORA, Lam., in which the tubes
are arranged upon lines, intercepting empty meshes; Twbi-
pora catenulata, Gm. ‘The FavositsEs, id. (Corallium
Gothlandicum) composed of hexagonal tubes, crowded closely
together, &c.

TUBULARIA, L.,
Have simple or branched tubes, of a corneous substance, from
the extremities of which the polypi issue forth, and show
themselves.

The polypi of the fresh-water tubularie,—PLUMATELLA,
Bosc. appear very much akin to the crystatelle, in the dispo-
sition of their tentacula.

We have some which creep over the plants of our dormant
waters. (Tubularia campanulata, Res.)

TUBULARIA MARINA,

Have polypiwith two ranges of tentacula; the exterior one
being developed in radii, the interior raised in the style of a

tuft.

ORDER POLYPI POLYPIFERI. 501

Our coasts produce one, Tub. indivisa, Lam. Ellis. Corall.
Xvi. c., with simple tubes, two or three inches high. Similar
to blade of straw.

TIBIANA, Lamour.,

Have zig-zag tubes, which give out from each angle, a small
open branch. (Tibiana fasciculata, Lam.)

CoRNULARIA, Lam.,

Have small conical tubes, from each of which issues a polypus,
with eight denticulated arms, like those of the alcyones, gor-
gones, &c. (Tubularia cornucopia.)

ANGUINARIA, Lam.,

Have small cylindrical tubes, adhering to a creeping stem,
each of which is opened laterally near its extremity, for the
passage of a polypus. (Sertularia anguina, Ellis.)

CAMPANULARIA, Lam.,

Have the ends of the branches through which the polypi pass,
expanded into the form of bells.

Lamouroux distinguishes them into CLyTIA, which have
climbing stems. (Sertularia verticillata, Ellis, &c.)

And into LAOMEDEA, which have not climbing stems, and
in which the bells are smaller, and with shorter branches.
(Sert. dichotoma, Gm., &c.)

SERTULARIA, L.,

Have a corneous stem, sometimes simple, sometimes branched,
and in its sides some cells of very various forms, occupied by
polypi, all attached to a gelatinous stem, which traverses the
axis after the manner of the pith of a tree. These zoophytes
have the appearance of little plants, equally delicate and

502 CLASS ECHINODERMATA.

agreeable to view. ‘Their propagation goes on by eggs, or
gemme, which are developed in some cellules, larger than the
others, and of different forms.

The various directions of their cellules, have given rise to
their distribution into several subdivisions. 'Thus when the
little cells are ranged on one side only over the branches, they
are then the AGLAOPHENIA of M. Lamouroux, which M.
de Lamarck names PLUMULARIA. (Sert. Myriophyllum,
Gm., &c.)

When they are assembled in certain places, like the small
tubes of an organ, they constitute AMATIA, Lamour., or
SERIALARIA, Lam. (Sertularia lendigera, Ellis.)

We may distinguish from them the species in which the
cellules thus disposed, surround the stem with a spiral figure.

When the cellules are placed around the stem, in horizon-
tal rings, these are the ANTENNULARIA, Lam., which M.
Lamouroux had named CALLIANYRA, and has since changed
into NEMERTESIA. (Sertularia antennina, Gm. &c.)

Thus the name of SERTULARIA proper, remains to those
species only in which the cells are on both sides of the stem,
whether opposed, Sert. abietina, Gm., &c. or alternate.
Sertularia operculata, Ell., &c. M. Lamouroux distinguishes
the first under the name of DYNAMENES.

The extreme smallness of the cellules has also caused him
to establish the genus THamA, (Sertularia heelicina, Gm. &c.)

The second family is that of

POLYPI CELLULOSI,

In which each polype is adherent in a corneous or calcareous
cell with their parietes, and does not communicate with the
others but by an external tunic very much attenuated, or by
fine pores, which traverse the parietes of the cellules. These
polypi have a general resemblance to the hydrz.

ORDER POLYPI POLYPIFERI. 503

CELLULARIA, L.,

Have cellules disposed so as to form branching stems in the
manner of the sertulariz, but without any tube of communi-
cation in the axis. Their substance besides, is more calca-
reous.

Lamouroux distinguishes among them the

CRISIA,

Whose cellules in two ranks, usually alternate, open on the
same face. (Sertularia eburnea, Gm., &c.)

ACAMARCHIS,

Which, with the same disposition, have a vesicle at each
aperture. (Sertularia neritina, Gm.)

LORICULA,

In which each articulation is composed of two cells, back to
back, whose opposite orifices are towards the top, which is
widened. (Sertularia loricata, Ell.)

EUCRATIA,

In which each articulation has but a single cellule, with an
oblique aperture. (Sertwlaria chelata, Gm., &c.)
We may approximate to them

ELECTRA, Lamouroux,

In which each articulation is composed of several cells, dis-
posed like aring. (Flustra verticillata, Gm.)

We should separate from them those which have cylindri-
cal articulations, empty in the interior, and hollowed at all
their surface with cellules, disposed like a quincunx. They
conduct to the flustrz, and perhaps to the corallme. I name
them SALICORNARIA, (Cellularia salicornia, Ellis, &c.)

504 CLASS ECHINODERMATA.

FLusTRA, L.,

Present a great number of cellules, united like the combs of
bees, and sometimes covering divers bodies, sometimes form-
ing leaves or stems, of which one side only is furnished with
cellules in certain species, and both in others. Their sub-
stance is more or less corneous. (Flustra foliacea, Gm.
&c. &c.)

CELLEPORA, Fadri.,

Present accumulations of little cellules, or calcareous vesicles,
crowded one against the other, and each pierced with a small
hole. (Cellepora hyalina, Gm., &c.)

TUBULIPORA, Lam.,

Are accumulations of little tubes, the entrance of which is as
broad as or broader than the bottom. (Millepora tubulosa,
Gm )

Some bodies exist in the sea, pretty similar to polyparia,
in their substance and general form, but in which no polypi
have as yet been observed. Their nature is therefore doubt-
ful; and some great naturalists, such as Pallas, and others,
have considered them to be plants. Nevertheless, there are
several who regard them as polyparia, with polypi, and with
cells exceedingly small. If this conjecture be true, they must
belong to the present order. Those among them whose inte-
rior is filled with corneous filaments present, however, some
analogy with the CERATOPHYTES.

CoRALLINA, L.,
Have articulated stems, supported on a sort of roots, divided
into branches equally articulated, at the surface of which no
pores are visible, and in which it has not been possible to per-
ceive any polypi.

ORDER POLYPI POLYPIFERI. 505

They are divided as follows :

CoRALLINA proper,

Have their articulations calcareous, of an homogeneous ap-
pearance, without any perceptible bark.

The bottom of the sea is entirely covered on certain shores,
with the Corallina officinalis, L. Ell. Corall. xxiv. a. A.b. B.,
the articulations of which are in a reversed oval, the small
branches disposed like pinnated leaves, and themselves sup-
porting other branches similarly disposed. Itis white, reddish,
or greenish. It was formerly employed in pharmacy, because
of its calcareous substance.

Lamouroux again distinguishes from them, but rather
slightly,

AMPHITROE.

The articulations of which are elongated. (Corallina rigens,
Sol. et Ell., &c.)

JANIA,

Which merely have the branches more slight, and the articu-
lations less cretaceous. (Corallina rubens, Ellis, &c.)

CYMOPOLIA,

In which the articulations are separated one from the other,
by corneous intervals. Their surface exhibits more marked
pores.

M. de Lamarck had already separated,

PENICILLUS, Lam. Nesea Lamouroux,

Which have a simple stem, composed internally of corneous
fibres, woven together, and as it were, felted ; encrusted with
a calcareous plaster, and terminated by a bundle of articulated
branches, analogous to those of the ordinary corallines. (Co-
rall. penicillus, &c.)

506 CLASS ECHINODERMATA.

HALYMEDE, Lamourouz,

Have stems articulated and divided like the corallines; but
the substance of their articulations, which are very broad, is
penetrated in the interior by corneous filaments, which are
easily deprived of their calcareous crust, by acids. (Corallina
tuna, Sol. et Ell.)

FLABELLARIA, Lamarck,

Have no distinct articulations, but form large foliaceous ex-
pansions, composed like the articulations of the halymedes,
and the stem of the penicille, of corneous filaments, encrusted
with a calcareous envelope. (Corallina conglutinata, Sol.
et Ell., &c.)

GALAXAURA, Lamourouz,

Have stems divided by dichotomy, but their branches are
hollow. (Corall. obtusata, Sol. et Ell., &c.)

LriaGora, Id.,

Have hollow stems, divided by dichotomy, but without articu-
lations. (Corall. marginata, Sol. et Ell., &c.)

It is, perhaps, at the end of the corallines that we should
place

ANADIOMENE, Lamourouz,

Vulgarly known under the name of Corsican moss, and so
usefully employed as a vermifuge. It is composed of articu-
lations regularly disposed in branches, of a substance a little
corneous, covered with a gelatinous coat. (Anadiomene fla-
bellata, Lamour.)

Among those productions without apparent polypi, which
by conjecture are referred to the polyparia, there are few more
singular than

ORDER POLYPI POLYPIFERI. 507

ACETABULUM, Lain.

A slender and hollow stem, supports a round and thin plate,
like a parasol, striated in radii, crenulated at the edge, and
having at the centre a small smooth disk surrounded with
pores. No polypi are perceptible in it. ‘The radii of its disk
are hollow, and contain greenish grains, which has caused it
to be regarded as a plant by Carolini.

There is one of them in the Mediterranean. (Tubularia
acetabulum, Gm. Donat. Adri. iii. Tournef. Inst. ccecxviii.)

PoLYPHYSA, Lam.,

Have, like the preceding, a slender and hollow stem, but
which supports at its summit, a packet of small closed vesi-
cles, instead of a disk formed of tubes. (Pol. aspergillum,
Lamour.)

The third family,

POLYFPI corticati,

Comprehends the genera in which the polypi are all attached
by a common, thick, fleshy, or gelatinous substance, in the
cavities of which they are received and which envelopes an
axis of variable form and substance. The polypi of those
which have been observed, are a little more complex than
the preceding, and approach more to the actinie. In their
interior a stomach is distinguishable, from which proceed eight
intestines, two of which are prolonged into the common mass,
and the others terminating sooner, appear to fill the place of
ovaries.

They are subdivided into four tribes.

The first is that of

CERATOPHYTA,

In which the interior axis has the appearance of wood or horn,
and is fixed. Two genera are known, both very numerous.
13

508 CLASS ECHINODERMATA.

ANTIPATHES, Lin. Vulgo. Black coral,
Have the substance of their axis branched, and of a ligneous
appearance, enveloped in a bark so soft, that it is destroyed
after death. Accordingly, in cabinets they resemble branches
of dry wood. (Ant. spiralis, Sol. et Ell.)

Goreonl,, L.,

Have, on the contrary, this ligneous or corneous substance of
their axis, enveloped in a bark, the flesh of which is so pene-
trated with calcareous grains, that it dries up on the axis, and
often preserves its colours in a state of great beauty and viva-
city. It is dissoluble in acids. The polypi of several species
have been observed. They have each eight denticulated arms,
a stomach, &c. like those of the coral, and the alcyone. (Gor-
gonia pinnata, Gm., &c.)
M. Lamouroux distinguishes from these,

PLEXAURUS,
Whose thick bark, with cellules not projecting, makes but
little effervescence in acids. (G. Crassa, Gm., &c.)
EUNICEA,

Whose bark, organised like that of Plexaurus, has projecting
nipples, from which its polypi issue forth. (Gorgonia antt-
pathes, Seba, &c.)

MURICEA,

Whose bark, moderately thick, has projecting nipples, co-
vered with imbricated and bristling scales. (M. spicifera,
Lam.)

PRIMNOA,

Whose elongated nipples are imbricated, hanging one upon
the other. (Gorg. Reseda, Gm., &c.)

ORDER POLYPI POLYPIFERI. 509
The second tribe,

LITHOPHYTA,

Has the interior axis of a stony substance and fixed.

Isis, L.,

Have the axis branched, and without impressions or cellules,
hollowed at its surface. ‘The animal bark which envelopes
it, is mixed with calcareous grains, as in Gorgonia.

CoRALIUM, Lam.,

Has its axis without articulations, and only striated at its
surface.

It is to this subgenus that belongs

The coral of commerce. Isis nobilis, L. Esp. i. vii., cele-
brated for the fine red colour of its stony axis, and the fine
polish of which it is susceptible, which renders it particularly
adapted for the composition of various trinkets. Its fishery
is very productive in several parts of the Mediterranean. Its
bark is cretaceous and reddish. Its polypi, as in many other
genera, have eight denticulated arms.

MELITE, Lam.,

Have the stony substance of their axis interrupted by inflated
knots, of a substance similar to cork. (sts ocracea, Espern.)

Isis, properly so called. Lam.,

Have it interrupted by strangulations, the substance of which
resembles horn. Their bark, thick and soft, falls more easily
than in the preceding. (Ls¢s hippuris, L., &c.)

M. Lamouroux yet distinguishes from the Isis, properly so
called,

510 CLASS ECHINODERMATA.

MopsEA,

The bark of which is thinner, and more adherent. (Isis di-
chotoma, Seba, &c.)

MADREPORA, Lin.,

Have their stony part sometimes branched, sometimes in
rounded masses, or in extended lamine, or in leaflets ; but
always furnished with lamellae, which are united concentri-
cally in points where they represent stars, or which end at lines,
more or less serpentine. In the living state, this stony part
is covered with a living bark, soft and gelatinous, and bristling
with rosettes of tentacula, which are the polypi, or rather the
actiniz, for they have generally several circles of tentacula,
and the stony lamine of the stars correspond, in some re-
spects, to the membranaceous laminz of the body of the acti-
nie. The bark and the polypi contract upon the slightest
touch.

The varieties of their general form, and of the figures which
result from the combination of their lamellz, have given rise
to several subdivisions, many of which, however, enter one
into the other. They cannot be definitively established, until
the relations of the polypi, with these dispositions, shall be
known.

When there is but a single circular star, or in an elongated
line, with very numerous laminz, these are the Funeta, La-
marck. Mad. fungites, L. Their animal truly represents a
single actinia, with large and numerous tentacula, and whose
mouth corresponds to the sunken part, where all the lamine
end.

We find among the fossils, stony polyparia, with a single
star, which appear to have been free from all adherence.
These are TURBINOLIA, Lamarck, Madr. turbinata, L. Cy-

ORDER POLYPI POLYPIFERI. 511

CLOLITHES, Mad. porpita, Linn., and TURBINOLOPSES,
Lamour. Turbin. ocracea, Lamour.

When the madrepore is branched, and there are no stars,
but at the end of each branch, it is a CARYOPHYLLIA, Lam.
The branches are striated ; at each star is a mouth surrounded
with many tentacula. (Madr. cyathus, Sol. et Ell., &c.)

OcULINA, Lam.,

Have small lateral branches, very short, which gives them the
appearance of having stars along the branches, as at the end.
(Madr. virginea, L., &c.)

MADREPORA (properly so called) Zam.,

Have all their surface bristling with little stars, with salient
edges.

His PocrILLopoRa have in the surface small sunken stars,
and pores in the internals. (Madr. damicornis, Esper.)

In SERIALOPORA, the little stars are ranged in lineal series.
(Madr. seriata, Pall.)

ASTREA,

Have a broad surface, most frequently convex, hollowed with
crowded stars, each of which has a polype furnished with
numerous arms ; but on a single range, at the centre of which
is the mouth. (Madr. radiata, Sol. et Ell., &c.)

When the surface is plane, or in broad laminz, sown with
stars on one side only, the animals are named EXPLANARIA.
(Madr. cinerascens, Sol. et Ell.)

The PoRITES are in some sort ramous astree. (Madr.
porites, Sol. et Ell.)

When this surface is hollowed with elongated lines, as it
were with valleys, separated by hillocks, furrowed cross-wise,
the animals are MEANDRINA, Lam.

512 CLASS ECHINODERMATA.

In each valley, from space to space, open some mouths, and
the tentacula, instead of forming rosettes around these mouths,
form a range along the sides of each valley. Some species
have none at all, but the margin of each mouth is merely
festooned. (Madr. labyrinthica, Sol. et Ell., &c.)

If the hillocks which separate these vales, are raised in
leaflets, or crests furrowed on both sides, the species are
PavoniA. There are mouths in the bottom of the valleys,
and usually without tentacula. (Madr. agaricites.)

When these hillocks are elevated in cones, as if they were
salient stars, M. Fischer names them HyDNoPHORA, M.
Lamarck, MONTICULARIA. They should be distinguished
according as their polypi are at the summit of the salient
part, as in the oculine, or in the bottom of the concave parts,
as in the meandrine. (Madr. exesa., Sol. et Ell.)

AGARICINA,

Are composed of laminz, hollowed on one side-only, by
valleys which are themselves furrowed. (Madr. cucullata,
Sol. et Ell.) :

It has been thought that we might approximate to the
madrepores in general, certain polyparie ; SARCINULA, Lam.,
formed of cylinders, whose section forms a star, in conse-
quence of the projecting lamina, which traverse the interior,
Madr. organum, Lin.; when there is a solid axis in the
middle of the lamine, these are SryLIN&Z. These polyparie
may also, perhaps, be related to the tubipora.

MILLEPORA, L.,

Have their stony part of very various forms, and its surface
only hollowed with small holes, or pores, or even without any
apparent holes.

M. Lamarck distinguishes

ORDER POLYPI POLYPIFERI. 51S

DISTICHOPORA,

In which the pores, more marked, are ranged on both sides of
the branches. (Millepora violacea, Pall.)
Among those in which the pores are equally divided, we
distinguish
MILLEPORA, (proper) Lam.,
Solid, diversely branched. (Mill. alcicornis, Pall.)

When their pores are not apparent, as sometimes happens,
they arenamed NULLIPORA. (Millepora informis, L., &c.)

EScHARA, Lam.,

Which have expansions flatted like leaflets. (Millepora
foliacea, Ell., &c.)

RETEPORA, Id.,

Which are eschare, pierced with meshes. (MMJ7llepora cel-
lulosa, Ell.)

ADEONA, Lamouroux,

Which are eschare supported on an articulated stem. There
are some entire, and some pierced with meshes. (Ad. grisea,

Lamour.)
The third tribe,

POLYPARIA NANTIA,
Whose axis is stony, but not fixed.
PENNATULA, L.,

Have the body common, free from all adherence, of a regular

and constant form, and able to move by the contractions of

its fleshy part, and also by the combined action of its polypi.

This body is fleshy, susceptible of being contracted, or dilated,
VOL. XII. Ll

514 CLASS ECHINODERMATA.

in its divers parts, by means of fibrous layers which enter
into its composition. Its axis enclosesa simple stony stem.
The polypi have generally eight denticulated arms. Most of
the species shed a lively phosphoric light.

Whatever may be the general form of the pennatule, they
have always one of their extremities without polypi. This
has been compared to the tubular part of the feathers of birds.

PENNATULA, (properly so called) Cwv.,

Which, having given their name to the whole genus, have them-
selves derived it from their resemblance to a quill. The part
without polypi is cylindrical and terminated in a blunt point.
The other part is furnished on each side with wings, or barbs,
more or less long, and broad, supported by spines, or stiff
sete, which spring from their interior, and bristle one of their
edges, without, however, being articulated with the petrous
stem of the axis. It is from the centre of these barbs that the
polypi issue forth.

The Ocean and the Mediterranean both produce

Pennat. rubra, et Penn. phosphorea, Gm., Albinus Annot.
Acad, i. vi. 3—4. Which has the stem between the barbs
very rough behind, except on a line which traverses its
length.

We find more particularly in the Mediterranean,

Pennatula grisea, Gm., Albinus, Annot. Acad. 1, 2. larger,
with broader barbs, more spiny, and a smooth stem.

VIRGULARIA, Lam.,

Differ from the pennatule, only because their wings, much
shorter in proportion to their total length, are deprived of
spines. (Pennatula mirabilis, Mill., Zool., Dan. xi., very.
different from the true Pen. mirabilis of Linneus.)

These wings sometimes represent only simple transverse
ranges of tubercles. (Pennat. juncea, Pall. et Gm.)

ORDER POLYPI POLYPIFERI. ol

Or

SCIRPEARIA, Cuwv.,

Have the body very long and very slender, and the polypi
isolated, ranged alternately along both sides. (Pennatula
mirabilis, Linneus.)

PAVONARIA, Cuv.,

Have also the body elongated and slender, but have polypi
only on one side, and they are crowded there in the shape of
aquincunx. (Pennat. antennina, Bohatsch.)

RENILLA, Lam.,

Have the body short, and instead of the part, which in the
proper pennatula is furnished with barbs, a broad kidney-
formed disk, supporting the polypi on one of its faces. (Pen.
reniformis, Ellis.)

VERETILLUM, Cuv.,

Have acylindrical body, simple, and without branches, fur-
nished with polypi in a part of its length. Their bone is
usually small, and the polypi large. We can trace more
easily than in any other composite zoophyte, the prolongations
of their intestine in the common stem.

We have one in the Mediterranean, pennatula cynomorium,
Pall., Misc., Zool. xiii. 1—4; alcyoniwm epipetrum, Gum.,
Rap. Ac. Nat. Cuv. xiv. p. 2. xxxviil. 1. Often more than
a foot in length, thicker than one’s thumb, remarkable for the
brilliancy of the light which it sheds. Finaily,

OMBELLULARIA, Cuv.,

Have a very long stem, supported by a bone of the same
length, and terminated at the summit only by a branch of
polypi. (Pennatula encrinus, Ellis.)
We find in the sea, and among the fossils, some small
L12

516 CLASS ECHINODERMATA.

petrous bodies pierced with pores, which have been thought
to approximate to the millepora. If they were, in fact,
enveloped with a bark, containing polypi, they would be
moveable polyparia, and should rather be approximated to
the pennatule. Such are

The OvuLITES, Zin., in the form of eggs, hollow inter-
nally, and often pierced at both ends; the LUNULITES, orbi-
cular, convex, striated, porous on one side, and concave on
the other; the ORBULITES, orbicular, flat, or concave,
porous on both sides, or at the edges. If the DACTYLOPORA
is free, as M. de Lamarck thinks, it would also appertain
to this division. It is a hollow ovoid, open at both ends,
with two envelopes, both pierced with meshes, like the
retepora.

In the fourth tribe, the animal bark encloses only a fleshy
substance, without either osseous or corneous axis.

ALCYONIUM, Linn.,

Have, like the pennatule, polypi, with eight denticulated
arms, and intestines stretching into the common mass of the
ovaries; but this mass is not sustained by an osseous axis.
It is always fixed to the body, and when it is elevated into
trunks or branches, we find nothing in its interior but a
gelatinous substance, traversed by several canals, surrounded
by fibrous membranes. The bark is harder, and hollowed
with cellules, into which the polypi retire more or less com-
pletely.

We have in abundance in our seas the

Alcyonium digitatum, Ell., Coral. xxxii., which is divided
into thick, short branches ; Alc. eaos., which has more slender
branches of a fine red, &c.

Linneus, and his successors, have united, on rather slender
grounds, to the alcyonia, divers marine bodies of various tissue,
but always without visible polypi. Such are

ORDER POLYPI POLYPIFERI. 517

THETHYA, Lam.

The interior of which is altogether bristled with long sili-
ceous spirals, which are united on a central nucleus equally
siliceous. ‘Their crust presents, as in the sponges, two orders
of holes ; the one closed by a sort of trellis-work, must be for
the entrance of water; the other, gaping, destined for its
exit.

We also place at the sequel of the Alcyonia,

SPONGIA, L.

The sponges are marine fibrous bodies, which exhibit
nothing perceptibly, but a sort of thin, fine, gelatine, which
dries up, and scarcely leaves any trace, and in which, as yet,
no polypi, or any other moveable part, have been observed.
It has been said that the living sponges undergo a sort of
tremor, or contraction, when they are touched ; that the pores
with which their superficies is pierced, palpitate in some
degree; but the existence of such movements has been con-
tested by Mr. Grant, and other writers.

The sponges assume innumerable forms, each according to
its species, as those of shrubs, trumpets, vases, tubes, globes,
fans. ,

Every one is acquainted with the common sponge, spongia
officinalis, which is found in great brown masses, formed of
very fine fibres, flexible, elastic, and pierced with a great
number of pores, and small irregular conduits opening one
into the other.

518 CLASS ECHINODERMATA.

FIFTH AND LAST CLASS OF THE ZOOPHYTES,
AND OF THE ENTIRE ANIMAL KINGDOM.

INFUSORIA.

Iv is customary to place at the end of the animal kingdom,
some beings so small that they escape the naked eye, and
which remained undistinguished, until the microscope had,
in some sort, revealed to us another world. ‘The majority of
them present a gelatinous body of the most extreme sim-
plicity, and this, undoubtedly, is their proper place ; but there
have also been left among the infusoria, some animals much
more complicated in appearance, and which resemble them
only in their minuteness, and the habitat in which they are
usually found.

Of these we shall make our first order, still, however, in-
sisting on the doubts which yet remain relative to their
organization.

FIRST ORDER OF INFUSORIA.

ROTIFERA,

Are distinguished, as we have just said, by a greater degree
of complication. Their body is oval and gelatinous. A

ORDER ROTIFERA. 519

mouth, a stomach, an intestine, and an anus near the mouth,
are distinguishable. Behind, the body is most frequently
terminated by @ tail, variously constructed, and in front it
supports a singular organ, diversely lobated, with denticulated
edges, the denticulations of which execute a successive vibra-
tion, which might cause the belief that this organ consisted in
one or several denticulated and revolving wheels. One or
two prominences on the neck, have even appeared to some
observers to support eyes. This revolving organ does not
serve to conduct the aliments towards the mouth; it might be’
suspected that it has some relations with respiration.

FURCULARIA, Lam.,

Have the body without armature, the tail composed of articu-
lations, which enter one into the other, and terminate by two
filaments.

It is upon one of them, the Furcularia, or Rotifére des toits»
that Spallanzani has made his famous experiments, as to
their resurrection. Covered with dust in the gutters, it dries
up, but yet, after several weeks will resume life and motion,
if it be moistened with a little water.

TRICHOCERCA, Lam.,

Do not appear to me to differ from the Furculariz, but in a
little less development of their vibratile organs. (Zrichoda
paxillum, Miill., &c.)

VAGINICOLA, Lam.,

Appear to be only trichocerce, enveloped in a transparent
case; but in this instance, there is reason to fear, that some
optical illusion has taken place. (Trich. innata. Mill.)

TUBICOLARIA, Lam.,

Do not differ from the furcularie, except that they live in

‘520 CLASS ECHINODERMATA.

small tubes, which they construct with foreign molecules,
but which make no part of their body, like those of the
polyparia. Their rotatory organ, nevertheless, appears out
of the tube, pretty nearly after the manner of the head of the
polypi.

We have one common enough on the conferve of our
marshes. Vorticella tetrapetala, Blumenb., Dutrochet. Ann.
Mus. xix. xviii. 1—10, whose rotatory organ is divided into
four lobes.

BRACHIONUS, Miill.,

With rotatory organs, and a tail pretty nearly similar to
those of the furculariz, carry a sort of membranous, or
scaly buckler, which covers their back, like that of certain
monoculi.

SECOND ORDER.

INFUSORIA HOMOGENEA,

Whose body exhibits neither viscera, nor other complications,
and often does not even present any appearance of a mouth.

The first tribe

Comprehends those which, with a gelatinous body, more
or less contractile in its various parts, still presents as external
organs, some ciliz more or less strong.

They are named URCEOLARIA, Lam., when they have the
form of a trumpet, from which the ciliz issue, as in the polypi
called Vorticelle ; 'TRICHOD#, when with a flat body, these
cilie are at one extremity; LEUCOPHRA, when they sur-

ORDER INFUSORIA HOMOGENEA. 521

round the whole body; KERONA, when there are some large
ones, representing a sort of horns; HIMANTOPUS, when
these pretended horns are elongated into a kind of filament.
The second tribe
Presents those which have no visible external organs, unless
we consider a tail as such.

CERCARIA, Miill.,

Have, in fact, their oval body terminated by a filament. To
this genus belong, among others, the animalculz, which are
observed in the semen of different animals, and on which so
many fantastic hypotheses have been founded.

When this filament is forked, as sometimes happens, M. de
Lamarck names these animals 'TURCOCERCA.

VIBRIO, Miill.,
Have the body slender, and round, like the little end of a
thread.

It is to this genus that belong the pretended eels in glue
and vinegar. Vib. glutinis et aceti. These last often dis-
tinguishable by the naked eye. It is asserted that they
change skin, that they have sexes, produce living young in
summer, and eggs in autumn. The frost does not destroy
them. The first appear in the glue or paste of diluted flour.

ENCHELIS, Miill.,

Have the body oblong, softer, less defined than that of vibrio.
CYCLIDIUM have it flat and oval; PARAMECIUM, flat
and oblong; KoLpopa, flat and sinuous; GONIUM, flat and
angular; BursartiA, hollow like a sac.
The most singular of all are

PROTEUS, L.

No determined form can be assigned to them; their figure

522 CLASS ECHINODERMATA.

changes every moment, and successively assumes all kinds of
limits, sometimes rounded, and compact, sometimes divided

and subdivided into strips in the most fantastic manner.
(Proteus diffluens, Reesel.)

Monas, Miill.,

Resemble, in the microscope, little horns, which move with

great quickness, although without any apparent organ of
motion.

VoLvox,

Have a small globular body revolving on itself, and often
enclosing smaller globules, which, doubtless, serve to pro-
pagate the race.

SUPPLEMENT

ON THE

FOURTH AND LAST GRAND DIVISION
OF

ANIMALS.

THE ZOOPHYTES.

UNDER this complex denomination, which signifies animal
plants, we comprehend those animals, which, not being
symmetrical, are not capable of being divided into two
similar sides, situated at the right and left of a secant plane,
or imaginary line, which should pass through the length of the
animal, all the parts of which might be referred to this plane.
But, on the contrary, in the animals in question, the parts are
disposed, in a manner more or less regular, round a common
point, taken as a centre, or the axis of the body. This has
caused them sometimes to be compared to flowers, of which
all the parts have also this disposition. From this, Pallas
has derived the denomination of centrina, which he has
given to one division of these animals, which has been
changed to radiata, radiated animals, and actinozoaria, by
some writers.

524 SUPPLEMENT

This last type of the animal kingdom, we do not find de-
signated under a collective name, except by the ancient and
the most modern zoologists. ;

Thus Aristotle, who appears, nevertheless, to have known
some species of the principal classes which constitute it, has
never employed the word zoophytes as a collective name or
otherwise, although, in relation to the sponges, he has said,
that they partake more of plants than of animals, and that it
may be doubted whether they are animals or vegetables.
But the compound word zoophytes, is not to be found in his
works, though some authors have erroneously attributed it to
him.

It does not appear that he was acquainted with the ani-
mals which are designated at present under the name of holo-
thuria. He certainly employs this denomination, the etymo-
logy of which is unknown; but he applies it to beings which
have not the faculty of locomotion, though they are not at-
tached any where, which leads us to presume, that by this
word he indicated the actiniz, which, nevertheless, were de-
signated by him under the name of acalephos, and which, in
fact, he classes among the animals which partake at once of
the animal and plant.

Aristotle, on the contrary, was perfectly well acquainted
with the echini and the asteriz, which he designates, the first
under the name of sea-urchins, the second, under that of sea-
stars. But he has made them animals of his division of tes-
tacea; an approximation which we shall find to have been
admitted, even to the end of the last century. He distinguishes
several species very well, such as spatangus brissus, the
sea urchins proper, and a smaller species. But still it does
not seem that his distinction is established on characters
sufficient to enable us to recognize at the present day, in any
very certain manner, the animals of which he intended to
speak.

ON ZOOPHYTES. 525

As for the asteriz or sea-stars, which in one passage he
enumerates among the equivocal beings between the animal
and plant, while in another he ranges them with the testacea,
the little that he says is very incomplete, and not very easily
to be understood.

The medusz also appear to have been known to Aristotle,
but he confounded them with the actiniz, properly so called,
under the common denomination of sea-nettles, acalephe and
knide, which signify nettle. These, again, are beings whose
nature is equivocal between the plant and the animal. In
fact, he tells us, it is the property of an animal to move itself,
to direct itself towards its food, to feel what it encounters, and
to use in its defence the firm and hard parts of its body. But
to have an organization extremely simple, to attach itself with
facility to rocks, and to have a mouth, but no apparent orifice
for the issue of the excrements; all this is more of the nature
of the plant. In other places of his works, Aristotle enters
into some details of organization and manners, respecting his
acalephai. Among other matters, he tells us that there are
some which remain fixed upon rocks, and other submerged
bodies, and others which are detached from them ; an obser-
vation which has led several authors to think that he was
speaking of actiniz and medusz; but this opinion is not free
from doubt.

Of all the rest of the animals which constitute the zoophytes
of modern zoologists, it does not appear that Aristotle was
acquainted with any except the sponges, respecting which he
gives us some details of tolerable extent.

As to the animals which he calls polyp?, it is well known,
that they are not the same as those so called in the present
day. We have already seen in our observations on the mol-
lusca, that they are the octopi, respecting which he has left
us some valuable remarks.

526 SUPPLEMENT

It is not certain whether his Pnewmon be a medusa, as
some authors assure us, and not a testaceum. As to his
tethys, it is evident that they are our ascidie.

Pliny, as might be well imagined, has not added much to
what Aristotle has said, concerning the zoophytes. He has
confined himself to translating the Greek names of urchins,
sea-stars, nettles, and sponges, by those of echinz, stelle ma-
rine, urtice marine, and spongie, without adding any thing
to the little said by Aristotle. Neither has he, any more than=
the Greek philosopher, made use of the term zoophytes,
though he has most certainly declared that these beings were
neither plants nor animals, but something of an intermediate
nature.

Nor has Alian employed this denomination of zoophytes,
or animal plants; and if we do find in different parts of his
collection, the names of urchins, sea-stars, marine lungs, it
is only in relation to some peculiarities, altogether insignifi-
cant, and even completely erroneous.

Oppian, in his poem on fishing, has introduced nothing
more respecting these animals, than the authors which pre-
ceded him.

Sextus Empiricus appears to have really been the author
who first employed the term zoophytes ; but it does not seem
that he did so for the purpose of indicating the beings which
Aristotle regarded as intermediate between animals and ve-
getables. He tells us that they are beings which are found
in the roads, and are produced by fire.

Isidore de Seville, and much later, Albertus Magnus, em-
ployed this expression for the true zoophytes; but these
writers have added nothing to the observations of the ancients
on the natural history of the animals. The first translators of
Aristotle, Budeus, and Theodore Gaza, also employed it,
and since their time, it has been generally adopted.

ON ZOOPHYTES. 527

Wotton, in the very remarkable work which he published
upon animals, also employs the same word for the same be-
ings. In fact, his zoophytes comprehend the tethys, the
holothuriz, the star-fish, the sea-lungs, the sea-nettles, and
the sponges. In the same author the expression purgamenta
maris, is to be found for a division of beings, with the rela-
tions of which he was not acquainted.

From that period, all the naturalists, at the revival of
letters, employed the classic denomination of zoophytes;
but there was always some uncertainty in the application
which they made of the names left by the ancients, to the
objects which they had under their immediate eye. Moreover,
they ranged among the zoophytes, animals of classes alto-
gether different, which they designated by names derived from
some rude resemblance with terrestrial beings. Thus Belon
placed there the anatife, or pollicipes, with the sponges ; the
holothuriz, and the tethys, which he appears to have known
very little, and confounded together, although his tethys is
evidently an ascidia. On the contrary, he ranged the sea-
nettles, a denomination which he reserved for the actiniz,
among the mollusca, in the same manner as he treated of the
urchins, and sea-stars, among the testacea, specifying them,
however, in a tolerably complete manner.

Rondelet, a short time after, in adopting the same divisions,
made pretty nearly the same confusion; but he began to make
known, not only some new species, but some animals of
genera altogether new. He applied, in a definite manner,
the denomination of holothuria, to the animals which we
know at the present day under this name. Nevertheless, he
placed one species among the sea-nettles, and on the other
hand, referred to holothuria, a species of firola. He clearly
distinguished the tethyes, which are the ascidiz of the present
day ; and he applied, in a definitive manner, the name of free
sea-nettles to the meduse, and that of fixed sea-nettles to

13

528 SUPPLEMENT

the actinie, supporting this distinction by recognizable
figures.

These different improvements were inserted in his great
Dictionary, by Conrad Gesner, published for the first time in
1604. In fact, he gave a synoptic table of the species cf
sea-nettles, divided as Rondelet had divided them. The
urchins and sea-stars are united among the testacea; but
the eschare and pinnatule constitute the marine zoophytes.
Some other species were’ also indicated, and figured by this
author. He likewise perfectly perceived the order of the gra-
dation of organization in this last division from the sponges
which approximate the closest to the plants, up to the conchs
which are preceded by the univalve shells.

Aldrovandus exhibits, perhaps, better than Gesner, the
state of zoophytology, because his compilation is methodical.
In that work, we find these beings forming the last division of
the whole animal kingdom, and composed of the actinia, under
the name of fixed sea-nettles ; of the medusz, under that of
free sea-nettles ; of the alcyones, under that of marine lungs,
and malum granatum; of the holothurie ; of the ascidliz
(named tethyes) ; of the pinnatule (pinne marine) ; of the
lobulariz, under the name of manus marine, and probably of
the encrusting species. ;

The echini are definitively placed among the testacea;
but by avery remarkable singularity, the asteriz are placed
at the end of the division of the insects. There is no division
for the purgamenta maris.

Here terminates the first part of the history of this science,
in which we find the denomination of zoophyte generally
adopted, with the notion that the beings ranged in this divi-
sion, were intermediate between animals and vegetables ;
but still it contained as yet but the smallest number of the
beings which modern zoologists have subsequently referred.
to it. .

ON ZOOPHYTES. 529

Towards the middle of the age in which the work of
Aldrovandus had made known the state of natural history
in general, appeared one of the most interesting works respect-
ing the natural history of the zoophytes, a work which com-
mences the long series of those for which we are indebted to
the naturalists of Italy on the same subject. ‘This was the
Natural History of Ferrante Imperato, of Naples. Besides a
number of observations on the living animals which have been
since ranged among the zoophytes, (some, perhaps, errone-
ously) we find there, on the corals, the madrepores, the tubi-
pores, &c., the bases of the opinion generally adopted as to
the truly animal nature of these organized bodies ; but before
the truth of this opinion had been recognized, they were suc-
cessively placed in the other two kingdoms.

The ancients, who had a very imperfect knowledge of
corals—the genius of Aristotle having left them nothing on
the subject—determined, after the mere consideration of the
external form, to make vegetables of them, from whence the
names of lithophyton and lithodendron, under which they
were known for a long time after Dioscorides. Before him,
we find them designated by the denominations of coralium,
curalium, and, finally, of corallium, (the etymology of which
is uncertain), in Theophrastus, Pliny, and Ovid.

At the revival of learning, the numerous commentators on
Dioscorides went little farther than himself. It therefore ap-
pears that Imperato was the first who had a glimpse of the
gradual passage from the corals to the tubulariz, and to the
madrepores, and who recognized in these last, the animal
character grow more and more pronounced, to such a degree
that he compares them to the velelle. It is also in this
original author, that we find for the first time, the terms pore,
madrepore, millepore, retepore, tubipore, as well as those of
fungite, astreolite, porpite, &c., which have since been applied
to those determinate forms, which we call genera. We also

VOL. XII. Mm

530 SUPPLEMENT

find in him the denominations of alcyone, (already employed
by Dioscorides), of coralline, of sertularize, and many others,
which have been adopted as designatory of genera by modern
zoologists.

These germs remained, however, for a long time buried,
insomuch, that these organized bodies, whose existence
Imperato had marked by good figures, and by particular
denominations, were regarded during the whole course
of the 17th century, as appertaining to the mineral kingdom,
by some writers, or to the vegetable by others. Nevertheless,
these different authors, (deceived as they were respecting the
nature of corals, which they divided into lithophytes and
keralophytes, according as their solid part, the only part
which was known, was calcareous or corneous), did not the
less augment the number of species, and divide them into
genera, which they endeavoured to characterize in a more
precise manner. Thus it was that the corallines, and sertu-
lari, which they placed among the mosses, the eschare, the
alcyones, and even the pinnatule, of which they made fuci,
were successively and very clearly established into distinct
genera.

From this time, we remark, however, many authors already
who, like Boccone and Lluid, suspected the animal nature of
some of these productions. Thus the former, although he
would have it that the coral was a stone, and not a plant,
maintained, erroneously, perhaps, that the aleyoniwm asbes-
tinum was a hive of animals, and the latter was of opinion
that the twhularia indivisa should be regarded as a zoophyte.

These different facts coincided with the point of time at
which the classification of plants began to take as its bases,
the character furnished by the flowers. It was natural, there-
fore, that Marsigli, probably awakened to the subject by the
apothecaries of Marseilles, who considered some flowers as
coral, described as such the polypi, which he had observed in

13

a

ON ZOOPHYTES. 531

the alcyone palmata, in the true coral, and in the antipathes.
Thus the opinion of the botanists, who claimed all the corals, all
the polyparia, as belonging to the vegetable kingdom, appeared
to be confirmed, and the true nature of these beings was still
unknown for'some time, although some chemists had made
the observation that the principles which entered into their
composition were much more animal than vegetable, and
Marsigli himself had remarked that the flowers of the coral
disappeared, when it was put into fresh water, or with-
drawn from the water altogether. Accordingly, the moment
was at hand when they should definitively pass into the
kingdom to which they really belong, although, even in 1700,
Tournefort published a memoir to distinguish marine from
maritime plants, and in which he employs the manner in
which he supposes the madrepores to grow, to establish his
opinion on the germination and vegetation of stones. Reau-
mur himself, in 1727, published a memoir to explain how
stony bodies can vegetate, by supposing, that in the coral, for
example, it was the bark alone which vegetated, and which
formed a stem, by depositing the red grains with which it is
filled. Rumph, who had occasion to examine a great number
of living corals in the Indian Archipelago, where they are
spread in profusion, having established a particular division
for the zoophytes, was perhaps the first who demonstrated
the animal nature of these pretended plants, in many species.
But it was only in 1727, that Reaumur reported to the
Academy of Sciences, the celebrated discovery made by
Peysor nel, in the Mediterranean, of the animality of the
lithophytes, proving that what Marsigli had described and
figured as the flowers of coral, were real aggregated animals,
altogether analogous. to the actinie, and by no means what he
had himself described as the flowers of marine plants in the
memoir just mentioned, and before; consequently, that we
must regard the madrepores, millepores, and in general all
Mm 2

532 SUPPLEMENT

the lithophytes, or aggregated teste, as the habitations of
these animals.

This important discovery, to which Peysonnel was un-
doubtedly conducted by the observations of Marsigli, was not,
however, immediately adopted; and Reaumur himself, in the
memoir in which he reported it, endeavoured to contest its
evidence, and was even afraid to name its author. But he
was obliged to admit it, when Trembley, in a letter addressed
to him in the month of December, 1740, had published all
the singularities of the natural history of a little animal,
known in the fresh waters of Europe, and which, already
signalized by an anonymous writer, in the transactions of our
own Royal Society, had been forgotten for more than ten
years. We find, in fact, in the fresh water polypus, named
hydra by Linnzus, the naked type of the coral animals.

Shaw, the traveller, in his Voyage to Barbary, vainly pro-
posed to regard as simple nutritive radicles, the undulating
filaments which he saw come forth from the stelliform im-
pressions of the madrepora ramea, and from some other
aggregated living madrepores. The discovery of Peysonnel
acquired all the corroboration which it deserved, especially
from the coasting voyages of Jussieu. These voyages were
undertaken, one in the Channel, and the other in the Atlantic,
for the express purpose of verifying and extending this dis-
covery, by applying it to a greater number of beings, which
was done for the tubulariz and other genera. The name of
polypus appears to have been first employed by Bernard de
Jussieu, to designate the little animals, which, inhabiting
pretended marine plants, are provided on the head or body
with horns, (tentacula) which serve them as hands or feet, to
take their aliment or to walk.

Reaumur, from this time thoroughly convinced, fully adopted
the views of Peysonnel, thus confirmed by Jussieu and Guet-
tard. He created the name of polypier (polyparium ) since

ON ZOOPHYTES. jae

generally adopted, perhaps without sufficient discrimination,
to express the solid part, of whatsoever nature it might be, on
which those little animals live, to which, with Jussieu, he
gave the general denomination of polypi. This name he had
given to those discovered by Trembley, because their tenta-
cula or horns appeared to him to be analogous to the arms of
the sea-animal which the ancients had named polypous. ‘Thus
definitively returned into the animal kingdom an entire and
an extremely numerous class of beings, which from the imti-
mate nature of their union, had been so long considered as
vegetables, and which, considered in part, had been re-
cognized as animals approximating to the actiniz, and con-
sequently entering into the grand division of the zoophytes.

Notwithstanding all these circumstances which we have
now detailed, and more which it might prove tedious to enu-
merate, Linneus, who in the first editions of the Systema
Nature, had imitated Ray, in placing the lithophytes, in the
vegetable kingdom, still preserved some doubts. In a disser-
tation on the corals of the Baltic, after enumerating succes-
sively the objections to the opinions of those who have main-
tained that these bodies were minerals, vegetables, or ani-
mals, he professes that he considers it a difficult matter which
opinion to choose. Some time after, however, he was con-
vinced of the truth, and in the sixth edition of his immortal
work, admitted them into the animal kingdom.

Thus at this second period of the science, the zoophytes
were definitively ranged in the animal kingdom, by systematic
writers. But they were still very far from being grouped and
united in a suitable manner, as we shall see in our examina-
tion of the particular researches of some writers on the
subject.

One of the first works which tended to bring this science
to perfection, was published by Vitali Donati, on the Adriatic

534 SUPPLEMENT

Sea, in which he has described the animals of a considerable
number of polyparia, already figured by Imperato.

It was also at the same period, that the more or less flex-
ible polyparia, known under the names of Sertulariz, &c. were
much better distributed, owing to the remarkable labours of
Ellis upon the corallines—labours which have served as the
basis of every thing valuable which has been subsequently
performed respecting the genera of these animals. This
writer, however, has not been eminently happy in the metho-
dical distribution of the numerous species which he has ex-
amined. He has united almost all of them under the com-
mon denomination of corallines, as Ray had done, who re-
garded them as plants.

Notwithstanding these new researches of Ellis, which
seemed irrefragably to confirm the discovery of Peysonnel,
some authors, and especially Hill, Targione, and Baster, were
still inclined to oppose the system—so difficult is the progress
of truth. But Ellis refuted these objections so completely in
the Philosophical Transactions, that Baster himself gave way
and adopted his opinion.

While the division of the zoophytes was augmenting in
number and consistency, by the approximation of newly dis-
covered beings, or of such as had been for a long time re-
moved from it, the groups which had been anciently admitted
into it, became more extended and better known by the par-
ticular labours of zoologists and travellers. Thus Link, in
1755, published a monograph of the asteriz, which still forms
the basis of all that has been done on the distribution of the
species of this very remarkable family. Others followed in
the same track, and by their attention to particular subdivi-
sions, illustrated and extended our knowledge of these

animals.
About the same time the observations of Trembley on

a i

ON ZOOPHYTES. San

animals of pretty small dimensions, led to the study of ani-
mals still smaller, to which the name of microscopic has been
given. Leuwenhoék and Hartsoéker led the way, but were
ably followed by Hill, Resel, and others, who considerably
augmented the number of discoveries in this kind. The dif-
ficulty of observation, and the want of proper principles to
guide most of the observers, prevented those animals from
being sufficiently known, to justify systematic writers in as-
sembling them in a single group, or even uniting them to the
zoophytes. All subsequent zoologists left them in the same
state, just as if the degree of size was of necessity in relation
with the degree of organization.

The first systematic author in which we find the micro-
scopic animals arranged, appears to be Hill. As, however,
he did not admit the system of subdivision founded upon
Aristotle, and has no class under the name of zoophytes, it
is not easy to analyze his labours. The animals to which the
most recent zoologists give this name, are placed by this
author in sections exceedingly remote from each other. The
infusoria, under the name of anzmalcule, are placed altogether
at the commencement of the animal kingdom. It would be
equally superfluous and disagreeable to follow him through his
groups, and to repeat his learned, but very cacophonous ap-
pellations. It is sufficient to remark, that in his system, or
no system, the meduse, actiniz, hydre, and asteriz, are in
the same section with the naked mollusca, and that the
setigerous annelida are between the insects properly so called,
and the amphibia, vertebrated animals.

- The work of Pallas on the zoophytes, may be considered
as one of the most classic, and the best executed which we
possess in zoology. He does not, however, by any means
treat of all the animals now comprehended under the name
of zoophytes; nor, indeed, are scarcely any of the animals

536 SUPPLEMENT ON ZOOPHYTES.

which the ancients regarded as intermediate between veget-
ables and animals, to be found among the zoophytes of
Pallas; but he has all those with which they were not ac-
quainted, or which they believed to appertain to the mineral
kingdom, that is, their Corallia.

SUPPLEMENT

ON THE

FIRST CLASS OF ZOOPHYTES.

THE ECHINODERMATA.

THIS term was invented by Klein, and applied by him with
sufficient exactitude, as he only comprehended under this
name the echini of Linneus, (echinites, Lam.) all of which
have the skin covered with hard prickles, varying somewhat
in form, which has caused them to be compared to hedge-hogs.
But Bruguiéres, by uniting under this name the asteriz to
the echini, has certainly not proved so correct in nomencla-
ture, inasmuch as none of the latter present any traces of
prickles on the surface of the skin. M. Lamarck, and the
authors who have followed him, have rendered this name still
more equivocal by including under it the holothurie, and
even the sipunculi, which may be considered almost as ge-
nuine worms. M. de Blainville has restrained this name to
the three orders, holothuriz, echinites, and asterias ; but is yet
of opinion, that the name of placyrodermata, would better
distinguish them, as indicating the principal character which
they present, which is the existence of a great number of ten<
tacular and respiratory suckers, by means of which the animal
performs the function of locomotion.

538 SUPPLEMENT

The ASTERIZ, or STAR-FISH, whose species are greatly
multiplied in all known seas, are remarkable for their stellated
form. Their body is invested with a coriaceous substance,
bristling with tubercles or spines, or covered with scales. In
some species it has the figure of a flatted pentagon. In others,
the angles of the disk extend in lobes, or are elongated into
radii, most frequently five in number, sometimes more numer-
ous, and simple, or divided into ramifications.

~The mouth, armed with five teeth, of a calcareous sub-
stance, is placed at the central part of the animal underneath.
No tentaculum is remarked there. It leads into a membra-
naceous sac, of small extent, which serves as a stomach, and
from which the excrements are rejected, and issue through the
same aperture. O. Fabricius, and Bosc, are, indeed, of opi-
nion, that the excrements are filtrated through an osseous
tubercle, which is observable in the back of the asterie, a
little on one side. But this opinion cannot be well founded,
inasmuch as this tubercle is not existent in all the species of
the genus. It seems to be generally wanting in the ophiuri.
Besides, we are not acquainted, as it would seem, with any
other animal, in which it is necessary that the excrements
should pass through a filter, to issue forth from the sac, or
alimentary canal. Some short, cylindrical, retractile tenta-
cula, very numerous, ranged in pairs underneath, or on the
sides of the divisions of the animal, are developed on the in-
stant, in which it is desirous to hook itself, or to walk. We
see on its upper part, but only while it isin the water, an in-
finity of small conical tubes. The mouth is a sort of respira-
tory organ, which constitutes with the stomach, and the ovary
divided into as many pairs of branches as there are arms, all
the apparent organs of the asteriz. Some osseous articulated
stems form the skeleton of each branch. A net-work of the
same nature strengthens the rest of the envelope.

The asteria are very voracious; they walk with difficulty,

ON ECHINODERMATA. 539

and very slowly. When they swim, they are seen to present
their body obliquely to the action of the water, and to agitate
their radii slightly. When they want to descend, they sus-
pend all motion, and allow themselves to fall perpendicularly
to the bottom. When they have succeeded in getting a shell,
they suck out the animal from it through the aperture. They
possess a wonderful power of reproduction.

The text is sufficiently explanatory of the organic differ-
ences which distinguish the genera.

ENCRINUS was a name first proposed by Ellis, to desig-
nate a very singular animal, whose place is still uncertain
enough in the natural series, so much so that while many
naturalists, with Guettard and Ellis, place it with the family
of asteriz, others with Linnzus, range it with the polyparia,
near the Isis. Ellis, in 1761, read to the Royal Society, a
very interesting memoir on this same genus, having made his
observations on an individual which came from the coast of
Barbadoes. This genus does not appear even yet to have
been examined with all the attention it deserves, for it seems
indubitable that some of its species, no longer in our present
seas, must have been very common there anciently, since
nothing is more multiplied in certain calcareous strata, than
these fossil remains, known under the names of entrochi, en-
crinites, &c. Our limits will not permit us to enlarge on the
characters of this genus, for which we must refer to the text
of Cuvier.

These animals, very probably, live in the bottom of the
sea, at considerable depths ; but it is not even known whether
they are fixed there, which, however, appears very likely to
be the case. It is to chance alone that the discovery has been
owing of three or four individuals only, which exist in the
European collections, and which come from the American
seas.

Under the denomination of ECHINUS, Linnezus, and the

540 SUPPLEMENT

zoologists of his school, comprehended all the animals, more
or less orbicular, whose cretaceous envelope bristles with a
number of spines, of a form more or less variable, and con-
stantly calcareous. This has caused these animals to be
compared to hedge-hogs, and accordingly, they are popularly
termed sea hedge-hogs, or urchins, and sometimes sea chest-
nuts. But at the present day, among modern zoologists, since
the researches of M. de Lamarck, this name is reserved for a
certain number of species, for those which really better merit
the title, in consequence of the long spines with which they
are armed. .

The exterior envelope, which determines the form of an —
echinus, (which is described in the text) can be compared to
nothing which exists in other animals. In the greatest part
of its extent, it is formed by two membranes, one external,
and thicker, the other internal, and so thin, that the name of
pellicle perfectly suits it, and between which there is a toler-
ably thick and solid testa, completely calcareous, and com-
posed of a great number of small polygonal pieces, evidently
immovable, but not cemented, at least, during the growth of
the animal. In the neighbourhood of the mouth and of the
anus, the skin is not thus solidified, accordingly, it is sensibly
thicker, and much more resistant.

The testa of the echini is entirely calcareous, almost without
any mucilaginous or animal part, and is fibrous perpendicu-
larly at the surfaces, which proves that the mode of growth,
though taking place upon the edges, nevertheless differs much
from the same operation in the shell of the mollusca.

The pieces which constitute the testa of an echinus may
be divided into coronal, and terminal. ‘The coronal are those
which by their union form the most important part, the most
extended, and which circumscribe the body in its circumfer-
ence; and the terminal are those which surround the buccal
orifice, and the anal orifice, and which fill the two apertures

ON ECHINODERMATA. 541

more or less considerable, which are left below or above, by
the assemblage of the coronal part.

The coronal pieces are subdivided into ten groups or series,
which radiate from one orifice to the other, a little like the
ribs of melons, and which form areas alternately full and per-
forate, equal or unequal. The name of ambulacraria, is
given to the series which are perforate, and that of anambu-
lacraria, to those which are not.

The anambulacraria are themselves constantly formed of
two series of pieces, more or less hexagonal, and usually
transverse, which are united at one extremity in the middle
of the anambulacrarium, and at the other, but less angularly,
with the ambulacraria. Each piece is raised at its external
surface, with a variable number of mammillz, more or less
projecting, well-rounded, polished at their summit, and wi-
dened at the base, without any trace of perforation.

The ambulacraria, sometimes more narrow than the others,
are, nevertheless, likewise formed of two series of polygonal
pieces, united angularly together in the middle line of the
ambulacrarium, and externally with the pieces of the anam-
bulacraria. They are also raised with mammillz, more or
less salient; but, besides, they are pierced at their external
side by pores, variable in number, and in disposition, for each
species, but which always traverse the testa from one part
to the other. This is what constitutes the ambulacra, pro-
perly so called.

The breadth of the anambulacraria is generally greater at
the middle than at the two extremities; but this is not the
case with the ambulacraria. They are always larger towards
the mouth, and the last presents at the interior a sort of apo-
physis or lamina, pierced with a hole in its middle, and which
affords an attachment for the motor muscles of the teeth.
These are named auricule.

The skin which surrounds the mouth is scarcely rough ;

542 SUPPLEMENT

there may, however, be remarked on it, some pairs of sub-
circular scales, a little concave, and which are exactly placed
two by two, in the direction of the ray, which should go into
the interstice of the teeth; each is pierced with an orifice.

Around the anus the coronal pieces fill almost com-
pletely the spaces which are left by the areas. They are, like
these latter, ten in number, alternately great and small. All
of them are usually granular, and pierced with a hole, much
broader, however, in the Jarge than in the small ones, which
correspond to the ambulacraria ; the large ones correspond to
the anambulacraria.

The holes with which the pieces of the ambulacraria are
pierced, give passage to small tentacular cuppers, proceeding
from the interior lamina of the skin, perhaps, from the hollow
respiratory lamine in their entire length, and terminated at
their extremity by a small swelling susceptible of being di-
lated into a cupper, or into a disk denticulated at its circum-
ference. 'These organs are remarkable for the great contrac-
tility which they possess, and can re-enter completely into the
interior, something like the horns of snails, or be considerably
elongated at the exterior.

Another portion of the locomotive apparatus of the echini,
is that from which their name is taken, though more frequently
these organs merit the name of little clubs, or tubercles, ra-
ther than that of bristles. What they offer in common, is the
having at their base, a small spherical concave head, with a
circular pad above. Their length, their form, and their thick-
ness, are extremely variable, and generally in relation with
those of the mammille of the testa. Their structure is equally
peculiar. When broken they have a vitreous sort of brilli-
ancy. ‘Their external surface is almost always finely striated,
and they are composed of concentric strata, each of which is
formed of a great number of irradiated fibres.

These organs, articulated like a knee on the mammille of

ON ECHINODERMATA. 543

the testa, are put in motion in every direction by the external
lamina of the cutaneous envelope, which attaches itself to the
circumference of the pad of their base, and which appears
stronger, and more evidently muscular at the spines of the
base of the echinus. In desiccation, it is impossible to per-
ceive any distinct muscular fibres, and sometimes even any
muscles, properly so called.

These animals are all aquatic and marine. They, never-
theless, constantly live on the sea-shore, in rocky and sandy
places. They are very rarely found abandoned by the tide.
It would seem, that if too much advanced to recede, they
possess the faculty of sinking more or less deeply into the sand.
In this case, it is easy to recognize the place where they are,
by the existence of a small hole in the form of a funnel, which
is remarked at the surface of the sand. They sink and recede
considerably less when the weather is fine, than when it is
tempestuous.

The echinus, in locomotion, which is never very quick,
makes use of its tentacular suckers, and its prickles, and es-
pecially of the inferior ones. But it appears, that this cannot
take place, except on a resistant soil. In the first case, it
elongates as far as possible (and it is astonishing the extent
to which it can be done) a certain number of the suckers,
which are in the direction in which it wishes to go. It at-
taches these strongly to some solid body, causing a vacuum
by means of the cuppers which terminate them, after which it
contracts them, and thus draws its body towards this point.
By thus reiterating the same manceuvre, the echinus may,
without doubt, advance with some degree of rapidity. In
the second case, when it employs its prickles, it extends those
on the side where it wishes to move, to the utmost possible
degree. Then it lowers them, pushing itself on with those on
the opposite side; and as it has some in all directions, it is
evident that it can walk in all ways. In general, its progress

544 SUPPLEMENT

is performed by turning, although the animal, never-
theless, finishes by arriving at the end which it desired to
attain.

The echini are said to be eminently carnivorous. It is even
admitted that they feed upon crustacea and bivalves, but
this is probably rather a conjecture deduced from the strength
of their jaws, than a fact ascertained by observation. M. de
Blainville has opened many, either taken alive, or preserved
in spirits of wine, and never found any thing but sand in
their stomach. M. Bosc, however, was a witness of the
mode in which an echinus got possession of a crustaceum ;
and it appears, that as soon as the latter was caught by some
of the tentacular suckers, it was speedily masticated, and
swallowed.

We are yet ignorant of the mode of reproduction in the
echini. We only know that it is in spring that they deposit
their spawn, which appears to contain an almost countless
number of eggs; and it is probable, that it is rejected in a
mass all at once. But it does not appear that any naturalist
has witnessed this.

Genuine echini are known in all the quarters of the globe.
The largest and most numerous, however, belong to the seas
of warmer latitudes.

The HOLOTHURIE were placed by Linnzus and Bruguiéres
among their molluscous worms; and subsequently ranged
by Pallas, Cuvier, and Lamarck, who better studied their re-
lations near the asteriz and echini. We shall not repeat the
characters of this genus here.

Many authors, such as Hill, Brown, and Baster, have
given the name of actinia to this genus. Linneus, for some
time, gave it that of priapus. Gcertner preferred the deno-
mination of hydra, and confounded these animals with the
actiniz proper. This wasimitated by Bohatsch. Pallas re-
turned to the name of actinia, which he divided into two sec-

ON ECHINODERMATA. 545

tions; one comprehending the holothuriz, and the other the
true actiniz.

The holothuriz, which the ancients usually comprehended
under the vague name of purgamenta maris, or of pudenda
marina, are found, as it would seem, in every sea, the deep-
est parts of which they most particularly inhabit, even as far
as three hundred feet and more. It is even to this cause that
the peculiarity seems owing, of these animals vomiting, as it
were, their intestinal canal, in consequence of the great dif-
ference of pressure. They more particularly remain in the
oozy bottom, and in the anfractuosities of the rocks, where
they fix themselves by means of sorts of cuppers, or papilli,
from tentacula, with which certain parts of their bodies are
provided. They can, by means of these organs, draw them-
selves along over the submarine bodies, and thus change
place. But it appears, that they can do so likewise, either
by alternate flexions of the body, after the manner of worms,
or even by filling their body with water, and shooting it
forcibly through the anus, so as to be able to swim, assisting
themselves with their tentacula. They feed on pretty strong
marine animals. It is thought that they are hermaphrodites,
and that they reproduce by internal gemmule, like the acti-
niz, whence it has been said, that they are viviparous. Fa-
bricius, in fact, tells us that he found in the anal part of one
individual a young holothuria, swimming freely.

The organization of the holothuriz had been studied by
many anatomists, and among others, by M. Bohatsh, and by
Vahl, but inanincomplete kind of way. M. Tiedmann, in his
dissertation, which gained him the prize proposed by the
Academy of Sciences in Paris, has added very considerably
to our acquaintance with this subject.

The species of this genus appear to be rather numerous,
and especially so in the seas of cold countries. But they
have been in general too ill described to be charac-

VOL. XII. Nn

546 SUPPLEMENT ON ECHINODERMATA.

terized. Some small generic groups have been introduced
by some naturalists. Thus M. de Lamarck has separated
the species whose tentacula are formed by small denticulated
and pedicled disks to form his genus fistularia. M. Oken
had already extended these divisions much further, since he
has established four genera according to the consideration of
the disposition of the retractile tubes, and the form of the
body. As these animals are extremely altered in appearance,
when they have been kept for some time in alcohol, it becomes
rather difficult to characterize the species. They seem to form
a passage from the radiata to the worms, and perhaps even to
the mollusea; for, in fact, we find some species which have
altogether the form of the thalassema, and others which exhibit
at the first glance, a resemblance to some dorides.

SUPPLEMENT

ON

THE EN TOZOA.

THE reader will doubtless have remarked that the allocation
of these animals among the zoophytes, or radiata, will admit
of some controversy, inasmuch as they are neither plant-like
nor radiated, and appear to have much more analogy with
the annelides, which they would seem more properly to follow
in the natural series.

The study of the worms, which are entirely apodal, and
which have no trace of appendages serving for locomotion, was
pursued but little until the middle of the last century, and
more especially that of such species as live continually in the
interior of other animals. Attention to them seems to have
been chiefly originated by a prize proposed by the Royal
Academy of Sciences in Copenhagen.

The ancients have scarcely noticed the round and flat
worms, and that solely in a medical point of view, confining
themselves to those which infest the human species. They
have further limited their labours in this way to mere nomen-
clature, without giving any external description.

The few authors who occu; ied themselves with the history
of the distinction of animals, previously to the revival of
literature, have added but little to our acquaintance with this
subject. From Isidore de Seville, Albertus Magnus, Belon,

Nn2

548 SUPPLEMENT

and Rondelet, we derive nothing in addition to what the
ancients have left us; and Gesner and Aldrovandus, who
compiled with so much patience, and frequently with so much
sagacity, all that had been said by their predecessors, one in
an alphabetical, the other in a systematic form, have col-
lected nothing new respecting the worms, and more particu-
larly respecting the intestinal ones.

It was only, in fact, towards the end of the seventeenth
century, that the science of helminthology may properly be
said to have had its birth, and this birth took place in Italy,
the mother of almost all modern art, science, and literature.
To that country belong the names of Redi, Malpighi, and
Vallisnieri.

The popular name of worm, under which these animals
have been included, sufficiently indicates that their body is
almost always cylindrical, more or less elongated, attenuated
at the two extremities, and of a diameter infinitely less than
the length. In some the body is more perfectly cylindrical,
in others sacciform. Even a certain number resemble
bladders, as the hydatids; or very depressed lamine, as the
fasciole, &c. Whatever be its form, it is always perfectly
symmetrical, as in all other binary animals, and most fre-
quently the dorsal face may be distinguished from the ventral,
by a little more convexity in the former than the latter.

It is but seldom that we can trace in the body of these
animals the distinction of head, neck, belly and tail. Never-
theless, it sometimes happens that the anterior extremity is
enlarged, and is well distinguished from the rest of the body,
and then the animal is provided with a cephalic enlargement,
as in tenia, &c. But most usually the body, attenuated in
front, swells out by degrees, and again becomes attenuated
at the posterior extremity.

In many of these animals articulations may be observed,
but they are sometimes extremely indistinct. In other cases

ON ENTOZOA. 549

the articulations are so much separated, that they seem to form
a sort of chain, which breaks with the greatest facility.

Never, or scarcely ever, are any appendages observable on
each side. The worms, in fact, are easy to be recognized by
this great simplicity in the external form.

Their organization, too, in general, is but little complicated,
and often, in consequence of their smallness and the trans-
parence of their tissues, it may be observed through the
teguments. It is particularly when they are young, and
living, that this transparence is almost perfect.

The external envelope, or skin, is almost always confounded
with the muscular substratum, which serves for locomotion.

The dermis is consequently not distinct; it is always very
soft, of a nature almost mucous, and we cannot distinguish
above it, any other of the parts of the skin, such as they have
been analyzed in this envelope, in superior animals. ‘Thus,
neither papilla, nor epidermis can be recognized. ‘The vascu-
lar net-work alone is sometimes tolerably developed, and we
may remark there a pigmentum sufficiently marked, at least
in some species; but all that are parasites in the intestinal
cavities, or parenchyma of animals, are constantly white,
unless they should be filled with some colouring matter,
which may be perceived, in consequence of the transparence
of their exterior envelope.

In a very small number indeed have any indications been
observed of special organs of sensation.

The apparatus of locomotion consists solely in the muscu-
lar stratum which doubles the skin, and the intestine itself.

We cannot even say that these animals have true muscles.
The muscular stratum is merely divided into eight longitu-
dinal bands, by the dorsal, ventral, and lateral lines, which
are themselves composed of interrupted fibres. In the vesi-
cular species, where the body terminates by a bladder, the
muscular fibres radiate all around its parietes.

550 SUPPLEMENT

As there are no appendages, it is evident that there can be
no muscles for the purpose of moving them, though some in-
distinct fasciculi may be observed in some of the exterior
species.

The apparatus of nutrition is also very simple in the
entozoa.

As for that of digestion, or the intestinal canal, it is gene-
rally extended from one extremity to the other of the body, at
least when it is complete. At other times it is irregular or
ramified, and, finally, in a certain number of species it is
vascular, or even sometimes completely imperceptible, or
even nullified.

When complete, it extends almost directly from one ex-
tremity to the other, but never without being free or distinct,
and consequently without any serous or peritoneal membrane.
It is truly comprehended in the cellular parenchyma, which
constitutes the mass of the body.

The mouth, almost terminal, is almost constantly very
small and circular.

It is never armed with teeth, properly so called, whether
calcareous or corneous. Sometimes certain projections, or
swellings, of the muscular contractile tissue may be found,
the edges of which bristle with remarkably fine denticu-
lations.

As there is no real armature of the anterior orifice of the
intestinal canal, we may easily conceive that there never
exists in these animals any distinct buccal mass.

Neither are there any salivary glands.

We may say, that in general, in the extent of the intestinal
canal, there is no distinction of cesophagus, of stomach, pro-
perly so called, of small intestine, and of rectum; such at
least is the case in all the truly intestinal worms.

No organs have been met with that could be regarded as a
liver, and still less asa pancreas. If the first does exist, which

15

ON ENTOZOA. 551

appears by no means probable, it is contained in the parietes
themselves of the intestines.

The termination of the intestinal canal, or anus, is always
medial, and yet approaching to be terminal.

This is the first sort of digestive apparatus found in the
entozoa. In the second sort, there is still a terminal mouth,
in the form of a sucker, and without armature ; but the intes-
tinal canal, which originates from it, after having been pro-
longed towards the middle of the body, is lost immediately
in vasculariform ramifications, which proceed into all its
parenchyma, and then there is no trace of anus.

Finally, in the third sort, the digestive system does not
commence by a single medial orifice, or by a true mouth.
There is even no true intestinal canal, but two or more an-
terior and lateral pores or orifices spring from the vessels
which are united to two lateral trunks; these are prolonged
throughout the entire length of the body, anastomosing
together, and ramifying, without doubt, into the parenchyma
of the animal. This is the organization of the teniz, &c.

Tn the ligula, which are the most simple of all binary ani-
mals, we can no longer recognize any trace of an intestine,
of whatever sort it may be, and consequently no circulatory
system. . ,

A special respiratory apparatus exists in none of the ani-
mals of this class. The organ, therefore, of respiration is
essentially limited to the skin, nor is there, in fact, any true
respiration, except in certain families, where something like
circulation may exist.

The blood, or recrementitial fluid, has been but little
studied.

The apparatus of decomposition consists solely of the organ
of generation ; for no other glands exist in any genus of this
group. ‘There are several distinct sorts of it, since it is some-
times composed of female and male parts separated on dif-

552 SUPPLEMENT

ferent individuals, and sometimes of such parts on the same
individual; at other times of female parts alone, and in fine,
we sometimes find scarcely any indications whatsoever, of this
apparatus. ;

The existence of a nervous system in these animals is very
doubtful, at all events in those which may be properly termed
entozoa. No one has been able to recognize any thing of the
sort in the tanize, or neighbouring genera.

The organization of the product of generation in both, in
the exterior and interior worms, has not been sufficiently
studied. Such eggs as have been discovered are oval, and
very regularly formed. They all appear to be in reality eggs,
with a distinct envelope containing grains. But this was the
most that could be distinguished, even with the microscope.

The physiology of worms presents nothing which can really
be considered as peculiar to themselves.

Their general sensibility appears to be considerable. In
fact, at the slightest contact of a solid body, or even of a
liquid of a heat or nature different from that in which they
are plunged, they torment themselves, and twist about in
all directions. The tenize do this almost as much as the
others, but only in a less extended portion of their body at
once. A special sensibility they do not seem at all to pos-
sess, nor any perception of bodies, whether by savour or odour,
and still less by the luminous rays which they send forth.

The contractility of worms is evidently very great, and
that almost in all their tissues, so that they have considerable
power of changing form and dimensions, as may be particu-
larly observed in some of them, which are almost in a conti-
nual state of agitation. ‘Their locomotion is, therefore, some-
times tolerably active.

They seem, in general, to possess but little tenacity of life.
Some, indeed, such as tenia, have been observed to live
many hours after having been extracted from the intes-

ON ENTOZOA. 553

tinal canal of an animal which had been dead for several
days. The ascarides and distome may be preserved alive
for many days. Rudolphi even speaks of one species of
ascaris, the A. spiculigera, which was resuscitated, after being
extracted from the intestine of a bird, which had been for
twelve days in very strong spirits of wine.

We are in possession of no proof that they can reproduce
any individual part which may have been lost or taken
away.

We may say, in a general manner, that all these animals
comprehended under the name of worms, or entozoa, live con-
stantly in a fluid, and never, or at least very rarely in the
atmospheric air. This fluid may be either living, or at least
constituting part of a living body. In this case, they are
more peculiarly entitled to the appellation of intestinal worms,
or entozoa; and, in fact, the great majority of the worms are
intestinal.

There is no tissue, nor any constituent parts of living
bodies in which some of these worms have not been found.
They are most frequently at the surface of some portion of
the exterior envelope, which has re-entered, to form either
the intestinal canal, the lungs, or organs of respiration, or the
genito-urinary apparatus. But at other times they are found
in the tissue itself of these parts, in the parenchyma, as in
the brain, the vessels, the muscular system, &c.

Moreover, there is scarcely any animal in which some of
these intestinal worms have not been found, at least if we
speak of all the classes of the vertebrata; for among the
invertebrata, they seem to be more rare. But as they have
been as yet so little sought for in these latter tribes, it is im-
possible to assure ourselves that they are so few as has been
generally asserted and believed.

It has been remarked that no intestinal worms have as yet

554 SUPPLEMENT

been discovered in the guinea pigs, though they have very
frequently been sought after in those animals.

Among vertebrated animals, the entozoa are in general
more common and more numerous in the aquatic species
than in the others ; more so in the females than in the males;
more so in the young than in the old; and, finally, more so
in weak individuals than in vigorous subjects.

It has been for a long time admitted in a general way, that
each intestinal worm more peculiarly infests some one ani-
mal, and even a determinate part of that animal; but this
opinion can by no means be supported in any positive man-
ner. In fact, it is certain that the asearis lumbricoides, for
example, is found in the human species, in the horse, the pig,
and some other animals. — It is equally proved that the same
species of tenia is to be found in the cat and in the dog.
Nor are we less assured that the bothryocephalus punctatus
is to be met with in the barbel, the turbot, and several other
species of pleuronectes.

Nevertheless, there are some species which are evidently
peculiar to some particular species of mammifera, such as the
human tzenia and the bothryocephalus.

Locomotion in these animals is but seldom, even slightly
extended, and a certain number of them do not possess the
faculty at all, but remain fixed in the parts in which they
live. These, then, are strictly parasites, altogether fixed, as
are the echinorhynchi, and the majority of the tznioides.
There are only, in such cases, some partial movements, or a
sort of undulation in those parts of their bodies which are not
adherent. It is not the same with several other species, such
as the ascarides, and even the porocephali, in which there is
a true general locomotion, or total transport of the body, in
the parts which they inhabit, for it is certain that the asca-
rides lumbricoides, whose normal position is in the small

55

Gr

ON ENTOZOA.

intestine towards its origin, do sometimes ascend into the
stomach, or descend into the large intestines. They have
even been known to penetrate into the peritoneal cavity, after
having perforated the intestine, or taken advantage of some
previous perforation which had been made there.

The nutriment of the worms is generally animal, and in a
fluid state, as may be supposed from the formation of their
buccal orifice. Among the external worms it would seem
that there are some exceptions to this rule ; but with such we
have but little to do in the present place.

The mode in which this nutriment is taken is very simple,
since in general it is drawn in by the successive action of the
parietes of the intestine, performing the office of a sucking
pump. ‘This is quite obvious in the medicinal leeches, which
are so analogous in structure to the animals of which we are
now more particularly treating, and the like probably also
takes place with the ascarides. But in these last, nutrition
must also take place by the action of the skin, plunged in the
mucous or chyleous matter, which lines or fills the intestinal
canal which they inhabit. As for the porocephali, the echi-
nocephali, and particularly the bothryocephali, and ligule, it
is clearly evident that they can have no other mode of nutri-
tion, the intestinal canal being no longer existent in them, or
being reduced to a merely vascular state. All the nutriment
is taken by the action of the suckers of the oral extremity, or
by those of each ring as in the teenie, the bothryocephali, and
lastly, by the pores of the skin alone, as must necessarily
take place in the ligule.

In those in which the sexes are distinct, as in all the asca-
rides, it is certain that the males are always obviously less
common than the females, and, most undoubtedly, must be
considerably less numerous. ‘There are even some species in
which it is very rare to find any, as in the ascarides, properly
so called. There are more in the strongyli.

556 SUPPLEMENT

The mode in which the intercourse of generation takes
place, is but little known. M. Bremser has observed it in the
strongyli. The pouch or sac of the male embraces the vulva
of the female.

The result of generation after this intercourse, or even when
no intercourse takes place, as is the case with all the monoga-
mous species, is, as we have already said above, often innu-
merable eggs, as in the tenie, for example. These eggs do
not adhere to the mother. They are formed in the meshes of
the cellular tissue which constitute the ovary, and are rejected
through a determinate orifice, in most cases, or through’ a
simple rupture, as in the teniz.

Be this, however, as it may, they fall into the substance in
which they are to be developed, without receiving any parti-
cular arrangement or disposition from the mother; with the
hirudines, which we have so often said are very analogous
animals, if, indeed, they ought not to be placed in the same
class, the case is different. Their eggs are united in small
packets, by a general mucous envelope, and are arranged by
the mother in determined circumstances. Such appears never
to be the case with the entozoa.

We know nothing, or scarcely any thing respecting the
mode in which their eggs are developed. M. Rudolphi thinks
that their development is rapid. Nevertheless, it appears,
that in the bothryocephalus, so common in the pleuronectes
maximus, the young subjects bear no resemblance to the
mother. They at first exhibit no trace of articulation. The
cephalic enlargement constitutes almost alone the whole of
the body of the animal, which is terminated rather abruptly,
by a small caudiform elongation. In the next degree of deve-
lopment, the body increases in size. The articulations be-
come sensible by simple lateral denticulations. They are as
yet few in number and very long. By degrees they cut and
wrinkle, and other articulations become defined. ‘This cir-

ON ENTOZOA. 557

cumstance, at the same time that the body is continually
shooting out, finishes by giving to the latter a very variable
length, but which sometimes exceeds two feet. We may
then observe some of these articulations, and more fre-
quently the posterior ones, fill by degrees with eggs, of
somewhat a different bulk, but of the same oval form, and
which after they issue forth, in their turn produce young
bothryocephali.

There are two interesting questions respecting the deve-
lopment of the intestinal worms; first, can such and such
species only, be developed in the body of such and such ani-
mals, and may not this development be sometimes continued
in another animal ?

The successful experiment of Pallas, in introducing the
eggs of the tenia elliptica, into the abdominal cavity of a dog,
is a reply to the first question.

As for the second, it appears certain that the ligula, when
it is found in fishes, never presents itself in the adult state, or
with developed ovaries, which is quite the reverse of what is
observed when it is taken in an aquatic bird. M. Rudolphi,
therefore, supposes, that born in the fish, it only acquires its
full development in passing into the birds, and that this is
owing to the heat of their body. He brings forward, more-
over, in support of this opinion, the case of a bothryocephalus,
which in the imperfeci state (B. solidus,) is found in a spe-
cies of gasterosteus, and in the adult state (B. nodosus,) in
aquatic birds only. He further explains by this, the curious
fact, that in the northern countries of Germany, and in Den-
mark, where this little fish is common, the aquatic birds are
infested with the B. nodosus; while in Southern Germany,
where this gasterosteus does not exist, the aquatic birds have
not this bothryocephalus.

We shall particularize only one species of this disgusting

558 SUPPLEMENT

class of animals ; namely, the F. medinensis, belonging to the
filariz, commonly called the guinea-worm.

This species, the most celebrated of all, is very long. The
edges of the mouth are inflated, and the point of the tail is
inflected. Itisof the size of a small cord, and of the same
diameter almost throughout. Its head is provided with a sort
of sucker, formed by the inflation of the lip which surrounds
the mouth, the orifice of which is very small. The tail is ter-
minated by a sort of inflected hook. Its colour is the same as
that of most of the worms that live in the interior of animals ;
that is, a dirty white, passing to yellow in alcohol. In length,
it appears to vary considerably. Kcempfer speaks of a foot,
of a cubit, and more. Grundler describes the one that he has
seen, as being three feet and a half, Rhenish measure. Kemse-
muller says it frequently exceeds two ells. Gallandat gives
it eight or nine feet ; and in fine, Fermin carries its length to
eight or nine ells, which appear, indeed, to be somewhat im-
probable. Be all this, however, as it may, this worm appears
hitherto to have been found cn the human species alone, in
the cellular tissue of different parts, and especially in that
of the legs, towards the malleoli. It also appears to be en-
demic in the burning regions of the old and of the new
continent. The names of medina-worm, and guinea-worm,
have been given to it, from the places where at first it was
observed.

There are among observers, great dissensions respecting the
origin of this worm. Some think that it is exterior, that it is
a true gordius, and that it insinuates itself into the skin of
such persons as walk barefooted; that it deposits its eggs
there, grows, and is developed there, and produces by its pre-
sence such painful symptoms, that it has received the deno-
mination of furia infernalis. Proofs have, in fact, been given
that it may exist in this manner for a considerable length of

ON ENTOZOA. 559

time. Other authors maintain that it is a worm altogether
interior, and allege, in support of their opinion, that it has
never been found out of the body of man; that it is entirely
similar to the other species, and especially to the filaria of
the simia; and that it is more probable, that it is born in
the interior of the parts; that it may exist there for months,
nay, entire years, without producing any sensible accidents ;
and that it is only when it approaches the skin, when it
pierces it, that these accidents may become serious enough
to produce intense pain, or other alarming symptoms. ‘This
is pretty nearly the opinion of M. Rudolphi, and it appears
the most probable. Nevertheless, some persons, more versed
in the art of surgery than in zoology, and influenced, no
doubt, by the existence of a sort of inflammatory tumour,
which the presence of the worm produces at the skin, have
ventured, in these latter times, some doubts concerning its
real existence, thinking it might be nothing but the cellular
tissue itself, struck with death, which thus moulded itself, as
it were, into a worm, in traversing the thickness of the skin.
M. Delorme, in a letter inserted in the eighty-seventh volume
of the Journal of Physical Science, has shown by facts, how
erroneous is this opinion ; he has confirmed all that was known
concerning the symptoms, and even the treatment of the af-
fection which follows the appearance of the worm at the skin.
The symptoms are a tumour with redness, and most violent
pain. Soon a little orifice appears, through which the worm
puts forth a small part of its body. The treatment consists
in seizing this part and rolling it with much caution round a
small stick, which is turned very gently every day, for fear of
breaking the body of the animal, which would render the ex-
traction more difficult; besides that, the presence of the re-
maining part which would putrify, might occasion accidents
still more fatal. The observation has been made, that the
people who walk barefooted, like the negroes, are more fre-

560 SUPPLEMENT ON ENTOZOA.

quently affected by it than others; and that it is towards the
malleoli that the affection takes place. This is difficult enough
to explain on the hypothesis that these animals issue forth
from the splanchnic cavities ; for it does not very clearly ap-
pear why very nearly all of them should come out at the same
place. The medina worm may yet become the subject of very
interesting observations.

SUPPLEMENT

ON

THE ACALEPH .

In our supplementary observations on this class, we must
chiefly confine ourselves to the Acalephe simplices, which
are mostly comprised in the great genus MEDUSA of Linnzus,
and to which M. de Lamarck has given the name of Me-
dusarie.

These animals are extremely: numerous in all seas, but
more particularly in those of warm climates, have been re-
marked at all times by the inhabitants of the sea shore, and
by all authors of natural history, from Aristotle down, though
they are scarcely of any utility to the human race. But the
singular property which they possess of being luminous to a
great degree in darkness, or obscurity, and that of producing
a painful sensation similar to the sting of nettles, when any
of them are touched, must have occasioned them to have
been observed early. Accordingly all maritime people have
particular denominations to designate them. ‘These names
almost always indicate one of these two properties, such as
knide, acalaphe, urtica marina, sea-nettle, &c.

These acalephe have a regular form, very circular, hemis-
pherical, more or less convex above, and concave underneath,

VOL, XII. 00

562 SUPPLEMENT

with a simple, rounded, medial orifice, usually very large,
surrounded, or not, with appendages of variable form. The
union, in a greater or less portion of their edge, of these buccal
appendages, constitutes a common pedicle, the cross-wise at-
tachment of which divides the orifice into four parts.

The hemispherical, and principal portion of the body, is
termed, as we see in the text, wmbrella. The buccal append-
ages are called arms. ‘The part composed by their union is
called pedicle. j

The umbrella, always regularly circular, is sometimes very
much depressed above, as itis underneath. At other times
it is subcylindrical from its great elevation. It is rarely
globular, finally, and most frequently it is nearly hemispheri-
cal. Its edges, or the line of junction of the convex with the
concave part, are sometimes entirely smooth, rarely raised
into angles, a little salient, or sub-lobate, or tuberculous.
Most frequently they are furnished with tentacular filaments,
more or less elongated, and which have been called tentacula.
We remark, also, in a certain number of species, in different
points of the circumference of the umbrella, similar organs, at
regular intervals, the use of which is unknown. They are
designated by the name of auricles. The aperture of the
middle of the concave face is sometimes very great, round,
or squared. It is sessile, or at the extremity of a sort
of labial elongation, in the form of a proboscis, or funnel,
more or less elongated. In the circumference of this aper-
ture, whether sessile or not, are often remarked appendages
or arms, sometimes rather long, of a fixed number, and which
are divided or ramified in all their extent, or at their extremity
only. Between these divisions are sometimes seen some
organs which Pallas and Peron have compared to the cotyle-
dons of vegetables. These appendages are often attached to
the circumference of the sessile mouth, and sometimes more or
less high on the proboscis. But it sometimes happens that

15

ON ACALEPHA. 563

they are also united in a more or less considerable portion of
their extent. From this results a pedicle, sometimes very
thick, which appears to divide the mouth into four parts.

These acalephe, which vary considerably in bulk, since,
though there are some truly microscopic, there are others
which attain to several feet in diameter, and weigh fifty
pounds, are of ail animals those which have the least of solid
substance. They are composed, as it were, of a sort of jelly,
more or less consistent, perfectly transparent, which, in con-
sequence of the loss of life, resolves itself into a limpid salt
water, leaving as aresidue but some grains of membranaceous
parts equally transparent. ,

The tissue of the meduse is not then really homogenous,
though it appears to be so. Their skin, or envelope, is never-
theless of an extraordinary thinness, not distinct. This may
be considered but as the boundary of their tissue a little con-
densed. Observed with a microscope, M. Gaéde perceived
that it was furnished with small grains, each of which ap-
peared to be composed of grains still smaller. Might this be
the source of the viscous matter, which transudes from all
parts of the body, and which Peron says that he has ob-
served in individuals put into sea-water frequently renewed,
to enable them to preserve all their vital activity, and which
is so abundant, that the thirtieth portion of water is as much
charged as the first. This does not seem probable. It
might, perhaps, rather be believed that this is the origin of
the eminently phosphorescent substance, which Spallanzani
has remarked in certain parts of the body of the luminous
medusz, and which possesses properties different from those
of the liquor which issues from a wound. ‘The latter has the
taste of salt water, and the other causes a painful sensation, to
that degree that having touched it with his tongue, Spallan-
zani felt a burning impression which lasted more than a day ;
a drop having by chance fallen upon his eye, the pain was

002

564 SUPPLEMENT

still more intense. The caustic quality of this humour is not,
however, always in accordance with the phosphorescent pro-
perty, since there are species which are not luminous, but
which, nevertheless, produce a sting.

These animals are in general perfectly colourless, and re-
semble the purest and most transparent rock-crystal. ‘There
are some, however, which have coloured parts, reddish, fine
ultra-marine blue, greenish, &c.

The apparatus of sensation in the medusa appears to be
limited to the skin. The name of tentacula, which has been
given to the filaments, more or less elongated, which border
the umbrella, the use assigned to them, as well as the brachial
appendages in certain species, might cause it to be suspected
that these organs enjoy a more exquisite sense of touch. But
there is nothing in the organization of these parts to confirm
this suspicion, and it is not even certain that these organs
serve for the uses which are attributed to them.

No trace of nervous system has ever been observed in these
animals, nor is it probable that any exists.

If, after investigating the organization of the medusz, we
turn our attention to the study of their functions, we shall
still find many other phenomena equally worthy of obser-
vation.

Their general sensibility appears to be extremely obtuse ;
and, perhaps, it is the same with the special sensibility of
the marginal and buccal tentacula, whose power of contracti-

lity, however, appears to be very great. The meduse do not —

seem to feel the hand that seizes them.

Their locomotion, which is very slow, and denotes a very
feeble degree of muscular energy, nevertheless, appears to
have no cessation, since, being of a specific gravity more con-
siderable than that of the water in which they are immersed,
these animals, so soft, that it is probable they could not rest
upon a solid ground, are obliged to move incessantly to sus-

a

ON ACALEPHA. 565

tain themselves in the fluid which they inhabit. Accordingly,
they are in a continual motion of systole, and diastole.
Spallanzani, who has observed them carefully in their mo-
tions, says that those by which they change place, are ex-
ecuted by the approximation of the edges of the umbrella, so
that its diameter diminishes in a very considerable manner.
By this a certain quantity of water contained in the stomachs,
and in the cavity of the umbrella, is expelled with greater or
less force, and the body is projected in an inverse direction.
Returned by the cessation of the muscular force to its first
state of development, it contracts itself afresh, and makes a
new step. If the body is perpendicular to the horizon, this
succession of contraction and dilatation causes it to ascend;
if it is more or less oblique, it advances more or less horizon-
tally. To descend, it is sufficient for the animal to cease its
movements ; its weight alone draws itdown. It is never in an
inverted position, with the convexity of the umbella under-
neath. Neither the tentacula nor the arms appear to be em-
ployed in these movements of transportation, at least the
latter, according to Spallanzani, are always extended follow-
ing the body. Some ingenious experiments related by this
observer, prove that it is only the muscles of the marginal
zone of the umbrella, which cause it totally to contract, since,
on removing them, the remainder of the umbrella undergoes
no change, while the removed zone continues its movements
of systole and diastole. In spite of this almost continual
action of the locomotive faculty, the medusz do not appear
to be able to overcome the smallest current, but are constantly
carried away by it.

According to all observers, the medusz feed on little ani-
mals, on mollusca, worms, crustacea, and even fish, which
they attract towards their mouth, by means of the appendages
with which itis armed. Spallanzani has supposed this, be-
cause he saw a small fish which was attached to one of the

566 SUPPLEMENT

appendages of an individual which he had just caught. M.
Gaéde says positively that he found in the stomach of the
medusz which he dissected, some small fishes and nereids.
M. de Chamisso and Eysenhardt, in their memoirs on these
animals, assure us that they have found several times in the
ventricles some heads and remnants of fish, as it were di-
gested. Several other naturalists, who have had copious op-
portunities of observation, aver the same thing; and M. de
Blainville has found some small fishes in the equorea, and
even in the rhizostoma. But he queries whether these little
animals were seized by the medusz for the purpose of nourish-
ment, or that they came there accidentally. The last opinion
is that of M. Cuvier, at least regarding the rhizostoma, which
appear to him to derive their nourishment through species of
suckers, as we have already stated.

We have been hitherto in ignorance, and, probably, shall
long remain so, concerning the duration of life in the meduse,
as well as the history of their development. It is probable
that they are rejected by the mother in a perfect state, and
differ from her only in size. It is known that they are larger
in spring and summer, that is, at the time when their ovaries
are distended by the eggs which they contain, and that in
the other part of the year they are smaller. It is also known,
that the appendages acquire with age a development and a
complication, which they did not at first possess.

We find some species of these animals in all the seas of
cold climates, as well as in those of warm, and more especially
far out at sea. Each, according to the observations of MM.
Peron and Lesueur, appears to be confined to determinate
portions of the globe, where the individuals are united in in-
numerable troops, and sometimes-form many square leagues
in extent. If they appear and disappear sometimes at deter-
mined periods, that, doubtless, depends upon the regular
winds and currents which carry them away and bring them

ON ACALEPHA. 567

back. They are sometimes thrown in great quantity upon the
shores of our climate, where endeavours have been made to
turn them to some advantage. It has been attempted, but
without much success, to extract ammonia from them. ‘They
have been more beneficially employed in the way of manure
upon arable land.

All the medusz in a state of death and putrefaction, appear
to be phosphorescent ; but there is only a small number which
appear to be so in the living state. We are indebted to
Spallanzani for a great number of curious experiments on
this subject. He first endeavoured to discover what the parts
are which more particularly possess this singular property.
And he found that they were, Ist. the great tentacula, or arms.
2nd. the muscular zone of the umbrella; and 3rd. the stoma-
chal cavity. The rest of the umbrella only shines by trans-
mitted light. He then occupied himself in observing to what
cause the phosphorescence is owing, and he became convinced
that it was to a peculiar glutinous humour, which issues from
the surface of the three parts just mentioned. This, however,
as we have said farther back, is altogether different from that
which issues from the body, and even from these same parts,
when they are cut. It is very corrosive, and its application
on the hand, and on the tongue more especially, occasions a
lively sensation of pain. Expressed into different liquids, as
into salt water, but particularly into fresh water warm, or
milk, it communicates to them a phosphoric light. A single
medusa thus expressed into twenty-seven ounces of cow’s
milk, rendered it so resplendent, that one might have read the
characters of a letter by it, at the distance of three feet. At
the end of eleven hours, it retained some degree of light ; when
it had lost this altogether, it was renewed by stirring it, and,
finally, when this means no longer produced any effect, it
was again obtained by heat, care being taken that the heat
was not too strong. The dead medusa also still possessed

568 SUPPLEMENT

for a considerable time the phosphorescent property, and it
was renewed by pouring fresh water upon it, even some time
after it had ceased to shine. On the living animal, it is
stronger in the state of contraction than in that of dilatation,
which is easily explained, because it is the part which is
particularly contractile, which exhales the phosphoric hu-
mour. The light may be suspended for more than half an
hour, which depends on the cessation of the oscillations,
and nevertheless the phosphorescence continues, although
to a degree much less intense, in the dead animal, even to
putrefaction. The phosphorescence is increased by giving a
commotion to the parts of the animal, or even by rubbing it
with the hand. When it is living, it communicates to the
water in which it is plunged, its phosphoric property, but
half as much again in fresh water as in salt.

Certain of these animals possess another property which is
more hurtful, which is that of producing a very sharp pain,
when they touch any part of our skin, which has occasioned
them to be called sea-nettles. Dicquemare, who has made
experiments in reference to this subject on himself, with the
cyanea cerulea, relates the effects of them in these terms;
“The pain is pretty nearly similar to that which is felt on
touching a bunch of nettles; but it is stronger, and endures
about half an hour. In the last moments reiterated stings
are felt, but proportionally more faint. ‘There appears a con-
siderable redness in all the part which has been touched, and
swellings of the same colour, which have a white point in the
middle. After the end of some days, when the pain is gone
by, the heat of the bed will cause the blisters of the skin to
re-appear.” This effect appears owing to a caustic humour,
which issues from the skin of the medusa. Is it different from
‘that which produces the phosphorescence ?

This appears probable, since, as we have observed before,
the species noticed by Spallanzani, which was eminently

ON ACALEPHA. 569

phosphorescent, produced no effect of urtication. The spe-
cies which possess this property in the living state, have it
also when dead. Certain others possess it in so small a de-
gree, that it becomes sensible only in the softest parts of the
skin.

Attempts have been made to ascertain whether the medusx
are susceptible of a reproduction of the parts which have
been removed from them; but such does not appear to be
the case.

The medusz serve as food to several other animals. The
actiniz seize these acalephe on their passage, and draw them
by degrees into their stomach. The whales also destroy an
immense quantity of them ; but it appears that these are spe-
cies or individuals of an exceeding smallness, with which the
waters of the sea, inhabited by these great animals, are filled,
and that they are there with many other animals of different
types, but which are likewise almost microscopic.

The PHYSALI®, which constitute the type of the second
division of acalepha, are a very singular race of animals, no-
ticed for a long time by sailors, who give them the names of
galleys, frigates, or even ships of war, in consequence of the
elegant manner in which they seem to sail on the surface of
the waters. They have received the name of physalie, or
sea-bladders, in consequence of their resemblance to a bladder,
or even that of sea-nettles, because it appears that they pro-
duce the same effect upon the skin as the meduse. Some
recent writers have thought proper to place them among the
mollusca; and certain it is, that they present little or nothing
of the radiated arrangement; but as the Baron observes, the
total absence of internal and complicated organs, of which he
has satisfied himself in many large individuals, will not al-
low us to admit of the notion that the physalia may be one of
the mollusca.

570 SUPPLEMENT

M. Tilesius writes thus concerning the physaliz: all the
physaliz consist of along bladder inflated with air, floating
on the water, having upwards a sort of comb, which answers
as a sail, and underneath some long tentacula, which consti-
tute at once the mouth and helm. Although to examine
these is difficult enough, because they burn more strongly than
nettles, when they are touched, he has been enabled to dis-
tinguish three different kinds at least, on separate individuals.

M. Tilesius has made most observations on the sting pro-
duced by touching these animals. He ascertained that the
burning sensation which is felt, when one has touched more
or less strongly the tentacula of a living physalia, and which
is more intense than that produced by nettles, is owing, not
to a mucous matter which covers them,.as he had supposed
at first, but to some little hairs of a rose colour, which the
mucosity introduces into the pores of the skin. In fact, one
day when he was severely burned by handling too much
the tentacula of a physalia, after having tried without success
to calm the pain, with vinegar, solution of salt-petre, salt,
sulphuric or ammoniac acid, he only achieved the point by
frequent lotions of soap and water on the affected parts, hav-
ing previously carefully taken out the little hairs with a
tweezers. We must, nevertheless, believe that the mucous
matter itself also possesses this burning property; for the
same observer found, that on washing himself in a porcelain
vase, in which a physalia had been preserved, and which had
not been sufficiently cleaned, his lips, nose and cheeks, were
severely burned.

The physaliz live in the waters of the sea, at tolerably great
distances from the shore; except when they are driven thi-
ther by currents, or by the wind. Observers not having seen
them, except at the surface, it has been generally admitted
that they are always there, the bladder being partly out of the

ON ACALEPHA,. 571

water, and the tentacula, &c. more or less deep in the sea.
M. Tilesius adds that these animals sound with their tenta-
cula all the bodies which may be near them under water, that
their suckers are applied upon wood, stone, and even upon
glass, and porcelain, and deposit a mucous matter there
which communicates to these bodies the same burning pro-
perty possessed by the tentacula themselves.

SUPPLEMENT

THE POLYPI.

In the fourth class of this great division, the first and most
extraordinary animals we meet, are the ACTINIZ, vulgarly
known by the name of sea-anemones, or fixed sea-nettles.
Their body is fleshy, very contractile, usually remaining fixed
upon its base, but able, however, to change place, either by
crawling on this same base, or walking upon this tentacula.
When the body of the actinia is the most contracted, it re-
presents a hemisphere, with a small aperture at its summit.
Such is the position which these animals retain, when they
are stranded, or when the sea is troubled and the sky over-
cast. But when they are hungry, or the weather is fine,
they expand and blossom. The small aperture then be-
comes as broad as the base, and the body represents a
short cylinder. The mouth is at the centre of the supe-
rior base of the cylinder, and the whole circumference is
furnished with several ranges of tentacula, which represent
extremely well in their fine colours and arrangement, the
petals of certain double flowers. ‘The mouth conducts into
the stomach, which is a sac wrinkled internally, but without
any other issue, at least visible, except the mouth. The in-

SUPPLEMENT ON POLYPI. 573

terval between the stomach, and the external skin of the body,
is filled with very singular viscera, which have not been yet
sufficiently developed to enable us to communicate a very
clear notion of them. Some membranaceous and vertical
lamine proceed from one of its surfaces to the other, like the
radii of a circle. They are not of equal height. Their
superior edge is furnished with very complicated fringes.
There are also found in the interior part of the body, some
long, tortuous, and very slender intestines. We do not find
in the body of these animals, any thing which can be regarded
as nerves or blood-vessels.

Through the experiments of Reaumur, of Baster, and
more especially of Dicquemare, the history of these animals
has become extremely curious. Their multiplication takes
place in two ways; the first is natural, and consists in a
spontaneous dilaceration of a portion of the ligaments of the
base, which is performed by the constriction of this part.
Then may be observed, escaping by this dilaceration, one or
several small portions of the animal, which in a little time
become new actiniz of the same species as that of which they
had composed a part. Dicquemare obtained an artificial
multiplication, at least equally singular. He separated some
parcels from the base of an actinia, and beheld them almost
immediately form so many new animals.

In the month of May, 1772, Dicquemare cut off all the ten-
tacula from an actinia, and in a short time after they rebudded.
He cut them afresh on the 30th of July following, and they
were reproduced in the same way in less than a month. An
actinia cleft through the middle of the body, appeared, after
the end of some months, as completely organized as before it
was mutilated. These experiments, and many others, the
detail of which might prove tedious, demonstrate in a positive
manner the faculty possessed by the actiniz of reorganiza-
tion in their destroyed parts.

574 SUPPLEMENT

Their food consists of small mollusca, shrimps, little crabs,
and meduse. They seize them with their tentacula, keep
them in the interior of their body for ten or twelve hours, and
subsequently void through the same aperture the solid parts
which they have been unable to digest. In the sea-water,
they can support very long fasts. It has been observed
already that the more hungry they are, the more they dilate
their aperture; it sometimes even happens that they turn
their stomach altogether, and render it convex, instead of
concave, as it was before. They perish directly in fresh
water. They are found attached by the base. When the
animal is desirous of changing place, it possesses several
methods of exercising this movement. It either slides slowly
upon its pedicle, or, detaching its base altogether, it swells
itself with water, and then becoming almost as light as the
volume of water which it displaces, the least agitation is suf-
ficient to impel it further. When it wishes to fix itself, the
body contracts, the water escapes, it proceeds to the bottom,
and its base becomes glued to the surface of the first body
within its reach. Though no organ of vision is observable in
these animals, a strong light evidently incommodes them.
They appear strongly affected by it. Dicquemare has ob-
served that those actinie from which certain parts were ab-
stracted, were more sensible to the glare of light than they
had been before they were mutilated. Severe cold does not
annoy them. They may be enclosed in a piece of ice, left
there all night, and on the following day they shall be found
alive. Placed under a pneumatic machine, they support the
effects of the vacuum without inflating themselves, and with-
out appearing in the least degree exhausted when the air is
restored to them. Dicquemare has made some further obser-
vations which may prove useful to mariners. He perceived
that all the changes of weather were announced by some ex-
traordinary movements in the actiniz which he brought up;

ON POLYPI. 575

and he arrived at this result, that the movements of these
animals were in accordance with those of the barometer.

The actiniz possess no maleficent quality, and are eaten
in several countries.

Dr. Spix has given some very curious details respecting
the organization of these animals, which he observed and dis-
sected upon the coasts of the channel.

In considering the gelatinous polypi, we shall confine our
remarks chiefly to the HYDRA. .

The hydre are animals exceedingly simple, which we can
scarcely compare to any thing but filaments of small thick-
ness, fixed at one of their extremities, by means of a sort of
sucker, and provided on the other with a crown of cirrhi, or
tentacula, more attenuated than the finest hairs, to the num-
ber of ten or more, and possessed of extreme contractility.
This disposition of the tentacula and even their uses, caused
these little animals to be compared to the polypi of the an-
cients, now denominated octopus, and occasioned Reaumur to
give them the name of polypi. The structure of the different
parts of the body of the hydre is throughout completely uni-
form. In fact, we discover in them, even with the assistance
of the microscope, nothing but a sort of parenchyma, formed
of globules, and cellular tissue, and which is capable of con-
traction, particularly in the tentacula, to such a degree as to
disappear almost completely. Accordingly, the general sen-
sibility of these animalcule is exquisite, so that they can feel
or perceive the light, and distinguish it from the shade; not
that we would be understood to say with some writers, that
they actually possess the power of vision, through the medium
of the general envelope ; but they are in the predicament of
plants, which direct themselves towards the light, the effects
of which they experience, without otherwise perceiving the
bodies which transmit it. The hydre have no traces of the

576 SUPPLEMENT

organs of sensation, except that of touch, which is perfect in
the tentacula, with which the mouth is armed. All the parts
of their tissue are capable of contraction, but without any
possibility of our perceiving in them distinct muscular fibres.
The hydre are, however, capable of changing place altoge-
ther, and they do so after the manner of the geometrical ca-
terpillars, and of some leeches. Most frequently, however,
they remain fixed by the posterior extremity, and extend,
more or less, their body and tentacula in the different direc-
tions necessary for seizing their prey. They feed upon very
small aquatic insects, such as monoculi, or naiades. They
attract them towards themselves by almost continual move-
ments of the tentacula, enlace them in their numerous folds,
agglutinate them by means of some secretion, or some mode
of suction, and finally direct them towards the aperture of the
mouth, which is in the centre of the circle formed by those ten-
tacule. ‘This mouth, which is capable of being dilated into
a sort of calyx, communicates into the stomach, which is hol-
lowed in the parenchyma itself, of the body of the little ani-
mal, without any distinct parietes, except the skin at the ex-
terior surface. Accordingly, the similitude of the external and
internal paries is so great, that Trembley, in one of his most
curious experiments, has proved that the little animal may be
turned inside out, almost like the finger of a glove, and that
digestion and absorption can be as well performed by the ex-
ternal as the internal side. ‘This sort of stomach has no pos-
terior orifice, and when the prey, whether digestible or not,
has remained there for some time, it is rejected, in the latter
case entire, and in the former such parts are expelled, as were
not susceptible of digestion. Hence it appears, that there is
no choice respecting the bodies which the little animal intro-
duces into its stomach, and that the stomach alone discrimi-
nates by its own action upon them, whether they are suitable

ON POLYPI. 5TP

or not. These animals, moreover, can support a very long
fast, probably, because they absorb directly from the medium
in which they live.

The reproduction of the hydrez is still more simple, if
it be certain that it takes place by buds in all parts of the
external surface of the body. During the summer, it is said,
that a little germ is observed to project from some part of this
surface, which enlarges by degrees, and assumes the figure of
the mother. Very soon from its free extremity we see like-
wise the tentacula sprout forth ; and at the end of a longer or
shorter time, which depends a little on circumstances, more
or less favourable, the young hydra, which, while it was at-
tached to the mother, sought and attracted its prey like her,
and fed upon it, ends by being detached from her, and pro-
ceeds to fix itself upon some submerged body, where it re-
produces in its turn in the same manner. Sometimes it
even reproduces while attached to the mother ; insomuch that
even eighteen of these animals have been reckoned thus
united.

The reproductive faculty of the hydre, carried to the
extent observed by Trembley, must tend to make us be-
lieve that this power is extended to all parts of the body.
In fact, after the very delicate experiments, but authen-
ticated beyond all doubt, of a philosopher so entirely wor-
thy of credit as Trembley, it is evident that not only the
various parts of the body, cut longitudinally or transversely,
can reproduce the parts that are deficient, and thus form so
many complete animals, often in two days only; but even
sometimes a portion of tentaculum can be developed, and
produce a perfect hydra, which Roésel assures us that he has
observed.

But it is not only by gemmation, or by artificial or sponta-
neous scissure, that the hydrz can be reproduced. Jussieu,
Trembley, Roésel, and Pallas himself, have observed, that

VOL. XII. Pp

578 SUPPLEMENT

towards autumn, they eject from their parenchyma some eggs,
which fall, are preserved during the winter, and are not deve-
loped until spring. It is also said, that the individuals which
have their origin in this mode of reproduction, are always
smaller than those which have come by gemmation. It has
been questioned, however, whether these are in reality eggs.
Thus the history of the hydra, in considering it as well
authenticated, brings to general physiology some considera-
tions of the greatest importance, since it exhibits to us an
organized body, composed of a homogeneous tissue, conse-
quently without distinction or separation of organs, not even
of skin and muscular fibres, endowed with a very great sensi-
bility, which permits it to feel the light, extremely contractile
in all its parts, which can seize small animals of greater re-
sisting solidity than itself, introduce them into its stomach,
and digest them ; and that not only with the surface which is

5

habitually digestive, but also with the external surface, arti-—

ficially become internal. It displays to us an animal, that
can graft itself upon another, or by a true continuity of sub-
stance, can form, by the union of several individuals, a com-
plex animal, with many heads, thus realizing in nature, the
hydra of the fable; considerations which would lead us to
believe that the hydrze are very inferior to the polypi of the
madrepores, and to those of the pennatule, &c. which are
evidently much more complicated in their organization, and
that consequently they ought to form the last link of the chain
of radiated animals.

Hydre are to be found in all fresh waters, and in those of
the sea, but more particularly, as it would appear, in the first,
when they are dormant, providing that be pure. It is during
summer that we must look for them, on all bodies submerged
in such waters; for, during winter, it seems that they contract
themselves and sink into the mud. They may be easily pro-
cured by taking acertain quantity of water-lentils, and putting

ae ~~

ON POLYPI. 579

them into a vessel full of water. After a certain term of re-
pose, the hydr are observed to begin to move and agitate
their tentacula, as in their ordinary position. Trembley, who
thus preserved and studied them for several consecutive
years, used to feed them with daphniz, and other small
aquatic animals.

The VorTICELLA of Miller, is a genus concerning which
some controversy has existed, as to whether it should be
placed with the polypi or the infusoria. ‘The common cha-
racters of the animals composing it are, that they are naked,
contractile, and provided with rotatory organs. But they
present enormous differences, some being binary animals, ap-
pendiculated, and very complex, others appearing radiated
and very simple.

The organization of the true vorticelle is much more
simple than that of the species retrenched from them by M.
de Lamarck. In fact, the vorticelle exactly resemble a flower
of the lily of the valley, supported upon a long filament.
This filament is cylindrical, and a little enlarged at its ter-
minal part. The body itself is formed like a small purse or
monopetalous flower, having its edges widened, and _ pro-
vided with groups of short and very fine ciliz, opposed
laterally, which should make the vorticellz binary animals.
When these little beings are in their state of complete deve-
lopment, they are attached to some submerged bodies by the
extremity of the pedicle, this part being extremely stretched,
as well as the body, at the anterior of which the two fasciculi
of cilia are agitated with great rapidity. From this action
results a sort of double vortex, or whirlpool, which separates,
or drives out, the extremely fine molecules which are found in
the ambient fluid, and which is regarded as serving to direct
the prey towards the buccal cavity. On the least shock, these
little animals contract themselves quickly, undulating their
pedicle, which being fixed, serves them as a point of rest.

Pp2

580 SUPPLEMENT

At other times they are observed to detach themselves spon-
taneously, and swim, drawing after them their pedicle ex-
tended in a right line. Finally, they sometimes fix them-
selves by the enlarged part of their body, and appear to move
by means of their appendages. This is chiefly observed in
individuals whose pedicle is short, or even nothing, which is
the case with the wrceolaria.

It appears that there are vorticella attached one upon the
other, so that they seem to constitute composite animals.

The vorticelle, properly so called, multiply by natural
sections, the body dividing by little and little in the middle,
in such a manner, however, that the pedicle remains to a
single individual. The promptitude with which this scission
takes place is in proportion with the state of the external tem-
perature, so that in fine weather, the multiplication of these
animals goes on with wonderful rapidity.

On the approach of winter, they produce oviform germs
or buds, which are preserved in the water during the whole
of this season, and are developed in spring.

The vorticelle particularly live in fresh and stagnant
waters, fixed upon all the bodies which are to be found
there.

Miiller has observed that the mode of generation in
the species called V. racemosa, is altogether peculiar. An
adult individual fixes itself upon some body. Then from its
own body, or at the base, germinate eight similar bodies,
which, in a few hours, are raised upon their own proper
pedicles. In a short time, each of these new bodies gives
birth to eight others, which provided in their turn with their
pedicles, go on serzatim to propagate in the same manner.
During this time the pedicles of the first and second order
cross like the branches of a vegetable. As to the pedicle of
the mother, and which supports all the others, it preserves
the same length.

ON POLYPI. 581

Previously to taking a short review of the principal groups
of the CORALLIFEROUS PoLypt, &c., it may not be unne-
cessary to say a few words in general on the bodies more or
less solid, with which these animals are united, and which
are now generally termed by naturalists Polyparia. ‘This
term, of very general, perhaps too general an extension, may
be thus defined. A polyparium is a fixed envelope, more or
less solid, calcareous, or corneous, in which a polypus resides,
and which is the evident result of a transudation from its
body of an excretion through certain pores of its skin, of
matters sufficiently composite to form, by their approxima-
tion, aconcrete body more or less solid, and altogether inor-
ganic. This definition, however, is strictly applicable only
to the madrepores and eschare of Linnzus, and is not equally
so to the other divisions. Therefore, if we persist in gene-
ralizing this name, it will be necessary to define it as a solid,
calcareous, or corneous, the residuum of one or several polypi,
without any attention to its mode of formation, or the manner
in which the polypi are placed there, and then the fibrous
mass of a true alcyon, the fleshy mass of a pennatula, the
corneo-calcareous lamina of an eschara, the plant-like stems
of cellaria and sertularia, the calcareous, arborescent, fron-
descent masses of the madrepores, will be equally polyparia.
We may even add to these the beautiful tufts of the corallina,
on the supposition that they support polypi, which, however,
is by no means clearly made out.

In considering the nature of polyparia, we find them to be
of several sorts, according as they are calcareous, or stony,
corneous, fibrous, corticiferous, gluey, or fleshy.

The CORALLINES form a genus of organized bodies, on the
nature of which, although it is very common in all the seas
of Europe, and has for a long time been employed in thera-
peutics, authors are by no means agreed, some regarding it
as appertaining to the vegetable, and some to the animal

582 SUPPLEMENT

kingdom; but our limits forbid us entering into this question,
or adding to the statement of the text, however brief, any
thing beyond the observations of de Blainville, who says, that
notwithstanding all the pains he bestowed in observing coral-
lines in the shade, or in the sun, or in the small holes of rocks
filled with water some time after the sea had retired, with a
very strong microscope, he was never able to discern the least
trace of animals, or even of filaments which might issue from
them. If, after having viewed the exterior of a coralline, we
come to study the internal structure, we shall not find, as
some authors say, that it is a fibrous corneous axis, sur-
rounded by a calcareous crust, but on the contrary, that it is
a sort of cellular tissue, in the meshes of which the calcare-
ous matter is deposited ; and in fact, when we put a coralline
into a weak acid, it is softened absolutely like a bone, with-
out being diminished in volume, without assuming another
form, or even changing colour. All this causes M. de
Blainville to doubt that the true corallines can be formed by
distinct polypi. But he puts the query—is the coralline
really a vegetable? On this point he is by no means assured,
although all the Italians, who have been the principal ob-
servers of these sorts of bodies, appear to be perfectly con-
vinced that it is.

Every one knows that under the name of CoRAL (Corallium)
is commonly understood a sort of arbusculum, more or less
branched, stony, calcareous, sometimes of a fine red colour,
sometimes more or less roseate, or even altogether white. It
has been employed from time immemorial in the manufac-
ture of toys, and other objects of ornament, and it gives rise
to a fishery and trade of great extent in different parts of the
Mediterranean.

The polypi which inhabit the cellules of the surface of the
coral, are very soft, altogether white, and not very transparent.
Their body, or belly, is cylindrical, and-entirely concealed in

ON POLYPI. 583

the cellule, to which, doubtless, itis adherent by its extremity,
which appears to be continued with the vessels of the fleshy
and common envelope. ‘This at least is the opinion of M. de
Blainville, who founds it on a supposed analogy with the
pennatulz, which he has dissected. Donati, however, tells us
expressly that it is entirely detached and separate. Be this
as it may, the body of the polypus is terminated by eight ap-
pendages, disposed in radii round the mouth, or an aperture
which Donati informs us is made by a shell, a little widened
at its root, with a large aperture at the summit, and hollowed
by eight broad furrows, between each of which arises a sort
of ridge. Between two of these elevations, is placed one of
the tentacular appendages, which are thus upon the same
plane. They are all perfectly equal, conical, a little com-
pressed, and provided on each side with appendages, or
barbles, regularly decreasing from the base to the extremity.
Donati adds, that he has seen at the inferior part of the body
of some polypi, some little hydatiform bodies, rather round,
extremely small, soft, transparent and yellowish. He thinks,
with reason, that these are the eggs, or reproductive cor-
puscula.

The coral lives in the Mediterranean sea only at consider-
able depths, though rather variable. The coral seems to re-
quire at least ten years to render its growth complete. Pro-
pagation takes place thus: the eggs, or reproductive corpus-
cula, rejected through the mouth of the animal, or rather,
perhaps, through the orifices which are at its margin, fall
upon some body, and adhere there by their soft and gelatinous
nature. They extend a little, and begin to grow, particularly
at the part in contact, which enlarges, and moulds itself on
the submarine body. From the middle of this sort of coral-
drop, rises a tubercle, in which are evidently seen an interior
cavity, and eight wrinkles, or plates at its superior part, but
without aperture. The polypus, in its interior, is as yet but

584 SUPPLEMENT

in the state of foetus, but it attains its growth successively.
All the parts become developed, and it is then that the
capsule opens, to permit it to put forth its tentacula, to seize
its nutriment, and perhaps to respire. The growth of the
central part then becomes more rapid. It deposits calcareous
matter in the middle. It sprouts more and more, and is
developed by means of new polypi in indeterminate points,
so that one might say that the polyparium is almost totally
independent of the polypus, and that its hard part, or axis,
is always softer towards the extremities of the branches, than
at any other place.

Chemical analysis has proved that the coral, or at least its
axis, is entirely composed of carbonate of lime, for it com-
pletely dissolves in nitric acid.

Imperato was the first writer who made use of the term
MADREPORE (Madrepora) which, in its application by
subsequent naturalists, has undergone several. modifications.
Without troubling our readers with an account of these, it
will be sufficient to say that the name is now reserved to
certain lamelliferous tree-like polyparia, the surface of which
is bristled with projecting cellules. Their classification is
unfortunately based only on a knowledge of the polyparium,
or cretaceous mass produced by the animals, for of the latter,
very little that is satisfactory has been ascertained. Imperato
was the first who suspected that the madrepores of Linnzus
belonged to animals. Rumph, who had occasion to observe
a great number in the Indian seas, confirmed this opinion,
but he observed in them nothing but a sort of animal jelly
covering the polyparium. Finally, Peyssonel removed all
doubts upon this subject, and to Donati and Cavolini, we are
most indebted for any details respecting the species.

Of the madrepores thus defined, none are known in the
seas of Europe, and hitherto they have been met with only in
those of South America and India. Fixed by their base at

ON POLYPI. 585

considerable depths, they elevate more or less their foliaceous
expansions. We are totally ignorant of their mode of growth,
multiplication, and death. We merely know that the poly-
parium, which is entirely calcareous, is of a closer tissue,
near its base, and that, on the contrary, the extremities of
the ramifications are always more porous. The inferior
cellules are always more effaced, (the reverse is the case with
the upper) and the extremity of the branches is often ter-
minated by an infundibuliform excavation tolerably deep.

It is said that the formation of the numerous reefs in the
South Seas, the Indian Ocean, and the Red Sea, is owing to
the very rapid growth of the madrepores, and particularly of
that species called muricata. It is certain that most of the
islands in those seas rest on a calcareous soil, entirely com-
posed of stony polyparia, and that their highest mountains
are thus composed. But it may be difficult to prove that the
madrepores are the species which are found there in the
greatest number. On this subject we are deficient in positive
observations.

PENNATULA is a genus of true zoophytes, established by
Linneus for a set of animals extremely singular, whose form
in the most common species resembles that of a quill, from
which its name is derived. These animals are composed of
a common part, or stem, most generally containing in its ex-
terior a long {calcareous stick, and a certain number of polypi
disposed in rather a fixed manner upon a part of the stem, or
on some appendages which are added to it, and which con-
stitute the barbs of the quill. To these species modern
zoologists have reserved the name of pennatula.

Without following naturalists in a very detailed description
of these animals, we may say in brief, that a pennatula is a
body of a determinate form, binary, symmetrical, composed
of a muscular contractile tissue, most frequently supported by
a solid calcareous part, produced by a particular membrane,

=

586 SUPPLEMENT

and of an areolar tissue, as it were spongy, susceptible of a
sort of erection by the introduction of an aqueous fluid; a
body with which is in organic communication a considerable
number of little animals, each having a buccal orifice, sur-
rounded with a rank of pennated tentacula, and an oviferous
sac, developed in the tissue itself of the pennatula.

The physiological phenomena which the pennatula pre-
sents is extremely interesting, since it exhibits the example
of a truly composite animal, that is, one in which animals, more
or less in number, really perfect as far as comports with the
grade of organization to which they belong, form part of a
common, living, contractile body, serving as an intermedium
both for locomotion and nutrition to all the individuals, so
that they are all carried together by the sole movements of
the common part, without the particular movements of each
occasioning any obstacle, and they are all nourished in a
mediate manner, by means of this common portion of which
they form a part. The nutriment which favourable circum-
stances have placed within the reach of one individual,
nourishes that individual first, and then by extension,
nourishes the common stem, and thus the other polypi, which
constitute organic portions of it, receive their share.

It is rather more difficult to conceive the mode of growth
in the pennatula, and its mode of reproduction. In all the
aggregate polyparia, as the madrepores, the growth proceeds
by the extremities, and consequently, very probably, by the
adherence of the gemmules, produced by the terminal polypi,
to the lodge of the latter. The accidental fall of these gem-
mules gives birth to new individuals. In the first case, we
must consider it rather an accumulation, than a true growth ;
and, in fact, there is a real death of all that is below the ex-
tremities. It cannot be so in the pennatula, which is a ter-
minated and finished whole, so that we must believe that the
growth here is really individual, at least in the common part.

ON POLYPI. 587

As for the composing polypi, each of them, without doubt,
must grow. But the truth is, all is conjecture here, nor is
our knowledge of the habits of the pennatule at all adequate
to assist us in throwing light on these very difficult points of
physiology.

‘ The pennatule, as it seems, live constantly in the high
seas, and are always floating. Although they are in a conti-
nual movement of systole and diastole, somewhat like the
medusz, which is produced by the contraction of the inflated
and posterior part of the animal, and especially by the wing-
lets, or polypiferous branches, it is not probable that they
possess the least power of directing themselves in the inte-
rior of the waters. 'They are altogether under the influence
of the currents, like the meduse themselves. Still less is it
admissible that the composing polypi can conspire toge-
ther in their movements, to direct themselves in determinate
tracks. This is an hypothesis which defies conception, nor
is the object of such a faculty at all perceptible. Hach poly-
pus acts independently of its neighbour, and the object of the
motion of its tentacula, is only to seize the little animals which
may come within its reach.

Pennatule have been observed in every sea, but their known
species are not numerous.

We shall dismiss the consideration of this class, with a
notice of the SPONGES (spongia ).

This is a group of organized bodies, extremely extended in
every sea, but particularly in those of warmer climates. ‘They
have been known since the remotest antiquity, and, never-
theless, naturalists are far from being agreed with respect to
their true character. Some will have them to be vegetables ;
others a wholly simple animal; and several, polyparia, of
which the animal is unknown. All the authors of antiquity
allowed them a sensitive life, and admitted that the living
sponges seemed to avoid the hand which would touch them,

588 | SUPPLEMENT

and that they appeared to adhere more closely to the sub-
marine rocks, the-greater the efforts that were made to detach
them. ‘They considered the sponges to be organized bodies,
intermediate to vegetables and animals, such as they subse-
quently named zoophytes. This opinion was maintained for
along time, and gained the assent of most of the Italian
writers, Spallanzani, Olivi, &c. some of whom, however,
granted a higher degree of animality to these productions.
Rondelet seems to have been the first who utterly refused all
sensibility to the sponges, and denied the fact mentioned by
Aristotle, above alluded to. From this an hypothesis arose,
that they were only vegetables, and it was adopted by Tour-
nefort, by many ancient botanists, and by Linnzus himself,
in the first editions of his Systema Nature. Such, for a time,
was also the opinion of Spallanzani, as far as some species
were concerned, because he observed in them no signs of
contractility. ‘The third opinion, which was Peyssonell’s, is
that sponges are sorts of polyparia, fabricated by animals found
in their excavations. But as this could not be supported, as
these animals have no adherence with the sponges, and are
often of totally different species, this hypothesis was modi-
fied by pronouncing the sponge to be a polyparium, the polypi
of which are unknown.

If naturalists still hesitate respecting the nature of the
sponges, it is, doubtless, because they have no sufficient no-
tion of their organization. Without touching on the merits
of the controversies concerning them, we shall lay before our
readers all that is known upon the subject.

Every one agrees that the sponges are generally formed of
at least two substances; the first, interior, more or less cor-
neous, fibrous, intercrossing in all ways, and forming a sort of
felt-like tissue, more or less compact. It is this which at-
taches the sponge to the submarine bodies; the second, soft
or gelatinous, enveloping the preceding, forms a sort of general

ON POLYPI. 589

stratum, which is the seat of sensibility and life. Olivi tells
us that there are species of sponges, which present three very
distinct substances. 1. The fibrous matter which forms the
support, or as it were, the skeleton of the sponge. 2. The
mucous gelatinous substance, surrounding the fibrous parts;
and 38. A terrene matter, mingled with the preceding, and
forming a sort of cortical substance, which surrounds the ge-
latine itself. According to Father Vico, however, the organi-
zation of the sponges is much more complicated, and he would
fain discover in them, a muscular and a nervous system, ova-
ries, seminiferous vessels, &c. As this opinion, however,
seems wholly untenable, it is unnecessary to dwell on the de-
tails on which it is founded. Olivi, whose opinion is more
probable, regards the fibres, not as very important organs, but
as the support, or frame-work of the living body, and the sort
of marrow, which is sometimes found in their interior, he sup-
poses to have originated at the period when the animal was
young. He thinks that the mucilaginous and cortical enve-
lope really constitutes the animal, but that this animal is
amorphous. :

Sponges are considered by M. de Blainville, after Pallas,
Cavolini, Olivi, Donovan, &c., as organized bodies, interme-
diate to the two organic kingdoms, without any regular deter-
minate form; presenting an absorbent surface having some
obscure traces of feeling, nourished by the molecules from the
surrounding medium, pretty nearly like vegetables. Repro-
duction takes place by a sort of pullulation, or scission of the
living or gelatinous matter.

The sponges are always adherent to submarine bodies, of
whatsoever nature they may be, at variable, though always
considerable depths, and consequently, in places where the
sea is tranquil. They are particularly to be found in great
abundance in the excavations of rocks. It is certain, however,
that some species can exist in places covered and left bare

590 SUPPLEMENT ON POLYPI.

successively by the sea, as is the case in our northern seas.
Some of them attain great dimensions, having been found
more than three or four feet in height. We are not exactly
acquainted with the duration of their life, nor with the degree
of rapidity in their growth ; but we must conclude that they
grow promptly if it be that they can be fished for, with suc-
cess, after the second year, in places which had been previ-
ously exhausted of them. ‘The sponges are very common in
the seas of warmer climates, where they attain the largest di-
mensions. They are less so in those of temperate regions,
and finally, as we approach the ices of the north, they become
more and more rare, and smaller, and utterly disappear near
the polar circle.

SUPPLEMENT
ON THE

INFUSORIA.

ON these curious beings, of which so little is known, and
whose place in the living series is so far from being deter-
mined, we cannot pretend to offer any thing more than a few
general observations.

The denomination of INFUSORIA, was introduced into
zoology by Otto-Frederic Miiller, to designate a class of
animals which are developed in vegetable or animal infusions,
and which, from their extreme smallness, have also been
named microscopic. All systematic authors since Gmelin,
have adopted the division and the name, though some have
rather restrained its application, and others, in admitting it,
have observed that it was very badly circumscribed. In fact,
Miiller was guided by no principle in the establishment of
this class, and it is therefore probable that it contains an
anomalous assemblage of animals of degrees of organization,
or types, extremely different, and equally different degrees of
development. The only common characters which they pos-
sess, if characters they can be called, are their extreme lit-
tleness and transparence, which render them appreciable
only by the microscope; their constant habitat in a fluid,

13

592 SUPPLEMENT

which is a consequence of their littleness, and their not being
developed for the most part, except in vegetable or animal
infusions, which, however, is as yet but doubtful. Their ge-
neral and particular form, the only thing which an observer
can seize, confirms the differences in their organization. In
fact, there are some whose form is truly binary and symme-
trical, not only in their body, but also in the appendages at-
tached to it, and which, besides, are clothed with a true cor-
neous envelope. Some have the body elongated, vermiform,
or depressed symmetrically, without any trace of appendages,
as the vibrio, &c. Others, on the contrary, have a form evi-
dently radiated, with a mouth or cavity apparent, as most of
the vorticelle which we have seen are transferred by the
Baron to the preceding class. Finally, there are some whose
body is amorphous, or without any determinate form suscep-
tible of definition, without buccal aperture, or trace of appen-
dages, as the proteus, the volvox, and the monads. Those
of the first sort are true animals, and even very elevated in the
scale, since we find in them locomotive appendages, very
distinct, which have been denominated wheels, filaments, &c. ;
a tail composed of several articulations, and often terminated
by appendages, variable in form and number; a true cepha-
lothoracic buckler, covering a trunk more or less distinct;
even a heart, eyes, and ovaries, have been remarked, and con-
sequently we cannot doubt that these animals are provided
with an intestinal canal. These animals thus exhibit some
relations with those crustacea called entomostraca, by
Miiller, and it is no very improbable conjecture, that some of
these infusoria of this first section, may be only degrees of
developments of species of entomostraca, well known in the
adult state, for some of them are susceptible of very distinct
metamorphoses, as has been proved by M. de Jurine, in the
nauplia and amynome. As for the second form in the infu-
soria, which is seen in the vibriones, we may conceive that it

¢

ON INFUSORIA. 593

might appertain to animals of the class of apod worms, since
the body is elongated and symmetrical, without any visible
articulations, and certainly without any appendages ; but it
would be too much to assert this as certain, since observers
say nothing of an intestinal canal, nor consequently of mouth
or anus. Still the numerous movements of these organized
bodies in determinate directions, will not permit us to doubt
of their animality. It is the same with the vorticelle, of which
we have spoken elsewhere, and which, though long ranked
here, have a great analogy with the hydrz or polypi. There
remain then the protei, and the volvoces, which we cannot refer
to any known type. They, in fact, are organized bodies,
without any determinate form, without any distinct organ,
being nothing but a small mass of cellular tissue, in the meshes
of which are contained fluids, and which is hardly condensed
at the circumference to form an envelope, so that all the func-
tions in these bodies, are reduced to immediate absorption of
molecules, already prepared in the ambient fluid, and to ex-
halation. ‘This may be considered as the term, the last link
of animal life, where no organ is distinguishable.

Be this, however, as it may, it clearly appears from what
has now been said, that the class of the infusoria is totally in-
admissible, because it contains animals of very different types.
This, indeed, could not have been recognized previously to
the establishment of the principle, that the general form of
the body carries with it a determinate degree of organization,
for in such little animals it is almost the form alone that can
be perceived. Thus we may consider that the genera brachion,
urceolaria, cercaria, furcularia, kerone, ‘trichocercus, and
himantopus, really belong to the type of articulated animals,
and particularly to the class of heteropods, order entomomos-
traca. Many species of vibriones may be regarded as apod
worms, and likewise the genera paramecia, and kolpoda; the
rest of the vibriones, the cyclides, and, perhaps, the leucophes,

VOL. XEN. aq

594. SUPPLEMENT ON INFUSORIA.

should come near the planaria. The true vorticellae we have
seen to be polypi. Finally, the genera gonium, proteus, vol-
vox and monads, if they can be certainly regarded as animals,
ought, in the opinion of M. de Blainville, to form a distinct
type, to which he gives the names of amorpha, and agastraria,
which are intended to express that they have no determinate
form, and that the external envelope does not turn into or form
a stomach, as in all true animals.

Though many first rate naturalists, such as Leuwenhoek,
and Spallanzani, have occupied themselves with the infusoria,
itis much to be wished that such labours were renewed with
juster views, and more scientific exactitude of observation.
Many things, no doubt, would be found to require rectifica-
tion, and the result would be important, not only to zoology,
but to general physiology. Many authors, admitting too ge-
nerally that these animals are born in vegetable or animal in-
fusions, have taken occasion from this position to maintain
the doctrine of spontaneous generation, and several other
notions, more or less erroneous. From some remarks on the
last of the infusoria, the generation from spontaneous scission
in the parent, in whose body gemmules might be formed, has
been also admitted. This from analogy is more probable; but
it would be well, if possible, to ascertain that it were true.
The greatest care should be taken in observation to avoid the
errors which the instrument we are forced to use may lead us
into.

Erratum in title of third order of Polypi.
For polypi polypiferi, read polypi with polyparia.

ALPHABETICAL LIST

OF THE

FIGURES OF MOLLUSCA*,

PL. FIG.
7. 3. AcasTa spinosula, Des.
Hyaline, valves tubercular
near the lips.
7. 4. Acasta Montagui, Leach.
Ashy white, valves lanceo-
late.
27. 5. Achatina Mulleri Férussac.
Pale brown, with deeper
streaks.
2. I. Anatifa levis, Lam.
Nearly white.
12. 3. Anatina hispidula, Cuv. (Lan-
terna, Lam.)
Ashy, with white spots, shells
very thin.
22. 3. Anatina elliptica, King.
Nearly white, striated.
32. 13. Ancillaria cinnamomea, Blain.
Cinnamon colour.
37. 9. Ancillaria Australis, Sav.
Light yellow,with ashy spots.
19. 3. Anodon Georgina, Gray.
Varied, purple red, shell
solid, smooth, covered
with a thickish olive co-
loured periosteum.
Rivers of Paraguay.
24. 1. Anodon Susanne, Gray.
Shell thin, covered with pale
olive coloured periosteum.
From South America.
24. 2. Anodon tenuis, Gray.
Periosteum sea green.
39. 6. Anomia ephippium, Lin.
Smooth, silvery, thin, varies

PL. FIG.
in shape with the sub-
stance it is attached to.
. Aplidium lobatum, Sav.
Pale brown.
. Arca granosa, Lam.

White, with transverse tux
bercles.

. Argonauta argo, Lin.

(The animal is crythoe an-
tiquorum, and has no mus-
cular attachment to the
shell.) Shell white, ani-
mal brownish.

. Arion Empiricorum.

Black, with cross lines.

. Asemus porosus, Cuv.

Purple.

. Aspergillum vaginiferum, Zam.

Ash coloured.

. Auricula Mid, Lam.

White, covered with brown-
ish periosteum.

. Avicula heteroptera, Lam.

Brown.

o
So st ° OO

7. 1. Balanus ovularis, Zam.

White.
7. 2. Balanus sulcatus.
White.
18. Bivalve shells, terminology of.
9. 10. Boltenia ovifera, Sav.

Pale brown.
10. 1. Botryllus polycyclus, Sav.
Pale ash colour, with green
spots.

* Most of the inedited shells figured in this work are from the collection in the British

Museum.

Qaq2

596

PL.

27.

37.

37.

12.

37.

FIG.
l.

i

INDEX.

Bulimus Guadalupensis, Fe-
rus. '
White, with brown bands.
Bulimus auris-vulpina, Gray.
(Struthiolaria arcuata,Lam. )
Pale yellow, with light band.
St. Helena.

. Bullzea semiplicata, Gray.

Pale buff; upper lip and
suture callous.

- Byssomia pholadis, Cuv.

Whitish, with a pale thin
periosteum ; syphon large,
pale pink.

. Calpurnus verrucosus, Mart.

(Ovula verrucosa, Lam.)
White and pink.

. Cancellaria asperula, Des.

White.

. Cardium fimbricatum, Zin.

Ashy.

. Cardita caliculata, Zam.

White, spotted with black.
Cassis decussata, Lam.
Brown, with darker bands
or spots.

. Cassidaria echinophora, Lam.

Whitish, shell thin.

. Catillus Cuvierii, Brongn.

Fossil.

. Cerithium leve 1, Gray.

White.
New Holland.

. Cerithium zonate, Lam.

Blackish, with white band.

. Cerithium truncatum, Lam.

Yellowish ash.

. Chama croceata, Lam.

Shell orange colour, sub-
spinose.

. Chrondrus avenaceus, Cuv.

Pale brown.

. and 11. Chthamatus stellatus.

Dirty white.

. Cineras vittata, Leach.

Dark ash, with black bands.

- Clavagella coronata, Lam.

Fossil.

. Clavatula Griffithii, Gray.

Fusiform, solid, ashy,
spirally striated, whorls
rounded with.a subpos-
terior dark band, inter-

a

. Conus tendineus, Lam.
. Coronula balznaris.

rupted by whitish tuber-
cles.

. Clavellina borealis, Sav.

Pale ash.

. Clausilia inflata, Lam.

Pale ash.

. Cleodora lanceolata.

Hyaline.

. Clio borealis, Zin.

Dirty white.

. Columbella Tylere, Gray.

White, with black lines,
leaving square white
spots; front transversely
striated, white and brown.

. Columbella harpeeformis, Sow.

Dark ash.

. Columbella suturalis, Gray.

Blue and brown.

. Concholepas Peruvianus, Lam.

Dark brown, inside white.

. Conia radiata.

Ashy white.

. Conovulus fasciatus, Des.

White, banded with brown.

. Conus Caledonicus, Lam.

Fulvous, with spiral lines.

. Conus bandanus, Lam.

Black, with triangular white
spots.
Blue.

Greenish white.

. Crania personata, Lam.

Fossil. '

. Creusia spinosula.

Hyaline.

PL. FIG.
9. 13
27. 6
3. 8
3. J
37. 1
37. 2
41. 3
32. 7
dome
27. 13
6. 1
G2
6. 3
qoole
4. 5
18
1h Wa

Crenatula avicularis, Zam.
Brown, with narrow pale

rays.
3. 9. Creseis virgula, Rang.

41.

LB

Hyaline.
Cryptostoma Javanica, Gray.
White.

3. 10. Cuvieria columnella, Rang.

28.

28.

i

Hyaline.
Cyclostoma articulata, Gray.
White, spirally grooved with
brown dots, umbilicus
deeply grooved.

3. Cyclostoma pulchrum, Gray.

Pale brown, with inter-
rupted, brown, radiated
streaks.

1 Erratum in the plate, Del. truncatum, lege leve.

INDEX.

PL. FIG.

28.

28.
4].

20.

19.

32.
38.

4.

bo

1 fe

or one

. Eburna spirata.
. Eledone moschatus, arm of.
. Etheria elliptica, Zam.

. Eurybia hemispherieca.

Cyclostoma
Gray.
Whitish, with narrow brown

spiral lines.

Madagasciensis,

. Cyclostoma auriculare, Gray.

White, apex reddish.

. Cyllene Owenii, Gray.

This shell in general ap-
pearance is assimilated to
Buccinum, but it has a
groove over the suture, as
in Oliva, and a sinus in
front of the outer lip, as
in strombus. Mr. Gray
has, therefore, separated
it generically.

. Cymbulia Peronii, Cuv.

Blueish white.
Cynthia momus, Sow.
Rose coloured.

. Cypreea stolida, Lam.

Pale, fulvous,
low.

teeth yel-

. Cyprea pediculus, Lam.

Animal.

. Cyrena similis, Gray.

Periosteum olive green, la-
teral teeth long.

. Cytherea Dronia, var.

Pale pinkish white.
Note.—This seems to be Cy.
lupinaria, of Lesson.

. Diadema Coronula Diadema.

Dirty yellow.

- Dolium perdix, Lam.

Brown.

. Donax hilairea, Valence.

Yellowish grey.
White.

Ashy, with yellowish spots.

- Euceelium hospitiolum, Sawv.

Pale reddish.
Hya-

line.

. Fasciolaria trapezium, Lam.

Brown, with darker spiral
lines.

. Fistulana gregata, Lam.

Dirty white.

| tah

FIG.

597

33. 3. Fusus morio, Lam.

38.

10.

Purple black, with a pos-
terior pale band.

. Galathea radiata, Lam.

Covered with clive perios-
teum.

. Gastrochena cuneiformis, Zam.

Dirty white; shell thin.

, Gervilia solenoides, Defrance.

Fossil.

. Glauconome Chinensis }, Gray.

White, covered with a pale
green periosteum.

. Glycimeris siliqua, Lam.

Dark green.

. Harpa ventricosa, Lam.

Pink, varied with brown

and yellow.

. Helix corocolla, Lin.

Animal reddish, with three
blue bands along the back.

. Helix argillacea, Gray.

Clay coloured.

- Helix mora, Gray.

Chestnut brown, edge of lips
white.

. Helix Cunninghami, Gray.

Pale, with broad bands.
New Holland.

. Helix Lamarkii.

Pale, with broad brown

bands.

. Helix viridis, Desh.

Green, banded with black.

. Helix Fraseri, Gray.

Pale, with many unequal
plain bands.
New Holland.
Hippocrenes macropterus.
Reddish ash.

. Hialea globulosa.

Dirty white.

. Hialea trespinosa, Leseur.

Dirty white.

. Hiatella arctica, Bose.

Whitish.

. Inoceramus sulcatus, Cuv.

Fossil.

. Limacina helicina, Cuv.

Dirty white.

} This is named by mistake on the plate Glycemeris Apineusis.

598

INDEX.

PL. FIG.
39. 3. Lima glacialis, Lam.

35.
4,

°13.

13.

13.

“14,

14,

14.

#14.
14.

14.

+14.

2.

White; covered with large
scales.
Limax variegatus, Lam.
Brownish yellow.

1. Lingula anatina, Cuv.

3.

5.
6.
2.
2.

—

15.

16.

to

a
4.

X

oe

o

oS

a)

Shell green, animal ashy.

Littoraria pulchra, Gray.
Reddish, with oblique

streaks.

Loligo Brogniartii.
Brown.

Lucina Jamaicensis, Lam.
Dirty yellow.

Lutraria elliptica, Lam.
Ashy.

Lymneeus stagnalis, Lam.
Whitish.

. Malleus vulgaris, Zam.

Black.
Marginella nubeculata, Lam.
Pearl white, with dark

clouded zigzag lines.
Marginella bullata, Lam.
Pale ash, with dark bands.
Melania Henriette, Gray.
Shell thin; pale brown;
ribbed, and crossed by
tubercles.
Melania Caroline, Gray.
Dark olive.
Melania lineolata, Gray.
Pale brown, with minute in-
terrupted bands.
Melania Frethii, Gray.
Black brown.
Melania quadriseriata, Gray.
Black, whorles flat, with
four series of rounded
tubercles.

. Melania conica, Gray.

Olive colour.
From Ceylon.
Melania globulosa, Gray.
Olive ; lips white.
Melania subcarinata, Gray.
Black brown, whorles, with
a nodulose keel.
Melania levis, Gray.
Black brown, smooth, with
two or three spiral
grooves.

. Melania retusa, Gray.
Olive brown, smooth, ovate.

PL. FIG.
14. 4.
22. 1
22. 2.
22. 4.
22. 6
40. 2
40. 5
FE
12) a;
30. 2.
22. 6.
i FSP 2
l 4
Dh Th
22. 9
7. 12.
Sel
2. 6

Melania lineolata, in plate, is
Cerethium truncatum.

- Mesodesma solenoides, Gray.

Pale white, rayed, wedge-
shaped.

Mesodesma denticulata, Gray.
White.
Mesodesma
Gray.
White, covered with a thin

periosteum.

subtriangulata,

. Mesodesma ornata, Gray.

Pale brown white, with

angular red lines.

. Mitra Chinensis.

Dark olive.

. Mitra orientalis.

Dark brown ash, obscure
strie.
Multivalve shells.
Mya truncata, Lin.
Reddish brown.

Nassa Northie, Gray.
Reddish brown.
N.B. The specimen is in-
complete.
Nassa reticula, Lam.
Shell dark brown; animal
white.

. Natica bifasciata, Gray.

Pale brown, with two nar-
row bands.

. Natica fluctuata, Sav.

White, with zigzag buff
bands. :
Nautilus pompilius, Zin.
Shell white, with brown rays,
hinder lip black.

. Nercea Chinensis, Gray.

White, concentrically grooved.

Ochthosia Stroemii.
Yellowish white.

- Octopus Cuvierii.

Claret colour.

. Olion Cuvierii, Leach.

Pale blue, with metallic re-
flections.

6. 12. Oliva ispidula, Lam.

Brownish white.

6. 13. Oliva auricularia, Lam.

Pale grey.

37. 3. Olivatessalata, Lam., var.

5.

6.

Brown, with dark square spots.
Onychoteusis angulata, arm of.

PL.
4.

39.
6.

FIG.
4.

I.
6.
a

OF

—

. Pneumodermon

INDEX.

Orbicula levigata, Blain.
Horn colour.

Ostrea cristagalli, Lam.
Black.

Ovula triticea, Zam.
Pale pink.

Ovula volva, Lam.
Pale red, spirally striated.

. Paludina Chinensis, Gray.

Olive green; mouth with
black edge.

. Paludina pulchra, Gray.

Pellucid, with red brown
spiral bands.

. Paludina subcostata, Gray.

Olive green.
From China.

. Panopcea Aldrovandi, hinge

of, Cuv.

. Parmacella Olivieri, Lam.

Dirty ash.

. Parmacella palliolum, head of,

Fer.

. Pecten purpureus, Lam.

Purplish white.

. Pecten gibbosus, Lam.

Reddish brown.

. Pentadina margaritifera, Lam.

Green.

. Perna ephippium, Lam.

Purple.

. Petricola lucinalis, Zam.

White.

. Phallusia nigra, Sav.

Black.

. Pholas striata, (papyracea.)

White.

. Phyche globulosa, animal.

Physa Nove Hollandiz.
Pale brown.

Pinna angustana, Lam.
Yellowish ash.

Placuna placenta, Lam.
Silvery White.

. Pleurostoma grandis, Gray.

White with red spots.
Pleurostoma carinata, Gray.
White, whorles keeled.

. Pleurostoma Babylonia, Lam.

White, with black spots.

. Plicatula cristata, Lam.

Dirty white.

diaphanum,
Quoy and Gay.

Dirty white.

13

599

PL. FIG.
3. 4. Pneumodermon Peronii, Cuv.
Dirty white.
2. 2. Polliceps cornucopia, Lam.
White.
2. 3. Polliceps mitella, Zam.
Dirty white.
2. 4. Polliceps scalpellum.
Dirty white.
4. Polyclinum constellatum, Sow.
Bluish ash colour, with
yellow spots.

10.

32. 12. Potamis fragilis, Brogn.
Fossil.

12. 10. Psammothea candida, Lam.
White.

3. Psyche globulosa.

Hyaline.

33. 6. Pterocera scorpio, Lam.
Brown, with reddish brown

streaks.

ll. 7. Pulvinites Adansonii, Dep.
Fossil.

27. 3. Pupa striatella, Fer.

Ash coloured, striated.
3. 13. Pyrgo levis, Dep.
Hyaline.
7. 7,8. Pyrgona cancellata.
10. 2. Pyrosoma rufum, Quoy and G.
Straw colour.
10. 3. Pyrosoma giganteum, Ana-
tomy of.
25. 3,4. Pyrula Mawe, Gray.
Shell deformed.
From China.
5. Pyrula perversa, Lam.
Light ash-coloured, with
brown streaks.
4, Pyrula striata, Sav.
Pale yellow, with deeper
spots.

White.
33.

37.

32. 2. Ricinula arachnoides, Lam.
White, with black tubercles.
8. Rostellaria pes-pelicani, Lam.

Brownish ash.

33.

2. Salpa cristata (scutigera) Cuv.
Ashy.

3. Salpa infundibuliformis, Quoy.
White, with ashy lines.

4. Salpa tricuspis, Quoy.
White, with ashy lines.

5. Salpa longicauda, Quoy.
Ash coloured.

6. Salpa fusiformis, Quoy.
Ash coloured.

pm oo © ©

600

INDEX.

PL. FIG.
9. 7. Salpa zonaria, Quoy.

White, with ashy shadow.

9. 8. Salpa cylindrica, Cuv.

4)

23.

23.

White, with ashy shadow.

9. Salpa pyramidalis, Quoy.
White with ashy shadow.
None of these salpze have
a shell.
9. Sanguinolaria livida, Lam.
Livid flesh colour.
11. Scarabus imbrium
Pale brown.
4. Sepia officinalis, Lin.
Purplish.
8. Solen vagina (truncata Wood)
Yellowish.
1. Solen novaculina, Gray.
White, periosteum dirty
olive.
3. Solen Sayii.
Pale flesh-coloured.
4. Solen tenuis, Gray.
Yellowish white.
11. Spondylus Americanus, Lam.

ao ow

i>)

2. Succinea

Reddish White.

. Spirifer trigonalis, Sav.

Fossil.

. Spirula australis, Peron.

Animal reddish.

. Strombus deformis, Gray.

White.

. Strombus Campbellii, Gray.

Brown, with obscure bands,

. Strombus papilio, Lam.

Black brown.
rubescens, Desm.

Reddish.

. Tellina Guildfordize, Gray.

White, inside bright yellow.

. Tellina linguafelis, Lam.

White, with reddish rays.

. Terebellum subulatum, Zam.

White, mottled with brown.

. Terebra subulata, Lam.

Reddish white, with brown
spots. The hinder part of
the whorles rounded into
acute keels.

. Terebra Africana, Gray.

Pale ash, with central brown
band, and streaked with
brown.

. Terebra muscaria, Lam.

White.

. Terebratula Gaudichaudii.

Colour of horn.

PL.
8.

FIG.

5

Teredina personata, Lam.
Fossil.

8. 2. Teredo navalis, Lin.

35.

20.

20.

21.

“4.
ae
1.

=

14,

wo 6

—
.

Dirty white.
Testacellus haliotideus,
Reddish ash-coloured.
Tetralesmis hirsutus, Cuv.
Brown.
Thalia cristata, Cuv.
Ash-coloured.

. Tridacna gigas, Lam.

White.

. Trigonia pectinata, Lam.

Pearly white, varying’ with
orange, reddish, and purple.

. Triton (alepis) fasciculatus,

Yellow.

. Triton Nassoides.

Spanish white.

. Triton iostoma, Gray.

White, streaked with brown,
mouth violet.

. Triton turbinelloides, Gray.

Reddish yellow.

. Triton elegans, Gray.

White, varied with brown.

. Triton vexillum, Gray.

Pale reddish, with bright
orange spiral bands.

. Trochus bicarinatus, Gray.

White, streaked with brown.
Trochus Cunninghami, Gray.
Pale buff, with deeper spots.
Tubicinella balenarum
Yellowish white.

. Turbinella ceratus.

White, with brown spots.

. Turbinella pyrum, Lam.

White, spotted brown.

. Turbinella tubercularis, Sav.

White, with brown patches.

. Turritella suturnalis, Sav.

Brown, with a white spiral
line,

Unio Childreni (unio chinen-
sis) Gray.
Dark brownish periosteum,
teeth small, compressed ;
from South America.

. Unio Smithii, Gray.
Periosteum dark olive,
disk whitish, varied with
olive.

Unio Leaii, Gray.
Dark ash periosteum ; from
China.

PL.

35.

INDEX.

White.

. Venus Danmonensis (Cras-
sina).
Periosteum pale brown.

5. Villorita cyprinoides, Gray
(Cyrena cyprinoides, Wood).
Olive green.

3. Vitrina pellucida, Lam.
Animal ashy, shell green.

. Voluta nivosa, Lam.
Brown, with white streaked
pale spiral bands.
. Voluta Aithiopica, Lam.

Pale brown.

FIG.
2. Unio Douglasiz, Gray.
Periosteum olive, inside
yellowish.
3. Unio Grayii, Lea.
Dark olive.
2. Unio tenuis, Gray.
Sea green, inclining to pink |
toward the apex.
Univalve spiral shells.
Univalve non-spiral shells.
7. Vaginula Taunaysii, Ferr.
Dark green, underneath yel-
lowish.
4. Venus cancellata.
Pale brown, radiated.
2. Venus exoleta, Lam.

26,

PL.

| 30.

34.

40.

40.

40.

601

FIG.

Voluta Broderipii, Gray.

Pale yellow, with two bands
of angular lines, spire
nearly flat.

Voluta Miltonis, Gray.

Pale ash, marbled with
brown spots.

From New Holland.

1, Voluta rudis, Gray.

Clay coloured, mixed with
white.

4, Voluta pallida,
Grayii, Sow.)
Pale buff, with two darker

bands.

Voluta Georgine, Gray.
Brown, varied in degree.
From Swan River.

1. Voluta Turneri
Brownish, with reddish irre-

gular lines.

3. Voluta papillosa.

Brown, with deeper patches,
and a light transverse
band.

4. Voluta gracilis.

Dark brown, with zigzag
lines.

Gray (Vol.

G. 14. Volvaria pallida, Lam. (Mar-

ginella pallida, Gray).
Palebrown,obscurelybanded.

END OF VOL. XII.

GILBERT & RivineTon, Printers, St. John’s Square, London.

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With 10 Engravings, from Designs by W. H. Brooke, F.S.A., foolscap 8vo. price L0s. 6d.
TALES and POPULAR FICTIONS; their resemblance and transmission
from Country to Country. By Tuomas KerGuTLey, Esq.

“A delightful volume, whether we regard the vast stores of learning brought to its aid,
its philosophy and critical acumen, or the alluring nature of its subject.’”—Court Journal.

Works just published by Whittaker and Co.

N

In 2 vols. foolscap 8vo, with 12 Plates and 32 Wood-Cuts by W. H. Brooke, F.8.A.
price 15s.
The FAIRY MYTHOLOGY, illustrative of the Romance and Super-
stitions of various Countries. By Tuomas KEIGHTLEY.
‘This is certainly one of the most delightful as well as curious books that we have for
many a day had the pleasure of perusing. It must form part of the library of every lover

of poetical antiquities, and every general scholar; we had almost said, of every reader for
mere amusement.”—Atheneum.

JVE

By the same Author,

In one large volume, 8vo. with 12 Plates from the Antique, etched on Steel, by
W. H. Brooke, F.S.A. price 18s.

The MYTHOLOGY of ANCIENT GREECE and ITALY, intended
chiefly for the Use of Students at the Universities, and the higher Classes in
Schools.

‘Delicacy has been scrupulously preserved, without any violation of fact. We recom-
mend it as a work of a most meritorious and useful character, compiled with great care,
clearly arranged, and very far superior to any thing of the kind in our language, equally
adapted for the student, the scholar, and the general reader.” —Metropolitan Magazine.

VILE

Price 4s. bound, gilt, and lettered.

The PARLIAMENTARY POCKET COMPANION, for 1834. Con-
tents :—

All Peers of Parliament, their Ages, Marriages, Residences, Offices,
Church Patronage, &c.

Lists of Places returning Members, with their Population, £10 Houses,
Assessed Taxes, prevailing Interests, &c. and several Particulars connected
with the last Election, including the Number of Voters registered, the gross
Poll at each Contest, and the Numbers who voted for each Candidate.

Members of the House of Commons, their Residences, Professions, Offices,
Church Patronage, Political Principles and Pledges, the Places for which
they formerly sat, and other Particulars of their Public Life.

Lists of the Cabinet Ministers, the chief Public Functionaries, Parlia-
mentary Agents, Officers of both Houses, British and Foreign Ambassadors,
&c.

Also, a Variety of Miscellaneous Information connected with the foregoing,
and with the several Public Offices.

The whole carefully compiled from official Documents, and from the per-
sonal Communications of Members of both Houses.

‘‘ Tt seems to be the most useful and the best executed of the many similar works that
have lately issued from the press, and with as much accuracy perhaps as is attainable in
such matters.”—T'imes.

‘We can safely recommend this epitome of Parliamentary biography.”—New Monthly
Magazine.

“This is avery neat and compendious manual, which every man, who either hears, or
reads, or talks about the debates in Parliament, ought to possess.”—Morning Post.

“It contains, within waistccat-pocket dimensions, just what is required to apprise the
ignorant, and to remind the forgetful of all thatneed be known or remembered in reading a
newspaper, ofthe Peers, of the Commoners, and of the places which the latter represent.”—
Record.

‘‘ Being entirely free from political bias, it must be acceptable to all parties. We know
it to be surprisingly accurate.”—Hull Advertiser.

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