564 MOLLUSCA. 
Mollusca. Family 1. Conwside—Furnished with a long proboscis, 
In general form, and in the structure and position of the Mollusca. 
Sy and produced tentacula, with the eyes near the summit on 
branchiz, the resemblance to the genera of the preceding === 
the outside. The lid is placed obliquely on the foot, and 
is too smalleto fill the mouth of the shell. The genera Co- 
nus and Terebellum form this family. 
Family 2. Cypreade—Cloak enlarged, and capable of 
folding over the shell. There is no lid. The genus Cy- 
prea is the type. 
Family 3. Ovwlade—Both extremities of the aperture 
canaliculated. The inhabitants of all the genera, Ovula, 
Calpurna, and Volva, are unknown. The last genus in- 
cludes the Bulla patula of Pennant. 
Family 4. Volutade.—Canal of the aperture abbreviated. 
Pillar-lip plaited. The foot appears to be destitute ofa lid. 
The genera are numerous; Voluta, Oliva, Cymbium, Mar- 
ginella, Cancellaria, Mitra, Ancilla, Volvaria, and Torna- 
tella. The last genus contains the Voluta tornatilis of Bri- 
tish writers. 
2. Shell turreted—The whorls of the shell, the revolving 
spire of which is subconical, scarcely embrace one another, 
but are merely united at the margins. Three families may 
here be established. 
Family 1. Buecinide—Canal short, scarcely produced 
beyond the anterior margin of the lip, and bent towards the 
right. The tentacula are remote, and the head is destitute 
of a hood. The mouth hasa-retractile proboscis. The fol- 
lowing genera belong to this family: Buccinum, Eburna, 
Dolium, Harpa, Nassa, Purpura, Cassis, Morio, Ricinula, 
and Monoceros. 
Family 2. Murtetde.—Canal produced, and straight. 
The tentacula approach the head and mouth as in the pre- 
ceding family. The genera are Murex, Typhis, Ranella, 
Fusus, Pleurotoma, Pyrula, Fasciolaria, Terebra, Triton- 
alia, and Turbinella. 
Family 3. Cerithiade.—Canal short‘and recurved. Head 
with a hood. ‘This family contains the marine Cerithium 
and Strutheolaria, and the fluviatile Potamidum, Melanop- 
sis, and Pirena. 
Family 4. Strombustde—Canal short, and bent towards 
the right. The outer margin of the aperture becomes nal- 
mated with age, and exhibits a second canal, generally near 
the former, for the passage of the head. The following are 
the genera: Strombus, Pterocera, Hippocrenes, and Ros- 
tellaria. 
2d Tribe. 
Shell internal. 
This tribe consists at present of only one genus, termed 
Sigaretus, two species of which are natives of Britain. The 
foot of the animals belonging to this genus, or rather of the 
species which constitutes the type, is oval, with a duplica- 
ture in front. The cloak is broad, with an indentation on 
the left side, in front, leading to the branchial cavity. A 
ring of transverse muscles unites the cloak with the foot. 
On the back is placed the shell, which does not appear on 
the outside, as it is covered by athick cuticle. Itis lodged 
in a sac, and united by a muscle, which adheres to the pil- 
lar. The hood is produced, at each side, into a flattened 
tentaculum, with an eye at the external base. The anus is 
situate at the branchial indentation on the left side. The 
penis is situate on the right side of the neck; it is external, 
with a crooked, blunt, lateral process near its extremity. 
The mouth is in the form of a short proboscis. The 
tongue is armed with spines, and is long and spirally folded. 
The salivary glands are large. The stomach is membrana- 
ceous, giving off the intestine near the cardia. The intes- 
tine makes two folds.. The liver, with the testicle in the 
‘male, and the ovarium in the female, occupy the posterior 
part of the body, under the spire of the shell. 
2d Subdivision. 
Heart traversed by the rectum. 
This group includes the order Scutibranchia of Cuvier. 
subdivision is very great. The animals differ, however, in 
many particulars. The heart is furnished with two auricles, 
and is perforated by the intestine. The sexes appear to be 
incorporated in the same individual, or rather the male or- 
gans are unknown. The body is protected by a shell, the 
aperture of which is wide, and never closed by a lid. 
lst Tribe. 
Shell ear-shaped, flat, with a lateral, and nearly concealed 
spire. 
i Family Haliotide.—The genera of this group exhibit well- 
marked characters in the shell. In the Halioéis, the left mar- 
ginof the shellis pierced by a row of holes. In Padola these 
holes arenearly obliterated; but there isan internal grooveand 
external ridge in the line of their direction. In Stomaéza, 
there are neither holes nor ridges. In: the Halyotis, the 
foot is oval and large. The sides of the body, all round, are 
ornamented with one or more rows of simple or branched fila- 
ments. The shell is placed on the back with the spiral part 
behind, and the row of holes on the left side, through which 
some of the filaments are protruded. The animal is attached 
to the shell by a single large muscle. The entry to the 
branchial cavity, which likewise contains the termination of 
the rectum and oviduct, ison the back. Thegills are in two 
ridges, consisting of complicated branched filaments. At 
the entrance of the cavity, the cloak is furnished with a slit, 
the left margin of which rests upon the pillar of the shell. 
The edges of this slit are furnished with filaments, which 
pass through the anterior holes of the shell. The usé of 
this singular arrangement is unknown. The branchial ca- 
vity likewise contains the viscous organ, in common with 
the Pectinibranchiz. 
The hood is emarginate, with a long tentaculum on each 
side, behind which, towards the side, is a cylindrical protu- 
berance, bearing the eye at the top. The mouth is in the 
form of a short proboscis, with two corneous plates as cheeks, 
and a long narrow tongue extending backwards, and co- 
vered with spines. The pharynx is dilatable, with internal 
folds. The salivary glands are very small. The gullet is 
very short. The stomach is divided into two portions, the 
first of which is striated longitudinally with a glandular struc- 
ture, and receives a biliary duct. The second is separated 
from the former by a valve, is smaller, with transverse striz, 
and a double ridge. It likewise receives bile through two 
apertures. There is another valve at the pylorus; and the 
intestine, after making some turns, is surrounded by the 
heart. There is an auricle on each side, receiving the aér- 
ated blood from each of the gills. 
2d Tribe. 
Shell conical, simple, or slightly’revolute at the apex. 
A. Cavity of the shell interrupted by a testaceous plate. 
This division consists of five genera, each of which may 
be regarded as the type of a family, although, for the pre- 
sent, they are all included in one. In the Crepidula, the 
gills form a transverse ridge on the roof of the cavity, con- 
sisting of filaments extending beyond the margin. The eyes 
are at the base of the tentacula. There is only one fluvi- 
atile genus, termed Navicella. 
B. Cavity of the shell entire. 
In the Capulus, the shell is entire, the foot is complicated 
on its anterior margin. The shell adheres to the animal by 
a circular muscle, leaving an opening in front, for the issue 
of the head and entrance to the branchial cavity. The gills 
form a single ridge across the roof. The mouth is in the 
form of an extended proboscis, with a deep groove above. 
The tentacula, which are two in number, have the eyes at 
the external base. The anus is on the right side of the 
branchial cavity. In the Carinaria, the foot appears to be 
compressed, and formed for swimming. The head is co- 
vered with a group of tubercles. The mouth is furnished 
