362 
MOLLUSCA. 
duce the water to the branchial cavity placed upon the back, and closed in every other place. The 
respiratory organ consists in a few small leaflets, attached in a transverse line to the bottom of that 
cavity. The animal appears to have no tentacula, but only a narrow veil upon the head. There are 
species in which the shell shows no appearance of the groove, and would perfectly resemble a Patella 
were it not that its vertex is turned backwards. [We must observe, says Rang, that we have seen 
young Patellae to have the character of Siphonaria, and to preserve traces of it at a more advanced age: 
it is only then provisionally that we adopt this genus, and assign it a place among the InferobrancMata.'] 
SiGARETus, Adans. 
The shell is flattened, with an ample round aperture, and an inconsiderable spire, whose whorls enlarge 
very rapidly, and are visible on the inside. It is hidden during life in the fungous shield of the animal, 
which projects considerably beyond it, as well as the foot, and is the true mantle. We observe in front 
of this mantle an emargination and a semi-canal, the use of which is to conduct water into the branchial 
cavity, but which leave no impressions on the shell. The structure indicates a transition to the following 
family. The tentacula are conical, with the eyes at their exterior base : the penis of the male is very 
large. 
There are species on our own coasts. [This remark is erroneous, unless we consider Cuvier’s Sigaretus the 
same as Pleurobranchus. See some remarks on the confusion in the nomenclature of this genus by Mr. Gray, in 
the Zool. Journ. i. p. 428.] 
Coriocella, Blainv., is a Sigaretus with a horny and almost membranous shell, like that of Aplysia. 
The Cryptostoma, Blainv. — 
Has a shell very similar to Sigaretus, supported, with the head and abdomen (which it covers), on a foot 
four times its size, cut square behind, and which produces in front a fleshy oblong part 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 the penis under the right tentaculum, but I have not seen any emargination 
in the cloak. 
THE THIRD FAMILY OF THE PECTINIBRANCHIATA,— 
The Buccinoides,* — 
Have a spiral shell, the mouth of which has, near the end of the columella, a sinus or canal, for the 
passage of the siphon or tube formed by an elongated fold of the cloak. The greater or less length of 
this canal when it exists, the greater or less width of the aperture, and the various forms of the 
columella, afford characters for a division of the family into genera, which can be grouped in various 
ways. 
The Cones (Conus, Linn.) — 
Are so named from the conical figure of their shells. The spire, 
either flat or slightly raised, forms the base of the cone, whose 
apex is at the opposite extremity : the aperture is narrow, 
rectilinear, or nearly so, extended from one end to the other, 
without protuberance or fold, either on the columella or the 
margin. The animal is of a thinness proportioned to the aper- 
ture through which it issues : its tentacula and proboscis are , 
much elongated, and we find the eyes near the apex of the 
former, on the outside : the operculum, seated obliquely on the 
hinder part of the foot, is narrow, and too short to close the 
mouth of the shell. 
The shells of this genus are in general beautifully coloured, whence 
Fij/. 175 .— Conus j-eiieraiis. it happens that they crowd our cabinets. Our seas produce only a 
very few species, [of which there is a full enumeration in Lamarck’s Histoire naturelle des Animaux sans vertebres.'] 
The Cowries (Cijprcea, Linn.) — 
Have also a [concealed or] very short spire, and a narrow aperture extending from one end to the 
other ; but the shell, which is ventricose in the middle, and almost equally narrowed at both ends, forms 
* Coequal with the Paracrphaluphora dioica siphunohranchiata of 
Blainville. 
+ M. de Blainville unites in one familj’’, najiied Angyostoma, the 
Conus, Cyprsoa, Ovula, Tcrebellum, and Voluta. In placing here the 
genera with a narrow aperture, we do not intend to say that they are 
nearest in affinity to the preceding family ; but we place them first 
because they exhibit the characters of the siphoniferous tribes in the 
most distinct manner. 
'(H" 
