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 
