GASTEROPODA PECTINIBUANCHIATA, 369 



very moderate, its whorls rapidly enlarging and seen within, but 

 concealed during the life of the aninial in the thickness of a fungous 

 shield, which projects considerably beyond it, as well as the foot, 

 and which is the true mantle. Before this mantle are an emargina- 

 tion and a semi-canal, which serve to conduct water into the bran- 

 chial cavity, and which form the passage to the following family, 

 but of which there are no impressions on the shell. The tentacula 

 are conical, with the eyes at their external basej the penis of the 

 male is very large. 



Some species are found on the coast of France. The 



CoRiocELLA, Blainv., 



Consists of Sigareti, the shell of which is horny and almost mem- 

 branous, like that of the Aplysie(l). 



Cryptostoma, Blainv. 



The shell, resembling that of a Sigaretus, with the head and abdo- 

 men, which it covers, supported by a foot four times its size, cut 

 square behind, and forming before a fleshy, oblong bundle that con- 

 stitutes nearly one-half of its mass. The animal has a flat head, two 

 tentacula, a broad branchial pecten on the roof of its dorsal cavity, 

 and a penis under the right tentaculum; but I can find no emargina- 

 tion in the mantle(2). 



FAMILY III. 



BUCCINOIDA. 



This family has a spiral shell, in the aperture of which, near 

 the extremity of the columella, is an emargination or a canal 

 for 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 



(1) The Coriocelle noire, Blainv., Malac, XLII, f. 1. This animal is not de- 

 prived of a shell, as the author of the genus imag-ined, but It Is thin and flexible. 



(2) Besides the species in the British Museum {Cr. Leachii, Blainv. Malac, 

 XLII, 3), we have one {Cr. carolinum, Cuv. ) sent from Carolina by M. L'Hermi- 

 nier. 



Vol. II. 2 W 



