GASTEROPODA PECTINIBRANCHIATA. 65 



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 base : 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 Aplysise*. 



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 emargination 

 in the mantle f. 



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 transmit- 

 ting the siphon or tube, which is itself but an elongated fold of *he 

 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. Lin. § 



So called from the conical shape of the shell ; the spire, either per- 

 fectly flat, or but slightly salient, forms the base of the cone, the 

 apex being at the opposite extremity ; the aperture is narrow, recti- 

 linear, or nearly so, extending from one end to the other without 

 enlargement or fold, either on its edge or on the columella. The 



* The CoHocolle noire, Blainv. Malac, XLTI, f. 1, This animal is not deprived 

 of a shell, as the author of the genus imaeined, but it is thin and flexible. 



f Besides ths species in the British Museum {Cr, Leachii, Blainv. Malac., XLIf, 

 3), we have one (Cr. corolinum, Cuv.) sent from Carolina by L. L'Herminier. 



X They are the Paracephalophora Dio'ica Siphonobranchiata of Blainville. 



§ M. de Blainville unites the Coni, Cypreee, Oindce, Terebella, and the Valuta, in a 

 family which lie calls Angyostoma. 



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. 



VOL. III. F 



