RINGICULA. 197 



Ex. C. pomum, Linnceiis, pi. 20, fig. 7. Shell, C. 

 ringens, Swainson, fig. 7, a. 



Cadiiwi, consisting of but few species, differs from 

 Dolum principally in its solid structure and ringent 

 aperture; its outer lip, moreover, is strongly toothed, 

 thickened, and reflected. 



Species of Cadiiim. 



clentatum, Barnes. ringens, Stvains. 



pomum, Linn. 



Genus RINGICULA, Deshayes. 



Shell small, ventricose, smooth or transversely sti'iated ; 

 spire small ; aperture with an oblique notch in front ; 

 columella callous, strongly plicated; outer lip thickened 

 and reflected, with a marginal callus. 



Syn. Auriculina, Gratel., not Gray. Auricularia, De 

 la Be die. 



Ex. R. buccinea, DesJiayes, pi. 20, fig. 8. 



From an examination of the animal in spirits, it ap- 

 pears that the eyes are on the outer bases of subulate 

 tentacles, and that the foot is unprovided with an oper- 

 culum. Many allied fossil genera are of much larger size 

 than the existing species of Rinyicula, and approach even 

 still closer, in the character of the shell, to the other 

 members of this family. 



Species of -Ringicula. 



acuta, Phil. exserta, Hinds. 



australis, Hinds. grandinosa, Hinds. 



buccinea, Desk. propinquans, Hinds. 

 caron, Hinds. 



