410 TROCHIN.E. 



false umbilicus with the margin simple ; columella with 

 the edge edentulate and ending in a point. . 

 Ex. C. pulcherrima, Grai/, pi. 46, fig. 3, 

 Camitia somewhat resembles Clanculus, but its surface 

 is entirely smooth like that of Umhonium. As in Clancu- 

 liis, moreover, the aperture communicates with the cavity 

 of the false umbilicus by means of an open, transverse fis- 

 sure. There are but two species at present known. 



Species of Camitia. 

 Grayi, A. Adams. pulcherrima, Gray. 



Genus CHRYSOSTOMA, Swainson. 



Shell turbinate, solid, smooth, umbilicated, umbilicus 

 almost covered by a large callus ; whorls few, convex ; 

 aperture effuse, round ; inner lip with a large, spreading 

 callus, covering, and nearly concealing, the umbilicus. 



Ea:. C. paradoxum, Bo7'n, pi. 46, fig. 4. 



The animal of this genus is unknown ; the shell some- 

 what resembles Umhonium, but the surface is not po- 

 lished ; the outer lip is marginate internally, and the 

 interior of the aperture is coated with a beautiful, golden, 

 nacreous deposit. 



Sub-fam. TROCHIN^. 



Operculum horny, orbicular, composed of numerous, 

 narrow whorls, with the nucleus central. 



Shell conoidal or pyramidal, the last whorl more or 

 less angulated at the circumference, and usually flattened 



