RAPANIN^. 133 



Si//i. Concholepas, Favanne. Conchulus, Rqfiii. 



Ex. C. Peruviana, Lamarck, pi. 14, fig. 2. Operculum, 

 C. Peruviana, fig. 2, a, 2, b. Shell, C. Peruviana, fig. 2, c. 



The only species known of this genus is from Peru ; it 

 lives upon the rocks and stones along the shore, and, con- 

 sidering the size of the foot, is, according to D'Orbigny, 

 very inactive ; the operculum is very large and thin, and is 

 placed transversely across the hind part of the foot. 



vSub-fam. RAPANIN^. 



Operculum ovate, blunt, nucleus elongate, forming the 

 outer or hinder edge. 



In this sub-family the shell is usually more or less pyri- 

 forra, and often produced anteriorly; the spire is short, 

 and the inner lip is convex and smooth. 



Genus CUMA, Humphrey. 



Shell pyriform ; spire elevated, acute, whorls angular or 

 spinose ; aperture oval-oblong ; columella convex, some- 

 times with a strong angular tooth in the middle ; outer lip 

 acute, grooved internally. 



Ex. C. kiosquiformis, Duclos, pi. 14, fig. 3. Oper- 

 culum, C. tectum, Chemnitz, fig. 3, a, 3, b. Shell, C. tec- 

 tum, fig. 3, c. 



The operculum of this genus resembles that o^ Pur- 

 pura ; some of the species bear a close affinity to those 

 of Rhizochilus, and in the one chosen by Swainson as 

 the type there is a prominent tooth-like projection in 

 the middle of the columellar lip. 



