298 



SHELLS AND SHELL-FISH. 



short; the base truncate and emarginate^ or with a 

 short recurved channel ; inner lip toothed or plaited.* 



Harpa Lam. Varices numerous and regular, forming 

 longitudinal ribs, coronated near the suture ; aperture 

 and lips highly polished ; base truncate {fig. Q5. &, c). 

 multicostata. Sow. Gen. f.l. crenata Sw. Bligh, Cat. 



CYPB^siCAssis Stuchhury. Shell oblong, oval, ventri- 

 cose, without varices ; spire very small ; aperture 

 cyprseiform ; outer lip thickened, convex, and ad- 

 vancing on the spire ; inner margin regularly toothed ; 

 inner lip thickened, convex, and spreading on the 

 body-whorl, without being detached j pillar angu- 

 lated internally, and crossed by uniformly slender 

 plaits ; canal very short, reposing on the body-whorl; 

 aperture very narrow, with a recurved channel above, 

 testlculus. Mart. f. 375. ? crumena. Mart. 37. f. 379. 



rufa. lb. 32. f. 341. harpaeformis. Lam. No. 26.1' 



Cassis Lam. Shell ponderous, marked with varices ; 



66 



out any varices. There is, in fact, every modification of shape among the 

 Tritons as they now stand ; some have the aperture wide, others narrow; 

 the channel is either very long or truncate ; the spire greatly lengthened 

 or greatly depressed ; the pillar toothed or smooth ; the varices either alter- 

 nate or none. But, the sub-genera not having been determined, I leave 



the group in this confused state. These facts, better than any theoretical 

 arguments, show the absolute necessity of defining the sub-genera. 



* Except in Dolium and Harpa. 



f Uniting this genus to Harpa. 



