308 MELANim^. 



Sub-gen. kitocris, H. and A. Adams. 



Shell thin, subglobose, whorls angulated, often carinate ; 

 inner lip subtruucate, or ending in a tubercle. 



carinata, Lea. inflata, Lea. 



costata, Lea. Kirtlandiana, Anthon. 



dentata, Couth. monodontoides, Gould. 



dilatata, Conr. occidentalis, Lea. 



dissimilis, Say. Rogersii, Conr. 



ebena, Lea. ■ subcarinata, Hald. 



Sub-gen. verena, H. and A. Adams. 



Shell subturbinate, whorls transversely Urate, carinated at 

 the hind part ; aperture not produced in front ; inner lip simple, 

 without a posterior callus ; columella subtruncate anteriorly, 

 forming a very short canaliculation. 



cren ocarina. Morel. 



Sub-gen. lythasia, Lea. 



Shell thick, solid, ovate, whorls gibbose or tuberculated at 

 the hind part ; aperture sub-canaliculated and produced in front ; 

 inner lip with a callus posteriorly, subtruncate anteriorly. 



genicula, Hald. salebrosa, Conr. 



neritiformis, Besh. semigranulosa. Desk. 



obovata, Say. 



Genus PYRGULA, Christie and Janson. 



Shell turreted, whorls numerous, carinated ; aperture 

 oval, emarginate anteriorly ; columellar lip free, reflected, 

 produced in front ; outer lip thin, simple. 



