10. 



299 



La Guayia, Salle. 

 laevissimus, Sow. 

 nigritus, Morel. 

 simplex, Say. 



sulcospira, Mouss. 

 testuclinarius, V. d. Busch. 

 verus, Pas. 

 Zanguebarensis, Petit. 



Sub-gen. aylacostoma, Spix. 



Shell elongately fusiform, thick, solid, whorls smooth, cari- 

 iiated or geniculate near the suture ; inner lip thickened, 

 callous ; aperture entire in front ; outer lip thickened internally. 



coarctatus. Lam. 

 cochlidium. Lea. 

 costellaris. Lea. 

 Cumingii, Lea. 

 impurus. Lea. 



moestus, Hinds. 

 rectus. Lea. 

 scalaris, Wagn. 

 sobrius. Lea. 



Sub-gen. potadoma, Swainson. 



Shell ovate, solid ; spire short, whorls smooth ; inner lip 

 somewhat thickened; aperture produced in front; outer lip 

 acute, simple. 



depygis, Saij. 

 fontinalis, Phil. 

 gracilis. Lea. 

 inornatus, Anthon. 

 Isevigatus, Lea. 

 Niagarensis, Lea. 

 Ococensis, Lea. 



ovoideus, Lea. 

 perfuscus. Lea. 

 rufescens, Lea. 

 sordidus. Lea. 

 subcylindraceus. Lea. 

 subsolidus. Lea. 

 Warderianus, Lea. 



Genus lO, Lea. 



Shell fusiform, whorls spinose ; aperture large, ovate, 

 dilated anteriorly, produced in front into a grooved beak ; 

 outer lip simple, acute. 



