Shdk. 



Crepidula. 



plana, Say. 



convexa,'Say. 

 Ancylus. 



rivularis, Say. 

 Velutina 



rupicola, Conrad. 

 Bulla. 



solitaria, Say. 

 Limax. 



one or more species. 

 Testacella. 



one or more species. 



ORDER III — TRACHELIPODA. 



Helix. 



albolabris, Say. 

 thyroidus, Say. 

 alternata, Say. 

 perspectiva, Say. 

 glaphyra, Say. 

 arborea, Say. 

 tridentata, Say. 

 hirsuta, Say. 

 fraterna, Say. 

 labyrinthica, Say. 

 minuta, Say. 

 subglobosa,(manusci ipt. ) 

 Pupa. 



fallax, Say. 



corticaria, Say. 

 Succinea. 



ovalis, Say. 

 _ campestris, Say. 

 Auricula. 



myosotis, Drap. 

 Planorbis. 



trivolvis, Say. 



bicarinatus, Say. 



armigerus, Say. 



campanulatus, Say. 



parvus, Say. 



two or more other species. 

 Physa. 



heterostropha, Say. 

 Lymnoea. 



eatascopium, Say. 



columella, say. 



ovata, Lam. 



two or more other species. 

 Valvata. 



arenifera, Lea. 

 Paludina. 



decisa, Say. 



limosa, Say. 



lapidaria, Say. 



one other species. 

 Natica. 



duplicata, Say. 



heros, Say. 



triseriataj Say, 



