210 NATURAL HISTORY BULLETIN. 



Valvata bicarinata Lea. Rather rare. 



LAMELLIBRANCHS . 



Sph/Erium rhomboideum (Say). Pr. Quite common. 

 Calyculina parTUMEIA (Say). Common. 

 Calyculina SECURE (Prime). Not common. 

 Calyculina transversa (Say). Very common. 

 Pisidium abditum Hald. Very common. 

 Unio* subrostraTus Say. Quite common. 

 Anodonta grandis Say. Common. 

 Anodonta imbecillis Say. Common. 



c. Species of the larger creeks and the river. 



GASTEROPODS. 



PlEurocera subulare (Lea) Try. Common. 

 Somatogyrus subglobosus (Say). Common. 



SOMATOGYRUS INTEGER (Say) Bttlfl. 



Campeloma subsolidum (Anth.) Call. Very common. 



Cajipeloma . Two other possible species. 



Lioplax subcarinata (Say ) Tros. Not common. 

 Ancylus rivularis Say. Very common. 



LAMELLIBRANCHS . 



Sph.-erium sulcatum (Lam. ) Pr. Very common. 



Sph,ERIUM solidulum (Pr.). Quite common. 



Sph.ERIUm striatinum (Lam.) Pr. Rather frequent. 



Unio .ESOPUS Green. Common. 



Unio alatus Say. Common. 



Unio anodontoides Lea. Common. 



Unio capax Green. Rather rare. 



L T xio coccineus Hild. Common. 



Unio CORNUTUS Barnes. Quite common. 



Unio donaciformis Lea. Quite common. 



Unio ebexus Lea. Rare. 



Unio elegans Lea. Common. 



Unio ellipsis Lea. Rather rare. 



Unio fragosus Con. Quite common. 



Unio gracilis Barnes. Common. 



Unio l^Evissimus Lea. Common. 



Unio ligamentinus Lam. Very common. 



*For convenience the old generic names of this group are here 

 retained. 



