77 



Co. (Nason, Swick) ; Spoon and Illinois rivers (Strode) ; South- 

 ern Illinois (Ulffers); Fulton Co. (Wolf); Havana, Mason Co. 

 (State Laboratory). 



Unio gibbosus delieatus Simpson. 



Cook Co. (Baker) ; Kent's Creek (Hinkley) ; Dundee, Kane 

 Co. (Swick). 



Unio crassidens Lea. 



Savanna, Carroll Co. (Baker) ; Northern Illinois (Calkins) ; 

 Illinois River, Utica, La Salle Co. (Ferriss) ; Kaskaskia and 

 Wabash rivers (Hinkley); La Salle Co. (Huett); Mercer Co., 

 Mississippi River (Marsh); Mt Carmel, Wabash Co. (Nelson); 

 Spoon River (Strode) ; Fulton Co. (Wolf). 



Section Uniomerm Conrad. 

 Unio tetralasmus Say (=jamesianus Lea). 



Washington and Perry counties, in creeks and ponds (Hink- 

 ley) ; Big Muddy River (Marsh) ; Phelps Lake, Fulton Co. ; Sid- 

 ney and Urbana, Champaign Co. (State Laboratory). 



Unio tetralasmus camptodon Say. 



Du Bois, Washington Co., in pond (Hinkley); Albion, Ed- 

 wards Co. (Jensen). 



Genus Pleurobema (Rafinesque) Agassiz.* 



Pleurobema clava Lamarck. 



Wabash River (Hinkley, Marsh). 



Section Plethobasus Simpson. 

 Pleurobema <esopus Green. 



Savanna, Carroll Co. (Baker); Northern Illinois (Calkins); 

 Fox River, Dundee, Kane Co. (Connor) ; Kankakee River (Fer- 

 riss, Handwerk) ; Mississippi River, Quincy, Adams Co. (Hart) ; 

 Green, Kaskaskia, Wabash, and Rock rivers (Hinkley) ; La 

 Salle Co. (Huett); Mercer Co., Mississippi River (Marsh); 

 Athens, Menard Co. (Nason) ; Mt. Carmel, Wabash Co. (Nel- 

 son) ; Spoon River (Strode) ; Southern Illinois (Ulffers) ; Ful- 

 ton Co. (Wolf) ; Illinois River, Havana, Mason Co. (State Lab- 

 oratory). 



* Pleurobema cor Conrad is reported from Southern Illinois by Ulffers, — a misidentifi- 

 cation, as the species is confined to the Alabama River system of Alabama and the 

 Flint River of Georgia. 



