76 



Genus Hemilastena (Agassiz) Simpson. 



Hemilastena ambigua Say ( = hildrethiana Lea). 



Cook Co. (Baker): Kankakee River, Wilmington, Will Co. 

 (Ferriss, Handwerk); Hickory Creek, Will Co. (Handwerk); 

 Wabash River; Mercer Co. (Marsh) ; Spoon River (Strode). 



Genus Margaritana Schumacher. 



Margaritana margaritifera Linne. 

 Illinois River (Calkins). 



Margaritana monodonta Say (= soleniformis Lea). 



Northern Illinois (Calkins) ; Mercer Co. (Call, Marsh); Kan- 

 kakee River (Ferriss, Handwerk) ; Mississippi River, Quincy, 

 Adams Co. (Hart); Mississippi River (Marsh ) ; Southern Illi- 

 nois (Ulffers) ; Fulton Co. (Wolf); Havana, Mason Co. (State 

 Laboratory). 



Genus Unio Retzius.* 



Section Elliptw Rahnesque. 

 Unio gibbosus Barnes (= arctiorlueo,). 



Oregon, Ogle Co.; Savanna, Carroll Co. (Baker); Cook Co. 

 (Baker, Calkins, Higley, Nason ) ; Northern Illinois (Calkins) ; 

 Kankakee River (Ferriss, Handwerk); Illinois and Du 

 Page rivers (Handwerk): Mississippi River, Quincy, 

 Adams Co. (Hart); Winnebago Co.; Wabash and Ohio 

 rivers (Hinkley); La Salle Co. (Huett) ; Mercer Co.; Mississip- 

 pi and Wabash rivers (Marsh) ; Fox River, Algonquin, McHen- 

 ry Co. ; Athens, Menard Co. ( Nason) ; Fox River, Dundee, Kane 



*Unio inflatus Lea ( = Lampsilis alabamensis Conrad) is reported by Wolf from Fulton 

 Co. (Am. Journ. Conch., VI., p. 29). This record is erroneous, as the species is 

 confined to the Alabama and Tombigbee rivers. 



Unio bvMatus Rafinesque is reported by Ulffers from Southern Illinois. I do not know 

 what species this is intended for. Ratinesque described an Obliquaria buUata, but 

 it is absolutely indeterminate. 



Unio torsus Ratinesque reported by Ulffers from Southern Illinois, is indeterminable. 



Unioniger Conrad is reported from Southern Illinois by Ulffers. I know of no spe- 

 cies of that name. Unio mytUoides Rafinesque is also an indeterminable species. 

 (Ulffers, p. 610.) 



Unio scalenius Ratinesque is reported from Southern Illinois by Ulffers. There is no 

 scalenius of Rafinesque, and scalenius Say = Pleurobema decisa Lea, which is 

 confined to the Alabama and Tombigbee river systems. 



Unio rubidundus Say i* reported by Ulffers from Southern Illinois. There is no rubi- 

 dundus or rubicundus described by Saw 



