74 



River, Dundee, Kane (Jo. (Nason) ; Spoon River (Strode) ; Ce- 

 dar Lake, Lake do. (State Laboratory). 

 Aiiodontoidcs feriixsacian us suhei/h'tidra.eei/,s Lea. 



(Jook Co. (Baker, Jensen); Northern Illinois (Calkins); 

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

 (Lyon) ; Lake Co. (Marcy) ; Peoria, Peoria Co. (State Labora- 

 tory). 



Genus Arcidens Simpson. 



Arcidens confragostis Say. 



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

 Springfield, Sangamon ('o., and Fox River (Call) ; Illinois River, 

 Utica, La Salle Co. (Ferriss, Handwerk); Mississippi River, 

 <^uincy, Adams Co. (Hart, Nason); Kaskaskia, Big Muddy, and 

 Little Wabash rivers (Hinkley) ; La Salle Co. (Huett) ; Spoon 

 and Illinois rivers (Kelly, Strode) ; Mercer Co., Mississippi River 

 (Marsh); Athens, Menard Co. (Nason); Southern Illinois 

 (Ulrt'ers); Fulton Vo. (Wolf); Lake Michigan, Chicago, Cook 

 Co.; Havana, Mason Co. (State Laboratory). 



Genus Symphynota Lea. 



Subgenus Hympliynota Lea.* 

 Symphynota comprcs.sa Lea {=preiisa Lea). 



Cook Co. (Baker); Hickory Creek, Will Co. (Ferriss); Uu 

 Page River (Gault) ; Illinois River (Handwerk) ; Kent's Creek, 

 Rockford, Winnebago C!o. ( Hinkley) ; Mercer Co. (Marsh) ; Mill 

 Race, Algonquin, McHenry Co. (Nason). 



Subgenus Lasmigona Rafinesque. 

 Symphynota costata Raiinesque (=rugosa Barnes). 



Savanna, Carroll Co. (Baker) ; Cook Co. (Baker, Jensen) ; 

 Northern Illinois; Fox River (Calkins) ; Fox River, Dundee, 

 Kane Co. (Engleholm, Nason) ; Hickory Creek, Will Co. (Fer- 

 riss) ; Du Page and Kankakee rivers (Handwerk) ; Illinois 

 River (Handwerk, vStrode) ; Mackinaw River, Kappa, Woodford 

 Co. (Hart); Winnebago Co. (Hinkley); La Salle Co. (Huett); 

 Spoon River (Kelly, Strode); Mercer Co., Mississippi River 



* Symphynota iwylcctn Lea is reported from Fulton Co. by Wolf (Am. Journ. Conch., 

 VI., ]). 29), but the record must rest upon a uiisidentification, as this species is 

 conlined to northern Alabama. ( 17</t' Simp.sun, Synopsis, p. 664.) 



