41 



SPECIES XXXII. Obliquaria retusa (Unio 

 retusa.) 



Shell thick, convex, without elevations, with 

 a slight terminal sinus; epidermis olivaceous, 

 with slight wrinkles, distant; nacre whitish. 

 Length diam. f axis of the breadth. 



A small species, one or two inches broad ; 

 rare ; found in the Ohio and Kentucky ; lamellar 

 tooth short, carinated,-jfassttfe not visible. 



SPECIES XXXIII. Obliquariajlexuosa (Unio 

 fiexuosa. 



Shell thick, with two slight elevations and a 

 broad flat depression between them ; sloped pos- 

 teriorly ; epidermis yellowish brown, lined with 

 brown at the base, with flexuous wrinkles, some- 

 what striated ; edge flexuous ; nacre bluish. 

 Length f diam. f axis f of the breadth. 



Found in the Kentucky, Salt and Green rivers 

 breadth about two inches ; lamellar tooth short, 

 almost doubled in the right valve ; fossule visi- 

 ble ; cardinal tooth small, striated ; muscular im- 

 pressions deep. 



Var. 1. bullata, with some broad tuber- 

 cles, flat and transversal on the eleva- 

 tions. 



