52 



Var. 1. tuberculata with some scattered 



tubercles. 



Var. 2. fasciolata fasciolated with green- 

 ish brown ; nacre roseate. 

 A pretty species, rarely longer than one inch ; 

 lamellar tooth somewhat oblique, straight, obtuse ; 

 cardinal tooth striated ; fossule visible ; rare 

 in the Ohio. 



SPECIES L. Obovaria cordata (Unio cordata.) 



Shell thick, ventricose, cordated inferiorly by 

 a sinus and a slight depression ; epidermis smooth, 

 brown ; nacre white ; apices somewhat promi- 

 nent ; inferior breadth j-i diam. of the length. 

 Axis medial. 



Var. rosea epidermis blackish, nacre 

 roseate. 



A small handsome species, about an inch long ; 

 found in the Ohio, &c. ; rare ; lamellar tooth 

 sharp, doubled, slightly oblique, straight ; cardi- 

 nal tooth furrowed ; resembles the Obliquaria 

 retusa. 



Seventh Genus PLEUROBEMA. 

 Shell oblong, very inequilateral; ligament 



