56 



Var. 2. pallida brownish, nacre pale. 

 Found in the Kentucky ; about two inches in 

 length ; it bears some resemblance to the Ellip- 

 tio and Obliquaria ellipsaria ; lamellar tooth 

 somewhat obtuse, very slightly oblique ; cardinal 

 tooth thick, rugose ; nacre fine, iridescent, change- 

 able with blue ; nofossule ; animal yellowish. 



SPECIES LV. Amblema torulosa (Unio 

 torulosa.) 



Shell thick, somewhat ventricose, square-ellip- 

 tical, with a slight oblique depression, and some 

 nodules ; borders flexuous ; epidermis olive co- 

 loured, with flexuous wrinkles ; nacre bluish 

 white. Breadth f diam. \ axis \ of the 

 length. 



Var. angulata depression slight, con- 

 tour nearly angular. 



Found in the Ohio and Kentucky ; length two 

 inches ; two or three nodules on the oblique ele- 

 vation ; lamellar tooth very straight ; no fossule ; 

 cardinal tooth wrinkled. 



SPECIES LVI. Amblema gibbosa (Unio gibbosa.) 

 Shell thick, ventricose, oval-elliptical, with 



