’ 
Mr. Barnes on the Genera Unio and Alasmodonta. 259 
‘ 2 
external surface is neither waved nor tuberculated. The 
teeth are less sulcated than those of the former, and only cren- 
ulated, or striated, generally triangular and elevated, and, in 
magnitude, bear a proportion to the thickness of the shell. 
The cavity of the beaks is small, or none, and neither angu- 
lar nor compressed. The shells have a smooth and regular 
appearance, and five of the seven species have the inside pur- 
ple. 
SPECIES. © : 
. @. outline 
10. unio eLtipticus. Fig. 19 ee 
: : Pe a 
d. sizes. 
Shell regularly oval, thick, convex, glabrous, beaks 
depressed. ‘Teeth elevated, triangular, striated. 
Unio Crassus. Mr. Say. Plate 1 fig. 8? 
Mya Complanata? Dillwyn. page 51. 
Inhabits Fox River. Mr. Schoolcraft. 
r. Mitchill’s Cabinet. 
My Collection. 
Diam. 1.0—2.0 Length 1.7—3.2 Breadth 2.5—4.9 inches. 
Shell long before, and short behind, equally rounded at both 
extremities; beaks nearly flat; ligament elevated above the 
beaks considerable. .Naker pearly white, iridescent, and 
Sometimes, of a beautiful flesh colour. 
; “a. inside. 
. , Ss. Fi * 10. 
11. UNIO CARINATU 5 b. outside. 
Shell oblong oval, biangulate before, rayed, hinge 
margin straight, compressed, keel-shaped, teeth 
finely striate. 
Inhabits Fox River. Mr. Schoolcraft. 
Dr. Mitchill’s Cabinet. 
My Collection. 
