272 Mr. Barnes on the Genera Unio and Alasmodonta. 
aon Pune Fe 16 Sale 
Shell ehoinbich=oval; pbs beaks depressed ; disks 
flattened, compressed ; teeth slightly elevated, 
smooth. : 
Inhabits the Wisconsan. Mr. Schoolcraft. 
Myf Collection. 
Diam, 1°3 Length 2:8 Breadth 4°8. 
Shell with the beaks flat, ligament broad and deeply in- 
serted between the valves; hinge margin straight and par- 
allel to the base; basal margin slightly arcuated ; ; anterior 
dorsal margin subtruncate ; epidermis brownish yellow ; 
surface deeply wrinkled ; cardinal teeth smooth, polished 
and slightly elevated; lateral teeth long and slender; —_ 
catrices rough ; cavity very small; naker bluish white tin- 
ged with purple and green. Anteraal surface wavy and tu- 
berculated. 
Remarxs.—The flatness of the shell and the smootl- 
ness of the teeth, readily distinguish this species from all 
its congeners hitherto described. It has been supposed to 
be the of M. Lamarck ; but besides being 
four times as large, it has not at all the general habit of an 
ta; wherereas M. Lamarck observes that his sbell 
“might be. mistaken for an anodonta unless it should be 
sarefully observed.” 
*****® Cardinal teeth small, oblique. 
25. Unio Triancutaris. Fig. 17. } bouilide 
eet eeapaler, faven inflated, rayed, gaping ; 
side mh Pigg attened, ribbed, cancellate ; in- 
side wh 
Inhabits Bois-blanc ia Detroit River.. Major Delafield. 
Dr. Mitchill’s Cabin 3 
Major Delafield’s Collection. 
My Collection. 
