266 Mr. Barnes on the Genera Unio and Alasmodonta. 
versely ; strface smooth and shining. Cardinal teeth cren- 
ulated, cavity of the beaks small; naker bluish white, or 
reddish yellow; surface smooth and pearly. 
Variety (a) very obscurely __ and much like Unie 
Purpureus in shape. 
Inhabits Saratoga Lake. 
tape (b) oval or very nearly as broad behind as be- 
Tikiabits the Wisconsan. Capt. Douglas. 
18. Unio Mucronatus. Fig. 13. wines of the 
Shell ovate, broader behind ; base compressed, fal- 
; beaks small, elevated, acute, inside pur- 
° 
Inhabits the Wisconsan.. Capt. Douglass. 
My collection. 
Diam. -7 Length 1:3. Breadth 2:3. 
Shell ovate, moderately thick, produced, narrowed, and 
compressed before ; rounded and broad behind ; disks com- 
pressed ; pater Tunule long, distinct, with a marginal fur- 
Ww rior lunule small, deeply impressed ; hinge mar- 
gin ceeded. “basal margin arcuated ; anterior dorsal rapid- 
ly narrowed and slightly emarginate ; epidermis horn-color, 
and obscurely rayed ; surface smooth; cardinal teeth ser- 
rate sulcate ; cicatrices deep ; naker purplish on the mar- 
gin, and whitish i in the centre. 
Remarxs.—This species has somewhat the outline “of 
the Unio Tuberculatus, but the outside is smooth. The in- 
dividual above described is probably not more than half 
grown, as the umbones are very little eroded. 
49. Unto Inrratus.—Shell oval, thick, tumid, 
beaks broad, obtuse behind, wedge-shaped be- 
fore, inside pearly white. 
Inhabits the Sie ota and Lake Erie. Capt. Douglass. 
Dr. Mitchill’s Cabine ; sorcerer 3 ET 
My collection, . 
