139 



base, at the sinus rather nearer the base than at the beak, or as 

 near. 



Length, two and a half inches ; breadth, four inches and seven- 

 tenths. Convexity, one inch and four-fifths. Inhabits Cumber- 

 land River. 



For this specimen I am indebted to Mr. Lesueur. I cannot 

 make it agree with the J., pi^pwracejis, Swains., though it bears 

 some resemblance to that species. It is, however, a more convex 

 shell, the beak not so far back, and much more obtusely rounded 

 before. The few specimens in the cabinet of my friend Lesueur 

 are not tinged with purle within. 



It has some resemblance to Lister's fig. 9, of pi. 154, which 

 Dillwyn calls fucatus, but the present is a longer shell, with some- 

 what more elevated beaks, more rounded at the base, &c. 



Anodonta grandis. — Shell very large, subovate ; disk un- 

 eqally wrinkled and undulated transversely, dark yellowish brown ; 

 umbo elevated; beak slightly elevated, with, generally, two or 

 three small sinuous, acute undulations ; hinge margin slightly 

 arquated, sometimes nearly rectilinear, somewhat angulated at its 

 anterior termination, thence the edge descends by a nearly recti- 

 linear, or slightly concave line to the anterior margin, which is 

 considerably narrowed ; sinus of the hinge margin, concave ; pos- 

 terior margin widely rounded ; within white margined, particularly 

 before, with dusky. 



Length, nearly five inches ; breadth over seven and a half inches. 

 Convexity, three and a quarter inches. Inhabits Fox River of the 

 Wabash. 



The great size of this species, distinguishes it from any other 

 I have met with. A favorable specimen, at first view, corresponds 

 with the figures on pi. 205 of the Encycl. Meth., named by La- 

 marck, A. trapezialis, but the diflFerent character is, in the words 

 of Lamarck, " La sinus de la lame cardinale est grande, et 

 form un angle rentrant, aigu." He described from a specimen 

 in his own collection, and as the figures exhibit this character, 

 thete can be no doubt that our shell is a distinct species. 



The finest specimen I have seen was presented to me by Mr. 

 Oliver Evans, who obtained it in Fox River, which is a serpentine 

 arm of th& Wabash. 



Anodonta impura. — Subovate, fragile, a little compressed. 



