139 
base, at the sinus rather nearer the base than at the beak, or as 
near. 
Length, two and a half inclies ; 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 M. 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 
Diilwyn calls fucatus, but the present is a longer shell, with s 6 me- 
what more elevated beaks, more rounded at the base, &c. 
Anodonta GRi^NDis. — Shell very large, subovate ; disk un- 
eqally wrinkled and undulated transversely, dark yellowish brown 3 
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 Rom 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 difierent 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, 
there 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 the Wabash. 
Anodonta impura. — Subovate, fragile, a little compressed. 
