30 DESCRIPTION OF NEW 
Hab. Williamsport, Tenn., Mr. Jos. Clark; Georgia or Alabama, Mr. C. M. Wheatley. 
My cabinet and cabinets of Mr. Clark and Mr. Wheatley. 
Diam. 1, Length 1.4, Breadth 2.2 inches. 
Shell smooth, elliptical, convex, on the umbones inflated, inequilateral, angular behind; 
substance of the shell thick, thinner behind; beaks rather prominent, subrotund, submedial ; 
ligament short and thick; epidermis reddish-brown, shining, with rather close, distinct 
marks of growth; posterior slope wide, and rather depressed; umbonial slope very obtusely 
angular; cardinal teeth rather thick, acuminate, granular, single in the right and double in 
the left valve; lateral teeth rather short, thick, arched, thicker towards the posterior end, 
separated from the cardinal teeth; anterior cicatrices distinct; posterior cicatrices con- 
fluent; dorsal cicatrices placed nearly in the centre of the cavity of the beaks; cavity of 
the shell deep and rounded; cavity of the beaks deep and angular; nacre white or salmon- 
coloured. 
Remarks.—There are two specimens before me of nearly the same size; that from 
Williamsport is slightly salmon-coloured in the cavity of the shell, and has rays over 
nearly the whole disk. The other has no rays whatever. This species is allied to 
U. crocatus, (Nobis,) but is a larger, thicker and more regularly oval shell. 
TI name it in honour of my friend Mr. Joseph Clark, of Cincinnati. 
Unio Frorwensis. PI. XXI. Fig. 31. 
Testa levi, obovatd, subtransversa, subcompressd, valdé inequilaterali, anticé angusta, postice sublata ; 
valvulis tenuibus; natibus prominulis, fere terminalibus ; dentibus cardinalibus parvis ; lateralibus longis 
subcurvisque; margarita alba. 
Shell obovate, rather wide, somewhat compressed, very inequilateral, narrow before and rather broad behind; 
valves thin; beaks somewhat prominent, nearly terminal; cardinal teeth small; lateral teeth long and slightly 
curved; nacre white. 
Hab. Chacktahachi river, West Florida, Major Le Conte. 
Cabinet of Major Le Conte. 
Diam. .9, Length 1.5, Breadth 3 inches. 
Shell reversely ovate, transverse, rather compressed, very inequilateral, narrow before 
and broad behind; substance of the shell thin, thickened before; beaks rather small and 
somewhat prominent; placed near to the anterior margin; ligament long and rather thick; 
epidermis light-yellow, with equal, somewhat distant lines of growth, apparently without ' 
rays; cardinal teeth very small, lobed, double in both valves; lateral teeth very long, very 
thin, and slightly curved; anterior cicatrices distinct; posterior cicatrices confluent; 
dorsal cicatrices placed in the centre of the cavity of the beaks; cavity of the shell rather 
shallow; cavity of the beaks shallow and subangular; nacre white. 
Remarks.—This is a species very distinct from any which I have seen. Its obovate 
form, while it is so wide, is very unusual. It cannot be confounded with U. modioliformis, 
(Nobis,) which is a thinner shell, rayed and much inflated. The teeth are remarkably 
small, for the size of the shell, and the lateral one particularly attenuate. The epidermis 
is of the yellow colour and texture peculiar to U. anadontoides, (Nobis,) and U. cariosus, Say. 
