14 DESCRIPTION OF FIFTY-TWO SPECIES OF UNIONID^. 



undulations of the tips. I owe to the kindness of Dr. Lewis the possession of 

 several specimens for my own cabinet. 



Unio crudus. pi. 4, fig. 10. 



Testa leevi, subrotuada, compressa, insequilaterali, antice rotunda, postice obtuse angulata ; valvulis 

 subcrassis, antice crassioribus ; natibus prominentibus ; epidermide rugosa, tenebroso-fusca, 

 eradiata ; dentibus cardinalibus subgrandibus, subcompressis crenulatisque ; lateralibus crassis, 

 subbrevis subcurvisque ; magarita argentea et parum iridescente. 



Shell smooth, subrotund, compressed, inequilateral, rounded before, obtusely 

 anaular behind; valves somewhat thick, thicker before; beaks prominent; epider- 

 mis rugose, dark brown, without rays; cardinal teeth somewhat large, subcom- 

 pressed and crenulate ; lateral teeth thick, rather short and somewhat curved; 

 nacre silver white and somewhat iridescent. 

 Proc. Acad. Nat. Sci., 1811, p. 190. 

 Hah.— Yrench Broad River, Pres. Lindsley ; Swamp Creek, Murray Co., Geo., 

 Major Downie ; Holston River, C. M. Wheatley and Miss Law. 



My cabinet, and cabinets of Mr. Wheatley and Dr. Lewis. 

 Diam. -9, Length 1-5, Breadth 18 inch. 



Shell smooth, subrotund, compressed on the sides, inequilateral, round before 

 and obtusely angular behind; substance of the shell rather thick, much thicker 

 before; beaks prominent, rather pointed; ligament short, rather thick and dark 

 brown ; epidermis rough, dark brown, with rather distant marks of growth and 

 without rays ; umbonial slope rounded and flattened ; posterior slope compressed, 

 cordate, with two slightly impressed lines ; cardinal teeth rather large, rather com- 

 pressed and crenulate; lateral teeth thick, rather short and somewhat curved; 

 anterior cicatrices distinct, rather small, but well impressed ; posterior cicatrices 

 distinct and well impressed; dorsal cicatrices placed on the under side of the plate 

 within the cavity of the beaks; cavity of the shell shallow; cavity of the beaks 

 rather shallow and obtusely angular; nacre silvery white and slightly iridescent. 

 ^" Remarks. —Among the many shells sent to me some twelve years since by Pre- 

 sident Lindsley, of Nashville, was a single adult specimen of this species with 

 imperfect beaks. Subsequently a young one was sent by Major Downie, and very 

 recently Mr. Wheatley has sent me an adult and Dr. Lewis two quite young speci- 

 mens. These last three entirely satisfy my mind that the species is undescribed, 

 and I no longer doubt of its place in the system. The two old specimens are 

 rather rough in the epidermis and present no appearance of rays ; but the three 

 young are yellowish, with interrupted dark rays. The outline is rounded, very 



