2^8 NEW UNIONID^, MELANID^, ETC., 



Remarks. — This species belongs to the ohesus group, and has nearly the same out- 

 line as ohesus and it has the same concentric folds at the beaks. The epidermis is of 

 the same color. All the specimens I have seen have the same color of nacre, whitish 

 in the cavity and a lively flesh or pinkish color towards the margin. The umbonial 

 slope has usually a dark, broad, greenish ray and the posterior slope has usually two 

 smaller ones. I am under obligations to Mr. Wheatley for a very beautiful suite. 



Unio Clinchensis. pi. 37, fig. 91. 



Testa Isevi, triangulari, ad latere planuiata, valde infequilaterali, postice obtuse angulata, antice ro- 

 tundata; valvulis crassis, antice crassioribus ; natibus prominentibus ; epidermide luteola, ad 

 latere radiata ; dentibus cardinalibus crassis, subcompressis corrugatisque ; lateralibus percrassis, 

 Curtis obliquisque ; margarita alba et iridescente. 



Shell smooth, triangular, flattened at the sides, very inequilateral, obtusely angular 

 behind, rounded before ; valves thick, thicker before ; beaks prominent ; epidermis 

 yellowish, radiated on the sides ; cardinal teeth thick, rather compressed and corru- 

 gate; lateral teeth very thick, short and oblique; nacre white and iridescent. 

 Proc. Acad. Nat. Sci. 1867, p. 81. 



Hob. — Clinch River, Tenn., Pres. Estabrook; French Broad Eiver and Holston 

 Eiver, Tenn., Dr. Edgar. 



My cabinet. 

 Diam. -8, Length 1-5, Breadth 1-8 inch. 



Shell smooth, triangular, flattened at the sides, very inequilateral, obtusely angular 

 behind, rounded before ; substance of the shell thick, thicker before ; beaks promi- 

 nent; ligament short and rather thick; epidermis yellowish, with interrupted rays on 

 the sides and with close marks of growth; umbonial slope slightly angular; posterior 

 slope elliptical and slightly raised, usually without rays ; cardinal teeth thick, rather 

 compressed, corrugate and double in both valves ; lateral teeth very thick, short and 

 oblique; anterior cicatrices distinct, rather small and well impressed; posterior cica- 

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

 plate, within the cavity of the beaks ; cavity of the shell rather deep and rounded ; 

 cavity of the beaks rather deep and subangular ; nacre white and iridescent. 



Hemcu-Jcs. — I have six specimens before me, all of which are from the upper tribu- 

 taries of the Tennessee River. In outline it is near to cuneolus (nobis), but it is more 

 oblique than that species. There is very little difference in the form of these six 

 specimens. All of them are more or less rayed on the sides. These rays are all in- 

 terrupted by the lines of growth and are much larger before the umbonial slope, the 

 smaller ones reaching but a short distance from the beaks. 



