306 NEW UNIONIDiE, MELANIDiE, ETC., 



compressed, oblique; lateral teeth rather long, thick, oblique and corrugate; nacre 

 salmon-colored, splendid and iridescent, 



Proc. Acad. Nat. Sci. 1868, p. 143. 



Eah. — Head-waters of Holston River, Washington Co., Va., Prof. E. D. Cope. 



My cabinet and cabinet of Acad. Nat. Sci. 

 Diam. -9, Length 1-5, Breadth 2-3 inches. 



Shell smooth, elliptical, somewhat compressed, inequilateral, obtusely angular 

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

 somewhat prominent; ligament large and dark brown; epidermis dark reddish- 

 brown, without rays, and with rather close marks of growth; umbonial slope de- 

 pressed and rounded ; posterior slope narrow-elliptical, subcarinate ; cardinal teeth 

 somewhat thick, compressed, and oblique ; lateral teeth rather long, thick, oblique 

 and corrugate; anterior cicatrices distinct, rather large and deeply impressed; 

 posterior cicatrices distinct, rather large and well impressed ; dorsal cicatrices placed 

 on the upper side of the cavity of the shell ; cavity of the shell rather shallow and 

 wide; cavity of the beaks rather shallow and obtusely angular; nacre salmon- 

 colored, splendid and iridescent. 



Remarhs.^-1 found a single specimen only among the large number of Unionidce 

 brought by Prof. Cope. At first I thought it to be a salmon-colored variety of Cojxi, 

 but while the outline is closely alike, the epidermis and interior are quite different. 

 The cardinal teeth differ in fassinans, being more robust and not so compressed ; in 

 the lateral teeth being thicker, more solid, and in having that of the right valve dis- 

 posed to be double. In the nacre all the four specimens of Copei are alike in having 

 a very dark purple color, while in fassinans the nacre is of a remarkably soft satin- 

 like salmon color. The cavity of fassinans is not so deep as that of Copei. The beaks 

 of this specimen are eroded, and therefore their character cannot be ascertained. 



Unio sparus. pi. 47, fig. 119. 



Testa laivi, lato-elliptica, subinflata, valde intequilaterali, postice obtuse angulata, antice rotundata ; 

 valvulis subtenuibus, antice crassioribus ; natibus prominentibus, ad apices minute undulatis ; 

 epidermide subcrocea, valde radiata ; dentibus cardinalibus parvis, erectis, conicis ; lateralibus 

 longis subcurvisque ; margarita salmonis colore tincta et valde iridescente. 



Shell smooth, broadly elliptical, somewhat inflated, very inequilateral, obtusely 

 angular behind, rounded before; valves rather thin, thicker before; beaks a little 

 prominent, minutely undulate at tip ; epidermis reddish-yellow, very much radiated ; 

 cardinal teeth small, erect and conical; lateral teeth long and somewhat curved; 

 nacre salmon-color and very iridescent. 



Proc. Acad. Nat. Sci. 1868, p. 143. 



Hah. — Swamp Creek, Whitfield Co., Georgia, Major T. C. Downie. 



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

 Diam. -7, Length 1-1, Breadth 1-8 incb. 



