76 DESCRIPTION OF NEW 



Unio simplex. PI. V. Fig. 15. 



Testa /frvi, elliplicd, subinflata; valvulis subcrassis; natibus subprominentibw; epidermide luted; denlibus 

 cardinalibus parvis; later alibus longis, crassis subrectisque; margarita alba el iridescente. 



Shell smooth, elliptical, somewhat inflated; valves rather thick; beaks somewhat prominent; epidermis yellow; 

 cardinal teeth small; lateral teeth long, thick, and nearly straight; nacre white and iridescent. 



Ilab Black Warrior River, Alabama. 13. W. Budd, M. D. 



My cabinet and cabinet of Dr. Budd. 

 Diam. .7, Length .1, Breadth 1.6 inches. 



Shell smooth, elliptical, somewhat inflated, rounded and full on the umbonial slope; sub- 

 stance of the shell rather thick, thinner behind; beaks rather prominent; ligament long 

 and narrow; epidermis yellow, shining, and finely striate, with a few capillary rays on the 

 posterior slope; cardinal teeth very small, single in the right and double in the left valve, 

 crenate; lateral teeth long, thick at the posterior end, and nearly straight; anterior cica- 

 trices distinct; posterior cicatrices distinct; dorsal cicatrices placed on the under side of 

 the cardinal tooth; cavity of the shell rather deep; cavity of the beaks rather shallow and 

 rounded; nacre very white and iridescent. 



Remarks. — Two specimens of this species were placed under my notice, by Dr. Budd. 

 It has somewhat the aspect of U. Hijdianus, (Nobis,) but differs in being less transverse 

 and having a more striate surface, and being without the numerous beautiful rays which 

 so generally prevail in that species. Both the specimens before me have the same capil- 

 lary rays on the posterior slope, and none whatever on the other portions of the disk. 

 The lateral tooth is remarkable for the thickness on the inferior side of the posterior end. 



Unio Gouldii. PI. VI. Fig. 16. 



Testa l&vi, ell ip tied, subinflata, inequilaterali; valvulis subcrassis; natibus prominulis; epidermide lenebroso- 

 fuscd; dentibus curdinalibus parvis, siibcrassis; laleralibus longis curvisque; margarita subaured et valde 

 iridescenle. 



Shell smooth, elliptical, somewhat inflated, inequilateral; valves rather thick; beaks slightly prominent; epider- 

 mis dark-brown; cardinal teeth small and thick; lateral teeth long and curved; nacre somewhat golden and very 

 iridescent. 



Hub. Tuscaloosa, Alabama. R. E. Griffith, M. D. 



Cabinet of R. E. Griffith, M. D. 

 Diam. .7, Length 1.1, Breadth 1.9 inches. 



Shell smooth, elliptical, somewhat inflated, inequilateral, rounded before and obtusely 

 angular behind; substance of the shell rather thick, thinner before; beaks slightly promi- 

 nent; epidermis dark-brown, without rays; cardinal teeth small and thick, double in both 

 valves; lateral teeth long, curved in the left valve, the superior one considerably shorter 

 than the inferior one; anterior cicatrices distinct; posterior cicatrices confluent; dorsal 

 cicatrices placed on the plate under the cardinal teeth; cavity of the shell rather shallow; 

 cavity of the beak rather shallow and angular; nacre very soft, satin like, somewhat 

 golden, and very iridescent. 



Remarks. — A single specimen of this shell only is before me. My attention was called 

 to it by Dr. Griffith. The beaks are so much worn as to prevent this character from 



