96 



what the outline of U. niger, as represented in the 



lower figure. 



UNIO LATIRADIATUS. 



Plate LIII. 

 DESCRIPTION 



Shell elliptical, rather thin; posterior side produced, 

 extremity obtuse, and subangulated; umbonial slope 

 rounded, undefined; beaks slightly prominent, with 

 rather coarse angulated plicae; basal margin arcuate; 

 posterior margin rectilinear and very oblique; epider- 

 mis yellow, polished, with very broad and intermediate 

 slender green interrupted rays; within white, highly 

 iridescent; cardinal teeth direct, pyramidal; posterior 

 side shewing the exterior rays through the substance 

 of the shell. 



SYNONYME. 



U. ixterruptus. Lea. Trans. Amer. Philos. Soc, new series, 

 vol. vi., pi. vL, p. 15, fig. 15. 



OBSERVATIONS. 



Inhabits streams in the vicinity of Nashville, Ten- 

 nessee. I have received a fine series through the 

 kindness of Richard O. Currey and Samuel M. Edgar 

 of Nashville. The species is remarkable for the 

 broad interrupted rays, and resembles in this charac- 

 ter and in general aspect U. tcenkdus; it is, however, 

 a thinner and less ventneose, as well as more elon- 



