﻿OBOVARIA 295 



lateral, with the remarkable character of the beaks nearest the 

 posterior end, that end being the same color as the rest of the 

 shell. 



Obovaria unicolor (Lea). 



Shell short elliptical or ovate, subintiated, rather solid, with 

 a low, but distinctly marked, somewhat rounded posterior 

 ridg-e ; beaks rather full and high, in front of the middle, with 

 feeble, imperfectly looped ridges ; surface nearly smooth, some- 

 what sulcate on the anterior end ; epidermis yellowish-brown 

 or brownish, shining, often distinctly, though not brilliantly 

 rayed, in the young shell greenish, lighter in front and having 

 green rays ; left valve with two radial pseudocardinals and 

 two curved laterals ; right valve with three pseudocardinals, 

 the central one much the larger, and a somewhat double lat- 

 eral ; beak cavities not deep, rather compressed ; muscle scars 

 small impressed ; nacre usually pinkish, but sometimes white 

 or bluish. 



Length 50, height 43, diam. 26 mm. 



Mississippi and Alabama, in streams flowing into the Gulf. 



Type locality, Tuscaloosa, Ala. 

 Unio unicolor Lea, Pr. Am. Phil. Soc, IV, 1845, P- 163 ; Tr. 



Am. Phil. Soc, X, 1848, p. 74, pi. iv, ftg. 12; Obs., IV, 1848, 



p. 48, pi. IV, fig. 12. 

 Margaron (Unio) unicolor h'EA, Syn., 1852, p. 34; 1870, p. 55. 

 Obozuria unicolor Simpson, Syn., 1900, p. 601. 

 Unio tinkeri B. H. Wright, Nautilus, XIII, 1899, p. 7. 

 Obovaria tifikeri Simpson, Pr. Acad. Nat. Sci. Phila., 1900, 



p. 78, pi. IV, fig. 3 ; Syn., 1900, p. 600. 



The type of this species, which is a young female, is some- 

 what broken and there is another shell in Lea's collection from 

 Jackson, Mississippi, which he has called Unio lens, that is a 

 young male. The name unicolor is rather infelicitous, as it is 

 the only rayed species in the group. These rays and its gener- 

 ally bright color are the best characters by which to distinguish 

 it from allied species. The female shell is a little more inflated 

 at the posterior base than that of the male. I have seen speci- 



