﻿298 OCOVARIA 



eordlike riclj^c above it; surface with a few, low, concentric 

 ridges, otlierwise nearly smooth ; ei)i(lerniis deep brown, nearly 

 black, a little lig^hter colored at the anterior end; left valve 

 with two low, broad, not very perfect, pseiulocardinals and two 

 short, curved laterals ; ri.qlit valve with one pseudocardinal, a 

 feeble tooth above, and a wide rouj^hencd area behind it, with 

 one somewhat double lateral ; beak cavities very deep, com- 

 pressed ; anterior muscle scars roughened ; nacre dirty white, 

 slightly iridescent behind, 



Length 49, height to top of eroded beaks 45, diam. 30 mm. 



Type locality, Escambia River, Escambia County, Florida. 

 Unio rotulatns B. II. Wright. Naut.. XI II, 1899, p. 22. 

 Ohovaria rofidafa Simpscin', Pr. .\c. N. Sci. Phila.. 1900, p. 



78, pi. IV, fig. 2; Syn.. 1900, p. 601. 



I have only seen a single si)ecimen of this, the type, which 

 seems to be one of the best marked species of the genus. Its 

 color pattern is i|uite ditierent from that of circiilits and allied 

 forms, and its low, irregular, broad pseudocardinals and the 

 remarkably deep, compressed beak cavities serve to distinguish 

 it. 



Subgenus Pskudoon Simpson, 1900. 



Pscudoon Simpson, Syn., i()oo, p. 601. 



Shell elliptical, inflated, solid, that of the males slightly 

 pointed at the upper posterior part ; epidermis brownish or 

 blackish, rayless or very feebly rayed ; beaks anterior ; pseudo- 

 cardinals solid, stvmipy, or slightly elongate in age, and show- 

 ing a tendency toward being parallel with the laterals ; cica- 

 trices deep ; nacre silvery, iridescent posteriorly. 



Animal having a mantle with a wide, thickened, double bor- 

 der, the inner edge being toothed throughout below ; gills 

 small ; marsupium not reaching to the posterior end of outer 

 branchire, though extending (|uite well forward ; ovisacs rather 

 numerous, large and distinct, tinted with piir])le l)elo\v ; anal 

 and branchial openings finely toothed. 



Type. Unio ellipsis Lea. 



