﻿OBOVARIA 293 



The female shell is very little more produced in the marsupial 

 region than the male and the difference between male and fe- 

 male shells in this species is less than in 0. lens. 



Oeovaria i.ens (Lea). 



Shell suborbicular, equilateral, subcompressed to subinflated, 

 with rather high, but not inflated, beaks ; beak sculpture fine, 

 doubly-looped ridges ; posterior ridge rounded ; posterior end 

 subtrtmcate; surface often with a few wide, low, concentric 

 ridges ; epidermis brownish, silky, lighter on the posterior slope; 

 left valve with two subradial pseudocardinals, and two laterals ; 

 right valve with three pseudocardinals, the middle one 

 largest, and one somewhat double lateral ; beak cavities rather 

 deep, compressed ; muscle scars small, impressed ; nacre white 

 or silvery. The female shell is slightly fuller than the male 

 just behind the center of the base. 

 Length 50, height 47, diam. 26 mm. 



Ohio River Drainage ; north to Lake Erie ; southern Michi- 

 gan. ; south to Columbus, Mississippi. 

 Type locality, Ohio and Tennessee. 

 Unio lens Lea, Tr. Am. Phil. Soc. Phila., IV, 183 1, p. 80, pi. 

 VIII, fig. 10; Obs., I, 1834, p. 90, pi. VIII, fig. 10. — Hanley, 

 Biv. Shells, 1843, P- 201, pi. xxi, fig. 4. — Chenu, 111. Conch., 

 1856, pi. VIII, figs. 10, loa, lob. — Reeve, Conch. Icon., XVI, 

 1865, pi. XXVII, fig. 134. — SowERBY, Conch. Icon., XVI, 1866, 

 pi. XXXVII, fig. 200. 

 Margarita (Unto) lens Lea, Syn., 1836, p. 33: 1838, p. 22. 

 Margaron (Unio) lens Lea, Syn., 1852, p. 34; 1870, p. 55. 

 Ohovaria lens Simpson, Syn., 1900, p. 600. 

 ? Unio Iccx'igatns Say, Am. Conch., VI, 1834. 



Var. depygis (Conrad). 



Shell having the beaks slightly nearer to the posterior end ; 

 anterior end somewhat narrowed ; posterior end not lighter col- 

 ored. 



Type locality, Harpeth River, Tennessee. 



