222 



MEMOIRS OF THE CARNEGIE MUSEUM. 



somewhat concave, before it reaches the level of the posterior angle of the male. 

 Thus the female shell has two blunt posterior angles on the hind end, but this 

 structure may be rather obscure. The female shell is generally higher than that 

 of the male, and the male seems to grow to a slightly larger size than the female. 



. L. H. D. 



Size: 1. Industry, Cat. No. 61.3556 (cf ) . . . ' 58 mm. 58 mm. 37 mm. 



2. do. " " 61.3555 (gravid 9 ) 58 " 64 " 39 " 



Soft parts (See Ortmann, 1912, p. 321, 322, fig. 20). Glochidia: Ortmann, 

 1912, PL 19, fig. 9; Surber, 1912, PL 3, fig. 47. Measurements: 0.22 X 0.27 

 (Ortmann); 0.240 X 0.295 (Surber). 



Breeding season: On Aug. 29, 1908 and Sept. 7, 1914, I found specimens with 

 eggs, and on Sept. 22, 1910 specimens with glochidia. This indicates the beginning 



Fig. 23. 



• Obovaria retusa. 



■ Obovaria olivaria. 

 + Obovaria subroiunda. 

 X Obovaria subrotunda levigata. 

 > Obovaria subrotunda levigata (from Indian garbage heap). 



of the season in autumn. Surber (1912) reports this species as gravid in September. 

 It probably is bradytidic. 



Remarks: There is no trouble in recognizing this species; the shape and the 

 color of the nacre are quite imique. 



Localities represented in the Carnegie Museum: 



Oliio River, Industry, Beaver Co., Pennsylvania. 



OUo River, Toronto, Jefferson Co., Ohio; Wheeling, Oloio Co., West Virginia; (W. F. Graham); St. 



Marys, Pleasants Co., West Virginia; Parkersburg, Wood Co., West Virginia; Portland, Meigs 



Co., Ohio; Portsmouth, Scioto Co., Ohio. 

 Tennessee River, Knox Co., Tennessee (Smith collection). 

 Clinch River, Clinton, Anderson Co., Tennessee. 



