406 UNIONID^, THEIR SOFT PARTS 



Unio nitens, Lea. Trans. Amor. Phil. Soc, vol. viii. pi. 12, fig. 19. Obs. vol. iii. p. 43. 



Branchial uterus occupies nearly the whole length of the outer branchiae and is 

 blackish on the lower edge. Branchial rather wide, slightly rounded below, the 

 inner ones much the larger, slightly free at the posterior end of abdominal sack. 

 Palpi small, subovate, not united on the posterior edges. Mantle very thin, with a 

 broad, slightly thickened margin. Branchial opening large, with numerous dark- 

 brown papillae, which are continued in a dark border below the opening to the basal 

 margin. Anal opening very small, with very minute brown papillae. Anal opening 

 small, with very minute brown papillae. Supei--anal opening small, united for some 

 distance below. Color of the mass light salmon. 



Embryonic shell elongate pouch-shape, white, very much in outline like obkisus, 

 has no hooks. See Journal Acad. Nat, Sci., vol. iv. pi. 5, fig. 1. Obs. vol. vi.p. 46. 



Othcalooga Creek, Georgia, Bishop Elliott. 



Unio anodontoides, Lea. Trans. Amer. Phil. Soc, vol. iv. pi. 8, fig. 11. Obs. vol. i. p. 91. 



Branchial uterus filled with rather coarse ovisacks on the posterior half of the 

 outer branchiae, forming thick lobes like cariosus, the lower border being black. 

 Branchice very wide, slightly curved below, the inner ones extending much beyond 

 the outer ones, united the whole length of abdominal sack. Palpi moderately large, 

 subtriangular, united half way down the posterior edges. Mantle very thin, with a 

 rather large, thickened margin. Branchial opening very small, with numerous light- 

 brown papillae. Anal opening very small, with numerous light-brown papilla?. 

 Super-anal opening small, united for some distance below. Color of the mass 



whitish. 



Embryonic shell elongate pouch-shape, clear white, has no hooks. See Journal 

 Acad. Nat. Sci., vol. iv. pi. 5, fig. 2. Obs. vol. vi. p. 46. 



Uchee Bar, below Columbus, Bishop Elliott ; and Ohio River, J. Clark. 



Unio obtusus, Lea. Trans. Amer. Phil. Soe., vol. viii. pi. 11, fig. 13. Obs. vol. iii. p. 39. 



Branchial uterus filled with large ovisacks on the posterior half of the outer 

 branchiae, like cariosus, having a dark inferior edge. Branchice large, nearly semi- 

 circular, the inner ones extending anteriorly much beyond the outer ones, united the 

 whole length of abdominal sack. Palpi very large, subelliptical, united one-third 

 down the posterior edges. Mantle thin, thicker at the margin, has large dark 

 papillae below the branchial opening. Branchial opening large, with numerous 

 brownish and black papillae. Anal opening small, with numerous very small, 

 brownish papillae, maculate with black. Super-anal opening rather large, colored 

 within and slightly united below. The rim of the anus seems to be crenulate. 

 color of the mass whitish. 



