AND EMBRYONIC FORMS. 409 



Embryonic shell pouch-shape, whitish, nearly the same with multiradiatus, has no 

 hooks. See Journ. Acad. Nat. Sci., vol. iv. pi. 5, fig. 17. Obs. vol. vi. p. 47. 



Flint River, Georgia, Bishop Elliott ; Roswell, Cobb County, Georgia, N. A. Pratt, 

 junior. 



Unio incrassatus, Lea. Trans. Anier. Phil. Soc, vol. viii. pi. 16 ; fig. 34. Obs. vol. iii. p. 55. 



Branchial uterus occupies the whole of the outer branchiae. Branchiae very large, 

 nearly semicircular, inner ones much the larger, free more than half the length & of 

 abdominal sack. Palpi rather small, suboval, not united on the posterior ed-es 

 Mantle thm, with a broad margin. Branchial opening large, with rather large, dirk 

 papillae. Anal opening very large, with small dark-brown papillae. Super-anal open- 

 mg rather small, slightly united below. Color of the mass light salmon. 



Embryonic shell brownish, triangular, has no apparent hooks. In outline very 

 much the same with Anodonta imbecilis. See Journ. Acad. Nat. Sci vol iv pi 5 

 fig. 36. Obs. vol. vi. p. 50. 



Flint River, Georgia, Bishop Elliott. 



Unio nigellus, Lea. Trans. Amer. Phil. Soc, vol. s. pi. 24, fig. 42. Obs. vol. v. p. 49. 



Branchial uterus occupies the outer branchiae in long ovisacks. Branchiae large, 

 much rounded below, inner ones much the larger, free nearly the whole lengthd" 

 abdominal sack. Palpi rather small, suboval, united only at the upper part of the 

 posterior edges. Mantle very thin, with a rather broad margin. Branchial opening 

 large, with numerous brown papillae. Anal opening very large, with very numerous 

 very small brown papillae. Super-anal opening small, slightly united below. Color 

 of the mass whitish. 



Embryonic shell, while rather broad pouch-shape, has no hooks, very nearly the 

 same with nasutus, Say. 



Flint River, Georgia, Bishop Elliott. 



Unio tortivus, Lea. Trans. Amer. Phil. Soc, vol. viii. pi. 12, fig. 17. Obs. vol. 3, p. 42. 



Branchial uterus occupies the whole length of the outer branchiae, but not the 

 upper portion. Branchial large, rounded below, inner ones much the larger free 

 nearly the whole length of abdominal sack. Palpi small, suboval, not united on 

 the posterior edges. Mantle thin, with a slightly thickened broad margin. Bran- 

 chial opening large, with brown papillae. Anal opening large, with numerous very 

 small, dark-brown papilla?. Super-anal opening small, united below. 



Embryonic shell broad pouch-shape, white, has no hooks. 



Flint River and Chatahoochee River, Georgia, Bishop Elliott. 



104 



