414 UNIONIDiE, THEIR SOFT PARTS 



reddish papillae. Super-anal opening large, colored on the inner edges and united 

 below. Between the anal and super-anal opening the edges of the mantle are at- 

 tached for some distance, presenting a flat, colored, fleshy attachment. Through 

 this there are, in all the ten specimens before me, one or two small, oval holes lead- 

 ing into the great cavity. The surface of the space is mottled reddish color.* 

 Color of the mass whitish. Immediately below the branchial opening the edge of 

 the mantle is much thickened, and there are a few small papillae, which fringe the 

 edges. On the upper part of this thickening there is a black dot on the outer sides 

 similar to that observed in Imeatus. The lower part of this thickening is termi- 

 nated by a fleshy process. 



Embryonic shell elongate pouch-shape, near to that of IT. anodontoides, has no hooks. 

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



Altamaha Eiver, near Darien, J. Hamilton Couper, Esq. 



Unio splendidus, Lea. Trans. Arner. Phil. Soc. (2), vol. vi. pi. 19, fig. 61. Obs. vol. ii. p. 70. 



Branchial uterus -. No ova were found here, nor in the ovarium. Bronchia} 



large, curved below, inner ones much the larger, united the whole length of the 

 abdominal sack. Palpi very large, thick, suboval, united half way down the pos- 

 terior edges. Mantle rather thick, much thickened and double on the inferior edges. 

 Branchial opening with small, dark-brown papillae. Anal opening with dark-brown 

 papillae. Super-anal opening rather large, dark on the interior edges and united 

 below. Color of the mass whitish. 



Hopeton, near Darien, Georgia, Major T. C. Downie. 



Remarks. — Among the eleven specimens before me none had ova, although several 

 were evidently females by the outward form of the shell. 



Unio lugubkis, Lea. Trans. Amer. Phil. Soc. (2), vol. vi. pi. 96, fig. 25. Obs. vol. ii. p. 30. 



Branchial uterus occupies nearly the whole length of abdominal sack, very much 

 as in complanatus. Branchiae, wide, slightly curved below, the inner ones very much 

 the larger, free nearly the whole length of the abdominal sack. Palpi large, ovately 

 triangular, united for a short distance on the posterior edges. Mantle brownish, 

 white along the margin. Branchial opening small, with small, blackish papillae. 

 Anal opening rather large, with numerous very small, blackish papillae. Super-anal 

 opening rather small, blackish on the inner edges and united below. Color of the 

 mass whitish. 



Altamaha River, near Darien, Georgia, J. Hamilton Couper, Esq. ; and Satilla 

 River, Major T. C. Downie. 



* I have never observed this character before, except in a single specimen of luteolus, where there were 

 four holes. See description, ante, page 402. 



