68 SUPPLEMENT TO ISAAC LEA'S PAPER ON UNIONIDiE. 



border. Branchial opening large, black, with large papillse. Anal opening not 

 large, black and without papillse. Super-anal opening long, black, and free above. 

 Color of the mass whitish. The form of the embryonic shell is very like that of 

 Ferussaciana (nobis), but is a little broader. 



For hardparts see Observations on Unio, vol. xi. p. 29, and Journ. Acad. Nat. Sci., 1864. 



Unio Hydeianus, Lea. 



Soft Parts. — Four males and one female were received from Dr. G. W. Law- 

 rence from Ouachita, Arkansas. No ova were found in the ovaries or branchial 

 uterus. Branchice rather large, inner one much the larger; slightly curved below; 

 united the whole length of abdominal sack. Palpi rather small, subtriangular, 

 united near the top. Mantle very thin, thicker at the margin. Branchial opening 

 large, with rather large papillae on the inner edges, which are black. Anal opening 

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

 and united below. Color of the mass whitish. 



EMBEYOI^IC FOEMS OF UKIOISriD^. 



Unio Nashvilleensis, Lea. PI. 21, fig. I. Pouch^shape; dorsal line short and 

 straight; side margins flattened above and curved below; basal margin gently 

 curved; color light brown. Has no hooks. Columbus, Mississippi. 



Unio nasutus, Say. PI. 21, fig. 2. Pouch-shape; dorsal line rather short and 

 straight; side margins regularly curved ; basal margin round; color white. Has 

 no hooks. Buffalo, New York. 



Unio PARVUS, Bar. PI. 21, fig. 3. Pouch-shape; dorsal line short and very 

 slightly curved ; side margins regularly curved ; basal margin nearly round ; color 

 very light brown. Has no hooks. Columbus, Mississippi. 



Unio congest ator. Lea, PI. 21, fig. 4. Narrow pouch-shape; dorsal line nearly 

 straight and rather short; side margins gently curved; basal margin nearly round; 

 color clear white. Has no hooks. Columbus, Georgia. 



Unio rubellinus, Lea. PI. 21, fig. 5. Pouch-shape; dorsal line rather long 

 and sKghtly curved; side margins much curved, above flattened; basal margin 

 round ; color clear white. Has no hooks. Othcalooga Creek, Georgia, 



Unio excavatus. Lea. PL 21, fig. 6, Pouch-shape; dorsal line very slightly 

 curved ; side margins much curved, above inflected ; basal margin round ; color 

 clear white. Has no hooks. Othcalooga Creek, Georgia. 



