AND EMBRYONIC FORMS. 427 



thirty-one ovisacks on each side, three-fourths of an inch long. Branchial very wide 

 and large, rounded below, inner ones the larger, united the whole length of abdominal 

 sack. Palpi large, suboval, united halfway down the posterior edges. Mantle thin, 

 thicker and doubled along the margin, which is colored and furnished with branch- 

 ing papillae below the branchial opening. In the male these papillae are very small. 

 Between this line and the outer edge of the mantle the interspace is granulate- 

 Branchial opening rather large, with numerous rather small papillae. Anal opening 

 rather small, colored, with granulations on the inner edges. Super-anal opening rather 

 large, colored on the inner edges and united below. Color of the mass whitish. 



Embryonic shell pouch-shape, clear white, has no hooks. See Journ. Acad. Nat. Sci., 

 (2), vol. iv. pi. 5, fig. 11. Obs. vol. vi. p. 47. 



Columbus, Ohio, H. Moores. 



Remarks. — This is another of the Uniones which are without papillae on the edges of 

 the anal opening. Its outward form and general character of the hard parts is very dif- 

 ferent from the previously described species. 



Unio verrucosus, Bar. Aiuer. Journ. Sci., vol. vi. p. 123. 



Branchial uterus . No ova were found here, but they were in the ovarium. 



Branchial very large, nearly semicircular, inner ones very much the larger, free nearly 

 the whole width of the abdominal sack. Palpi large, subtriangular, united one-third 

 down the posterior edges. Mantle thin, with a wide thickened border. Branchial 

 opening very large, with numerous rather small, colored papillae. Anal opening large, 

 without papillae. Super-anal opening very large, not united below. Color of the 

 mass whitish. 



Columbus, Ohio, H. Moores. White River, Indiana, D. H. Shaffer. 



Remarks.— This is an another of the Uniones which have the edges of the anal 

 opening without papillae. The anal and super-anal openings not being united 

 cause a Ions; slit. 



J & 



Unio subrotundus, Lea. Trans. Auier. Phil. Soc, (2), vol. iv. pi. 18, fig. 45. Obs. vol. i. p. 127. 



Branchial uterus occupies the four leaves of the branchiae, and the ovarium was 

 filled with red ova, but no developed embryonic shells were in the branchiae. 

 Branchial large, semicircular, nearly of equal size, free nearly the whole length of 

 the abdominal sack. Palpi rather large, subelliptical, united half way down the 

 posterior edges. Mantle thin, with a very wide, broad, thickened, red margin, black 

 on the edge, inside of which it is yellowish and salmon. Branchial opening large, 

 with numerous dark-brown papillae, branching, dendritic form, somewhat like Mar- 

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

 almost like crenulations. Super-anal opening rather large, colored within the edges 



