428 UNIONIDyE, THEIR SOFT PARTS 



and slightly united below. Color of the mass very dark salmon, the adductor 

 muscles and the foot being almost red. 



Columbus, Ohio, H. Moores. Cincinnati, Ohio, D. H. Shaffer. 



Remarlcs,. — This is a very remarkable species in several respects. It is one of the 

 four among all the Uniones I know, which have all four of the branchial leaves oc- 

 cupied by the uterus;* it is one of the only three which have red ova ;f and it is 

 peculiar, so far as I know, in the male having red spermatic matter in the glandular 

 flattened lobules of the scrotum, the color of which, however, is not of so deep a red as 

 the ova in the female. See remarks on rubiginosus, page 416. 



Unio pustulosus, Lea. Trans. Arner. Phil. Soc. (2), vol. iv. pi. 7, fig. 7. Obs. vol. i. p. 86. 



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



Branchial not large, nearly semicircular, inner ones much the larger, free two-thirds 

 the length of the abdominal sack. Palpi rather long, subtriangular, united onedialf 

 down the posterior edges. Mantle thin, with a wide, thickened margin. Bran- 

 chial opening large, with rather small, branching papillae of a nearly white color. 

 Anal opening not large, has no papillae, but has very small crenulations on the inner 

 edges. Super-anal opening exceedingly large, united below. Color of the mass 

 whitish. 



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



Remarks. — This species was found to be very sensitive to light. 



Unio lens, Lea. Trans. Amer. Phil. Soc. (2), vol. iv. pi. 8, fig. 10, and Obs. vol. i. p. 90. 



The several specimens examined were all males. Branchiai small, semicircular, 

 united the whole length of the abdominal sack, which is very large. Palpi very small, 

 elliptical, united but a very short distance on the posterior edges. Mantle thin, thicker 

 doubled and colored on the margin, fringed below the branchial opening. Bran- 

 chial opening rather small, with very small papillae. Anal opening very small, with 

 very small papillae. Super-anal opening rather large, united below. Color of the 

 mass whitish. Columbus, Ohio, H. Moores. 



Unio trigonus, Lea. Trans. Amer. Phil. Soc. (2), vol. iv. pi. 16, fig. 40, and Obs. vol. i. p. 120. 



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



ovarium. Branchiai rather small, semicircular, free two-thirds the length of the 

 abdominal sack. Palpi rather small, subelliptical, united half way down the poste- 

 rior edges. Mantle thin, thicker and darker on the border. Branchial opening small, 

 with very small papillae. Anal opening small, with minute papillae. Sup>er-anal 

 opening rather large, united below. Color of the mass whitish. 



Columbus, Ohio, H. Moores. 



*Mu.ltiplieatus, rubiginosus, Kleinianus and subrotundus. fRubigpiosus, jEsopus and subrotundus. 



