SUPPLEMENT TO ISAAC LEA'S PAPER ON UNIONID^. 67 



SOFT PARTS OF UlSTIOII^ID^. 



Unio Tappanianus, Lea. 



Soft Parts. — Branchial uterus occupies more than two-thirds of the anterior 

 portion of the outer branchiae, the sacks being filled with mature embryos as well 

 as ova which had merely segmented. Branchia large, semicircular, inner ones the 

 larger, free the whole length of the abdominal sack. Palpi small, obliquely trian- 

 gular, united only at the upper posterior edges. Mantle thin, with a rather thick, 

 broad border. Branchial opening rather small, with small papillae on the inner 

 edges. Anal opening small, without papillae on the edges, but slightly crenulate- 

 Super-anal opening rather long and united below. Color of the mass light salmon? 



Remarks. — I owe to the kindness of Prof. S. S. Haldeman the specimen from 

 which the above description was made. He had had it for a long time in alcohol, 

 and it was not in a very good state for description. It was, however, a well devel- 

 oped female and the embryonic form was easily made out. 



Unio Powellii, Lea. 



Soft Parts. — Several specimens were sent to me in alcohol by Mr. J. McNiel, 

 having taken them in Estero Peal, Nicaragua, West Coast. None had ova in the 

 ovarium or branchial uterus. Branchiae large, inner ones the larger, curved below, 

 free the whole length of abdominal sack. Palpi small, oblique, united towards the 

 top. Mantle very thin, thickened at the margin. Branchial opening large with 

 numerous dark brown papillae. Anal opening large, dark colored, with very minute 

 numerous papillae. Super-anal opening not large, united below. Color of the mass 

 white. 



For hard parts see Observations on Unio, vol. vii. p. 74, and Journ. Acad. Nat. Sci., 1859. 



Anodonta Leonensis, Lea. 



Soft Parts. — Seven specimens were sent to me by Dr. John H. Janeway, Post 

 Surgeon at Fort Hays, Kansas, having taken them in the Smoky Hill Piver branch 

 of the Kansas. Three had charged branchial uterus. No ova in the ovaries. 

 Branchia large, gently curved below, free the whole length of abdominal sack. 

 Palpi large, ovate, united half way on posterior edge. Mantle thin, thick on the 



