NKW UNIONID.E OF THE UNITED STATES. 113 



scarcely prominent, finely and closely undulate at the tips ; epidermis yellowish olive, 

 shining, striate at the margin, without rays ; nacre bluish white and very iridescent. 

 Proc. Acad. Nat. Sci. 1860, p. 30G. 



Hah. — Chiloweyuck Depot, near Puget Sound. Washington Territory. C. B. Ken- 

 nerly, M. D. 



My cabinet and cabinet of Smithsonian Institution. 

 Diam. -8, Length 1-2, Breadth 2-6 inches. 



Shell smooth, elliptical, subcylindrical, somewhat vcntrico.se, very inequilateral, 

 somewhat truncate before and biangular behind ; substance of the shell very thin, 

 semitransparent ; beaks scarcely prominent, finely and closely undulate at the tips ; 

 ligament long, thin and light brown ; epidermis yellowish olive, shining towards the 

 beaks and striate towards the margin, without rays, with rather close marks of growth ; 

 umbouial slope slightly raised and subbiangular ; posterior slope rather narrow, slightly 

 carinate, with two indistinct rays on each valve from the beaks to the posterior 

 margin; anterior cicatrices confluent and slightly impressed; posterior cicatrices con- 

 fluent and very slightly impressed ; dorsal cicatrices none pd'cejitible ; cavity of the 

 shell rather shallow and wide ; cavity of the beaks very shallow and rounded ; nacre 

 bluish white and very iridescent. 



Soft parts. — Branchial uterus. — No ova in the branchial ovisacks, but ova were 

 found in the ovarium. Brancldcc large, inner ones much the larger, curved below, free 

 two-thirds the length of abdominal sack. Palpi small, subtriangular, united one-third 

 down the posterior edges. Mantle very thin. Branchial opening very large, with 

 numerous small, brownish papillae on the inner edges, and lined with a dark brown 

 band inside. Anal opening without papillae, light brown on the edges, lined with a 

 dark brown band inside. Super-anal opening very small, united for some distance 

 below. Color of the mass dirty white. 



Remarlcs. — Several specimens in alcohol were sent to me by the Smithsonian Insti- 

 tution. In outline it is near to Ferussaciana, (nobis), but it is rather wider and has not 

 a green epidermis. It reminds one oi frag His, Lam., in the color of the epidex*mis, 

 and the marks of growth, as well as the thinness of the valves, but it is more trans- 

 verse, and is rather a smaller species. The anterior margin is disposed to be trun- 

 cate, which is not the case with either of the above named species. I name this 

 species after Dr. Kenncrly, who accompanied the North West Boundary Survey under 

 A. Campbell, Commissioner. 



