NEW UNIONIDJE OF THE UNITED STATES. 109 



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. I860, p. 306. 



Hob. — 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 ventricose, very inequilateral, 

 somewhat truncate before and biangular behind ; substance of the shell jyery 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 ; 

 umbonial 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 perceptible ; 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. Branchia; 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 papillse on the inner edges, and lined with a dark brown 

 band inside. Anal opening without papillse, 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. 



Remarhs. — 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 of frag His, Lam., in the color of the epidermis, 

 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. Kennerly, who accompanied the North West Boundary Survey under 



A. Campbell, Commissioner. 



28 



