50 



SOLENIDiE. 



epidermis is entire. The liony substance of the valves is so thin, 

 that the lighter-colored radiations are quite obvious within. 



Its special distinguishing marks will be more particularly pointed 

 out in the description of the next species. 



Solemya borealis. 



Shell fragile, oblong ; epidermis dark brown, with fifteen to twenty lighter 

 radiating lines ; within grayish-blue ; cartilage-support forked, the hinder branch 

 directed obliquely forwards. 



Solemya borealis, Totten, Silliman's Journ. xxvi. 366, fig. 1. — Stimpson, Shells of New 



England, 21. 

 Solemya velum, Conrad, Anier. Mar. Concli. pi. 66, fig. 16. 



This shell would be described in terms so similar to those em- 

 ployed for the ])receding species, that a notice of those points in 

 which they ditfer will be the best description. 



It greatly excels in size ; the smallest that has been noticed ex- 

 ceeding the largest S. velum. The valves are less convex, and very 



much more solid, and their 

 color within is always a gray- 

 ish-blue or lead-color; the basal 

 margin is a little arched in- 

 wards ; the ends are a little 

 scalloped, there being a slight 

 projection corresponding to 

 each fissure of the epidermis ; 

 the cartilage-support instead of being arched is forked, and the 

 hinder branch is directed obliquely forwards, extending half-way 

 to the anterior margin ; the e})idermis is always of a very dark 

 brown or tar-color, marked with fifteen to twenty radiating lines ; 

 the projecting margin is slashed as in the other species, but the 

 angles of the lobes are not rounded, their edges have a thinned, 

 crim])ed margin, and are usually rolled back. 



Chelsea beach is the only locality in Massachusetts, that I know 

 of, where this species has been found. A very large and perfect 

 specimen was found there by Mr. J. P. Couthouy, and is now in the 

 cal)inet of the Boston Society of Natural History. Colonel Tottcn 

 found it in considerable numbers in the vicinity of Newport. Whole 

 coast of New England {Stimpson} ; Nahant beach (^Haskell) ; Fish- 

 ing Banks (Wi/Iis'). 



Only two other species of this genus have been described ; the 



