﻿AND SPECIES UE THE FAMILY UNlOMD^E. ■ 303 



yellow ; cardinal teeth rather long, compressed and double ; lateral teeth long and 

 nearly straight ; nacre salmon colored and iridescent. 

 Proc. Acad. Nat. Sci. Vol. 8, p. 94. 



Hob. — Sina River, India. Major Le Conte ; Ahmednugger, India, S. Shurtleff, M. D. 

 My cabinet, cabinets of Major Le Conte, Dr. Shurtleff and Dr. Ingalls. 

 Diam. *6, Length -7, Breadth 1-6 inch. 



Shell minutely folded, elliptical, inequilateral, somewhat cylindrical, obtusely 

 angular behind, regularly rounded before and slightly flattened at the sides ; substance 

 of the shell somewhat thick, thinner behind ; beaks a little prominent, pointed and 

 minutely undulate at tip ; posterior slope raised into a small carina, and covered with 

 very delicate small undulations, and furnished with two indistinct lines from the beak 

 to posterior margin ; ligament rather short and thin ; epidermis greenish yellow, with 

 obscure green rays ; umbonial slope rounded ; cardinal teeth rather long, compressed 

 and double in both valves ; lateral teeth long and nearly straight, single in the right 

 and double in the left valve ; anterior cicatrices distinct ; posterior cicatrices confluent ; 

 dorsal cicatrices placed within the cavity of the beaks and on the under side of the 

 posterior portion of the cardinal tooth ; cavity of the shell rather deep ; cavity of the 

 beaks shallow and subangular ; nacre slightly salmon colored and iridescent. 



Remarks. — Several specimens of this shell are before me. Two of them are odd, 

 young valves. The specimen figured has been in my possession some years, but being- 

 very closely allied to U. gratiosus, Phili., I feared it might prove a variety only of 

 that species. The young specimens and other adults since received, satisfy me that 

 they are distinct. The specimens of gratiosus which I have in my cabinent are 

 much less transverse and much smaller. They are precisely the same in outline and 

 folds with Dr. Philippi's figure, (Conchylien, v. 1, t. 1, f. 5.) The Shurileffianus is 

 more cylindrical and the basal margin is disposed to be emarginate. The folds are 

 beautifully disposed over the upper part of the disk up to the tip of the beaks. They 

 are remarkably minute, and so divergent and re-entering, as to make zigzag lines. In 

 outline and size the Shurtleffianus is very near to cceruleus, (nobis,) also from India, 

 but it may easily be distinguished from that species by being devoid of that bluish 

 color, by the posterior margin being less angular, by the beaks being more medial and 

 the nacre being salmon colored. The teeth are also less lamellar and the folds more 

 numerous. It differs from crispatus, Gould, in having coarser folds, in color of nacre, 

 as well as in having the teeth more lamellar, and the posterior margin being less acute. 



I have dedicated this species to Dr. Shurtleff, to whose kindness I owe specimens of 

 several ages. 



Unio effulgens. PI. 28, fig. 18. 



Testa sulcata, clliptica, sujiinflatfi, intequilaterali, postirr obtuse aneulata ; valvulis subcrassis ; natibus 



