﻿CinSTAKTA 



233 



There are two Cristarias in the National Museum, said to 

 come from Japan, that are a little longer in proportion than 

 the described. specimens, and a little more inflated at the pos- 

 terior base, but it is probable that they are females. 



CrIvSTaria gentiliana Heude. 



Shell somewhat elliptical, subsolid, compressed, with low 

 beaks, with two dark, radiating lines on the posterior slope; 

 the dorsal line not so much rounded as the basal one ; with a 

 very feebly developed anterior and posterior dorsal wing; 

 rounded in front; the posterior point blunt and raised above 

 the median line; epidermis black, apparently feebly rayed; 

 right valve with two delicate, lamellar pseudocardinals and one 

 lateral ; muscle scars probably shallow ; nacre greenish-purple, 

 iridescent. 



Length 80, height 50, diam. 20 mm. 



Le-Fou-Kien, China. 

 Cristaria gcntiUanus Mkudi;, Conch. Fluv. Nank., YII, 1881, 



pi. iM\, fig. 98. 

 Cristaria gentiliana Simpson, Syn., 1900, p. 586. 

 Barhala gentiliana P^TEi., Conch. Sam., Ill, 1890, p. 175. 



The epidermis is darker than that of C. discoidea, the nacre 

 is differently colored, the pseudocardinals of the right valve 

 are two in number, while in discoidea there is only one, and 

 the shell is longer in proportion than shells of discoidea of the 

 same size. Younger shells of the latter are often as much 

 elongated as is Heude's species and I think it more than prob- 

 able that it is only a variety of Lea's discoidea. 



Cristaria swinhoei (H. Adams).. 



Shell rhombic obovate, thin, scarcely inflated, without a de- 

 fined posterior ridge, but with a couple of very faint, dark 

 ridges on the posterior slope; beaks low and compressed, their 

 sculpture not discernible from the specimens examined ; an- 

 terior end rounded and apparently without a dorsal wing ; 

 posterior dorsal wing moderate, ending behind in an angle ; 

 surface with irregular, concentric growth lines, rayless, green- 



