﻿IIYRTOPSIS 217 



line curved in front, straight behind : pseudocardinals generally 

 entire ; plications below the laterals faint ; nacre dull lurid 

 purplish or lead-color. 



HvRiopsis scHLEGEi.i (vou Martens). 



Shell large, irregularly long-ovate, subsolid. rather com- 

 pressed, slightly gaping before and behind, with a well-de- 

 veloped, somewhat biangular. posterior ridge ; beaks low, ap- 

 parently compressed, but very deeply eroded in all the speci- 

 mens seen ; there is a faint post-dorsal wing anrj from this the 

 shell is obliquely truncate behind ; epidermis shov^ing concen- 

 tric growth lines, very thick and black, having a tendency to 

 crack oft' ; left valve with two low. radial pseudocardinals ; the 

 right valve has one and they show a tendency to split up into 

 radial denticles ; there are two remote straight laterals in the 

 right valve and one high truncated one in the right ; beak cav- 

 ities shallow, with a row of pits pointing towards the anterior 

 end of the shell ; muscle scars well impressed, the anterior ones 

 distinct ; pallial line deep in front ; nacre dirty lurid whitish,, 

 generally with large, darker blotches, much thicker for a short 

 distance in front. The limited amount of material I have seen 

 does not justify me in saying that the shells of this species 

 are dimorphic. 



Length 200. height 100. diam. 50 mm. 



Japan. 

 Unio schlegeli von Martens, Mai. Blatt.. VTT. t86i. p. 55. — 



KoBELT, Abh. Senck. Nat. Ges., XI, 1879, p. 421, pi. xiv. — 



VON Martens. Nov. Conch.. V, 1879, p. 192, pi. clviii, figs, 



4, 5- 

 Barbala schlegeli P_^Tel, Conch. Sam., Ill, 1890. p. 175. 



Hyriopsis schlegeli Simpson, Syn.. 1900, p. 581. 



A very large, elongated, compressed and rather unattractive 

 species, which is not very closely related to any other known 

 form. There are traces of plications on the posterior slope. 



