rAKKI-.VSIA I 121 



Unio sikkimensis Lea. Pr. Ac. N. Sci. Phila., Ill, 1859, p. 151 ; 

 Jl. Ac. N. Sci. Phila., I\', 1859, P- -5^ P'- xxxix, fig. 131 ; 

 Obs., VII, i860, p. 69, pi. XXXIX, fig. 131.— SowERBY, Conch. 

 Icon., XVI, 1868, pi. Lxxvi, fig. 400. — Hanley and Theo- 

 bald, Conch. Ind., 1876, p. 6, pi. xi, fig. 4 ; p. 44, pi. cvii, 

 figs. 6, 7. 

 Margaron (Unio) sikkimensis Lea, Syn., 1870, p. 64. 

 Parreysia sikkimensis Simpson, Syn., 1900, p. 845. 



A small species, of which the type is not in the Lea collec- 

 tion. Four shells, however, are before me, two of them from 

 Sikkim, the other two from Tulpigorie, India, which agree 

 well with Lea's figures and description. The species seems to 

 be smaller than P. burmana, the posterior ridge is double, the 

 surface has less zigzag sculpture and the form is rather more 

 rhomboid. 



Parreysia gowiiattensis (Theobald). 



Shell small, short rhomboid, convex, inequilateral, scarcely 

 subsolid ; beaks only moderately full and elevated, with very 

 fine, zigzag-radial sculpture, which extends all over the sur- 

 face and is subangular in places ; besides this, the shell is deli- 

 cately but decidedly, concentrically sculptured ; posterior ridge 

 inclined to be double, ending in a feeble biangulation near the 

 base of the shell ; epidermis pale yellowish-green back to the 

 posterior ridge, over this and the hinder end of the shell it is 

 green, sometimes faintly rayed ; pseudocardinals ragged ; an- 

 terior scars impressed ; nacre bluish, sometimes yellowish in 

 the cavities, iridescent. 



Length 24, height 15.5. diam. 10 mm. 



Oowhatti. in Assam. 

 Unio gowliattetisis Theobald, Jl. As. Soc. Beng., XLII, 



1873, P- -o*^' pl- >^^'ii. fig'- 4- 

 Parreysia goichattensis Simpsox. Syn.. 1900. p. 845. 

 Unio gozvlattensis P.l;tee, Conch. Sam., Ill, 1890, p. 154. 



Distinguished from the other members of the group by its 

 small size and wonderfully subgranulous sculpture that covers 

 the entire shell, the light anterior and dark posterior portions. 



