204 Records of the Indian Museum. [Vol. XVI, 



hinder rudimentary and one lateral ; laterals granular and showing 

 traces of vertical striation, muscle scars well impressed, the anterior 

 ones rough, the posterior elliptical; nacre whitish or purplish; 

 thickened in front, generally showing small pits. 

 Laos Mountains, Cambodia : vSiam : Burma." 



Margaritanopsis woodthorpi, n. sp. 

 (Plate XV.) 



Locality. — Fort Stedman, Shan States (Woodthorpe). Two 

 specimens received. 



Shell very elongate or broad, somewhat flattened, solid, um- 

 bones high, nearly level, inequilateral, posterior ridge straight, 

 long. Anterior end of shell rounded, posterior end also, ventral 

 margin pinched in or compressed with considerable convexity. 

 Surface eroded on umbones, then smooth followed by strong lines 

 of growth next and up to the margin, epidermis greyish-black 

 (pi. XV, fig. i). Left valve (pi. xv, fig. 2) with a solid pro- 

 jecting pyramidal cardinal tooth, having well defined layers of 

 growth, with two long posterior lateral teeth or rather flanges, no 

 anterior. Right valve (pi. xv, fig. 3) with a smaller projecting 

 cardinal which fits and drops in in front of the left valve cardinal. 

 One posterior flange. Anterior muscle scars well impressed, the 

 adductor large, circular, protractor pedis small, anterior retractor 

 above rather larger and deeper. Posterior muscle scar eliptical, 

 smooth. Nacre pale cerulean blue and extremely smooth. 

 Diameter 29-0, length 40*0, breadth 127 mm. 



The figures of this shell are from the excellent photographs 

 of my friend and neighbour Mr. J. S. Gladstone. 



Dr. Annandale informs me, this subgenus was not found by 

 him in Inle Lake, Woodthorpe must, therefore, have obtained it in 

 one of the larger streams that flow into the lake, and it may 

 possibly have habits somewhat like those of Solenaia of Cachar. 

 How far the anatomy will compare with that subgenus has to be, 

 ascertained. As to the extension west in the vSalween basin of 

 Margarifanopsis is also of interest. I found nothing like it in 

 Manipur nor would it be likely to be found there. The streams 

 of that valley are nearly all very sluggish, with discoloured water 

 and muddy bottoms, as far as the Logtak lake. I do not know 

 the country to the south of that, the subgenus might possibly 

 occur there. 



A few notes on the Genus Solenaia may be introduced here. 



The exact locality in Cachar and the conditions in which U. 

 soleniformis lives have been recently given me by Mr. F. Ede of 

 Silchar. He says : '' It is only possible to obtain this bivalve when 

 the rivers are extremely low in the height of the dry or cold 

 season. I found specimens in the Daleswari in Hailakandy between 

 Katlicherra and Cookicherra, also (once only) on some rocks by 

 diving in a very dry season, in the centre of the Barak River 

 opposite the old pukka club in Silchar, but since then have only 



