I92I.] 



B. Prashad : Notes on Lamellibranchs. 



141 



In 



distribution of this species 

 specimens from Ratnasiri near 



the Indian Museum there are 

 Bombay on the west coast of 

 Peninsular India and from the west coast of India (exact locality 

 not stated). All these specimens agree closely with Preston's 

 figures of the type-specimen and with Deshayes' description. The 

 species therefore, has a wide range comprising Australia, the Phil- 

 ippines, Dutch East Indies, Ceylon and Peninsular India. The 

 following are the measurements of the specimens from the two 

 localities in the Indian IMuseum collection. 



Measurements (in millimetres). 



Length 

 Height 

 Thickness 



West Coast of India. 



61 

 60 

 33 



52 



48 



31 



Cyrena proxima, Prime. 

 Plate XX, figs. 8, 9. 



1S63. Cyrena proxima, Prime, Cat. Corbiculidae, p. 6. 



1864 Cyrena proxima, Prime, Ann. Lyceum Nat. Hist. Soc. New 



York, VIII, p. 85. fig. ,34. 

 1869. Cyrena proxima, Prmie, Cat. Corbiculidae in Amer. Joiirn. 



Conch. V, p. 147. 

 1879. Cyrena proxima, Clessin, Cycladeen in Martini-Chemn. Conch.- 



Cab. p. 127, pi. xxi, fig. 2. [165- 



1889. Cyrena proxima, von Martens, Journ. Linn. Soc. Zool. XXI, p. 

 1915. Cyrena proxima, Preston, Faun. Brit. Ind. Fresh-Moll. pp. 206, 



207. 



In the Indian Museum collections C. proxima is represented 

 by a large series of shells collected by Dr. J. Anderson in Sullivan 

 Island (not Sulliman Is.) in the Mergui Archipelago, and referred 

 to by the late Dr. E. von Martens in the paper cited above. The 

 specimens are stated to have been collected in fresh water, but it 

 is unlikely that the water was quite fresh as no species of the 

 genus occur in quite fresh water. It is probable that the water 

 in the streams, from which the specimens were collected, was 

 subject to the influence of the tides and had variable salinity, as 

 is the case with the estuarine areas in the streams of the Gangetic 

 Delta where C. bengaknsis is found. 



The distinguishing characters of the species are the suborbi- 

 cular and nearly equilateral shell with the anterior and posterior 

 borders curving regularly downwards to the podial and gonial 

 angles, the greatly arcuate ventral border and the inwardly curved 

 and somewhat approximate beaks. 



The largest specimen in the Indian Museum measures 64 mm. 

 X59 mm. X37 mm., and is much larger than the specimens in the 

 British Museum. 



The species is known from Sullivan Island and Siam only. 



