ig2i.] Manipur Molluscs. 617 



sills. The oesophageal region is short and curves back to open 

 Into the spicious stomach. The intestiaa! region is comparatively 

 short without any loops, and after a postero-dorsal course curves 

 back to form the rectum, which after passing through the pericar- 

 dium curves down to open at the anus just behind the posterior 

 adductor muscle. The liver is large and well developed, the 

 greater part of it lying within the umhonal region. The foot is 

 a very elongate, tongue-shaped structure in continuation of the 

 abdominal ma<=s and has the statocyst lying just a little below the 

 boundary line between the abdominal mass and the foot. 



The nervous and reproductive sj^stems are quite similar to 

 those of Calvculina figured bv Gilmore. 



The species is quite common in the Manipur Valley, and a 

 large number of specimens was collected by the Manipur Survey 

 party from various streams and ponds in different places. 



Sphaerium austeni, sp. nov. 



Shell elongate-ovate, swollen, sub-equilateral, comparatively 

 thick, opaque ; anterior margin small, broadly rounded; posterior 



margin truncated, nearly straight ; lower 

 border somewhat carved. Umbones pro- 

 minent, somewhat swollen, incurved and 

 nearly touching each other in the middle. 

 Epidermis rather smooth in young, with 

 closely situated concentric striae in fuU- 

 I'lu. 35. — Shell of Sphaeri- grown specimens ; of a dark horny to a 

 iim a/isteiii, sp. nov. yellowish-hrown in colour, shining, and 



with a distinct pale band along the mar- 

 gin. Nacre whitish to light blue. Right valve with two lamellar 

 laterals, of which the lower is better developed and has a broad 

 triangular flange projecting inwards and upwards, and with two 

 cardinals, of which the anterior is large and triangular and the 

 posterior small and rounded. Left valve with a single lateral on 

 each side and two cardinals, the anterior rounded and pad-like 

 and the posterior small, thin and lamellar. 



Measuremen's of Shelh (in millimetres). 



Length 



Breadth 



Thickness 



Type-series. — M 7141-8/1 Zool. Surv. Ind. [hid. Mas.). 



The type series is from the Nnga Hills Assam, and was prob- 

 ably collected bv Lt.-Col. H. H. Godwin-Austen, with whose name 

 I have associated the species There is also another series of this 

 species from Manipur in the Indian Museum. 



