6i8 Records of the Indian Museum. [Vol. XXII, 



The species though closely allied to S. indicum differs from 

 it in the relative length and breadth of the shell, in the umbones 

 being more swollen, in hinge-structure and the sculpture of the 

 shells. 



Genus Pisidium, Pfeififer. 



1913. Pisidium, Woodward, Cat. Brit. Species of Pisidium, |5p. i, 2. 

 1915. Pisidium, Preston, op. cit.. pp. 224, 225. 



The Indian species of this genus are verj- imperfectly known, 

 the descriptions of older authors being incomplete. A revision 

 of the Indian species is in preparation and will be published 

 separately ; here I have only assigned the Manipur specimens to 

 their proper species. 



Pisidium clarkeanum, G. and H. Nevill. 



1S71. Pisidium clarkeanum. G. and H. Ncsill, Journ. As. Soc. Bengal 



XL, p. g. pi. i, figs. 4, \a-d. 

 1015. Pisidium clarkeanum , Preston, op. cit., p. 225. 



The original description of the species by G. and H. Nevill, 

 as was pointed out by Theobald,' is inaccurate in that the authors 

 have wrongly described the posterior side as longer instead of the 

 anterior ; their figures, however, show the posterior side as the 

 shorter of the two. 



In the Manipur collection there is a single specimen of this 

 species collected by the Survey Party at Potsengbam near the edge 

 of the Loktak Ivake. I assign this single specimen to this species 

 with confidence as I have compared it with the types, which are 

 in the collection of the Indian Museum. 



Pisidium hydaspicola, Theobald. 



187S. Pisiditim hydaspicola. Theobald, Journ. As. Soc. Bengal 



XLVII, p. 147. 

 1915. Pisidium hydaspicola. Preston, op. cit., p. 225, fio-. j^. 



The species was originally described from Shupion in Kashmir, 

 but there is a specimen of it from Bhagalpur, Bihar, and Mr. S. L. 

 Hora also collected many specimens in a stream near the Yaribuk 

 Bungalow and also from small streams on the road to Shugui from 

 Wai-khong in the Manipur Valley. 



Most of the specimens are very small. Of those in spirit some 

 are gravid. An account of their anatomy will be published along 

 with the revision of the genus. 



1 Journ. As. Soc. Bengal, XLV, pt. ii, p. 188 (1876). 



