540 



Records of the Indian Museum. 



[Vol. VIII, 



with indistinct, fine, spiral striae 



Figs. 3, 3^. — Paludonius rotnugeiisis, 

 sp. n., X 3. 



suture impressed, margined 

 below ; columella margin 

 livid, obliquely descending 

 in a slight curve diffused 

 above into a thick, well 

 defined, restricted, parietal 

 callus which joins the up- 

 per margin of the labrum ; 

 labrum simple, somewhat 

 dilated, especially below, 

 where it is also rather thick- 



ened; aperture large, ovate. 



Alt. 4'25, diam. maj. 825, diam. min. 5-5 mm. 

 Aperture: alt. 475, diam. 4 mm. 



Hab. — Upper Rotung {Type); Upper Rotung, at an alti- 

 tude of 1300 ft., in a small stream; young specimens only (S. W. 

 Kemp). 



Family PALUDESTRINIDAE. 

 Bithynia pulchella (Benson). 



{Paludina), J. As. Soc. Bengal, V, 1836, p. 746. 



Dibrugarh, N.-E. Assam, Brahmaputra River (5. W . Kemp). 



Bithynia dibrugarhensis, sp. n. 

 (Fig. 4, p. 541.) 



Shell imperforate, ovate, pale straw colour ; whorls 4, smooth, 

 the first three regularly increasing, the last large, convex, rapidly 

 descending ; suture impressed ; columella margin vertically des- 

 cending in a slight curve ; labrum continuous, very slightly re- 

 flexed, of a brownish colour; aperture ovate; operculum whitish, 

 slightly concave, finely laminiferous, with central nucleus. 



Alt. 5"25, diam. maj. 3-5, diam. min. 3 mm. 



Aperture : alt. 3, diam. 2*25 mm. 



Hab. — Dibrugarh, N.-E. Assam, Brahmaputra River (S. W. 

 Kemp). 



Family VIVIPARIDAE. 



Vivipara (Idiopoma) heliciformis (Frauenfeld). 



(Palitdina), VerJiandl. Zool-bot. Ges. Wien, XV, 1865, p. 582, pi. xxii. 



Thingannyinaung, E. base of Dawna Hills, at an altitude of 

 900 ft. {F. H. Gravely) ; Dibrugarh, N.-E. Assam, Brahmaputra 

 River {S. W. Kemp). 



Family CYCLOPHORIDAE. 



Diplommatina perobesa, sp. n. 



Shell obliquely ovate with exserted spire, pale flesh colour, 

 solid, opaque; whorls 7, the flrst two submammillary, the third 



