270 Records of the Indian Museum. [\'oi,. XXII, 



vallej'. Westwards it is replaced, apparenth- quite gradually, by 

 viandiensis and southwards bj^ eburnca. The race nepalensis 

 occupies the base and lower valleys of the Eastern Himalayas 

 from Nepal to the east of Assam, but in the plains of Assam is gra- 

 dually replaced by halteata, which in its turn gives way to dollar is 

 in the vallej's of Burma. In no instance is it possible to draw a 

 precise line, either structural or geographical, between the different 

 races. 



The form that I have called race colairensis differs from the 

 others here recognised as races, in that it has been found only in one 

 locality. A large number of individuals were, however, examined 

 and the racial characters seem to be remarkably distinct. 



In a sense two {incrassata and fachydolicha) of the four 

 phases here recognised, are modifications of the local race ehurnea 

 rather than of the species as a whole, but in the other two {annan- 

 dalei and halophila) the phase-characters mask the racial ones and 

 the phase is found in the territory of more than one race. 



For these reasons I have carefully avoided a specious appear- 

 ance of precision in defining the diagnostic characters of races and 

 phases. I have also refrained from giving measurements of in- 

 dividual shells. These I have found most misleading in diagnosis, 

 the differences in form depending not so much on point to point 

 measurements as on the curvature and inclination of the outlines. 

 Such differences can be properly demonstrated only by good figures. 

 Unless it is otherwise stated, I have examined large numbers of 

 specimens of each race and phase from several or many localities. 



Race bcngalensis (Lamarck). 



(Plate I, figs. 1-3.) 



1822. Paludina beiigalensis. Lamarck, Anim. s. Vert. W (2), p. 174. 

 1822. Paludina elongata, Swainson, Zool. III. Ser. I, II, pi. xcviii 



top. 

 1S41. Palitdijia bcngalensis, Delessert, Pec. de Coqiiilles, pi. 31, figs 



22, 2b. 

 1S52. Paludina bengalensis, Kuster, in Martin and Chemnitz's Conch. 



Cab.. Paludina I, p. 17, pi. 3, fi,a;s. 15, 16. 

 1862. Paludina bengalensis and P. gigantea. Reeve, Con. Icon., pi. ii. 



figs. 5a. 56, and 7. . , , , 



1S76. Paludina bengalensis, and P. bengalensis var. gigantea, Hanley 



and Theobald, Con. Iiidica, pi. Ixxvi, figs. S, 9, 10 and pi. 



Ixxvii, fig. 5. 

 1877. Paludina bengalensis, (Typical sect, in part) Nevill, Cat. Moll. 



Ind. Mus., pp. 26-28. 

 18S5. Paludina bengalensis (in part), with subvar. phaeostoma. elong- 



ata. gigantea and canalicnlata, Ne\ill, Hand List Moll. 



Ind. Mus., II, pp. 20, 21. 

 1909. Vivipara bengalensis, Kobelt, in Martin and Chemnitz's, Concii. 



Cab., Paludina, II, p. 271, pi. Iv, figs. 1-4, 



I regard the race found in the lower Ganges valley as the 

 /anna typica of the species. The typical shell of this race is about 

 If times as high as broad and the spire and body-whorl as seen 

 in dorsal view are about equally high. The whorls are rather 

 tumid and the body-whorl is evenly convex in profile, not 



