192 1.] N. Annandale & R. B. S. .Seweli, : Vivipara. 271 



Ijiangulate. The mouth of the shell is sub-circular and has a 

 narrow black margin when complete. It is nearly as high as the 

 spire and very little oblique. The umbilicus is narrow. The colour- 

 ation is never very brilliant. The ground colour is greenish and 

 opaque. The dark bauds are variable and irregular, but the alter- 

 nating of broad and narrow bands can always be seen if the shell 

 is clean. The bands are hardly incrassated. The interior of the 

 shell is white. 



The elongate type of shell occurs occasionally with the typica 

 one. In it the height is about ij times the maximum diameter- 

 Its mouth is relatively small. The gigantic type is rarer than the 

 elongate one, but occasionall}' occurs almost as a distinct phase. 

 It is, however, also found with the typical form, apparently as an 

 aberration. 



Nevill has given the name subvar. canalictdata to a curious 

 shell from Raniganj in Bengal. This specimen, which is the only 

 one of the kind I have seen in this race, has a somewhat turbinate 

 form and a broad, deepl}' impressed suture. It must be regarded 

 as a mere abnormality. 



This race is usually found in large ponds, marshes and back- 

 waters with a properly aquatic vegetation. Where the vegetation 

 is scanty the shells are usually dwarfed. 



Race mandiensis, Kobelt, 

 (Plate I, figs. 4 and 10.) 



1909. Vivipai-n bengaleiisis, vai'. mandiensis, Kobelt, op. cit.. p. 414, 

 pi. Ixxvii, tigs. 8, 9. 



This race is so like the jornm typica that I have kept it dis- 

 tinct with some hesitation and only after ascertaining that the 

 differences persist with fair constancy over a large territory. These 

 differences, small as they are, are well shown on plate I. The spire 

 is rather more conical and a little narrower than in the forma typica, 

 the aperture not quite so broad, but more projecting, the umbili- 

 cus broader. There is great variation in colour, probably due to 

 the nature of the water in which the animal lives. The shells in 

 the type-series are pale, but have the alternating broad and 

 narrow spiral bands well developed. Shells from Ambala in the 

 plains of the Punjab are very similar. Specimens from shallow 

 ponds in Lahore have the shell pale and translucent like opal glass, 

 the periostracum extremely thin and evanescent and the dark 

 markings often almost obsolete. In such specimens the animal is 

 also very pale. Shells from the island of Bombay, on the other 

 hand, are unusually brilliant in colouration, the ground-colour being 

 bright olive-green and the bands well defined, dark and regular. 

 Type-series. No. M5081/1 Z.S.I. 



Geographical range. — The type-series is said to be from Mandi, 

 a small native state high up in the Kangra valley in the Western 



