412 Journal of the Asiatic Society of Bengal. [(N.S., XIX, 
conical, of a greenish colour (which turns brown or black on 
exposure) and normally without dark spiral bands. The 
operculum has a well-defined pit on the external suriace corres- 
ponding to a boss or tubercle on the internal surface and 
the muscular scar is poorly developed. The radula has no very 
characteristic features, but the inner lateral denticulations of 
the lateral teeth exhibit a curious but inconsistent tendency 
to become bifid. I have seen this in Chinese and Japanese 
species as well as in the type-species from Manipur. 
Three distinct but closely allied species are found in 
Yunnan and occur in the Gregory collection. They may be 
distinguished as follows :— 
1 Shell ovate, at least 1-7 times as high as broad, with 
the upper surface of the whorls convex and the mouth 
ovate and projecting little beyond the outline of the 
upper part of the body-whorl .. L. lecythoides. 
Il. Shell more globose, not more than 1-4 times as hig 
as broad, with the upper surface of the whorls dis- 
tinctly flattened and the mouth projecting consider- 
ably beyond the outline of the upper part of the body- 
A. Shell decorated with numerous 
fine, distinct spiral linear ridges L. malleata. 
B. Shell without such ridges .. JL. lecythis. 
As these forms remain distinct over a very broad area. 
while exhibiting a wide range of variation in themselves, it 
seems better to regard them as species rather than varieties, 
as some conchologists have done. There seems to be very 
little anatomical differentiation in the genus. 
_ In Yunnan and in China generally, as I have already 
pointed out, the species of this genus completely replace the 
‘‘apple-snails’’ or Ampullariidae, which are the largest fresh- 
water Gastropods in Peninsular India east of the Punjab and 
also in Burma. In the valley of Manipur, in which L. lecythis 
is one of the dominant forms, the Ampullariidae are scarce 
and have only been found in the immediate neighbourhood of 
Imphal, where they may have been introduced. ‘They also 
appear to be scarce in the eastern parts of Upper Burma. 
The Ampullariidae have a profoundly modified respiratory 
apparatus which fits them for long periods of aestivation an 
hibernation ont of water and permits them to breathe air 
the mantle enables the orifice of the branchial cavity to be 
closed tightly. This may be useful not only in excluding 
i - 

