460 Journal of the Asiatic Society of Bengal. [N.S., XIV, 
and not to the Elasmognatha of the sub-order Stylommatophora 
in which is included the family Succineidae. 
The geographical distribution of the genus is at present 
apparently discontinuous, but as Benson pointed out in his origi- 
nal description, the animal is hard to discover and extremely 
local. This is the case in Japan as well as in Rohilkhand and 
Bengal. We can claim considerable experience of the aquatic 
fauna at any rate of the latter part of India, but have never 
come acrossaspecimen. Mr. Hirasé informs us that the Japan- 
ese species is only known to him from Kogomura in the Osaka 
district, and a very careful search for specimens made by one 
of us in apparently suitable spots in the country round Lake 
Biwa, which is situated in an adjacent district, was unsuccess- 
ful. If Godwin-Austen’s identification of the Eocene species 1s 
correct, the genus must have had at one time a very wide range 
in the Palaearctic region. : 
ish this note, with figures of three allied species, 
in the hope of attracting attention to a very remarkable genus 
of molluscs, which has lain perdu for nearly half a century. 
a2. 
possible to express an opinion on the basis of such material, 
species is identical with those of that genus. The shell differs 
from that of the short-spired species of Limnaea only in having 
e believe that the differences from the normal type | 
Limnaea are sufficiently great to justify generic separation a 
propose for the genus thus formed the name Omua, deriv’ : 
from that of the Japanese province in which the type-specl™ 
was found. 
_A genus of the family Limnaeidae consisting of epooies 
which the shell is dextral, small, thin and neritiform. 
| Ann. Mag. Nat. Hist. Ser. 8, xvii, p. 160 (1916). “ter. 
Suss-und Brackwass. Moll.” ‘nt Webar’s Zool. Ergeben Neider 
Ost-Ind. iv, p. 2, pl. 1, figs. 1 and 2, xii, figs. 1 and 3 (1897). 
