24 Records of the Indian Museum. [VOL. XVIII, 
The radula is very like that of Amnicola, s.s., its central tooth 
being produced at either side and bearing a central process on its 
disk which projects downwards below its lower margin, as well as 
two or three lateral basal denticulations on each side. 
Type-species. Ammicola ststanica, sp. nov. 
This new subgenus is very closely related to Amnicola, s.s., 
but differs in its long snout, calcareous oval or ovoid operculum 
and lunate penis. From Pseudamnicola it differs in its much 
larger, spiral operculum and in having more than one basal denti- 
culation on each side of the central tooth of the radula. It is, 
indeed, a link between the two groups of species, each of which 
we regard as having subgeneric rank. 
(B= 
Woe 
Fic. 1.—Radular teeth of Amnicola { X 500). 
A. Teeth of Amnicola (Alocinma) sistanica, sp. nov., from the reed-beds 
of the Hamun-i-Helmand. 
B. Teeth of Amnicola (Alocinma) alticola (Annandale), from the Inlé 
Lake, Southern Shan States. 
Among the species that must be placed in the new subgenus 
are the common “‘ Bithynia’’ orcula of Bengal and also Ammnicola 
alticola (fig. IB) from the Southern Shan States. In the former 
as well as the latter the operculum is distinctly spiral and both 
have the other subgeneric characters. 
Amnicola (Alocinma) sistanica, sp. nov. 
(Pl. iti, figs. 1-5.) 
This species is very closely related to Amnicota orcula, but the 
shell is more hyaline and more globose and has the suture more 
oblique and more impressed. It may be described as follows :— 
