50 Records of the Indian Museum. [VoL. XVIII, 
are practically identical, but the vas deferens differs slightly in 
proportions. 
This variety exhibits both individual variation and plasticity 
in a higher degree than L. gedrosiana, s.s. The shape of the mouth 
of the shell and of the whole body-whorl differs considerably in 
individuals from the same environment, while individuals from 
one environment differ in having a narrower shell than those from 
another. The two localities from which we have examined fresh 
specimens are the Kushdil Khan reservoir, situated at an altitude 
of 5000 {t. in the hill-country of Baluchistan north of Quetta, and 
a small pool in the desert some miles south of Nasratabad in 
Seistan. The Kushdil Khan reservoir is a large body of clear 
shallow water artificiallv confined and liable to dry up in summer. 
In winter it contains at certain places a fairly dense submerged 
vegetation consisting of Potamogcton pectinatus, Naias major, ete. 
The pool near Nasratabad was quite a small one. At the time of 
our visit it was completely isolated in the desert, but in flood-time 
is evidently connected with alarge backwater of one of the effluent 
channels of the Helmand. Its vegetation consisted in December 
of dead reeds and a scanty growth of broad-leaved Potamogeton. 
Specimens from Kushdil Khan were much larger and asa rule 
considerably broader than those from Seistan (cf. figs. I-3, 4-6 on 
pl. vi). All the shells from each locality belonged, though differing 
considerably, quite definitely to the variety. 
At Kushdil Khan dead shells, some with remains of the 
animal, were collected in flood-drift on the edge of the reservoir, 
while a few individuals were found adhering to the lower surface 
of stones near the margins. ‘The molluscs in the desert near Nas- 
ratabad were attached in large numbers to dead reed-stems and to 
the droppings of goats, flocks of which watered at the pool. 
Measurements of Shells (in millimetres). 
Specimens from A—C are from Kushdil Khan reservoir (Baluchistan), and 
specimens D—F from a small pool, some miles south of Nasratabad, Seistan. 
A B IG D E F 
Length a PS TESST EAR EATS 2 SEP eae ae 
Maximum breadth a GIO: Oar 828.7 37 OS PEs 
Length of aperture , MEE. “TO TO°7-- *UOr2'= 6:9" S72 
Breadth of aperture SE O45) 70 530 95 5 eee 
Length of spire (dorsal) 3 B75 394) 28" 250" Saas 
Breadth of base of spire 3°) S34. Bt5)  -32t Soran eae 
Type-series. M 11534/2, Zoological Survey of India (Ind. 
Mus.). 
Limnaea truncatula, Gray. 
1850. Limnaea truncatula, Hutton, fourn. As. Soc. Bengal (2) XVIII, 
p. 656. 
We have seen no specimens from Baluchistan or Seistan, but 
have examined a large series from different parts of the Western 
