1g1Q.] N. ANNANDALE & B. PRASHAD: Mollusca. 51 
Himalayas. ‘These specimens provide evidence of much local plas- 
ticity, some agreeing with European shells, others having the form 
of the var. longula figured by von Martens in the report (in Rus- 
sian) on the molluscs in Fedtschenko’s Rezse in Turkestan (vol. 1, 
pl. ii, fig. 26, 1874). Specimens from some Himalayan localities are 
much larger than those from others. 
Hutton states that L. truncatula is common in the marshlands 
bordering the Helmand at Girishk and also in similar situations at 
the Kogrick Pass and at Quetta. ‘The fact that it was not found 
at Quetta in winter is, therefore, interesting. The species seems 
more susceptible to drought and unfavourable conditions than most 
of the genus! and probably conceals itself in cold weather. Had it 
occurred at all commonly in Seistan, however, dead shells would 
probably have been recovered from the recent deposits examined 
at the edge of the Hamun and elsewhere. The presence of a liver- 
fluke of the genus Fasciola in the country does not necessarily 
imply that this mollusc is the intermediate host of the liver-fluke, 
for L. truncatula does not occur in North America and yet Fasciola 
hepatica is prevalent in some districts”; moreover, as Mr. Kemp 
points out in a note appended to this paper, the Seistan liver-fluke 
is not identical with the European one. 
Limnaea hordeum, Mousson. 
(Pie vite fies 55) 
1874. Limnaea hordeum, Mousson, Fourn. Conchyl. XXII, p. 42. 
The shell is extremely small and rather thick, narrowly elon- 
gate but blunt at the apex. Our single specimen is bleached 
white and has a somewhat porcellaneous appearance. There are 
four whorls but the apical one is very small and projects little. 
The suture is impressed and very oblique, so that the spire is much 
shorter in the ventral than in the dorsal view. The third whorl is 
more than 3 times as long as the second and the body-whorl consider- 
ably longer than the spire. ‘The mouth is small and rather narrow, 
almost straight and practically oval, being little contracted and 
not at all pointed posteriorly. The lip is somewhat expanded and 
has a thickened appearance due to a blunt ridge running round it a 
short distance inside the margin. The columella is slightly folded, 
its callus narrowly expanded over the rimate umbilicus. The 
callus is joined posteriorly to the outer lip. The surface of the 
shell is marked with faint longitudinal striae, which are regular 
and set close together. 
We have compared our single specimen with two of Mousson’s 
species from the edge of the river Euphrates and can find no 
difference. The species was originally described from that river. 
Our Mesopotamian specimens are from Nasariyeh. We obtained 
a single dead shell in a drift at the edge of a small pool in the 
! Walton, Parasitology X, p. 243 (1917) 
2 Ward, Fresh Water Biol. N. America, p. 389 (1918). 
