PEA OU A CCEA UN ARO (S Eats a AGN 
A SUMMARY. 
By N. ANNANDALE, D.Sc., F.A.S.B., Director, Zoological 
Survey of India. 
The aquatic fauna of Seistan is a scanty one, fairly rich in 
individuals, as is usual in a fauna living in abnormal conditions, 
but poor in species. The most salient fact about it is that it is 
essentially a mountain fauna acclimatized to live in a swampy 
depression. Before discussing its geographical and biological rela- 
tions as a whole I will first consider briefly the different species 
found in the different bodies of water that exist in the country, 
viz. desert springs, stagnant pools, rivers and other water courses, 
and the Hamun-i-Helmand or basin into which the Helmand 
finally drains. An account of these will be found in the Introduc- 
tion to this volume. 1 have given in foot-notes references to the 
species of animals not otherwise noticed in the volume. 
THE FAUNA OF SPRINGS IN THE SEISTAN 
DESERT. 
In our hurried journey across the desert of Seistan and the 
Afghan-Perso-Baluch frontier we had little opportunity to examine 
many of the springs we passed, but those we did examine were 
very uniform in their animal life, which did not appear to be much 
affected by the varying degrees of salinity of water accepted under 
stress of necessity as potable by man and beast. None of the 
springs contained fish, but all the larger ones had a small but 
healthy fauna of molluscs, insects, Entomostraca and leeches. 
MoxiLusca. Only three species of molluscs were found, Mela- 
noides pyramis (Benson), Gyraulus euphraticus, Mousson and Cor- 
bicula fluminalis (Miller). Of these the most commonly present 
was the Melanoides. Of this species all our specimens belonged to 
Nevill’s var. favida, a form perhaps peculiar to situations of the 
kind and originally described from Persian Baluchistan. The shell, 
though not of the largest size attained by the species, is not 
dwarfed or in any way distorted. A single specimen of this race 
is also known from Mesopotamia. The Gyraulus is perfectly 
normal, though found in water distinctly bitter to the taste. It is 
noteworthy that the species has an extraordinarily wide range 
(from Mesopotamia to China) and must, therefore, be extremely 
adaptable. Thesameis true of the Corbicula, which is found practi- 
cally all over Africa and southern and middle Asia, was originally 
