EEE Sab eo 2S EM SHG Ne 
By N. ANNANDALE, D.Sc., F.A.S.B., Director, and SUNDER 
Lat Hora, M.Sc., Research Assistant, Zoological 
Survey of India. 
( Plates XV—XVII.) 
INTRODUCTION. 
The fish of Seistan have a particular interest on account of 
their geographical isolation and of the peculiar structural modifica- 
tions that some of them possess. An account of the geography of 
the country, in so far as it affects the aquatic fauna, will be found 
in the Introduction to this volume. It may be well, however, to 
reiterate here-the fact that Seistan is a comparatively deep depres- 
sion (less than 2,000 feet above sea-level), and lies surrounded by 
desert and mountains much higher than itself. Its only connection 
by water with the outside world (apart from a few short and fitful 
streams that flow into it from the Afghan hills directly to the 
north) is the Helmand, which runs through the Afghan desert from 
the mountains in the north-eastern part of that country. Seistan 
is, in an almost literal sense, the child of the Helmand, which 
alone makes it a living country. Moreover, no ancient connection 
with any sea or any other large river can be premised. 
The following nine species of fish are known to us from Seistan 
or its immediate section of the Helmand system :— 
Fam. CYPRINIDAE. 
Subfam. CYPRININAE. Subfam. SCHIZOTHORACINAE. 
Discognathus adiscus. Schizothorax zarudnyi. | 
Discognathus phryne.* Schizopygopsts stoliczkae.F 
Scaphiodon macmahont. Schizocypris brucer.t 
Fam, COBLEID AE: 
Nemachilus stoliczkae.t 
Adiposia macmahont. Adiposia rhadinaea. 
The species whose name is marked with a * is also found in 
the hills of northern Baluchistan; those with a f are widely distri- 
buted in the headwaters of the rivers that run northwards from 
the Himalayas and the Hindu Kush, while that with a { is only 
known, apart from Seistan, from the mountains of Waziristan on 
the North-West Frontier of India. ‘The rest, so far as we know, 
are endemic in Seistan. 
