152 Records of the Indian Museum. [Vo.L. XVIII, 
These endemic species belong to two categories, those allied 
to fish that live at high altitudes in Central Asia, and those allied 
to representatives of the fish-fauna of Baluchistan. To the former 
category belong Schizothorax zarudnyt and the two species of 
Adiposia, to the latter (with which may be classed Discognathus 
phryne) D. adiscus and Scaphiodon macmahoni. ‘The fish-fauna of 
Seistan may, indeed, be separated as a whole into two geographi- 
cal divisions. The Cyprininae, which do not occur in the highlands 
of Central Asia, represent an element derived from the country 
lying south and south-east of the Helmand basin; while the 
Schizothoracinae and the Cobitidae have been brought by the 
Helmand from the Hindu Kush and are probably descended from 
the fish-fauna of the ancient and once extensive Oxus system. 
There is very little affinity with the scanty fish-fauna of the 
Persian plateau, a noteworthy difference being the complete 
absence of the Cyprinodontidae, several species of which, as 
Jenkins! has shown, are common in the Shiraz district. 
We have as yet little information about the fish of north- 
western Baluchistan and the adjacent parts of Afghanistan, which 
are not remote from the sources of the Helmand system, but 
probably these fish will be found to have Central Asiatic affinities 
and to be closely related to those of Seistan. The fish of southern 
Baluchistan seem to be quite distinct. They have recently been 
discussed by Zugmayer,’ whose collection was mainly from Tas 
Bela, Kelat and the Mekran. ‘The fish-fauna of south-eastern 
Baluchistan was described many years ago by Day,’ with a few 
records from the Quetta district, in his account of that of south- 
eastern Afghanistan ; McClelland* as long ago as 1838 published 
descriptions of a good many species from the Kabul district, and 
Gunther ° discussed a comparatively small collection, mainly from 
the Murghab river in western Afghanistan, in 1889. Not a single 
species recorded from any of these districts (except Discognathus 
phryne from Quetta) has been found in Seistan. We must look still 
further north for the main origin of its fish-fauna, and to a 
country lying at much greater altitudes above sea-level. This 
fauna, indeed, is a remarkable instance of the acclimatization of a 
mountain fauna in a low-lying swampy depression. 
The acclimatization has probably taken place in compara- 
tively recent times, and the question naturally arises, how far has 
it affected the structure of the fish ? Before attempting to answer 
this question, however, it is necessary to say a little more about 
the provenance of the collections on which we have worked, and 
| Jenkins, Rec. Ind. Mus., V, p. 123 (1910). 
2 Zugmayer, ‘‘ Die Fische von Baluchistan,”” Abh. k. Bayerischen Ak. Wiss. 
(Math.-phys. Klasse), XXV1, pt. 6 (1913). 
3 Day, “On the Fishes of Afghanistan.” Pvoc. Zool. Soc. London, p. 224 
(1880). 
4 McClelland, Fourn. As. Soc. Bengal, VII (2), p- 944 (1838). rie: 
5 Gunther in Aitchison’s ‘‘ The Zoology of Afghan Delimitation Commission,” 
Trans. Linn. Soc. London, V (2), p. 106 (1889). 
