806 MR. F. DAY ON THE FISHES OF YARKAND. [Dec. 5, 



tor, H. Buch. ; Labeo varicorhinus, Heck. ; Nemacheilus marn/o- 

 ratus, Heck. ; Callichrous lamghur, Heck. 



These fishes demonstrate relationship with three districts : — 

 Schizothorax with Afghanistan and East and West Turkestan ; Ore- 

 inus with the slopes of the Himalayas in their whole extent; Cirrhina, 

 Barbus, and Callichrous with the neighbouring fauna of Hindustan. 



Having examined what are the ingredient parts of the fish-fauna 

 of Western Turkestan, Afghanistan, Hindustan, Yarkand, Tibet, 

 and Cashmere, it will be interesting to endeavour to discover if these 

 localities are possessed of any indigenous forms, and, if so, how far 

 they extend into contiguous countries. 



1 do not propose inquiring into whether the great desert region 

 of Central Asia can or cannot be included in one Tartarian sub- 

 region ; but, as the zoology of this portion of the globe is at present 

 rather obscure, I think it will be more useful to limit one's self strictly 

 to ascertained facts. 



Dr. Sclater observes (Address, Biological Section, British Associ- 

 ation, 18/5) that Mr. Forsyth's embassy "to Yarkand has led 

 naturalists into the fringe of the Tartar subregion." I would, how- 

 ever, suggest, in an ichthyological point of view, whether the Russian 

 investigators have not been more on the outskirts of a peculiar region 

 of which Yarkand may be the centre; for certainly it is richer in 

 forms of Schizothoracince than Western Turkestan appears to be. 



In the cold and hilly districts of Tibet and Yarkand we observe 

 an absence of spiny-rayed and Siluroiu fishes ; whilst amongst Carps 

 we see the genera Schizothorax, Ptychobarbus, Schizopygopsis, 

 and Diptychus — fishes belonging to a peculiar division of Carps 

 {Schizothoracince, or Hill- Barbels), which may be thus defined : — 



Carps more or less covered with minute scales, or destitute of any. 

 A membranous sac or slit anterior to the anal Jin, which is laterally 

 bounded by a row of vertically placed scales, like eave-tiles, and 

 which are continued along the base of the anal fin. 



The fishes composing this are mostly of an elongated form, and 

 are divisible into : — 



o. Those with transverse mouths, as Oreinus, Ptychobarbus, Schi- 

 zopi/gopsis, Diptychus. 



/3. Those with compressed mouths, as Schizothorax. 



The genus Oreinus is spread from the Helmund river and Jella- 

 labad in Afghanistan, along the whole Himalayan and contiguous 

 ranges of hills to at least the confines of China. So far as I know, 

 these fishes appear to be strictly residents of rivers in hilly regions, 

 neither descending far into those of the plains nor found on the level 

 plateaux on the summits of the mountains. This accounts for their 

 absence from the Yarkand collection; and from the foregoing extracts 

 it appears probable that they are not found to the north of the Oxus. 

 This genus appears to be on the outskirts of the rest of its group ; 

 and its mouth armed with a sucker, to resist its being washed away, 

 makes it well able to sustain a mountain-torrent life. 



