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Show 806 MR. F. DAY ON THE FISHES OF YARKAND. [Dec. 5, tor, H. Buch.; Labeo varicorhinus, Heck.; Nemacheilus marmoratus, Heck. ; Callichrous lamghur, Heck. These fishes demonstrate relationship with three districts:- Schizothorax with Afghanistan and East and West Turkestan ; Oreinus 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 Association, 1875) that Mr. Forsyth's embassy "to Yarkand has led naturalists into the fringe of the Tartar subregion." I would, however, 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 Schizothoracina than Western Turkestan appears to be. In the cold and hilly districts of Tibet and Yarkand we observe an absence of spiny-rayed and Siluroid fishes ; whilst amongst Carps we see the genera Schizothorax, Ptychobarbus, Schizopyyopsis, and Diptychus-fishes belonging to a peculiar division of Carps (Schizothoracina, 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 fin, which ix 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 :- a. Those with transverse mouths, as Oreinus, Ptgchobarbus, Schi-zopygopsis, Diptychus. /3. Those with compressed mouths, as Schizothorax. The genus Oreinus is spread from the Helmund river and Jellalabad 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 oii 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. |
