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



Among Siluroids the Indian genera Callichrous and ? Amblyceps 

 have been doubtfully recorded from Afghanistan ; but neither have 

 spread to Turkestan, where, however, the Silurus glanis is found, 

 evidently a wanderer from its more northern home. 



It is clear that in India there is a gradual diminution of Siluroids 

 as we proceed inland until we arrive at the Himalayas. On the 

 slopes of these mountains we at first obtain a few peculiar genera and 

 species organized for a mountain-torrent life ; but as we rise, even- 

 tually (as was the case in this Mission) an elevation is attained which, 

 taken in connexion with the latitude and paucity of food, seems to be 

 beyond the limit of the Indian Siluroids. 



The Siluroids along the slopes of the Himalayas appear to be 

 mostly confined to the following : — A few, as Macrones and Calli- 

 chrous, ascend a short distance ; but this may be considered accidental. 

 Pseudecheneis is a more distinct hill-form, possessing a sucker formed 

 of transverse folds between its pectorals on the chest, and by the aid 

 of which it prevents itself being carried away by the torrents. 

 Glyptosterniim has also an adhesive sucker, but of longitudinal folds, 

 and likewise placed on the chest. These fishes, however, appear to 

 be more intended for rapid rivers in the plains ; but some ascend the 

 slopes of the Himalayas. I have taken larye specimens from the 

 rivers at the base of the hills in which the suckers were scarcely 

 visible : whether they had outgrown them, or, owing to the suckers 

 not having been primarily well developed, they had been unable to 

 maintain their footing in the hill-streams, of course, one cannot 

 decide. Amblyceps is a Loach-like form found in the waters of the 

 plains and also of the hills ; it is abundant near Kangra. E.vo- 

 stoma, an example of which exists in the Yarkand-Mission collection, 

 is also a remarkable form. It has a broad and depressed head and 

 chest, the latter forming a species of sucker to enable it to sustain a 

 mountain-torrent life. 



This fish (Exostoma stolicz/.ce) belongs to a genus which has only 

 been recorded from hilly regions, neither extending to the waters of 

 the comparatively levels of the high lands, nor descending any dis- 

 tance towards the plains. The following six species are known : — . 

 1. E. stoliczkee, from the head-waters of the Indus; 2. E. blythii, 

 from near Darjeeling, where the waters descend to the Ganges ; 

 .']. E. lubiatum, from the Mishmi Mountains and Eastern Assam. 

 4. E. andersonii, from near Bharno on the confines of China ; 5. 

 E. davidi, from the must easterly portion of Tibet near the 

 head-waters of the Yang-se-kiang ; 6. E. berdmorei, from Tenas- 

 serim. 



The distribution of the foregoing six species of this genus is inter- 

 esting, because it is suggestive of whether at some remote period the 

 Himalayan range, the mountains between Tibet and China, and the 

 spur or continuation southwards through Burma and Siam, may not 

 have been connected one with another. 



Whilst adverting to this point, I would mention another circum- 

 stance : the only Siluroid stated to be lound in Turkestan is the 

 Silurus glanis, Linn. Three other species of the same genus have 



