Report on fishes, part ii : sisoridae and cyprinidae 353 



Spitok, Upper Indus : Ladak (Sta. L 17) ; ca. 10,730 ft 2 (300 mm. ; 1 10 mm.) 



A large rapid stream between Tangtse and Mugleb: Ladak (Sta. L37) ; ca. 13,700 ft 6 



Stream above Lukong; Ladak (Sta. L 54a) ; ca. 14,164 ft 3 (50-72 mm.) 



Stream into Pangur Tso; Ladak (Sta. L 74) ; ca. 14,203 ft 1 (77 mm.) 



Yalapuk, Upper Indus near Nyoma ; Ladak (Sta. L 79) ; ca. 13,521 ft 2 



It is apparent from the a!jove detailed distribution that only the young and small adult 

 specimens were obtained by the Expedition from the shallow streams and pools in the vicinity 

 of Pang-gong and Pangur lakes, while the larger individuals were taken from the Indus 

 river itself. This suggests that either the species breeds in the shallower waters of the 

 streams and pools that are associated with the lakes and the river, or the young forms 

 migrate to the former habitat for the opportunity of having better food supply and other 

 more favoural>le conditions of life that naturally prevail there. The former view finds 

 support in the fact that the Yale North India Expedition collected mature eggs of 5". stoHczkae 

 from the streams between Tangtse and Mugleb." The eggs are comparatively large, their 

 average diameter being 2 mm. Further, the Second Yarkand Mission also obtained "fry 

 and small fish from Lukong and Chagra" (Day). 



Breeding: Steivart {op. cit.) has observed that the "breeding season (of S. stoUczkae) 

 in tiie neighbourhood of Gyantse appears to occur about June. In the less favoured waters 

 near watershed it is probably later." The mature eggs of the species referred to above 

 were collected by the Expedition on the 27th June, and indicate that the breeding of the 

 species in Western Tibet probably occurs at almost the same time as in Eastern Tibet. 



Bionomics: The peritoneum is black. The air-bladder of ^. stolicckae, as is character- 

 istic of the cyprinoid fishes, is free in the abdominal cavity, extensive, and bipartite ; the 

 posterior chamber is longer and somewhat narrower than the anterior one which is short and 

 rounded and marked off from the former by a deep constriction. A well developed pneu- 

 matic duct opens at the junction of the two chaml^rs (Text-figure 17). It is interesting 

 to niite that unlike the cyprinoid fishes of the typical calm waters, such as lakes, ponds, etc., 

 both the chambers of the air-bladder of S. stolicckoe are very thick-walled. This type of 

 air-bladder is to be expected in this species in so far as "its characteristic habitat is in the 

 streams and small rivers of the (jpen, tree-less, flat, grassy uplands at an elevation of 

 11-16,000 feet; broad valleys in the centre of which a river runs witli moderate rapidity, 

 while on either side are marshy pools fed by springs, shallow ponds or irrigated land." 

 (Stewart, op. cit. ). i\ stolicchac, owing to its being a denizen of rapid waters and in con- 

 sequence of ground habitat, does not use the air-bladder as a hydrostatic organ, and its wails, 

 therefore, become more and more thick. 



The alimentary canal is much convoluted; in young and half-grown specimens its 

 length is a little less than twice the length of the body including the caudal fin, while in adult 

 individuals it is just a little more than twice. The stoiuach contents of some of the young 

 specimens obtained by the Vale North India Expedition show that, in young and immature 

 individuals at any rate, S. stulic::kcie, like the young of most of its allies, feeds on nymphs 

 and lar\ae of insects, such as I'lecoptera, Diptera, etc. The examination of the gut con- 



" The piipulaticiii in tlie Chagra stream is isolated, ami it is clear that its largest members never reach the 

 size of the largest specimens from the Indus. An operculuiii froiu the shore of Tso-Nyak suggests this species, 

 and indicates a very large fish. — G. E. H. 



