/2 jXMl'IIU'Ol) CUrSI AlKA UK Tll|-. CKNl'S CA M M AKUS 



for Gamjmints is about 7.i-~.S ami, wlicu tlic \a1uc falls In-low ().3, llic water has a toxic 

 effect upon Gammarus. 



Ik'sides such a chemical relation in the area of the present iinestigation, all of the llow- 

 ing- water in the intermediate region has run ilowu from hi_i;h valleys at alliiiules at which 

 the species occurs. It seems therefore very improbable that such a peculiar distribution is to 

 be explained by chemical factors alone, though in some other parts of the world, as cptoted 

 above, calcium content of waters would play an important role in this respect. It must be 

 added that Gaiiiinanis was found in immense numbers in Lakes Panggong Tso and Khyagar 

 Tso in T-adak, both ha\'ing water of brackish nature. 



2. ]->i()lo^ic(il I'ticlors 



The types of habitat of G. piilr.v in the area of investigation vary very much, including 

 swampy pools covered with Lemna, large open-water lakes and streams with a rapid flow. 

 There niav therefore be no lack of food for Gainiininis. although I have at present no data 

 relating to this point. Pentland (op. cit.) is of the opini(jn that the food vegetation is one 

 of the important limiting factors upon the distribution of G"(7;/n;/((/-h.s-. If the source of lime 

 upon which Gamniants depends should be in some plants containing calcium compounds, such 

 as Chara or Lcmna, as suggested by Schumann (op. cit.), the ab.sence of sucli |)lants in the 

 intermediate region in Kashmir must be considered. 



Finally, there is a more important biological factor, namely natural enemies, especi- 

 ally fishes. On this point, Dr. Hutchinson wrote to me that "the presence or absence of fish 

 cannot be a complete explanation for the distributions, because Gaiiiiiianis may be taken in 

 streams and lakes where there are many iish, as in the stream between Tangtse and Mugleb, 

 and in Pangur Tso and Yaye Tso, and there is no very great difference between the fish fauna 

 of the upper and intermediate zones." However, in the brackish-watcr-lake Khyagar Tso, 

 Gamniants was found very abundantly, swimming in the open water, and in this locality its 

 abundance is probably correlated with the complete absence of fish. Such a case was also 

 observed in some Japanese lakes, where there was an abundance of gamniarids before the 

 introduction of trout, and Pentland (op. cit. ) also writes that the presence of trout appears to 

 control the distribution of Gaiiiiiiarus. li lish are in any way a limiting factor for Gammarus 

 in North Indian localities, it is probable that the presence of genus Schizothorax of the 

 family Cyprinidae rather than of fish in general is concerned. According to Dr. Hutchinson's 

 statement, he observed no locality in which Schizothorax occurs with Goiiunanis except 

 Wular Lake in Kashmir. 



Note by the Biologist of the Expedition 



Gammunis was found in several samples after the collection had been forwarded to 

 Dr. Ueno and examined by him. These sam])les are enumerated below: 



L i? Between Tangtse and Mugleb, stream, all. e. 417.^ ni. _'(> June, 1932. 

 L 38 Two to three miles west of Mugleb, alt. c. 4200 ni. 17 June, 1932. 

 L 47 Chagra, alt. 4636 m., warm spring, temp. 21.7 C. 8 July, 1932. 

 L 74 Pangur Tso, alt. 4329 m., margin at west end. 12 .\ugust, 1932. 

 L75 Chushol, spring, alt. c. 4330 m. 12 .\ugust, 1932. 



