XXXI. REPORT ON A COLLECTION OF 

 AQUATIC ANIMALS MADE IN TIBET BY 

 CAPTAIN F. H. STEWART, I. M.S., DURING 

 THE YEAR 1907. 



Part I. — Introduction, Ccelenterates, Nematomorpha , 



Rotifers and Gastrotricha, Entomostraca, 



Arachnids, Fish {Systematic) and 



Batrachia. 



INTRODUCTION. 

 By F. H. Stewart, M.A., D.Sc, M.B., Capt., IMS. 



The collection which forms the subject of the following report, 

 was made in the district between the Tang-la and the town of 

 Gyantse in Tibet during the year 1907. The Tang-la is the pass 

 which leads from the Chumbi Valley into Tibet proper, crossing the 

 watershed of the main chain of the Himalayas at a height of 15,000 

 feet above sea-level. To the north of it the streams run into the 

 Tsang-po, to the south into the Brahmaputra and the Ganges. 

 Gyantse lies about one hundred miles by road north of the Tang-la 

 at an altitude of 13,100 feet. Collections made in this region thus 

 obviously have a double interest, firstly from the geographical 

 position, and secondly from the altitude of their source. 



No general collections of the aquatic invertebrate fauna of this 

 part 1 of Tibet have been made previously, but fishes and amphi- 

 bians were collected during the Tibet Expedition of 1904 in this 

 district, while those from the upper reaches of the Sutlej and Indus 

 may also be counted as Tibetan. 



In crossing the Tang-la the character of the country is seen to 

 change entirely. We are leaving the well-watered sphere of the 

 monsoon for a region of dry arid hills which, during the greater part 

 of the year, are entirely bare of vegetation. The rainfall changes 

 from the steady six months' downpour of Sikkim to a scanty fall 

 for one month only about August. Snow also falls in ver}^ small 

 quantities except in the immediate neighbourhood of the passes. 

 During the winter of 1906-07 it only lay in the Gyantse valley for 

 one day, and on the hihs around for short periods which, if added 

 together, would not total more than one month. Thus during the 

 greater part of the year the lakes and rivers are fed only from 

 springs, which arise here and there on the hillsides. 



1 Specimens of the Phyllopods Branchinecta orientalis and Estheria davidi 

 were collected in Gyantse by Capt. Uoyd, I.M.S.> and noticed by Gurney in 

 Journ. Asiat. Soc. Bengal, ii (N.S.), 1906. 



