1907.] 



Records of the Indian Museum. 



37 



23 'lb. This second pond had a fauna almost identical with that 

 of the first except in the absence of the Hydrozoon ; but its flora 

 was entirel}^ cryptogamic. 



I am indebted to Capt. J. A. Black, I. M.S., Chemical Examiner 

 to the Government of India, for a more detailed analj^sis of a sample 

 from the second pond taken on Januar}^ 6th. It is as follows : — 



13 "8 parts per thousand. 



Total 



17 '5 



Stoliczka's analysis was, in detail, as follows :- 



" Chloride of Sodium (including Potassium) 

 ,, ,, Calcium . . 



,, ,, Magnesium 

 Sulphate of Magnesium . . . . 



Carbonic acid, etc. 



9-81 

 0*46 



0-93 

 I-I7 

 0-50 " ; 

 the soluble substances being also calculated in parts per 1,000. 



Stoliczka noted that the water in the ponds was almost fresh 

 during the rains, and in the tank from which my first sample 

 was taken the water-level had sunk only a short distance below 

 the top of the bank, the dry weather having been of no more 

 than a few weeks' duration. All that can be said, therefore, as re- 

 gards the salinity of the water in the ponds, is that it varies con- 

 siderably at different times of the year. The range in variation 

 which the members of the fauna are able to survive, is perhaps more 

 remarkable than what may be regarded in different instances either 

 as the deficiency or the excess of salt in the medium in which they 

 live, 



THE FAUNA OF THE PONDS. 



I do not propose at present to attempt more than a general 

 description of the fauna of these ponds, with notes on some parti- 

 cularly striking species. Specimens of several important groups 

 are now in the hands of specialists in Europe, whose determinations 

 will make a more detailed discussion of greater value after their re- 

 searches are complete. 



Pyotozoa. — The most conspicuous representatives of the Pro- 

 tozoa found in the ponds are Carchesium polypinuni and Folliculina 

 ampulla. The latter of these is commonl}' found in salt water but 

 also occurs in fresh, while the Carchesmin is commonl}^ an inhabitant 

 of fresh water. In the ponds, F. ampulla occurs most frequently 

 in close association with the Hydroid stage of Irene ceylonensis. 

 Indeed, so frequently is this the case that I was able in almost 

 all instances to detect the presence of the Hydroid^ itself almost 



