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On the air breathing Fish of Ceylon— By The Revd. 

 Principal Boake. 



Having been recently induced to make some experiments on the 

 respiration of certain species of fish, in order to ascertain the cor- 

 rectness of a statement of mine which had been communicated to 

 Professor Huxley by Sir Emerson Tennent, I am under the im- 

 pression that an account of those experiments with a description of 

 the habits of the fish in question, will come within the scope of the 

 Asiatic Society's operations, and may perhaps be deemed by the 

 Committee to possess sufficient interest to entitle a paper on the 

 subject to admission into its Journal. 



During my residence in England in 1855 — 1856, I became ac- 

 quainted with the facilities which recent discoveries, or, to speak 

 more accurately, the ingenious application of old discoveries to the 

 construction and management of aquaria had afforded to those 

 who wished to observe the habits and natural history of the various 

 tribes of aquatic animals. Knowing that very little attention had 

 been paid to that branch of natural history in Ceylon, I lost no 

 time, on my return to the Island, in establishing a fresh water 

 aquarium; and, in watching the proceedings of its inhabitants, my 

 attention was very soon attracted to a peculiar habit which some 

 of them had, of ascending at nearly regular intervals to the surface, 

 so as to bring the mouth for an instant in contact with the air. 

 That habit is particularly conspicuous in the fry of two species, 

 viz., the Loolla and the Maddecariya, which speedily cover the 

 surface of the water in which they are confined, with small bubbles 

 of air or gas. I noticed also that the species of fish, to which that 

 habit belonged, were much less sensitive to any impurity in the 

 water in which they were confined than were those which did not 

 pay periodic visits to the surface. Had I been a practised natura- 



