136 



THE AIR BREATHING 



edly backwards and forwards between the space above and that 

 below the diaphragm. Two, however, were quite dead, a Loolla 

 and a Maddhacariya, both air-breathers. None of the water 

 breathers in this vessel had died. 



These experiments not being satisfactory, in consequence of the 

 imperfection of the apparatus, it was determined to repeat them, 

 with a more perfect diaphragm, and a quantity of fish better pro- 

 portioned to the volume of water in which they were confined. 



The diaphragm was extended about six inches below the surface 

 dividing the aquarium into two compartments, in the lower of 

 which were confined specimens of Maddhacariya, Hoonga, Magoora, 

 Connia, Loola, Kawaya, and Poolootta, all air-breathers, together 

 with six Ancoottas, water-breathers. In the upper compartment, 

 separated from those below only by a diaphragm of mosquito net, 

 were placed Maddhacariyas, Kawayas, Hoongas, Conniyas, and 

 Ankootas. In this compartment there were also aquatic weeds, 

 and a siphon was kept running for the greater part of the day, so 

 as to change the whole body of water frequently while the experi- 

 ment was going on. The diaphragm was fastened in its place 

 about i l j a. m., in presence of Mr. Layard. Very soon after the 

 fish in the lower compartment were cut off from communication 

 with the air, they began to emit bubbles of gas, and it was remark- 

 able, that, while the air bubbles which were carried down through 

 the mosquito net along with the fresh water from the siphon, made 

 their escape at once back to the surface, the bubbles of gas emitted 

 by the fish were detained by the net, shewing that the air had. 

 undergone a considerable change while detained in their systems. 



Notwithstanding the pains which were taken to secure the dia- 

 phragm, one of the Pooloottas, and one or two of the Conniyas 

 contrived to escape into the upper compartment; the remaining 

 Poolloota, after having been confined for about three hours, began 

 to manifest great uneasiness, and contrived by a desperate effort 

 to force himself through a hole in the net, which did not appear to 

 be large enough to allow a fish of one quarter of his size to escape. 

 The diaphragm was removed at p. m., in presence of Messrs. 



