276 DR. F. DAY ON INDIAN FRESHWATER FISHES. [May 14, 



the Callichthys asper, it is stated that in the marshes of the Savan- 

 nahs it dives into the swampy ground and is captured by making 

 holes in the grass and digging in the mud beneath *, evidently 

 from the Indian fishermen being aware of the fact of the fish rising 

 to obtain air. Sir R. Schomburgk, in his ' Fishes of Guiana,' states 

 that the Callichthys littoralis (C subulatus, Cuv. Sc Val.) can exist 

 in muddy lakes without any water whatever, and is sometimes dug 

 up from such situations. 



Mr. Boake, in an interesting paper f, makes some remarks on his 

 experiments with reference to the respiration of fishes. Having 

 divided his specimens into what he terms air-breathers and water- 

 breathers, he made a diaphragm of net which he placed horizontally 

 across the centre of an aquarium full of water so that the fish could 

 not rise to the surface to obtain air. He found that the water- 

 breathers were unaffected by this circumstance, while the air- 

 breathers all died in a shorter or longer time. 



Dr. Jerdon, who kept some of the Climbing Perch (Anabas scan- 

 dens) in an aquarium, observes that they were in general very sluggish, 

 but every now and then rose slowly near the surface of the water, 

 then made a dash to the top, and down to the bottom again with all 

 speed J. This was unquestionably done to obtain atmospheric air. 



Mr. Boake gives the following account of capturing fishes in 

 Ceylon, where he found men and cattle moving about in the rank 

 grass growing on the surface, and fishes inhabiting a watery, muddy, 

 intermediate locality between the surface and the earth, the inter- 

 mediate fluid, or diluted mud, being as thick as pea-soup. The fishes 

 were detected in this fluid by the emission of bubbles of air when 

 they rose to the surface to breathe. But the description is so inter- 

 esting that I trust it may not be deemed too long to give in full. 



" When the swamp is in a proper state for such operations, viz. 

 when the water is neither too high nor too low, and the surface is 

 covered, as I have described, with a firm sod with two or three feet 

 of diluted mud beneath it, a native goes out at night when the air is 

 still, and, walking through the swamp, listens for the peculiar sounds 

 which the fish make in breathing. Having selected a part in which 

 these sounds are heard so frequently as to afford a prospect ot 

 catching a considei'able number, he proceeds to remove the sod from 

 a few circular patches, each about three feet in diameter, in those 

 places in which there already exist small holes in the sod, which the 

 fish frequent for the purpose of breathing. When that is done he 

 returns home for the night. I did not think it necessary to be pre- 

 sent at the nocturnal part of the operations, but I accompanied the 

 fishermen the following morning to the spot which he had prepared 

 during the previous night, and I found it a most laborious effort to 

 make my way over the treacherous surface, although the natives 

 appeared to traverse it without any difficulty. When we reached 

 the fishing-ground, operations were commenced by making a kind of 



* Cuv. & Val. ' Hist. Nat. des Poissons,' vol. xv. p. 311. 



t Journal of the Ceylon Branch of the Asiatic Society, 1865. 



J lladras Journal of Litci-ature and Science, vol. xv. 1818, p. 144. 



