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Show 276 DR. F. DAY ON INDIAN FRESHWATER FISHES. [May 14, the Callichthys asper, it is stated that in the marshes of the Savannahs 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. & 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 scandens) 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 intermediate 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 interesting 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 considerable 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 present 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 % Madras Journal of Literature and Science, vol. xv. 1818 p 144 |