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Show 1868.] DR. F. DAY ON INDIAN FRESHWATER FISHES. 277 enclosure, to cut off from the rest of the swamp that portion in which the circular patches had been cleared of sod the night before. This was done by breaking the sod in a narrow line encompassing the space which it was intended to enclose, and trampling a portion of it down to the more solid mud at the bottom. The long grass which is thus carried down makes a kind of fence, which is supposed to confine the fish, but which one can hardly suppose to be very efficacious, as they would have but little difficulty, if so inclined, in making their way through it. When this is done, the diluted mud in the holes that have been opened overnight is thickened by mixing it with some of the more solid mud, or peat, scooped up from beneath. Some of the long grass which grows on the surface is then laid over the thickened mud in two strata, the stalks of which the one is composed being at right angles with those composing the other. The whole is finished off with a coating of mud. Nothing then remains to be done but to watch for the appearance of the fish. The first indication of their presence is the rising of bubbles of air; and in each instance when these bubbles appeared, the natives who were standing by named correctly the species of fish by which they were emitted, being guided probably by their size and by their coming up singly or in larger numbers. After a bubble of air has appeared but a short time elapses before the head of a fish appears protruding above the surface of the mud. There is no difficulty in securing a fish when he shows himself in this way, as the blades of grass which have been arranged so as to cross each other beneath the surface of the mud form a net through which he cannot easily force his way back. I remained watching the process for about an hour, during which I saw eleven fish taken, and the natives told me that as the day advanced larger fish would be caught and in greater numbers. None of those I saw taken were large. They were of three species, Connia (Ophiocephalus kelaarti), Magoora, and Hoonga (Clarias taysmanii). It is obvious that this mode of catching the fish is entirely based upon the fact that they cannot breathe water, but are forced to ascend at stated intervals to the surface to breathe atmospheric air-a fact which I afterwards verified by drowning two or three specimens by inverting a net over them " In 1866, when engaged in carrying out my experimental introduction of fishes from the plains on to the Neilgherry Hills, my attention was drawn to certain peculiarities in the respiration of the Ophiocephalidae and some other genera; but it has only been recently that I have been enabled to make the following series of experiments, which, I trust, may, in conjunction with the preceding observations, assist in elucidating the question of the respiration of at least a few species. Iu the transportation of the Ophiocephalidse I found that if m u d were mixed with the water they did well, but if the water were pure they died. The solution of this is that the muddy water does not pass through their branchiae as they respire air direct, whilst the muddy state of the water decreased the amount of agitation they were subjected to in clear water. Experiment No. 1.-Three of the Ophiocephalus punctatus |