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Show 1874.] RESPIRATION OF FRESHWATER FISHES. 315 about to hiss), and took in air, the branchial sacs behind the commissure of the lips becoming inflated *. The fish was, on the ninth day, removed from the water and placed in a basket with some moistened grass. It lived there for five days without water. Unlike other fish kept for experimental purposes, it refused food of any description during the whole time it remained alive. Exp. 5.-A specimen of Lepidocephalicthys balgara was placed in the glass jar, which was half filled with fresh water. No diaphragm was used. The fish was observed to pass to the surface of the water rapidly, and apparently blow off from the mouth some air-bubbles. It immediately retreated to the bottom, and there the action of the gill-covers was exceedingly rapid, so rapid as to be impossible to count, perhaps 200 in a minute. It was seen but on two occasions to go to the surface during the whole day; but from the presence of bubbles on the surface it was suspected that it went on many other occasions when not observed. The glass jar with the fish in it was taken for the night into my bedroom. About one o'clock I was awakened by some noise, and heard a sound between a grunt and a squeal. I thought a Rat had got into the room (a not uncommon occurrence in the East), and lit a candle to see where the intruder was. On going to that part of the room whence the sound proceeded, I was surprised to find that my little fish was the cause of all the disturbance. He had leaped out of the glass jar (the edge of which was 3 inches above the surface of the water), and had fallen to the ground, a distance of 4 feet. I found him wriggling about in the dust, occasionally uttering a squeal. On taking the fish into m y hand he again made the same noise, which is very peculiar. On the following evening the same fish remained in the glass jar without water from 8 P.M. to 10.30 P.M., and on being again placed in water appeared to have sustained no injury. When placed in shallow water it remained suspended in the water, its head just beneath the surface, respiring very rapidly. It supported itself in this position by resting on its tail and lying against the side of the vessel, precisely as Amphipnous cuchia in Exp. 4. On the approach of any object close to the side of the vessel, the fish always turned its head towards the object, and the gill-covers ceased to move, the animal regarding the intruder intently for some time ; then, when satisfied that no immediate harm was to be feared, the action of respiration was resumed, the gill-covers moving as rapidly as before. Two days after its attempt to escape at night the same fish (which appeared quite as lively as when first obtained) was placed in the same glass jar. A double net was stretched about half an inch beneath the surface of the water. Fifteen minutes afterwards the fish suddenly rose and attempted to reach the surface, then sank * The branchial sacs in the inflated condition appear to act also as floats, retaining the head of the animal near the surface of the water in a convenient position for capturing its prev. 21* |