AMPHIBIOUS FISHES.

Lyttelton Times, Volume XCIX, Issue 11531, 18 March 1898, Page 2

AMPHIBIOUS FISHES.

[By C. F. Holder.] ' (Scientific American.) Recently, in collecting below the high tide mark on one of the Pacific coast islands, the writer found beneath almost every stone overturned a little fish, literally out of water and in no way inconvenienced by the lack of its native element. In the majority of instances the fished were clinging to a stone by a singular sucker formed by the anal fins. Their bad been left by the retreating water, but had apparently preferred the change! and were now for several hours breathing air directly instead of taking it from the water after the manner of fishes in general. This peculiar habit has been observed in the European blenny (Blennix ts pholis). In specimens kept in an aqua rium it was found that they became restless when the tide went out. The observer now placed a stone in the water, and the little fish at once crawled upon it and. rested there, after the manner of a frog, for over an hour, then returning to. it? native element. Such fishes are almost as truly amphibious as the frogs and other animals which appear to be. equally at home on land or in the water. The case of '-the blenny would seem to be remarkable, but there’ are a number of fishes which are not only able to breathe out of water, but HABITUALLY SEEK THE IB FOOD OH LAND. The most interesting examples are found among the Gobies of the tropics. The head in this fish is large, the eyes conspicuous and protruding, the pectoral fins powerful, resembling legs more than fins, and capable of lifting the fish and enabling it to jump along the sands or muddy shores of certain tropical islands. Two genera are known, Periophthalmus and Bolsophthalmus, both equally remarkable for their amphibious habits. They are particularly fond of a shelless mollusc known as’ Onchidium, which is often left stranded on the shore, to obtain which the fishes crawl out upon the muddy flats and hop along like frogs. They are so active that it is difficult to catch them. Colonel Nicolas Pike informed the writer that he secured his specimens by shooting them with a shot gun. This was at Mauritius, at Matuku Island. Prolessor Moseley, the naturalist of the Challenger expedition, found them in great numbers also at Ceylon. They were hopping about on the mud flats beneath the mangrove trees, and Professor Moseley states that when pursued they prepared to escape by taking to the land rather than to the water. At each jump they would clear a foot. He says: “ I have chased one at Trincomali Harbour, which skipped along before me until it reached a rock, whore it sat on a ledge out of the water iu the sun, and waited till I came up, when it skipped along to another rook.” The species at the Fijian Islands is P. Koelreuteri, and it is usually found sitting or resting upon the dry roots of the mangrove trees, PERFECTLY AT HOME OUT OP WATER. The first fish ever observed to leave the water, by a European naturalist, was the now famous climbing perch (Anabas). Daldorf in visiting India heard the story as told by natives, to the effect that these fishes left their native element and walked overland, using their fins as limbs, but did not believe it. One day a native came to’ his camp and offered to take him to a spot where the emigrating fishes could be seen. Following the man through the forest, they finally came to a pool or swamp that was rapidly drying up, and from the mud proceeded a line or procession of fishes, making their way up through the grass by the aid of their fins, presentinga remarkable spectacle. The fishes were _ emigrating overland; the water of their pool had dried up, and they .were deliberately marching away in search of a locality better suited to a water-loving community. Daldorf 'later saw these fishes climbing small palms, presumably in search of food, though regarding this there ismuchdbubt. In certain parts of India this migratory habit of fishes is so well known that the natives anticipate and repair to the localities with baskets and capture them by hundreds. Mr E. A. Legard states that on the Singalese River also this habit is so well known that all the inclosuros in which the Anabas are kept are provided with, covers,' TO PREVENT THE FISHES FROM CLIMBING OUT. A little fish (Oolius sopor at or), common on the coast of Texas, is almost equally remarkable. A naturalist, in collecting specimens, placed them in a pail, bub was astonished, upon returning, to find that the fishes had all crawled up the sides), and were slowly but surely making their way to the water, and were, apparently not inconvenienced by the .change of element. In Gambia the fish Protopfcerus has a similar habit. ' At the- first-suggestion- of the dry season it begins to-explore themud in the bottom of the stream in which it is living, and there forms a ..burrow in which it spends the weeks and months with not a drop of water until the rainy season begins again and it is released. The natives of Kottiar repair every year to the dry banks of the Vergel River and dig out certain fishes by hundreds as they would potatoes. They perform the work with, pick and shovel, the fish .-in its case being dropped heavily, -breaking open, displaying the animal eight or ten. inches in length, and often as lively as though taken directly - from the - water. It is evident that these fishes, which-can so 1 READILY CHANGE THEIR METHOD OF • LIFE, must in some way differ from their com* panions which find water an essentiaL An examination of the fishes shows that they have gills over which water- flows, and by which air is taken and made,to serve its peculiar purpose. In other ; words they have true gills, but in Periophthalmus and Boleophthalmus the gill cavity is much larger than in many fishes, and the gills do not fill it, leaving a spaco which. might be filled with air or water. In other fishes which habitually leave the water, ‘as Anabas already;;re,ferrßd to, the gill cavity reaches upward, the mucous meihbrane-’formjng a complicated foliated labyrinthine structure, 'so . that ■ the 'gills really present more of a surface than those of ordinary fishes, which: spend all. their time in the water. This labyrinthine structure long ago attracted the attention of naturalists, and it waasupposedto be a provision for the storage. of water when the fish was travelling overland; but investigation does not carry out this idea, and it has been shown that the cavities never contain water and are in no sense reservoirs. The theory held to-day is that the complicated organs are so adapted that they permit the animal to breathe either in the water or directly from the atmosphere. In other words, the labyrinthine organs are lungs, formed, according to Semper," by modifies-, tion of a portion of the water-breathing gill-cavity; the fishes that have them are, therefore, to be regarded as amphibious with quite as much reason as toads and frogs, or even better, since they are capable of changing the nature of their respiration —of air, that is, or of water—at willl and suddenly, without any interruption; nay, are actually accustomed so to change .it.”