THE NATURALIST.

Otago Witness, Issue 2928, 27 April 1910, Page 86

THE NATURALIST.

Beaver-trapping in Canada. Not many years ago it was considered that the beaver, as anything- more than an emblem, was almost as nearly extinct as the buffalo, and in order to preserve as far as possible the few which were left and to .perpetuate the species stringent game laws were enacted by the various provinces of the Dominion forbidding the hunting, shooting, trapping, wounding, or killing of any animal of the species for an almost indefinite period. It was thought that in this way, even if the useful animal should never again increase sufficiently t- "ome an asset of any intrinsic vah the Dominion, a sufficient number. - at least be preserved for park and i**.«u*&t history purposes. Perhaps there was no more interesting exhibit at the FrancoBritish Exhibition in London than the Dominion Government's beaver dam. The plan alluded to succeeded beyond the fondest imaginings of the game .guardians, for the beaver, left unmolested, has increased to such an extent throughout the various provinces as to become quite numerous. Indeed, complaints are being received by the various game guardians to the effect that the enterprising little engineer is doing damage to drains and lands in the vicinity of the dams. Owing to the general gratification felt, however, by the guardians, as well as by sportsmen and others, over the excellent results of the close 6eason, little attention has been paid to these complaints, as it was felt that the alleged damage done by damming the streams and thereby flooding the neighbouring - lands will be obviated when the projected drainage work has been completed. It is asserted that the complaints were largely originated by persons who desired the season opened for killing beaver so that "cy could make a profit from the furs. n Manitoba the close season for beaver is indefinite, and there is no intimation that a date will be fixed when they may be trapped or Killed in any way. There are many colonies of the animal in the province, on the Oohre River, in tlie Swan River district, in the neighbourhood of Lake Dauphin, and along the Souris River, beaver dams being ve'ry plentiful. In Saskatchewan, no one may trap or kill beaver in any manner until December 10, 1910, nor may anyone during that time destroy a beaver dam. In Albeirta the season is closed until December 31, 1912, while in British Columbia the beaver is immune from destruction until August 1, 1911. In Ontario, as ir Manitoba, an 'indefinite period haa been fixed for the protection of beaver, and the result of the closed season for the past few years is appreciably apparent. Whilst in most parts of Ontario the beaver is practically exterminated, in Algonquin Park they have multiplied very rapidly. As instancing the difficulties encountered through the dams being constructed by the animals, a member of the M'Laehla.n Mill Company, on making ono of his periodical inspections of the company's remaining timber, at a point where portaging was necessary, found that the beaver had dammed the river. He decided to cut i portion out of the dam in order to relieve the flood, and did so, placing a. net across the cutting. This he found on his next trip repa.ired, and the dam as before. He then placed two crosscut saws with the teeth pointing up the river at the gap, which also was ineffectual, and he then placed a revolving wheel across the aperture which he had reeut in order to prevent the rebuilding of the dam. On bis return the wheel was completely built in, and the laborious portage had to be repeated. In sheer desperation he played' his last card, and, knowing the timid nature of the beaver, he constructed a figure in. the shape of a man and placed it in the centre of the aperture, where it remained a grotesque object for several days. On his return, to his amazement he found only the head and shouldens of the figure remaining sticking up above the completed dam. After this be gave up endeavouring to clear the portage. In the eastern part of the province and in the Lake of the Woods district the species is also increasing very rapidly, and the prospective laws are justifying themselves. In fact, at thee present rate of increase the beaver will in a few years l be a valuable source of revenue to the entire Dominion.—E. J., in the Field.

" Flat" Fish.

(By th© Rev. Theodore Wood', F.E.S., iri the Church Monthly.) You vrill notice that in the heading to this paper the word "flat" has been placed! between inverted commas. That is because soles, and plaice, and dabs, and flounders, and the rest of these so-called "flat" fishes are not really flat fLibes at all. They are thin fishes, narrow fishes, or compressed fishes. For what everybody regards as the the back, of a sole is not its back but one of its sides. And what ever body regards as its lower .surfac;? is not its lower surface, but its other side! The fact of the matter .'.s this: When a sole, or a plaice, or a flounder is first hatched, it swims just as other fishes do—upright, with its back upwards, its lower surface downwards, and its sides on either side. A.nd both sides of its body are pearlv or silvery white. But when it is- abou'fj a month or five weeks old an irresistible desire com.es over it to li-ei down on one slide on the mud at the bottom of the sea," and to spend the rest of its life there. Then three very remarkable changes take place. _ In the first place, its colour alters. For it is obvious that if a fish with silvery or pearly white sides lies down on one side on dark brown mud it a±, once becomes a very conspicuous object, and would certainlv be seem and most likely be snapped up by the first hungry fish ,vhieh happened to pass by. But as soon as the fish assumes its recumbent (position th© colour of the upper surface.—whichever it may happen to be, for some of the.se fishes lie on "their right side and others on their left—begins to darken. And the chang© goes rapidly on, until before very long it exactly resembles the hue of the surrounding mud. If the fish happens to be a plaice, which lies on sand, instead of mud., then its upper surface becomes coloured like the sand. If it happens to be a flounder, which sometimes lies on the one and sometimes on the other, them its upmost surface becoraea ©ither light brown or dairk as the case may be. One would almost think thai the colouring was under the control of the fish, and the resemblance is so perfect that if you visit the Brighton Aquarium and look into one of the tanks containing these

so-called "flat" fishes, you cannot see the fishes for some little time. Their colours harmonise so perfectly with those of the substance on which they are resting that for all practical purposes they are invisible. That is the first change. The second change takes place in the manner of swimming. When these fishes are first hatched, they swin just as other fishes do, by means of their tails. For the fins of a fish are not used in swimming, but are merely balancers, which serve to keep the body upright in the water, while the motive force is provided by the tail, which acts after very much the same manner as the screw of a steamboat. As soon as they settle down upon the mud, however, thev abandon this 'method of swimming, and thenceforward ,vhen, they wish to travel from one place to another they wind their way through the water in an. undulating and peculiarly graceful manner, aided by the dorsal and ventral fins, which run along almost the entire length of the body- But they are not very fond of swimming- in this •way, probably because it renders them too conspicuous, and generally creep along over the surface of the mud. so slowly and cautiously that their movements are scarcely visible. But the strangest change of all takes place in the position of the eyes. It will readily be understood that if a fish with an eye on each side of its head lies down on one side in the mud, the lower eye becomes useless, so that.it would seem to be doomed to spend the rest of its life with only one. available eye'. This difficulty is overcome, however, by a most extraordinary provision of Nature. For as soon as the little fish lies down on the mud, the lower eye begins to work its way along the surface of the bead, and travels steadily on, until at last it settles down by the side of the other! This seems like the wildest romance; yet it is strictly and absolutely true. I have Bean a tiny sole', some six weeks old. which had been mounted as a microscopic object, and on inspecting it one could clearly trace the channel along which the eye had been slowly travelling. I possess a series of photographs, too, showing the whole journey of the eye, from the time when it first begins to move to that in which it finds a permanent resting place by the side of the) other. And if you examine the soles or the plaics in a fishmonger's shop you will notice at once that the two eyes, in every case, lie closely side by side above the same corner of the mouth, causing the whole head to appear grotesquely distorted. It is difficult to imagine anything much more remarkable than this. Not only has the eye itself to travel, often for some little distance, along the surface of the head, but the optic nerve in connection with it has to alter its position accordingly. It is very much as if a man's left eye were to journey across his forehead and settle down at last by the side of his right ear! -It would seem to be an impossibility; yet in every one of these so-called "flat" fishes it actually happens. There are more wonders by far in the world of Nature than most of us imagine. Truth is indeed stranger than fiction. And the greatest marvels of all, perhaps, are to be found in the waters of the' sea. Well does the Psalmist say, "They that go down to the sea in ships and whose business is in the great waters see His wonders in the deep."