Voyaging along the margin of a lake, we may see on the shores numbers of little flattened oval nests composed of reeds and sedges, while numerous holes in the bank, with quantities of shells, chiefly of the fresh-water mussel, scattered round, show the entrance to the habitations of the musquash, or ondatra, called also the musk-rat. As evening approaches, the creatures may be seen in fine balmy weather gambolling on the surface, swimming rapidly here and there, or now and then diving below, apparently fearless of the passing canoe. The little sedge-built hut of the water-rat is constructed much in the same way as the beaver's larger mansion. The creature itself looks somewhat like the beaver, and some of its habits are also similar. It is rather more than two feet in total length, of which measurement about ten inches is occupied by the tail. The upper part of the body is of a dark brown colour, tinged in parts with a reddish hue, while the lower part is ashy grey. Its tail is flattened, but vertical. Like the beaver, it is furnished with an undercoat of soft downy fur. Its safety has been provided for by its peculiar colour, which is so like that of the muddy bank on which it dwells, that a keen eye can alone detect it. Its hinder feet are webbed, the imprint on the soft mud being very similar to that of a duck. With the exception of the flesh of the water-mussel, its food is vegetable. It is a great depredator in gardens, which it has been known to plunder of carrots, turnips, and maize--the stalks of which it cuts close down to the ground. It is sought-for on account of its fur, which is very valuable. The traps are set close to a tree, and when one of the creatures is caught, its companions will instantly attack it and tear it to pieces. Generally, however, in its struggles to get free, it carries the trap under the surface, and is thus drowned. Audubon, the naturalist, gives us an interesting description of them:--"They are very lively, playful animals, when in their proper element--the water--and on a calm night, in a sequestered pool, may often be seen crossing and recrossing in every direction, leaving long ripples in the water behind them, while others stand for a few moments on tufts of grass, stones, or logs, and then plunge over, one after the other, into the water. At the same time others are feeding on the grassy bank, dragging off the roots of various kinds of plants, or digging underneath the edge. These animals seem to form a little community of social playful creatures, who only require to be unmolested in order to be happy." It has been proposed to acclimatise these little rodents in England, under the idea that thus a valuable addition to the bank fauna of sluggish English streams would be obtained. PRAIRIE-DOGS.