This industrious animal is generally found in Canada and the northern portions of the United States, where it makes its home on the banks of the rivers and lakes. Here they assemble in hundreds to assist each other in the construction of their dams, and in the building of their houses, which are put together with a considerable amount of engineering skill. The materials used in building the dams are wood, stones, and mud, which they collect themselves for that purpose, and after finishing the dam, or winter storehouse, they collect their stores for the winter's use, and then make a connection with their houses in the banks. Their skins are valuable in making fine hats, and their flesh is much relished by the hunters. The beaver is an interesting animal in many respects, and the expression "busy as a beaver" is borne out by its habits. [Illustration] [Illustration: THE TURTLE-DOVE.] [Illustration: THE CUCKOO.] [Illustration: THE PEACOCK.] [Illustration: THE TAME, OR MUTE SWAN.] [Illustration: THE LIONESS AND CUBS.] [Illustration: THE LEOPARD.] [Illustration: THE SYRIAN BEAR.] [Illustration: THE JACKAL.] LIONESS AND CUBS. The lioness is much smaller than the lion, and her form is more slender and graceful. She is devoid of the mane of her lord and master, and has four or five cubs at a birth, which are all born blind. The young lions are at first obscurely striped and spotted. They mew like cats, and are as playful as kittens. As they get older, the uniform color is gradually assumed. The mane appears in the males at the end of ten or twelve months, and at the age of eighteen months it is very considerably developed, and they begin to roar. Both in nature and in a state of captivity the lioness is very savage as soon as she becomes a mother, and the lion himself is then most to be dreaded, as he will then brave almost any risk for the sake of his lioness and family. [Illustration] A PET JACK. The first fish I ever saw in an aquarium, twenty years ago, was a "Jack," as he is called when young, or a "Pike," when he grows older; and ever since then I have contrived to have a pet one, and this, drawn from life by Mr. Harrison Weir, is an accurate portrait of the one I now possess in the Crystal Palace Aquarium. There he is, just as he steals round the corner of a bit of rock. He is glaring at a minnow, at which he is taking most accurate aim; he hardly seems to move, but yet he does by a very trifling motion of the edge of his back fin--sometimes resting a little on the tips of his two foremost fins, as they touch the ground, carefully calculating his distance; and then, at the very moment when the minnow has got into a position which leaves a space of clear water in front, so that Mr. Jack shall not hurt his nose against any hard substance when he gets carried on by the violence of his rush, he darts at the minnow with the speed of Shakspeare's Puck:--