Relatives of the monkeys, and yet in many respects very different from them, are those very strange animals, the lemurs, which are sometimes called half-apes. The reason why that name has been given to them is this: Lemurs by the ancients were supposed to be ghosts which wandered about by night. Now most of the lemurs are never seen abroad by day. Their eyes cannot bear the bright sunlight; so all day long they sleep in hollow trees. But when it is quite dark they come out, prowling about the branches so silently and so stealthily that they really seem more like specters than living animals. When you see them close, they do not look very much like monkeys. Their faces are much more like those of foxes, and they have enormous staring eyes without any expression. The true lemurs are only found in Madagascar, where they are so numerous that two or three at least may be found in every little copse throughout the island. More than thirty different kinds are known, of which, however, we cannot mention more than two. The first of these is the ring-tailed lemur, which may be recognized at once by the fact that its tail is marked just like that of the marmoset. The head and body are shaped like those of a very small fox, and the color of the fur is ashy gray, rather darker on the back, and rather lighter underneath. It lives in troops in Central Madagascar, and every morning and every night each troop joins in a little concert, just like the gibbons and the howlers. But, oddly enough, this lemur is seldom seen in the trees. It lives on the ground, in rough and rocky places, and its hands and feet are made in such a way, as to enable it to cling firmly to the wet and slippery boulders. In fact, they are not at all unlike the feet of a house-fly. The body is clothed with long fur, and when a mother lemur carries her little one about on her back it burrows down so deep into her thick coat that one can scarcely see it at all. The ruffed lemur is the largest of these curious animals, being about as big as a good-sized cat. The oddest thing about it is that it varies so very much in color. Sometimes it is white all over, sometimes it is partly white and partly black, and sometimes it is reddish brown. Generally, however, the shoulders and front legs, the middle of the back, and the tail are black, or very dark brown, while the rest of the body is white. And there is a great thick ruff of white hairs all round the face. The eyes of this lemur are very singular. You know, of course, how the pupil of a cat's eye becomes narrower and narrower in a strong light, until at last it looks merely like an upright slit in the eyeball. Well, that of the lemur is made in very much the same way, except that the pupil closes up from above and below instead of from the sides, so that the slit runs across the eyeball, and not up and down.