I have already said that the tail of nearly all the American Cebidæ is long and prehensile; that is, endowed with a peculiar faculty of winding or clinging round any object. [Illustration: ATELES CROSSING A RIVER.] In the genus _Ateles_, or "Spider Monkey," for example, it virtually forms a fifth limb, by whose agency the animal suspends himself in the air, and darts from one tree to another with more than the agility of a Leotard. It amply compensates for the imperfection with which Nature has afflicted him by leaving his fore-paws deprived of thumbs. He owes his popular designation of the Spider Monkey to his long slender limbs and sprawling gestures. In the colour of his skin, his methodical slowness, and the suppleness of his movements, he resembles the gibbons. Of all animals he alone has the biceps of the thigh resembling that of man. He is fond of the society of his kind, and mainly subsists on insects, small fish, and molluscs, which he catches with all the address of a practised angler. Travellers affirm that he frequently crosses the wide American rivers without descending to the ground. He and his comrades form a living chain, which hangs suspended from a lofty branch, and, by a series of more or less nimble movements, succeeds in _hooking itself on_ to a tree on the other side. This chain serves at first as a flying bridge for the whole troop; then it accomplishes its own passage, by detaching itself from its point of suspension to fall back on the opposite bank. The tale, however, has an improbable air about it, which makes a large demand on the reader's belief. It is from South America, and notably from Brazil and Guiana, that we import into Europe the apes most valued by our itinerant mountebanks and by zoological amateurs, on account of their gentleness, their domesticity, their intelligence, and their singular instinct of imitation--almost amounting to genius--which renders them wonderfully apt in the performance of all kinds of tricks and amusing exercises. Nearly all these apes belong to the very numerous genus of _Sajous_, or _Sapajous_. Thus we have the Squirrel Monkey (_Callithrix sciurus_), not much larger than the animal whose name he bears, and infinitely more nimble and diverting. He is of a bright golden yellow colour, with feet and hands of a deeper yellow. His head is round, with a blackish nose, and hairy ears. His tail is very long, and tipped with black. The nails of his hands are flat, while those of his feet resemble claws. The Ouistitis, which are frequently imported into Europe, are very pretty animals, clad in a soft kind of fur, and with their ears ornamented by long brush-like tufts of black or white hairs. They are very easily tamed, are mild and intelligent, and, owing to their small size, conveniently kept in apartments; but they do not acclimatize in Europe, and, even if they survive the voyage, die very shortly after their arrival.