Mr. Wallace remarks that the convergence of the hair towards the elbow on the arms of the Orang serves to throw off the rain when, as is the custom of this animal, the arms are bent, with the hands clasped round a branch, or over its own head. But the previously-mentioned naturalist aptly remarks that the attitude may not determine the direction of the hair; and that, on the contrary, the direction of the hair may determine the attitude. Of course the darkness of the negro makes any likeness, real or imaginary, with the Monkey, all the greater, and really the resemblance of the American Monkey--whose name (_Satanas_) indicates his ill looks with its jet-black skin, white rolling eyeballs, and hair parted at the top of its head, to a young negro, is laughable enough. Any one who visits the Zoological Gardens soon becomes aware that there is a great variety of expression in the eyes and muscles of the face of Monkeys, and infinitely greater in amount than in any other animals, and in some points infinitely less than in man. Mr. Darwin has collected facts, and given the result of his own observations upon the different methods of expression produced by the facial and other muscles, and the following is from his work on the “Expression of the Emotions”:-- “It is not possible to distinguish in Monkeys, at least, without more experience than I have had, the expression of pleasure or joy from that of affection. Young Chimpanzees make a kind of barking noise when pleased by the return of any one to whom they are attached. When this noise--which the keepers call a laugh--is uttered, the lips are protruded; but so they are under various other emotions. Nevertheless, I could perceive that when they were pleased, the form of the lips differed a little from that assumed when they were angered. If a young Chimpanzee be tickled, and the armpits are particularly sensitive to tickling--as in the case of our children--a more decided chuckling or laughing sound is uttered, though the laughter is sometimes noiseless. The corners of the mouth are then drawn backwards, and this sometimes causes the lower eyelids to be slightly wrinkled. But this wrinkling, which is so characteristic of our own laughter, is more plainly seen in some other Monkeys. The teeth in the upper jaw in the Chimpanzee are not exposed when they utter their laughing noise, in which respect they differ from us; but their eyes sparkle and grow brighter, as Mr. W. L. Martin, who has particularly attended to their expression, states.