XONKEY, fti Littman genus of mammalia, of the Linnxan order primates, and of Cuvier's order quadrumana, now constituting the family simiadce. The word monkey was formerly of almost, if not altogether, the same signification with ape ; but the name ape is now more generally applied to those simiadce which have no tail and no cheek pouches; the name monkey to those which have cheek-pouches and lone tails, prehensile or whilst the name baboon (q.v.) is applied to creatures considerably dif ferent from both. The smaller tailless simiadce are, however, still not infrequently spoken of as monkeys, and the term is also sometimes used to comprehend all the simiadce.
Of all animals, the simiadce exhibit the greatest resemblance to man, both in their general form and their anatomical structure. This is particularly the ease with some of the larger apes. In none of them, however, is there a natural adaptation for the erect position so characteristic of man, which is assumed rarely, and in general only by cap tive individuals, as the result of training and constraint, all of the monkey tribe prefer ring to walk on four feet rather than on two, but all of them being adapted for living chiefly among the branches of trees, or—according to the habits of a comparatively small number of species—among bushy cliffs, where they make use of the four extremities for prehension, as hands. Most of them leap from branch to branch with wonderful agility, and some also swing themselves from a branch by their long prehensile tail, till they can seize hold of another branch. The thumb, in all the four extremities, is opposable to the fingers, which are long and flexible; but there arc some monkeys which want the thumb of the fore-limbs, or have it merely rudimentary, whilst the hind-limbs are always fur nished with perfect hands. In attempting to walk erect, an ape necessarily treads, not on the soles, but on the sides of its feet, which are turned inwards, and the muscles of the legs do not enable it to maintain an erect position long or easily. This difficulty is increased by the way iu which the head is affixed to the vertebral column, the occipital foramen being further back than in man, so that the weight of the head is thrown for ward. The face of a monkey exhibits a grotesque resemblance to that of man; but the lower forehead, the less perfect nose, and the more projecting jaws, give it a brutal char acter. The dentition of monkeys is so similar to that of man, that the dental formula for very many is the sante, although many others have an additional molar on each side of each jaw; but in many, the great size of the canine teeth is a marked brutal charac teristic. The digestive. organs are generally very similar to those of man, but in some of the simiadce, more exclusively confined to vegetable food, there is a remarkable differ ence in a peculiar and very complicated structure of the stomach. The food of mon
keys consists chiefly of corrt;a4id '.other;vegetable.sphstances; but most of them Also catch and 'eat insects, and balk Of the eggs of which they are also very fond.
In captivity they learn to eat and drink almost everything that is used by man, and show a great fondness for sweet things, and for alcoholic liquors. The skin of monkeys is geuenilly covered in all parts with hair, but sonic have the face partially naked, and many have naked callosities on the buttocks. Many have capacious cheek-poaches, in which they stow away food which they cannot consume with sqlticieut expedition. They are mostly gregarious, although to this there are sonic exceptions. Many of the species display strong attachment to their mates and to their offspring. One or two young are generall:s produced at a birth. They display a remarkable propensity and talent for imitation; and this, with their extreme agility, their curious prying disposition, and their love-of trick or mischief, makes them very amusing, whether in it wild or a captive state. Many of the stories told of monkeys manifest also a high degree of inlet. ligence. although it may be doubted if the intelligence of auy of the species exceeds that 01 the dog or the elephant. Notwithstanding their resemblance to the human form, their imitative propensity, and their intelligence, none of the monkeys show the smallest capacity for imitating the human voice; and their "chattering" is very unlike articulate speech.
The species of this family are very numerous, but are all confined to the warm parts of the world; Australia, however, and the South Sea islands being destitute of them. They are divided into a number of genera, some of which belong exclusively to particu lar portions of the world. But in this respect, the most remarkable circumstance is the difference between those of the old world and those of America, the geographical dis tribution corresponding with the division of the family into two principal groups—the monkeys of the old world (Catarrhini of some naturalists), to which alone the name simiado is sometimes restricted, having the nostrils separated only by a narrow septum, and the tail wanting, short, or long, but never prehensile; the monkeys of the new world (Platy•aini), the family cebick of some naturalists, having the nostrils widely separated, the tail always long, and often prehensile, most of them having also the foul additional molar teeth already noticed, which none of the monkeys of the old world possess; but none of them having cheek-pouches, which many of the monkeys of the old world have. The most interesting genera and species of monkey are noticed in separate articles.