At first sight they resemble the Colobi, inasmuch as they have long bodies, long hind legs, and long tails, but the fore limbs are short in the Guenons, and the tail, which is as long or longer than the body, is stout and not slender. Moreover, they have well-made and exceedingly useful cheek-pouches, besides the callosities behind. The face of the Guenons is long, and rounded, and the eyes are somewhat prominent. On examining the inside of one of these particularly African species the stomach is found to be single, and not to resemble that of the genera last described, and on looking at the lower jaw it will be found that the last crushing teeth on each side have only four points, or cusps, and not five, as in Semnopitheci. The wearing of the first premolar tooth next to the lower dog tooth, and behind it, resembles somewhat that noticed before, and which will be described in treating of the Inui, or Macaques, in the next chapter. The hands and feet are well grown, and the thumbs are long and useful. So that the distinctive peculiarity, or what is called the _diagnosis_ of the group, or genus Cercopithecus is--Monkeys with long hind and short fore limbs, and with long tails, cheek-pouches, single stomachs, and callosities, there being only four cusps on the last lower molar teeth. [Illustration: DIANA MONKEY.] Many of the Guenons are often seen in menageries and zoological gardens, or as the more or less unwilling companions of organ-grinders; and their trick of crowding everything into their mouth, and allowing it to distend the cheeks, is sure to be noticed. The quantity of nuts which can be stored away is enough for a good meal; and hence these Monkeys are not only good purveyors for themselves, but great robbers of the riches of cultivators. In the wild state they assemble in troops in the forest, for they are essentially tree dwellers, and make raids on all sides of their favourite home, moving with such rapidity under the shadow of leaves and boughs that they are rarely seen by men. In their own little tract of forest they are very noisy and restless; they chase away in a body all intruding Monkeys, and whilst the more aged spend their time in more or less restless movement, in occasional family jars, and in picking the insects from their young and from each other, the juvenile part of the troop are full of play, mischief, and wanton aggression upon the quietude of their elders. A Snake may appear, and there is a terrible noise made, and a general rush off out of danger, the little ones clinging to the fur of the mother, and being carried off safely in spite of her bounds and jumps from tree to tree. Or a Leopard may make a spring, and not always fruitlessly, and great is the surrounding howling and grimacing at it. The hatred of Snakes is carried into their captivity; and Mr. Darwin having read Brehm’s account of the instinctive fear which his Monkeys had of Serpents, and