THE MAMMALS (Mammalia)
Mammals constitute the highest class of animal creation, and include Man. They have a hard, bony skeleton and a vertebral column or backbone; warm red blood flows in their veins; they breathe by means of lungs, and suckle their young, which they bring forth alive. Their bodies are generally covered with hair. More than three thousand species of mammals are known.
THE MONKEY TRIBE (Quadrumana)
Monkeys are animals whose four feet are hand-like, and hence their scientific name, Quadrumana, which means four-handed. They are distinguished from the other animals by their docility, and, more especially, by their power of imitation. It is evident at the first glance that they are nearer related to man than any other animal.
The monkeys have long, loosely hanging arms, with elongated, claw-like fingers; their feet resemble hands. They swing themselves with ease from branch to branch and from tree to tree; they are good climbers, and bring down fruit from the topmost branches. But notwithstanding the aptitude of their hands for climbing, the latter cannot equal the dexterity of the human hand, which is justly described as the tool of all tools.
Monkeys differ outwardly from man in many respects: their foreheads are low, and almost disappear under the overhanging hair; their ears are directed upwards; their nose is exceedingly flat and scarcely projects; their teeth resemble those of the animals of prey; their chin is receding; their entire skin is hairy, except in a few places; and their movements are, in most instances, only possible with the assistance of their long arms.
The intellectual qualities of monkeys are not of very high order. In this attribute, they are surpassed by the dog, the horse, and the elephant. There is especially no trace of those qualities of fidelity and gratitude which we so highly value in the animals last mentioned.
All of the American monkeys are true monkeys, but in the old world there is no line between ape, baboon, gibbon, macaque and monkey. Most of the American species (the marmosets excepted) have one more molar tooth on each side of each jaw than does man, but the forms of the eastern continent are like man in that respect, as they are in having nails rather than claws on at least some of the fingers and toes. Many of the new world species have prehensile tails, but this never occurs in the others, the tail exhibiting a tendency to be reduced, at last disappearing in the man-like apes.
The American apes have the nostrils widely separated and opening sidewise, while in the others they open in front and downward as in man.