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 monkeys of the New World, which have a thicker partition and have a broader nose. (Figs. 403, 404.) The monkeys of America all have six molar teeth in each half jaw (Fig. 352); the monkeys and apes of the Old World have thirty-two teeth which agree both in number and arrangement with those of man.

Which of the primates figured in this book appear to have the arm longer than the leg? Which have the eyes directed forward instead of sideways, as with cats or dogs?

Nearly all the primates are forest dwellers, and inhabit warm countries, where the boughs of trees are never covered with ice or snow. Their ability in climbing serves greatly to protect them from beasts of prey. Many apes and monkeys are able to assume the upright position in walking, but they touch the ground with their knuckles every few steps to aid in preserving the balance.

The Simians are the highest family of primates below man, and include the gorilla, chimpanzee, orang, and gibbon. Some of the simians weave together branches in the treetops to form a rude nest, and all are very affectionate and devoted to their young. How are apes most readily distinguished from monkeys? (Figs. 401, 406.)

The study of man as related to his environment will be taken up in detail in the part called Human Biology. We will there examine the effect upon man's body of the rapid changes since emerging from savagery that he has made in food eaten, air breathed, clothing, and habits of life.