Any of certain anthropoid primate s of Africa and Asia (also called catarrhines), as distinguished from the New World monkey s (platyrrhines).
Catarrhines are generally distinguished from platyrrhines in having a narrow nose, narrow septum, close-set nostrils directed forward or down, bony ear passages, two premolars in each half of each jaw, a nonprehensile tail (if any), and hard patches of bare skin (ischial callosities) on the buttocks. The terms Old World monkey and catarrhine usually apply only to members of the families Cercopithecidae (monkeys with cheek pouches: guenons, baboon s, and others) and Colobidae (leaf monkeys) but may also include the families Hylobatidae ( gibbon s), Pongidae ( ape s), and Hominidae (human beings). See also colobus monkey ; proboscis monkey ; vervet monkey .