Closely allied to these are the small group of night monkeys, which have large eyes, and a round face surrounded by a kind of ruff of whitish fur, so as to give it an owl like appearance, whence they are sometimes called owl-faced monkeys. They are covered with soft gray fur, like that of a rabbit, and sleep all day long concealed in hollow trees. The face is also marked with white patches and stripes, giving it a rather carnivorous or cat like aspect, which, perhaps, serves as a protection, by causing the defenseless creature to be taken for an arboreal tiger cat or some such beast of prey. This finishes the series of such of the American monkeys as have a larger number of teeth than those of the Old World. But there is another group, the Marmosets, which have the same number of teeth as Eastern monkeys, but differently distributed in the jaws, a premolar being substituted for a molar tooth. In other particulars they resemble the rest of the American monkeys. They are very small and delicate creatures some having the body only seven inches long. The thumb of the hands is[1] not opposable, and instead of nails they have sharp compressed claws. These diminutive monkeys have long, non-prehensile tails, and they have a silky fur often of varied and beautiful colors. Some are striped with gray and white, or are of rich brown or golden brown tints, varied by having the head or shoulders white or black, while in many there are crests, frills, manes, or long ear tufts, adding greatly to their variety and beauty. These little animals are timid and restless; their motions are more like those of a squirrel than a monkey. Their sharp claws enable them to run quickly along the branches, but they seldom leap from bough to bough like the larger monkeys. They live on fruits and insects, but are much afraid of wasps, which they are said to recognize even in a picture. [Transcribers note 1: Changed from '... it not opposable', ...] This completes our sketch of the American monkeys, and we see that, although they possess no such remarkable forms as the gorilla or the baboons, yet they exhibit a wonderful diversity of external characters, considering that all seem equally adapted to a purely arboreal life. In the howlers we have a specially developed voice organ, which is altogether peculiar; in the spider monkeys we find the adaptation to active motion among the topmost branches of the forest trees carried to an extreme point of development; while the singular nocturnal monkeys, the active squirrel monkeys, and the exquisite little marmosets, show how distinct are the forms under which the same general type, may be exhibited, and in how many varied ways existence may be sustained under almost identical conditions. LEMURS.