the teeth cause the lips to be pushed more forward, the lower jaw is larger, and the cheek-bones show more plainly. In old age the whole upper part of the face becomes more marked, the nose and eyebrows still more prominent, the cheeks hollow from absorption of the fat, the space from the nose to the chin (as in infancy) shortens from loss of teeth, but the chin, being more fully formed, projects as the jaw rises to fill the space occupied by the teeth. The angles of the jaw are also very sharp and square, the eyes sunk in the head, and the whole skin of the face loosened and wrinkled from loss of substance beneath. With respect to sex, in the Male the facial bones are more fully formed, the shoulders broader and higher, the collar-bones longer and more curved, the chest wider, the hips narrower, and the legs longer, and every bone has its processes or markings more fully developed, and is more contorted from the action of the muscles, which are larger and more powerful than in the Female. In the Female (fig. 83) there is a greater deposition of fat, and, in many other respects, a tendency to a child-like conformation. [Illustration: FIG. 82--HEAD OF AN OLD MAN.] [Illustration: FIG. 83.--HEAD OF A FEMALE.] The body is everywhere covered by a common integument called the skin, beneath which is a layer of areolar and adipose tissue, which last has its cells filled with fat, which during life is in a liquid or oily state; this serves to protect the parts beneath both from cold and violence, fills up the hollows and irregularities between the muscles, and gives the body a more rounded and graceful appearance. Man, in common with all the higher animals, is possessed of the five "special senses," namely, sight, smell, hearing, touch, and taste, the organs of which are the eyes, nose, ears, skin, and mouth; but these are developed in very different degrees in different animals. [Illustration: FIG. 84.--FRONT VIEW OF EYE.]