The supporting framework of the body, the osseous skeleton, exhibits important differences in man and woman. The bones of women are on the whole smaller and weaker. Especially extensive sexual differences are noticeable in the pelvis. Wiedersheim regards these sexual differences of the woman’s pelvis as a specific characteristic of the human species. In all the anthropoid apes they are far less strongly marked than in man. Moreover, these differences exhibit a progressive development, which is to an important extent dependent upon advancing civilization. For this reason, as G. Fritsch, Alsberg, and others, point out, among the majority of savage races the differences between the male and the female pelvis are far less extensive than among civilized nations. The characteristic peculiarities of the pelvis of the European woman, which can be distinguished from the male pelvis at a glance--namely, its greater extent in transverse diameter, the greater depression and the wider opening of the anterior osseous arch--are far less marked among women of the South African races and among the South Sea Islanders. The enlargement of the female pelvis in the course of human evolution is dependent upon the most important of all the factors of civilization, the =brain=. Even in the human fœtus the great size of the brain gives rise to a far greater proportionate development of the skull than we find in the fœtus of any other mammal. This influences the pelvic inlet and the sacrum, but also the large pelvis, since, in consequence of the adoption by man of the upright posture, the pregnant uterus expands more laterally, and thus opens out the iliac fossæ. In the lower races of man, it is precisely this plate-like expansion of the iliac fossæ which is so much less developed than in the case of civilized races. Another physical difference between the sexes concerns =stature= and =body-weight=. The mean stature of woman is somewhat less than that of man. Among Europeans it is about 1·60 metres (5 feet 3 inches), as compared with 1·72 metres (5 feet 7-3/4 inches) for the average stature of the male. According to Vierordt, the new-born boy is already on the average from 1/2 to 1 centimetre (1/5 to 2/5 inch) longer than the new-born girl. Johannes Ranke characterizes the individual factors which give rise to these differences in the following manner: “The typical bodily development of the human male is characterized by a trunk relatively shorter in relation to the whole stature; but in relation to the length of the trunk, the upper and the lower extremities are longer, the thighs and the legs longer, the hand and the foot also longer; relatively to the long upper arm and to the long thigh respectively, the forearm and the leg are still longer; and relatively to the entire upper extremity, the entire lower extremity is also longer.