72 THE HUMAN SPECIES 



extremely narrow and is divided into two almost equal parts 

 by the spine (similarly to the scapula of the carnivora) ; indeed 

 in many respects the scapula of the hylobates is even less human 

 in character than that of the semi-apes, particularly the Indri 

 of Madagascar. Among the mammals, however, with the 

 exception of the anthropoids, the scapula of the bat most 

 closely resembles that of man. The fossa supraspinalis is 

 small, the fossa infraspinalis much larger. Like man, the bat 

 uses the upper extremities only to a very slight degree as 

 organs of support. 



Man's broad, flat back is one of his most distinctive char- 

 acters, and no less important is the form of the trunk, which 

 somewhat resembles an hour glass, thus causing the abdominal 

 organs to be entirely supported by the pelvis. The pressure of 

 the intestines caused by the erect position has resulted in that 

 transverse broadening of the iliac bones, which, contrasted with 

 the narrow pelvis of the anthropoids, is so distinctive a human 

 character, and in the human female has been still more increased 

 through sexual adaptation. 1 



This sexual difference in the human pelvis (see Figs. 32 and 

 33) is a specific human character ; in the lower races of man 

 the difference is less strongly developed. Wiedersheim ' 2 states 

 the case with admirable clearness, showing that in the human 

 being the pressure of the uterus during pregnancy is sagittally 

 directed and not ventrally as in the other mammals. The 

 uterus is supported by the iliac bones. 



It has further been shown by Wiedersheim that the number 

 of vertebrae above the sacrum was originally greater, that the 

 pelvis was situated more towards the back and that the forward 

 tendency still persists. This is proved by cases where the 

 fifth and even the fourth lumbar vertebra has joined the sacrum 

 similarly to the case of the orang, chimpanzee and gorilla. In 

 man the coccyx generally consists of four, in rare cases of five, 

 vertebras, in all of which, with the exception of the uppermost 

 one, the true vertebrate form is rudimentary. More than five 

 coccygeal vertebrae have never been observed in man, even in 

 the embryo. 



The absence of a tail is no distinctive character of man, for 



1 Wiedersheim, loc. cit., p. 41. z Ibid., p. 86. 



