50 DISTINCTIVE CHARACTERISTICS OF MAN. 



of it; iu many Mammalia, as in the Elephant, it forms nearly a right 

 angle with the vertebral column ; and in several others, as the Horse, Ox, 

 etc., the angle which it makes with the axis of the pelvis and vertebral 

 column is acute. In these respects, then, the skeleton of Man presents an 

 adaptation to the erect posture, which is exhibited by that of uo other 

 Mammal; but that of the anthropoid Apes presents a far nearer approxi- 

 mation to the Human model in all the foregoing particulars, than it does to 

 that of the lower Quadrumana. 



31. There is a considerable difference in the form of the trunk, between 

 Man and most other Mammalia ; for his thorax is expanded laterally, and 

 flattened in front, so as to prevent the centre of gravity from being carried 

 too far forwards ; and his sternum is short and broad. Between the bony 

 walls of the thorax and the margin of the pelvis, a considerable space inter- 

 venes, which is occupied solely by muscles and tegumentary membranes ; 

 and these would be quite insufficient to sustain the weight of the viscera, if 

 the habitual position of the trunk had been horizontal. In these particu- 

 lars, however, the most anthropoid Apes agree more or less completely with 

 Man. 



32. The lower extremities of Man are remarkable for their relative length, 

 which is greater than that which we find in any other Mammalia, except 

 the Kangaroo tribe. The chief difference in their proportions between Man 

 and the semi-erect Apes, is seen in the thigh ; and it is from the relative 

 length of this part in him, that the middle point of the height of the 

 body is in the adult as low as the symphysis pubis, and further, from the 

 comparative shortness of his anterior extremities, his hands only reach 

 the middle of his thighs, whilst in the Chimpanzee they hang on a level 

 with the knees, and in the Orang they descend to the ankles (Fig. 9). 

 The Human femur is distinguished, however, by its form and position, as 

 well as by its length. The obliquity and length of its neck still further in- 

 crease the breadth of the hips; whilst they cause the lower extremities of 

 the femora to be somewhat obliquely directed towards each other, so that 

 the knees are brought more into the line of the axis of the body. This ar- 

 rangement is obviously of great use in facilitating the purely biped progres- 

 sion of Man, in which the entire weight of the body has to be alternately 

 supported on each limb ; for if the knees had been kept further apart, the 

 whole body must have been swung from side to side at each step, so as to 

 bring the centre of gravity over the top of each tibia ; as is seen to a cer- 

 tain extent in the female sex, whose walk, owing to the greater breadth of 

 the pelvis and the separation between the knees, is less steady than that of 

 the male. There is also a marked difference between the knee-joint of Man 

 and that of even the highest Apes. In the former, the opposed extremities 

 of the femur and the tibia are so expanded as to present a very broad ar- 

 ticulating surface, and the internal condyle of the femur being the longer 

 of the two, the two condyles are in the same horizontal plane in the usual 

 oblique position of that bone; so that by this arrangement the whole weight 

 of the body, in its erect posture, falls vertically on the top of the tibia, when 

 the joint is in the firmest position in which it can be placed. The knee-joint 

 of the Orang, on the other hand, is comparatively deficient in extent of ar- 

 ticulating surface; and its whole conformation indicates that it is not in- 

 tended to serve as more than a partial support. In regard to the general 

 conformation of the bones of the extremities, it may be most explicitly 

 affirmed that the differences which undoubtedly exist between Man and the 

 anthropoid Apes are much less considerable than those which present them- 

 selves between the latter and those Baboons and Lemurs whose ordinary 

 mode of progression is quadrupedal. And thus, after contrasting one part 



