8 



GORILLAS AND CHIMPANZEES 



frame of the ape is much more massive in its pro- 

 portions than that of man, but while this is true of 

 some kinds of ape the reverse is true of others. The 

 average height of the adult chimpanzee is about 

 63 inches. 



In man the sacrum is more curved in the plane of 

 the hips than it is in the ape, while the bones of the 

 digits in man are straighter. The arms of man are 

 shorter than the legs, while in the ape these features 

 are reversed. 



In the cranial types, it is readily seen that the 

 skull of man is nearly round and the face is vertical, 

 while the skull of the ape is elongated and the face 

 receding. These facts deserve more notice than the 

 mere mention of their being so. 



In the whole scheme of nature certain laws obtain 

 in the projection of skulls. The angle between the 

 plane of the face and the spinal axis is co-ordinate 

 to the angle between the spinal axis and the perpen- 

 dicular. 



To be more exact, the spine of a snake is in a 

 horizontal line, and the face occupies a plane of the 

 same kind. At the other end of the scale is man, 

 whose spine is in a vertical line, and his face oc- 

 cupies a like plane. Between these two extremes 

 are types which tend in various degrees, from the 

 lower to the higher form, and just in proportion as 

 the spinal axis approaches a vertical line from one 

 side, the plane of the face approaches it from the 

 other. 



In accord with this fact it will be observed that 



