VERTEBRATA 197 



gorilla is most manlike in bulk (sometimes reaching 

 the height of five feet six inches), in the proportions 

 of the leg to the body and of the foot to the hand, in 

 the size of the heel, the form of the pelvis and shoulder 

 blade, and volume of brain. 67 



FIG. 192 Gorilla. 



Man differs from the apes in being an erect biped. 

 In him, the vertebrate type, which began in the hori- 

 zontal fish, finally became vertical. No other animal 

 habitually stands erect ; in no other are the fore limbs 

 used exclusively for prehensile purposes, and the hind 

 pair solely for locomotion. 



His limbs are naturally parallel to the axis of his 

 body, not perpendicular. They have a near equality 

 of length, but the arms are always somewhat shorter 

 than the legs. In all the great apes the arms reach 

 below the knee, and the legs of the chimpanzee and 

 gorilla are relatively shorter than man's. 



Only man has a finished hand, most perfect as an 



