412 



SYSTEMATIC ZOOLOGY 



for locomotion, and articulate speech is found only in man. But 

 the greatest difference lies in the enormous capacity of the human 

 cranium and the corresponding great development of the brain. 

 When, however, we take into account the variations in the size 

 of the human brain which occur in adult individuals in different 



Fig. 394. Gorilla gina or Troglodytes gorilla, fas. gorilla. (From a photograph provided 

 by the American Museum of Natural History.) 



races, and certain fossil crania which have been discovered, we 

 find that the anatomical differences between man and the anthro- 

 poid apes are less than the differences .between the anthropoid 

 apes and the New World monkeys. 



We have had occasion to refer from time to time to the 

 relationship between different groups of animals ; according to 



