STRUCTURE OF THE VERTEBRATES 



137 



The general characteristics of the mammal skull have been 

 discussed. The evolution of the human skull shape depended 

 upon the shortening of the face and the great growth of the 

 brain. These two movements automatically carried the calvari^-m 

 upward and forward, until in the human a line drawn from the 

 foramen magnum to the chin is at right angles to the vertebral 



C. Chimpanzee 



F. Recent Man 



'*^W^^^ 



B. Old World Monkey 



E. Neanderthal Man 



A. Lemur 



D, Pithecanthropus 



Fig. 74. Skulls of Primates. Note the increase in size of the brain case 

 (calvarium) and the shortening of the face. The calvarium is stippled. 



