CHAPTER XXV 

 CLASS MAMMALIA (Continued): MAN 



467. General Statement. — Man agrees, as we have seen, 

 with the higher primates in all the essential structures and 

 functions which make them mammals and primates. In many- 

 minor details, too, he resembles them. The form of the fingers 

 and the flat nails; the number and arrangement of the teeth; 

 the shape of the face, and numerous other superficial things 

 might be chosen to show the likeness between man and the 

 higher apes. It is agreed by zoologists that there is less differ- 

 ence of structure between man and the higher apes than between 

 the apes and the monkeys. 



In general, man agrees with all animals in all that is necessary 

 to make an organism an animal; he agrees with all the verte- 

 brates in the vertebrate characteristics ; he agrees with all the 

 mammals in their distinctive features ; and finally he agrees with 

 the primates in the special qualities that separate them from the 

 lower mammals. 



468. The Structural Distinctions Between Man and the 

 Other Mammals. — Man differs from the other primates in the 

 fact that he is more upright in position. This brings about a 

 greater development of the hind legs and the pelvic bones for 

 support and leaves the hands free to serve the individual in ways 

 other than locomotion. He differs also in the size of the brain 

 and in the convolutions of it. The brain of the average man 

 weighs from two to three times that of the gorilla, while the 

 heaviest known human brain is only twice as heavy as those of 

 the lowest races of men. There is a corresponding difference 

 in the shape of the head (compare Figs. 244 and 245). The great 

 toe cannot be opposed to the other toes as in the case of the apes 

 (Fig. 243), or as man can oppose his thumb. There is freer 

 motion of the big toe, however, in newly born babes than in 

 adults. The canine teeth of man are somewhat less developed, 

 and the body covering of hair is not so pronounced, though the 



466 



