142 



ARBOREAL MAN 



that the development of the mammary glands is in har- 

 mony with the number of offspring produced at a birth, 



Fig. 53. — The Mammary Line upon a Hypothetical Mammal, 



TO SHOW THE SiTES AT WHICH MAMMARY GlANDS AND NiPPLES 

 MAY BE DEVELOPED. 



and so suckled simultaneously. Animals with large 

 families possess multiple mammary glands for the suckling 



