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 SlTES AT WHICH MAMMARY GLANDS AND NlPPLES 

 MAY BE DEVELOPED. 



and so suckled simultaneously. Animals with large 

 families possess multiple mammary glands for the suckling 



