THE GROWTH FORM OF POPULATIONS 



325 



O Z Q T 



1925 



1928 



Fig. 



119. Number of mice (Apodemus), and percentage of adult females pregnant by months, 

 plotted against time. (From Elton.) 



o 



1840 



1850 I860 



TIME IN YEARS 



1870 



1880 



Fig. 120. Population cycles of colored foxes in Labrador computed from pelt returns reported 

 by Moravian Missions. (From Elton.) 



