18 



HELEN DEAN KING 



The data in table 4 are shown graphically in figure 5. 



In figure 5 the graphs for males (1 and 2) run parallel and 

 at nearly the same level until the age period of about 300 

 days. Up to this point the space between the graphs repre- 

 sents a weight difference in the two groups of approximately 

 4.5 per cent, the weights of the smaller individuals being taken 

 as the standards in computation. Subsequently the two graphs 



Body weight in grams 



1 Large males 



2 Small males 



3 Large females 



4 Small females 



Age in days 



Fig. 5 Body growth in pairs of large and small individuals from the same litter. 



diverge sharply; graph 1 mounts upward rapidly, graph 2 

 rises at a slower rate. At the 400-day period the larger males 

 had increased their weight excess to 10 per cent, and they 

 were 22.3 per cent heavier at the end of the weighing period. 

 Growth graphs for the two groups of females (3 and 4) run 

 much the same as those for males, although they begin to 

 diverge at an earlier age period. At 212 days the space be- 

 tween the graphs represents a weight difference between the 



