10 



C. M. JACKSON 



According to table B, it is seen that the average body weight 

 of the male was greater at every age noted, except at six weeks, 

 when the female was slightly larger. At seven days, however, 

 the male was but slightly the greater. 



The extent of the variation in the ratio of body weights between 

 males and females of the same litter may be noted from data 

 in table 1. Further information of interest is afforded by table 



TABLE B 



TABLE C 



Ratio of average male to female gross body weight in individual litters at 



successive ages 



LITTER AND NUMBER 

 OF EACH SEX 



A 32 

 M 9 

 M 9 

 M 6 

 MIO 

 M 8 



M 

 M 

 M 

 M 



A 29 



A 28 



(3 m. 5f.) 

 (5 m. 3f.) 

 (3 m. 3 f.) 

 (5 m. 3 f.) 

 (2 m. 4f.) 

 (3 m. 5f.) 

 (2 m. 4f.) 

 (Im. 4f.) 

 (4 m. 1 f.) 

 (4 m. 1 f.) 

 (2 m. 4f.) 

 (4 m. 2f.) 



1.05 

 1.12 



1.02 

 1.08 



1.03 

 1.061 

 1.06 

 1.04 

 1.05 

 1.06 

 0.98 



1.16 

 0.99 



1.11 



1.222 



1.00* 

 1.04 

 1.10 

 1.08 

 0.90 



1 Two males of this litter were killed at 7 days. 



* In this litter, the ratio at 10 weeks was 1.39. 



' One male, a 'dwarf,' died before the age of 30 days. 



* One female a 'dwarf at these ages. 



