II SIZE OF THE BODY AND ORGANS 



77 



responsive, and at G 10 the body weight of the captive Grays 

 exceeds that of the wild strain by 17 per cent in the males 

 and by 16 per cent in the females. 



If data for the wild gray Norway, taken from reference 

 table 187, are compared with data for the Albino, taken from 

 reference table 144, using the body lengths that belong to 

 each sex of the captive Grays, it appears that at G 10 the body 

 weight of the Albino exceeds that of the wild gray Norway 

 by 15 per cent in the male and by 19 per cent in the female. 



Thus, the deviation in the body weight of the captive Grays 

 from that of the wild gray Norways is similar to the devia- 

 tion shown by the Albino. The captive Grays have, there- 

 fore, approximated the Albino in this relation. It seems most 

 probable that lack of exercise and the supply of abundant 

 food are the influences which have brought about this modi- 

 fication. 



Attention should be called at this point to the sag in the 

 graphs in chart 13, at G 6 and G 7 . A corresponding sag occurs 

 in the graphs for most of the other organs, and in the present 

 instance is to be explained as the result of unfavorable con- 

 ditions acting on these generations (chart 1). 



Chart 13 Deviations of observed body weight from standard body weight 

 on observed body length. Standard: Wild Norway, table 187. 



ON THE WEIGHTS OF THE SEVERAL ORGANS IN THE CAPTIVE GRAYS 



Introduction 



There are two ends in view. In the first place, it is the 

 purpose of this study to determine whether the captive Grays 

 have departed from the standards for the wild strain. 



