SIZE, SHAPE AND PHYSICAL CONSTITUTION OF THE EGG. lOQ 



4. The egg is more variable in length than- in breadth. In a 

 few individuals the difference between the variation in the^e 

 characters is not significant. 



The following Hst arranges the &gg characters in the order 

 of their variability. 



( Egg weight. 



I 



Yolk weight. 

 Albumen weight. 



[ Shell weight. 

 Length. 

 Breadth. 



It is especially worthy of note than the variation coefficients 

 for yolk and shell are much higher than for the whole tgg, 

 and the coefficient for albumen is at least as high. There 

 must then be a compeiisatory variation among the parts. The 

 data show also that the eggs of the breeding season have dis- 

 proportionately large yolks and a consequent smaller percentage 

 of albumen than the eggs at other seasons. 



The eggs of each individual (as well as the means of the 

 different individuals) vary less in respect to the dimensional 

 characters than in respect to w^eight. The eggs must vary 

 simultaneously in both dimensions. 



Whereas a comparison of the means for the different individ- 

 uals shows that intra-racially the eggs are more uniform in 

 yolk weight than in the weight of the other parts or of the 

 whole &gg, wdthin the eggs of the individual the yolk weight is 

 almost as variable as the shell weight and much more variable 

 than the weight of the albumen or of the whole egg. 



THE RELATION OP EGG CHARACTERS TO OTHER CHARACTERS. 



The factors which bring about the individuality in the eggs 

 of the different birds are too complex for analysis from the 

 data in hand. Other -facts known about the birds were investi- 

 gated to discover possible relationships between the variation 

 in egg characters and variation in other characters. The re- 

 sults were as follows : 



I. The early hatched birds laid earlier in the fall than those 

 hatched during the middle of the season, while the late hatched 

 birds did not lay until spring. 



