308 EARL W. BENJAMIN 



13. No definite tendency is shown toward a reduction of the variability 

 of type of eggs produced by individual birds during successive years. 



14. During the pullet year the size of the eggs produced increases 

 rapidly, but after the first year's production no appreciable change in 

 the size of the eggs produced can be found. 



15. There seems to be no perceptible and consistent difference between 

 the shapes of eggs laid by pullets and those laid by hens. 



16. There is a tendency for the eggs produced each year, even in the 

 pullet year, to have a gradually increasing index until the fifth or the 

 sixth month of production, after which this index gradually decreases 

 until the season's production ceases. 



17. The eggs produced by hens two years old or older, are more likely 

 to be tinted, or are tinted darker, than the eggs produced by the same birds 

 during their pullet year. 



18. There is no gradual darkening of the shell pigment after the second 

 year's production. 



19. Each year there is a tendency for the eggs produced to gradually 

 become whiter during the first five or six months of production, and then 

 to become more tinted again toward the end of the production season. 



20. The data presented show that when eggs are laid by an individual 

 bird for two or more successive days, the eggs become successively smaller, 

 have a larger index, and are more deeply tinted. 



21. A distinct positive correlation is found between the size of the eggs 

 incubated and the vigor of the respective chicks hatched, at various 

 ages of the chicks. The correlation is especially significant during the 

 period of severe weather conditions. 



22. A constant figure to represent x in the ratio, female weight : male 

 weight : : x : 1, was calculated for a part of the available material at 

 various ages, and this figure was found to agree closely with Galton's 

 constant for human stature of 0.93. 



23. There is a significant positive correlation between the size of the 

 eggs incubated and the size of the respective chicks hatched. This 

 correlation persists during the life of the birds as far as it was studied; 

 that is, during a period of 228 weeks. 



24. All of the eggs produced by any one hen tend to be of a characteristic 

 type as to size, shape, and color. 



