258 



EARL W. BENJAMIN 



began laying in December and continued laying for about the same period 

 as the others (until August). No material difference can be observed 

 between the types of curves shown in figure 31, and those shown in 

 figures 28, 29, and 30. There seems, then, to be no marked error due 

 to the possible selection of birds in the study of the random flocks, and 

 it is probable that the curves for heavy producers are not materially 

 different from those for lower producers. 



Dec. 



Jan. 



Feb. 



March 



April 



May 



June 



Aug. 



FlG. 31. MEAN MONTHLY SIZE RECORDS FOR FIVE NORMAL INDIVIDUALS FOR A PERIOD 



OF FIVE YEARS 



After the great increase in the size of the eggs from the first to the second 

 year, there seems to be a gradual decrease in the size of the eggs produced 

 during successive years. This last statement does not agree with the 

 results of Curtis (1914 a). 



No decreased size of the eggs produced at the beginning and at the end 

 of the litter is observed, as claimed by Fere (1898b) and Curtis (1914 a), 

 and there is no appreciable difference in the variations for the birds laying 

 large, medium, and small eggs (fig. 30). 



