230 



EARL W. BENJAMIN 



years T/7/rrf t/ecrrs /E>t/rf/7 i/ears f/ffft years 



T)th 



Gth 



7th 



8th 



9th 



10th 



llth 



FlG. 33. 



MONTHLY VARIATION IN SHAPE OF EGGS PRODUCED DURING A PERIOD OF SIX 



YEARS 



The figures in parenthesis designate the number of birds available for the respective calculations 



