262 



Earl W. Benjamin 



75 — — 



74 



73 



72 



70 



Dec. 



Jan. 



Feb. 



March 



April 



May 



June 



July 



Aug. 



Fig. 35. mean monthly shape records for five normal individuals for a period 



OF five years 



These results do not agree with deductions to be gained from Curtis 

 (1914 a) or from Thompson (1908). It would appear from these results that 

 the tension of the oviduct wall may gradually relax during the first five or 

 six months of the bird's production each year, and then increase again as the 

 season closes, causing at first a rounding of the egg and later a lengthening. 



Color character 



The study of the monthly production as to the variations of color is 

 summarized in figures 36 to 39. There is a definitely increased amount 

 of pigment in the eggs produced by the hens after their pullet year as 

 compared with their first year's production (fig. 36). There is a distinct 

 tendency for the eggs to become whiter as the production continues for 

 the first five or six months, and then to become more tinted again toward 

 the end of the season's production. It would seem that the amount of 

 pigment is decreased during the period of most abundant egg production. 



As shown in figure 37, there is no distinct and gradual increase in the 

 pigmentation of the eggs from the second to the sixth year's production, 

 but during each year when enough birds are available for the data to be 

 considered of value, there is a tendency for the same monthly fluctuations 

 as are exhibited in figure 36. The grouping of the birds according to their 

 life means in figure 38 shows the same monthly fluctuations as were 

 previously observed. 



