Mar. 4. 1918 Winter Egg Production of Rhode Island Reds 571 



individuals the pause comes comparatively early in the winter so that the 

 following [spring ( ?) cf . Pearl and Surface (7)] cycle of production may 

 begin as early as the middle of January. This may mean, perhaps, that 

 the winter pause in Rhode Island Reds is not homologous with that of the 

 Maine Station birds. Whether or not this is so, it would seem desirable 

 to look at it from a somewhat dififerent standpoint. It may be that this 

 pause follows an initial cycle of production. It may be, too, that we are 

 not dealing wholly with an inherent pause but with a pause that depends 

 in part on the environment for its manifestation, which is due to a 

 difference in resistance on the part of individuals to the weather con- 

 ditions at this season of the year. 



NUMBER OF EGGS LAID BEFORE THE WINTER PAUSE AND LENGTH 



OF WINTER PAUSE 



In those instances where the winter pauses could be determined with 

 some degree of accuracy, we have determined the range and mean num- 

 ber of eggs laid before the pause and the same constants for the pause 

 itself, for the pullets of the April and May hatches shown in Table XIII. 

 It should be borne in mind, however, that in most instances the limit 

 specified earlier has been used for the lowest number of days indicative 

 of the winter pause. 



For the number of eggs before the pause, the range has a value of 

 2 to 96,^ with a mean of 35.98 eggs. The length of the pause has a 

 range of 8 to 72 days, with a mean of 34.23 days. For the birds listed 

 under section B of Table XIII, the values are for eggs; range i to 96,* 

 mean, 36.98, and for length of pause range, 3 to 104, mean 24.87. 



The possibility of a correlation between the number of eggs laid before 

 the pause and the length of the pause has been examined and found 

 to be practically nonexistent. 



MODE OF INHERITANCE OF THE WINTER CYCLE 



From the data that have been presented in the preceding pages it is 

 clear that some individual Rhode Island Reds exhibit a definite winter 

 cycle, while others as definitely show no winter cycle. For purposes of 

 description we may describe the former as "winter cycle," the latter 

 as "no winter cycle." It is clear, moreover, from an examination of 

 the family records (Tables I and XIII) that the character is inherited 

 and that segregation takes place. When the ratios are examined, how- 

 ever, no evidence of an entirely satisfactory character is afforded us as 

 to the mode of inheritance of the winter cycle, although there is some 

 evidence that the winter cycle is inherited according to the simple 



1 The rather absurd values for the lower end of the range result from the inclusion of a few records that 

 are obviously out of the ordinary but which can not be excluded. The next lower value is 9. 



