200 



RAYMOND PEARL 



bird without question carried either Li or Lo (or possibl}'' both) 

 and the reproductive system started to function in the normal 

 way and bring to somatic expression these gametic factors. But 

 before this could be done the diseased condition of the organs 

 brought the bird as a whole into such a condition of reduced vital- 

 ity that egg production was impossible. 



The other bird's zero record is probably a somatic fluctuation 

 from an 'Under 30' hereditary constitution. She began laying 

 very shortly after the end of the winter period. 



It is of interest to note that the mean winter productions 'are 

 relatively rather low for the ' Over 30' classes in all matings. The 

 contrast between & D31 progeny and that of cf 563 (vide supra) 

 in this respect is striking. This matter will be discussed in 

 detail later. 



Summary and discussion of matings of class 7 Barred Plymouth 

 Rock males. Having now presented in detail the evidence 

 respecting the matings of class 7 males with various types of 

 females it is desirable to collect and summarize this material. 

 In tables 11 to 16 inclusive are given the assembled results of all 

 matings of certain particular types. It will be understood that 

 these are all pure Barred Rock matings and represent the summa- 

 tion of the data previously given. These tables give the total 

 numbers of different males and females from which data were 

 obtained in each class of matings, as well as the classification of 

 the adult female progeny in respect to fecundity. 



TABLE 11 

 Showing the results of all matings of class 7 c^d^ X class 19 9 

 /Z1L2 . fhLi X /L1L2 . Fhh 



