inheritance; OB^ FECUNDIT-V in domestic EOWIv. 



3SI 



must be present together to cause high fecundity, either of them 

 alone, whether present in one or two 'doses,' causing the same 

 degree of low fecundity. 



5. The second physiological factor L2 behaves as a sex- 

 limited (sex-correlated or sex-linked) character, in gametogene- 

 sis, according to the following rule : the factor /;: is never 

 borne in any gamete which also carries P. That is to say, all 

 females which bear L2 are heterozygous with reference to it. 

 Any female may be either homozygous or heterozygous with 

 respect to Li. Any male may be either homozygous or hetero- 

 zygous with reference to either L^, L2 or both. 



How well this hypothesis agrees with the facts has been shown 

 in detail in the preceding sections. By way of, summary the 

 following table shows the accord between observation and ex- 

 pectation for all matings of each general type taken together. 

 For reasons set forth below, the lumped figures do not give an 



TABLE 33 



Shozving the observed and expected distributions of winter egg 

 production for all matings taken together 





Winter Production of Daughters 



Mating 



Class 



Over 30 



Under 30 



Zero 



AUB. P. R. X B. P. R { 



Alio. I. G. X C. I. G... { 



All i^i 1 



All F2 and back-crosses* . . . . t 



Observed. . . 

 Expected. . . . 

 Observed. . . 

 Expected. . . . 

 Observed. . . 

 Expected. . . . 

 Observed .... 

 Expected 



3651 



381.45 

 2 





 36 



S6.5 



571 



68.60 



2591 



257 .25 

 23 

 Z5 

 79 



88.75 

 981 

 95.00 



31 



17.30 



15 



15 



8 



5.75 

 23 

 15.40 



1 With exception of the matings of C. I. G. c? 578 m Barred i^i ? V . Cf. p. 246. 



altogether fair estimate of the matter, but some sort of a sum- 

 mary is necessary. , 



Considering the nature of the material and the character 

 dealt with it can only be concluded that the agreement between 

 observation and hypothesis is as close as could reasonably be ex- 

 pected. The chief point in regard to which there is a discrep- 

 ancy is in the tendency, particularly noticeable in the B.P.R. X 

 B.P.R. and the F-^ matings, for the observations to be in defect 



