INHERITANCE OF WINTER EGG PRODUCTION 91 



from a physiological character like egg production, viz., there is 

 a deficiency in the group of high producers, that is, the genes for 

 high production riiay be present, but do not come to expression. 

 This failure may be due to other genetic causes, such as a 

 tendency to slow development or subnormal vitality. But what- 

 ever the explanation, it is clear, on the alternative theory, that 

 all Cornish males by Barred Plymouth Rock females show a 

 slight deficiency of high producers. 



In the case of male no. 578 mated with barred Fi females 

 (Pearl, '12, p. 373), the alternative theory gives ratios that fit 

 the observed ratios, though this instance does not conform to 

 Pearl's theory, as he himself recognizes. 



The results of mating male no. 578 to black Fi females can be 

 explained on the alternative theory as was done for male .no. 558. 



In table 31 (Pearl's) the grouping of the parents precludes an 

 application, of the alternative theory. 



DATA ON RHODE ISLAND REDS AND CORNISH 



General 



In table 5 is given a comparison between the observed (Roman 

 type) and expected (italics) ratios arranged according to the two 

 theories under consideration and the various division points 

 assumed. The mean winter egg production of the various 

 groups is also given under the heading 'Pearl's theory in black- 

 faced type. 



The records made in the winter of 1913-14 are those of pullets 

 from non-pedigreed stock. The succeeding years represent 

 mainly succeeding generations descended from this stock. Con- 

 siderable new blood, however was added in 1915. As any 

 number is assigned to only one individual, the reader can readily 

 ascertain which males were used in more than one breeding 

 season. With the exception of 1914-15, males have always 

 been assigned the same gametic constitution. The egg pro- 

 duction for 1914-15 is clearly abnormal, nevertheless, by not 

 attempting to assign the same gametic constitution as in other 



