No. 552] INHERITANCE OF FECUNDITY 



701 



5. A study of winter egg production (taken for prac- 

 tical purposes as that from the beginning of the laying 

 year in the early fall to March 1) proves that this is the 

 best available measure of innate capacity in respect to 

 fecundity, primarily because it represents the laying 

 cycle in which the widest difference exists between birds 

 of high fecundity and those of low fecundity. 



6. It is found to be the case that birds fall into three 

 well-defined classes in respect to winter egg production. 

 These include (a) birds with high winter records, (b) 

 birds with low winter records, and (c) birds which do 

 not lay at all in the winter period (as defined above). 

 The division point between a and b for the Barred 

 Plymouth Rock stock used in these experiments falls at 

 a production of about 30 eggs. 



7. There is a definite segregation in the Mendelian 

 sense of the female offspring in respect to these three 

 fecundity divisions. This is demonstrated by extensive 

 statistics in the complete report of this work. Here a 

 single table only may be given by way of illustration, the 

 one chosen being taken because all three classes are rep- 

 resented among the progeny of the particular type of 

 mating with which it deals. 



TABLE II 



Showing the Results oe all Matings of Class 4 B.P.R. <$J X Class 

 1 B.P.R. ??. Gametic Constitution • fL,L 2 . flj, X fL,L 2 . FIJ 2 



8. High fecundity may be inherited by daughters from 

 their sire, independent of the dam. This is proved by the 

 numerous cases presented in the detailed evidence where 

 the same proportion of daughters of high fecundity are 



