INHERITANCE OF FECUNDITY 225 



Counting the two 'Over 30' records as somatic fluctuations 

 belonging gametically to the 'Under 30' class the agreement 

 between observation and theory is perfect. Thus it is seen that 

 the same hypothesis which has been shown to account for the 

 inheritance of fecundity in the Barred Plymouth Rock breed 

 characterized in general by relatively high egg production, also 

 accounts perfectly for the inheritance of this character in the 

 entirely unrelated Cornish Indian Game breed, which is charac- 

 terized by relatively poor egg production. 



Reciprocal crosses of Barred Plymouth Rocks and Cornish Indian 

 Games. Fi generation 



In connection with studies of the inheritance of plumage 

 patterns and colors extensive experiments in crossing these two 

 breeds have been carried out (cf. 40, 41). The results of these 

 experiments in respect to fecundity form a crucial test of the 

 validity of the Mendelian interpretation of the data from pure 

 races set forth in the preceding pages. If the interpretation 

 which has been given is correct it should account for the observed 

 results in the Fi, Fi and subsequent cross-bred generations. Should 

 it fail when subjected to this test, it would necessitate its accept- 

 ance with great reservation, if at all, for the pure races. On the 

 other hand, agreement of the results from these cross-bred mat- 

 ings with those obtained from the pure-bred would afford the 

 strongest confirmation which it is possible experimentally to 

 obtain of the essential soundness of the general conclusions 

 reached. 



Matings of Barred Plymouth Rock males and Cornish Indian 

 Game females. Two different males were used successfully^^ in 

 matings of this sort. Both of these birds were of class 7, having 

 the gametic constitution /ZiLo . fhLo. One of them (cf 554) was 

 used in a number of pure B.P.R. matings with results already dis- 

 cussed in a previous section. 



*' i.e., got adult daughters. 



