inheritance; of fecundity in domestic fowl,. 367 



families are small. The pure Cornish females used were of 

 constitution fLiU.. FhL The results follow. 



c^ 577 fhk. fkU X fUU. Pkk. 

 2 Progeny 



Winter Prodnciion: Over 30 Under 30 Zero 



(? F7) • O I T 



(? Fll) ; O 2 I 



Total observed o 3 2 



Total expected 1.2^ 2.5 1.23 



Mean winter production of $ ? 



in indicated class 7.33 eggs eggs 



Matings of Barred Plymouth Rock males zmth Barred Pi fe~ 

 males. While several matings were made here they all fell into 

 one or the other of two gametic types. The Barred Rock males 

 males used in these matings have, of course, already had their 

 gametic constitutions determined through their matings with 

 pure Barred Rock females. 



A. Type of mating: fhU. fhU X fl^l^- FL^h. The results 

 of this type of mating are shown in table 30. 



There are several points which need to be noted about this 

 table. While in general it is apparent that the observed result 

 falls out in fair accord with expectation, the three zero birds are 

 outstanding exceptions. No zero birds should occur in any of 

 these matings. A careful study of the individual cases, how- 

 ever, indicates that only one of these apparent exceptions is 

 really such. Two of these zero birds were very late hatched and 

 began laying immediately after March i, i.e., just after the arbi- 

 trary point of ending the winter period. Their records during 

 the spring period were such as to indicate that they bore the 

 factor Li, and not that they lacked it. The third zero bird (no. 

 558) was an extremely interesting case. Something was at 

 fault physiologically with her reproductive organs, as a result 

 of which she never laid an tgg. However, she gave clear evi- 

 dence that she bore the factor Lt. (or Li — not both) gametically. 

 This she did through her nesting records. For some years past 

 I'ecorc^s have been kept in this work not only of when a hen 



