188 RAYMOND PEARL 



one of these two was 28 eggs. There is no doubt that this bird 

 was a somatic variation belonging gametically to the 'Over 30' 

 class, (cf. p. 173). In general it is obvious that the agreement 

 between observation and expectation here is very satisfactory. 

 Further the difference in average winter production of the birds 

 in the ' Over 30' and ' Under 30' classes is so great as to leave no 

 doubt of the real distinctness of these classes in respect to fecun- 

 dity. 



B.P.R. cT 562. Indicated gametic constitution = //1L2 . fhLo. 



This male got comparatively few adult daughters. He was used 

 during only one breeding season (that of 1910), having been 

 hatched in the spring of 1909. 



Malings: A. With 4 9 9 indicated to be of class 1 = /L1L2 . Fhh. 



9 Progeny 



Winter Production: Over 30 Under 30 Zero 



Observed 5 6 



Expected -'>.''' 5.5 



Mean winter production of 9 9 



of indicated class 42.40 eggs 11.67 eggs 



B. With 2 9 9 indicated to be of class 2 = JLiLo . Fhh. 



9 Progeny 



Winter Production: Over 30 Under 30 Zero 



Observed. 8 



Expected 8 



Mean winter production of 9 9 



of indicated class 70.00 eggs 



All 9 Progeny 



Winter Production: Over 30 Under 30 Zero 



Observed 13 6 



Expected 13.5 5.5 



Mean winter jM-oduction 59.38 eggs 11 .67 eggs 



In spite of the comparatively small number of individuals 

 here, the evidence of segregation of high and low fecundity in 

 accordance with gametic expectation is clear and indubitable. 



