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THE AMERICAN NATURALIST [Vol. XLV 



tral" theory and indeed is in flat contradiction to one of 

 the most fundamental tenets of that faith. 

 Let us next consider the question, 



Are Somatically Equal Variations in Fecundity of 

 Equal Hereditary Significance? 

 In the spring and summer of 1907 were reared 250 

 pullets, all of which were the daughters of hens that had 

 laid approximately 200 or more eggs in the first year of 

 their life. This group of mothers was reasonably homo- 

 geneous in respect to records of egg production. All had 

 laid about the same number of eggs. Their daughters 

 were, however, far from a homogeneous lot with respect 

 to egg production. 8 It is plain from the results obtained 

 in that experiment that the egg record of a hen is a most 

 unreliable criterion of the probable number of eggs 

 which her daughters will lay. This is demonstrated by 

 examination of individual cases. Thus consider the two 

 mothers nos. 253 and 14. Their winter production 

 records were nearly identical (65 and 66 eggs, respect- 

 ively). Their daughters' average winter productions 

 were 23.87 and 2.40 eggs, respectively! Certainly it 

 seems reasonable to conclude that the gametic constitu- 

 tions involved in the breeding of 253 and 14 were quite 

 different, though both these hens laid the same number 

 of eggs. Again, take birds no. 386 and 911. One had a 

 winter record of 55 and the other of 52 eggs. Yet their 

 daughters' average winter productions were, respect- 

 ively, 4.88 and 27.33 eggs. Many more instances of this 

 kind could be brought forward. Taken together, the 

 whole evidence shows beyond the shadow of a doubt that 

 the presence of high fecundity in an individual, and that 

 factor which makes high fecundity appear in the progeny, 

 are two very different things, either of which may be 

 present in an individual without the other. We plainly 

 have here the basis for the distinction of phaenotypes and 

 genotypes just as in beans. 



Me. Agr. Exp. Sta., l&Cttf See particularly Table I. 



