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THE AMERICAN NATURALIST [Vol. XLIV 



firm the present writer's hypothesis first published in 1908 3 

 concerning the method of inheritance of this character. The re- 

 sults obtained are consistent with the hypothesis that barring is 

 allelomorphic to the female sex element. Thus, when male 

 Plymouth Rocks are used in the cross only the male offspring 

 are barred, the females being black. The plates accompanying 

 the text show excellent illustrations of the nature of the barring, 

 both in Hie pure bred Barred Rocks and in the hybrids. The 

 hybrids are darker than the pure breeds, there being more pig- 

 ment in the feathers. 



Davenport has recently published an important contribution 

 in the Carnegie Institution scries on inheritance in poultry. 4 

 While he deals with many other characters than those relating 

 to color, for lack of time to present an adequate review of the 

 whole article, and because of its relation to the present subject, 

 I give here only his results relating to color factors. The factors 

 determined were as follows: 



C = presence of color (absence of C gives albinism); 



J === Jungle Fowl pattern and coloration; 



N = super Melanic factor (nigrum) ; 



X = super Xanthic or buff factor ; 



He found the Silkies and White Cochins both to be pure 

 albinos having the gametic formula cJnwx. 



White Leghorns were found to be grays with the formula 

 CJNWx. This formula shows that W is an inhibiting factor 

 which renders J and N invisible. 



Black Minorcas and white-faced Black Spanish were found 

 to have the formula CJNwx. In these breeds N obscures J, but 

 the latter modifies the character black color. 



Black Cochins were found to have the formula CINwx. In 

 this formula I is a modification of J in which the pigmentation 

 usually associated with J is absent. 



Black Games were found to have the same formula as Black 

 Cochins, but the pigment due to the factor N is less intense. 



Buff Cochins were found to have the formula CjnwX. Tin 

 author notes some variability in the degree of albinism, certain 

 recessive whites showing specks of pigment. "The coloring 

 enzyme may be absent to small traces." 



1 !> iv. ii|...rt. <"\ B., "Inheri 



