212 Bulletin No. 155.— 1913. 



inheritance of this inhibiting character is sex-hmited, being trans- 

 mitted from the 9 9 to the c^ c^ only. 



The differences in plumage-color (i. e., heavily splashed Fi birds- 

 from the W. S. cf X W. L. 9 mating, etc.) are more difficult to 

 explain and no attempt will be made to do so at this time. 



In conclusion it may be merely pointed out that the factor which 

 inhibits black pigmentation in the pluma^ge corresponds with Bate- 

 son's and Punnett's inhibitor of Silky pigmentation in so far as its- 

 effect is observed only in W. S. 6^ X W. L. 9 matings. But the 

 factors seem to be distinct in that, while the inhibitor of Silky pig- 

 mentation is strictly sex-limited (preventing deep pigmentation in 

 the Fi d' d' from W. S. d' X B. L. 9 ), the W. L. inhibitor of black 

 in plumage does not appear to be sex-limited, since the Fi from the 

 W. S. d^ X W. L. 9 cross are also deeply splashed with black. It 

 therefore appears that the White Leghorn breed of fowls possesses 

 at least two distinct color-inhibiting factors, — one for the Silky type 

 of pigmentation, the other for black pigmentation in the plumage. 

 These points require further study. 



4. — The presence of the haired pattern in other breeds of fowl char- 

 acterized by the R-white. Outside of the White Plymouth Rocks, 

 which as is well known possess barring as a cryptomere, only two 

 other breeds characterized by the R-white have yet been tested for 

 their possession of the barring factor. These are (1) the White Silky, 

 (2) the White Minorca. 



In the first of these crosses between the W. S. d^ and B. H. 9 , of 

 9 individuals all were black; these manifested also the dark shanks, 

 skin, and crest of the Silky. In F2 the results were: 



Black, including 2 blue 33 



White 10 



Game pattern, variously modified 9 



Thus the expected 3: 1 ratio appears among the black and the 

 white birds with no observed manifestation of the barred pattern. 

 No attempt will be made at this time to explain the appearance of 



