meHdeliAn experiments on fowls. 351 



similar to back, but just a little heavier in the dark colour; breast 

 a rich chestnut right up to the throat, running off to a white, but 

 not pure on the tliighs; tail almost a pure white." 



5 and 6. Xo brown but scattered dark speck.s, n)any of the 

 feathers in these with minute points of black all over, 

 appearing grey. No. 5 with more black than ISTo. 6 but of 

 same type. 



7. Deep black isolated feathers on wings and back, with slight 

 trace of I'ed, uniform over back. 

 One chick had been lost. 



It will be seen, therefore, that on July 16th in these F^ birds 

 there were two groups— one of four cocks and four hens of the 

 pile type, and the other of four cocks and three heiis with small 

 scattered spots of black and red. No. 5 among the cocks belonging 

 to the second group is more similar to the pile, but with colour 

 much less developed. 



Subsequently the red colour in the cocks increased considerably, 

 and the pile coloration was more completely developed. Thus on 

 Sept. 27 the birds were nearly full grown and with fully-developed 

 plumage. There were six cocks that looked like fairly typical 

 piles, i. e. white birds with rich red backs. In addition there 

 was one with similar marking, but straw colour on the back 

 instead of red, and another with rather smaller comb and wattles 

 and no broad area of colour on back, but separate spots, and a lean 

 and game-like shape. The four pile hens were much the same as 

 before, and the other three hens still had only scattered specks of 

 black and yellow. 



In December one of the pile cocks was accidentally killed. The 

 last of the cocks described above, which was more backward in 

 development than the others, had by this time developed the pile 

 coloration like the rest, but with pale yellow colour in the back 

 and saddle, not red. 



Thus the Fj generation in this experiment shows that the pile 

 coloration in the cocks is a heterozygote. It may be said that 

 the white of the Leghorn is dominant to the black in the black- 

 red, but not to the red : hence the heterozygote is white-red 

 instead of black-red. The dominance to black is not, however, 

 quite complete, as black specks or occasional black feathers occur. 

 In the hens the pile coloration takes a different distribution, 

 corresponding to the different distribution of black in the hen of 

 the black-red. 



F, Generation. Year 1920. 



In Feb. 1920 I mated the F^ fowls in two separate pens for 

 breeding. In one pen were put one of the most deeply coloured 

 pile cocks with the four typical pile hens. One of the latter died 

 before breeding. In the other pen were one of the palest pile 

 cocks with three hens which were white with spots and specks of 

 colour, A number of eggs, about 25 from each pen, were obtained, 



9-1* 



