R C. PUNNETT AND P. G. BaILEY 205 



which we bred, 38 in number (cf. Table, Pen 6, 1911, and Pen 3, 1912), 

 and did not shew much variation. 



44 Fi birds were bred from the mating Langshan $ x Brown Leg- 

 horn {/• and its reciprocal. All of them exhibited some degree of leg- 

 feathering though in all cases it was less than that of the pure Langshan. 

 The extent of the feathering varied but no attempt was made to grade 

 the birds into different classes. Of the F^ birds 4 </(/ and 14 $ ? 

 were used to produce an F2 generation, viz. Pen 10 and Pen 11 in 1911, 

 Pen 13 in 1912, Pen 4 and Pen 11 in 1913. The number of F^ birds 

 from these pens was 429. Of these 323 shewed feathering on the leg 

 while 106 had clean legs — a very close approach to a 3 : 1 ratio. The 

 extent of the leg-feathering varied considerably though here again no 

 grading was attempted. But our records make it clear that in some 

 cases the feathering was rather heavier than in the average Langshan, 

 while in others it was quite slight. In three cases F^ birds from this 

 cross were bred together. Pen 16, 1912, consisted of two such birds, 

 both with feathered leg. The distribution of feathered and clean- 

 legged birds, 34 to 15, suggest that both parents were here hetero- 

 zygous. In Pen 11, 1912, an i^2 cT with feathered leg was mated with 

 an F.2 $ which had clean legs. Of the 23 chickens hatched 11 had 

 feathered and 12 had clean legs, a near approach to the expected 

 equality on the assumption that the cock used was heterozygous. In 

 the third pen, Pen 13, 1912, two feathered-legged birds bred together 

 gave 7 chickens all with feathered legs. The numbers are too small to 

 draw any definite conclusion, but it is not unlikely that at any rate 

 one of the parents here was homozygous for the character. One other 

 F^ bird, $ 487 ex Pen 11, 1913, was subsequently tested in Pen 5, 1916, 

 by mating her with cT 35 which, from his breeding, must be supposed 

 to have been heterozygous. As all the 22 children produced had 

 feathered legs $ 487 must be regarded as in all probability a homo- 

 zygous F2 bird. All the data from the Langshan-Leghorn cross are 

 evidently consistent with the view that leg-feathering behaves as a 

 simple dominant to clean leg. On this view we must suppose that 

 the variation in the extent of the feathering, though partly dependent 

 upon whether the bird is" homozygous or heterozygous for the feathered- 

 leg factor, must be dependent also upon some other factor or factors 

 not yet analysed. 



The Langshan-Hamburgh results, with one exception, are not dis- 

 similar. 12 Fi birds were raised in Pen 9, 1912, and Pen 15, 1913. 

 Of these 11 had feathered legs, while one, which will be referred to 



14—2 



