192 Peculiar Pigmentation of the Silky Fowl 



records refer to birds which were not killed and critically examined. 

 The extent to which the pigment development is inhibited exhibits 

 individual variation, and it is likely that in some birds the inhibition 

 is so complete that they are indistinguishable from birds which lack 

 the pigmentation factor. Here we may mention also that we bred 

 from a fully pigmented F.^ hen ($ 150, see p. 197) with results similar 

 to those which we olitained from the Silky hens. 



(/3) From the Silky ^. 



[Nature of mating Ffpp 1% x ffPPii.] 



Our original Silky ^ was mated at different times with two pure 

 Brown Leghorn hens. The Fi males from this mating were precisely 

 similar to those produced from the reciprocal cross. The F^ hens 

 however were nearly as deeply pigmented as the Silky (cf Figs. 2 and 4). 

 To the one exception, a slightly pigmented ?, we shall return later 

 (p. 200). 



TABLE II. 



Males P^eniales 



Reference Nature of mating Full Some None Full Some None 



1005 Pen .51, 404 1 „ ^ 



1906 „ 18, 404/ i^-L.^xStlky, - 8 8 - - 



1908 ,, 18, 



1909 ,, 18, 



281) 

 281/ 



29 31 1 — 



2. The fj generation. 



(o) From the Silki/ ^. 



[Nature of mating FfPpii xffPpIi.'] 



In Figure 3 we have already indicated the results which are to be 

 expected from this form of mating. One quarter of the total offspring 

 should be completely unpigmented while the remainder should be 

 equally divided between the fully pigmented and the partially pig- 

 mented classes, the expected ratio being three fully pigmented, three 

 partially pigmented, aud two unpigmented out of every eight bird.s. 

 Moreover the ratio should be the same for each sex. In Table III the 

 results of six such matings between F^, birds are given. There is a 

 slight excess of fully pigmented % % due to the unusually high pro- 

 portion of such birds in one of the matings (1909, Pen 4, 329), but on 

 the whole the facts are in close accord with expectation. 



