872 



SCIENCE 



[N. S. Vol. XXXII. No. 833 



The expectation here is that all the off- 

 spring, both (? and ?, will be barred. 



Experimental Result. — There were 9 ma- 

 tings of this kind made. From these matings 

 were produced 62 d" and 61 2 chickens.* All 

 were barred. 



II. Mating: Pure B.P.B. ^ X Non-barred F, 

 Cross-bred $. 



Expectation : 



Bf .Bfxbf .bP = Bf . bf = Barred j^c?, 

 + Bf . 6f = Barred S2- 



The expectation here is that all the progeny, 

 both c? and 2, will be barred. 



Experimental Result. — There were 9 ma- 

 tings of this kind made. From these matings 

 were produced 27 d" and 37 2 chickens. All 

 were barred. 



III. Mating: Pure C.I.G.^ X Barred F^ Cross- 

 bred 2- 



Expectation: 



bf.bfxBf.bF=bf.Bf = Barred c^j?, 



-\-bf ■bF = Non-barred 22- 



The expectation here is that all the d pro- 

 geny will be barred and all the 2 non-barred. 



Experimental Result. — There were 4 ma- 

 tings of this kind made. From these ma- 



* In this and all of the following cases the num- 

 bers of offspring given denote the number which 

 survived until such time as they bore adult 

 plumage. It is impossible to make use of chicks 

 in the down plumage in the study of inheritance 

 of barring, because the barred pattern does not 

 appear in the down feathers at all but only in the 

 adult plumage. A full discussion of this point 

 will be found in our first paper on the subject 

 (too. cit.). In general the use of chicks in the 

 down plumage for the study of the inheritance of 

 pattern and color characters in poultry is open 

 to very serious criticism. The reason for this is 

 that in many cases there is no definite or fixed 

 relation between the color of the chick in the 

 down and in the adult plumage. A chick which 

 is pure white in the down may be black as an 

 adult: a chick which shows the down characters 

 of a Barred Rock may have the adult pattern of 

 a Game and so on. A full discussion of this 

 point, with definite statistical data will be pre- 

 sented in a later paper. 



tings were produced 53 c? chickens — all bar- 

 red — and 56 2 chickens — all non-barred. 



IV. Mating: Pure C.I. G. ,^ X Non-barred F, 

 Cross-bred 2- 



Expectation: 



bf -bf xbf -bF^bf . bf = Non-barred <?£?. 

 -f- bf ■ 6P = Non-barred 22- 



The expectation here is that all the progeny, 

 both d" and 2, will be non-barred. 



Experimental Result. — There were 4 ma- 

 tings of this kind made. From these matings 

 were produced 19 c? and 16 2 chickens, all 

 non-barred. 



V. Mating: F^ Cross-bred ^ X Pure B.P.B. 2- 

 Expectation: 



Bf ■ bf X Bf . bF = Bf . Bf = Barred d'd, 

 -{-bf .Bf= Barred dd. 

 -\-bf .bF — Non-barred 22. 

 -\-Bf ■ &F = Barred 22- 



The expectation here is that all the c? prog- 

 eny will be barred, and that of the 2 progeny 

 one haK will be barred and one half non- 

 barred. 



Experimental Result. — There were 6 ma- 

 ting? of this kind made. From these matings 

 there were produced 38 c? and 32 2 chickens. 

 All the (S<S were barred, and of the 22 13 were 

 barred and 19 were non-barred. 



VI. Mating: F^ Cross-bred S X Pure C.I.O. 2- 

 Expectation : 



Bf .bf Xbf .bF = Bf .bf = Barred J^, 



-{- bf ■ bf = Non-barred cjc?, 



■{-Bf. !)F = Barred 22. 



+ bf .bF = Non-barred 22- 



The expectation here is that barred and 

 non-barred birds will appear in equal numbers 

 in both c? and 2 progeny. 



Experimental Result. — There were 6 ma- 

 tings of this kind. From these matings were 

 produced 14 <S chickens, of which 9 were barred 

 and 5 non-barred, and 23 2 chickens, of 

 which 4 were barred and 19 non-barred.° 



VII. Mating: F^ Cross-bred,^ X Barred i*". Cross- ' 

 bred 2- 



Expectation : 



' For the probable explanation of this and other 

 deviations from the expected ratio in the case of 

 the 22. see below. 



