POULTRY NOTES — 1909. 89 



Let P denote "femaleness," i. e., the 5 sex character. 



Let / denote absence of F (i.e., "maleness" by difference, 

 a? it were). 



Let B denote the barring factor. 



Let h denote the absence of B. 



Then a pure B. P. R. J* has the gametic formula Bf . Bf 



and " " B. P. R. ? " " " " hF . Bf 



" " C. L G. c^ " " " " bf . bf 



" " C. I. G. ? " " " " bF . bf 



Then the mating B. P. R. c^ x C. L G. $ would be sym- 

 bolically 



Bf.Bf X bF.bf = Bf.bf (barred <^) +Bf.bF (barred ?) 

 the offspring of both sexes being heterozygous with reference 

 to barring. 



The reciprocal mating is symbolically 

 bf.bf xbF.Bf=bf.Bf (barred d") + bf .bF (non-barred $) 

 the non-barred $ oft'spring being homogygous with regard to 

 the absence of barring. 



It is evident, without further discussion, that the experimental 

 results set forth above are, so far as they go, precisely what we 

 should expect to get if Spillman's hypothesis is correct. In so 

 far they support that hypothesis. They do not. of course, 

 demonstrate that another hypothesis might not be devised which 

 would fit the facts equally well. 



The barred pattern obtained in these hybrids is not the same 

 as that exhibited by the parent Barred Plymouth Rock stock. 

 A detailed description of the points in which the hybrids dift'er 

 in color from the parent stock is given in the complete paper 

 and cannot be repeated here. Some of these points of dift'er- 

 ence are shown in Fig. 78. 



Sex-limited inheritance, in which a particular somatic char- 

 acter is correlated with sex in a definite way, is now known to 

 occur in a number of cases. In poultry we have besides the 

 inheritance of barring as worked out by Spillman, Goodale and 

 the present writers, and on the other hand, the inheritance of 

 "Bankiva" pnd "Erown-red" color pattern in game bantams 



