W. Bateson and R. C. Punnbtt 



193 



(/3) From the Silky %. 



[Nature of mating, FfPpIi x ffPjjIi.] 



As indicated in Figure 4 expectation is here different from that in 

 the preceding case where the F^ $ was from the cross Brown Leghorn $ 

 X Silky (/. The slightly pigmented F^ $ is here heterozygous for the 

 inhibitor factor; /, and there comes into play the repulsion between 

 / and F so that all the male gametes produced by such birds contain /, 

 while this factor is carried by none of the female gametes. From this 

 mating therefore we should not expect any fully pigmented males since 

 every bird of this sex must contain /. Nevertheless, as the data in 

 Table IV show, many of the males resulting from this mating were recorded 

 as being heavily pigmented. By far the greater number of chicks in 

 this generation were killed and recorded on hatching, and a peculiarity 

 of the (^^ booked as fully pigmented lay in the fact that the toes of 

 these birds were always light in colour. We regard these birds as of 



