THE INHERITANCE OF THE MUZZLE COLOUM 



347 



TABLE II. 

 P-buU no. 100 gave the following descendants. 



PXP=12P P 



XM=|^ 



3P 

 K 



PXK: 



3. There is a yellow pigment factor epistatic to the intensity factors 

 producing dark pigment. The flesh coloured muzzle is due to 

 the presence of this yellow pigment factor or to the absence of 

 the intensity factors. 



The first hypothesis seems to be out of the question because of 

 two facts. The flesh coloured muzzle would be recessive in all cases 

 according to the first hypothesis, but the work of Wriedt (3) showed 

 that flesh coloured muzzle in English red polls was dominant to 

 pigmented muzzle in Norwegian red polls. Furthermore, crosses 

 between pigmented muzzles in the heterozygous state would give 

 rise to a much greater number of flesh coloured muzzles than is shown 

 to be the case in the tables. For the P-bulls as well as the P-cows 

 listed in the tables are mostly heterozygotes with regard to the muzzle 

 colour. 



There is na real difference between the second and third hypo- 

 thesis. In the third it is assumed that the inhibiting factor is a 



