346 



H. FUNKQUIST 



TABLE I. 



colour in some of the bulls most extensively used has been followed, 

 and the results are put together in the tables to follow. Wholly pig- 

 mented animals are called P, the mixed ones are termed M, and the 

 flesh coloured K. 



The tables show that at least two pair of factors are involved 

 in the crosses between dark pigmented (P) and flesh coloured muzzles 

 [K). Either P or K would be dominant if only one pair of factors 

 was involved. It is found, how ever, that P X ^ is able to give K, 

 and Ky^K give rise to P. P X ^ would not give rise to K if P was 

 recessive, and K X K would not give P if K w^as recessive. The 

 intensity of the colour varies greatly among the dark coloured 

 muzzles. This variation is probably due to the presence of different 

 intensity factors. It is difficult to explain the numerical relations 

 found in another way. 



In order to explain the inheritance of the muzzle colour three 

 hypotheses have been tried. 



1. Provided that a fundamental factor is present the dark coloured 

 muzzle is produced by one or more intensity factors. If the 

 fundamental factor or the intensity factors are wanting, the 

 muzzle becomes flesh coloured. 



2. There is an inhibiting factor preventing the intensity factors to 

 act. The flesh coloured muzzle is due to the presence of this 

 inhibiting factor or to the absence of the intensity factors. 



