358 H. FLNKOLIST 



That M is able to originate from K X^' may be due to the cir- 

 cumstance that K in one or both of the parents is caused by a yellow 

 pigment factor (or an inhibiting factor). It is also a question if the 

 mixed muzzle always belongs to the variation series of the pigmented 

 muzzle. A mixed muzzle constituted for instance GgPPPiPi might 

 originate if the yellow pigment did not cover the dark one. However, 

 the mixed muzzle has probably as a rule the constitution ggPpjhPi or 

 ggppPiPi. It may also be due to incomplete dominance involving 

 another factorial combination within the dark pigmented series. The 

 following genealogical table shows such a case. 



cj"-calf no. 51, born -^m 1910 

 muzzle colour P 



cf no. cS2r) ^ no. 746 



muzzle colour M muzzle colour A' 



Ö no. 11Ü 5 no. (U2 ^^ no. 98 S no. ()16 



muzzle colour A' muzzle colour P muzzle colour M muzzle colour P 



No. 51 should belong to one of the genoty})es ggPPP\P\, ggPPPi]),, 

 ggPpPiPi, ggPpPiPx- ggPPpiPi or ggppP\P\ according to my hypo- 

 thesis, but this would have been impossible, if no. 826 had the con- 

 stitution ggPppiPi or ggppP\p\ because of the fact that no. 746 from 

 the cross M X P must have the constitution ggppp\p\- Provided that 

 the mixed muzzle of bull no. 826 or bull no. 98 do not originate 

 from the incomplete covering of the yellow pigment, the constitution 

 of bull no. 826 is probably identical with one of the genotypes of 

 the P-animals just stated. 



The mixed muzzles in the following genealogical table may have 

 the constitution ggppPiPi or ggPppiPi as the flesh coloured muzzle 

 of no. 892 may belong to the colour type produced l)y the yellow 

 pigment factor. 



c^-calf, born V^ 1917 

 muzzle colour P 



^ no. 892 ■ $ no. 786 



muzzle colour A' muzzle colour M 



o^no. 110 $ no. 511 ^ no. 100 2 no. 544 



muzzle colour A muzzle colour A muzzle colour 7^ muzzle colour A 



The examination of the descendants from the P-bulls nos. 110 

 and 117 strengthens the belief that sometimes mixed muzzles appear 



