,'^18 



MR. C. C. HURST : EXPEBIMENT.VI; STUDIES 



The apparently pure grey has so far bred true in tlie third 

 generation, but tlie numbers are not yet sufficient to test 

 the matter definitely. The hybrid greys give a mixture of greys 

 and blacks in Mendelian proportions. Owing to dominance, 

 the pure and hybrid greys are indistinguishable in appear- 

 ance, and can only be determined definitely by experimental 

 breeding. 



In regard to the greys, an interesting complication was 

 observed. The original grey used was a pure yellow-grey, con- 

 taining more yellow pigment and less black than the ordinary 

 wild grey. The greys o£ the first, second, and third generations 

 were all wild greys, and, so far, there has been no return to the 

 original pure yellow-grey. 



Self-colour and Dutch onarJcings. — So far as the experiments 

 go, these characters appear to be neither dominant nor recessive 

 to one another, but give variable intermediate marked hybrids in 

 the first generation. Segregation into the three forms in Men- 

 delian proportions, however, takes place in the second generation, 

 and, so far, the extracted self-coloured and Dutch-marked forms 

 have bred true in the third generation, while the intermediate 

 marked hybrids give the three forms again in accordance with 

 the Mendelian principles. 



Latent factors in Albinos. — With regard to simple albinism, 

 albinos of any ancestry so far breed, true, the factor for normality 

 being apparently eliminated in accordance with the Mendelian 

 principles. 



"With regard to characters other than albinism, hut compatible 

 loith it, such as short and Angora coat, these are carried by 

 albinos in either a patent or recessive state. With regard to 

 characters other than albinism, but incompatible with it, such 

 as grey and black coat, self-colour and Dutch markings, these 

 are also apparently carried by albinos, but in a latent state 

 only. 



Grey and hlacTc coat. — Albinos of the same ancestry extracted 

 from hybrid greys, containing recessive black, so far appear to be 

 of two kinds, viz. : — albinos carrying black, and albinos carrying 

 grey and black. 



Pure-bred albinos, with all albino ancestors for at least eight 

 generations, and probably many more, so far appear to be of the 

 same two kinds. 



