3O COAT CHARACTERS IN GUINEA-PIGS AND RABBITS. 



The following experiment likewise bears upon the point which is 

 under discussion. Agouti <? 2017, mated with albino 9 785, produced 

 3 agouti and i agouti > red young (as stated on p. 29). The albino 

 9 785 was born of albino parents, but part of her grandparents 

 and great-grandparents were spotted black-red-white, part of them 

 albinos; none were agouti-marked. It seems probable, therefore, 

 that the pigment characters latent in the gametes of 9 785 were in 

 everv case black-red. If so, her agouti young should contain recessive 

 white with which black-red had been introduced as a latent constit- 

 uent, and should, as explained on page 28, form in equal numbers 

 gametes of four sorts, viz, agouti, black-red, albino [agouti latent], 

 albino [black- red latent]. If two such sets of gametes be combined 

 (as in mating these hybrid young) , and all gametic unions prove equally 

 fertile, their young should be, on the hypothesis that agouti is dominant 

 over black-red, in the proportions 9 agouti to 3 black-red to 4 albino; 

 but on the hypothesis that agouti and black-red are alternatively domi- 

 nant, the young should be in the proportions 6 agouti to 6 black-red to 4 

 albino. That is, on one hypothesis, agouti young should be three 

 times as numerous as black-red ; on the other hypothesis, both sorts 

 should be equally numerous. The result observed is 7 agouti to 3 black- 

 red to 3 white, which certainly favors the hypothesis that agouti domi- 

 nates over black-red, though the number of young is undesirably small. 



The details of the experiment follow : 



Other matings of agouti cf 1509 support the hypothesis that agouti 

 gametes dominate over black-red ones. Thus he was mated with three 

 different albino females derived from the same black-red-white spotted 

 stock as his mother. The gametes of these females undoubtedly trans- 

 mitted the black-red, never the agouti character. On the hypothesis 

 that agouti is dominant over black-red, the young produced by these 

 matings should be in the proportions, 2 agouti to 2 black-red to 4 albino ; 



