COAT CIIARACTEHS IN GU1NKA-P1GS AND RABBITS. 27 



agouti, showing alternative dominance with respect to it. When this/ 

 result was obtained I at once questioned the purity of 9 2018, suspect- 

 ing that she might contain recessive black, but her purity has since been 

 established with considerable probability by a mating with albino cf 635, 

 neither of whose pigmented parents was an agouti. This mating 

 produced 4 young, all agouti or agouti spotted with red. Previously 

 9 2018 had been mated with agouti c? 2017, producing 3 agouti young. 



Further support for the idea that agouti and black may show alter- 

 native dominance is afforded by matings of hybrid agouti (albino)* 

 9 2020. This animal contained recessive albinism in which black 

 apparently was latent. For, when mated witli agouti c? 2017, she 

 produced 2 agouti and 2 black young, indicating that at least half her 

 gametes bore the black character, and that this dominated over agouti in 

 at least two out of four cases. When mated with albino c? 2039 she pro- 

 duced i albino, i spotted white >f red-black, and i spotted red-black 

 young. Mated with hybrid red (albino) c? 1019, she produced 2 black 

 > red young. Manifestly only part, if any, of this female's gametes 

 bore the agouti character, though all apparently bore the character 

 black, either in the agouti combination or in the segregated state. 



Again, an agouti daughter of 9 2020 by agouti c? 2017, viz, agouti 

 (black?) 9 IO 35> when mated with albino <$ 2059, produced 2 agouti > 

 red, and 2 black > red young. This result indicates that 9 1035, 

 like her mother, formed gametes, half only of which bore the agouti 

 character, half the black character. But the black character is appar- 

 ently present in 9 1035 as a simple recessive, not latent in recessive 

 albinism as in her mother ; for the mating of 9 1035 with albino 

 cT 2059, though it produced 4 young, gave no albino offspring ; and 

 a subsequent mating with white > red-black (albino) cf 1631 like- 

 wise gave no albino offspring, but i agouti and i black-red young. 

 This 9 1035 undoubtedly arose from the union of an agouti gamete fur- 

 nished by the father (since he was shown by breeding tests to be pure) 

 with a gamete bearing the black character furnished by the mother, 

 9 2020. But if 9 1035 does not contain recessive albinism, the gamete 

 furnished at her formation by 9 2020 can not have been an albino 

 gamete. It would seem then that 9 2020 furnished certain gametes 

 bearing black, not latent in association with albinism, but active. If so, 

 she must have borne two different pairs of contrasted pigment poten- 

 tialities, viz, (i) centripetal pigmentation -vs. albinism; (2) agouti 

 pigmentation vs. black pigmentation ; and she must have transmitted 



* A character indicated thus in parentheses is present in a recessive condition. 



tThis symbol is used to indicate inequality in the extent of body areas of 

 different character as regards pigment. Thus, white > red means an animal 

 with more white than red fur on its body. 



