ALLEN, — THE HEREDITY OF COAT COLOR IN MICE. 137 



coat. Ill the cases cited by Bateson, therefore, chocolate seems to be 

 present as a character recessive toward black ; for, except in the cases 

 noted, black breeds true and is dominant over chocolate. Bateson's 

 white females, A and B, were probably from chocolate parents, and so 

 transmitted that pigment character only, for when bred to the heterozy- 

 gous male, A, they both gave black as well as chocolate offspring, but 

 when bred to chocolate males, chocolate pigment alone was produced. A 

 third albino female, D, was probably heterozygous with respect to the 

 black and the chocolate characters, for she gave young of both these 

 colors by a chocolate male. In all cases where chocolate mice were in- 

 terbred, chocolate was the only pigment obtained. The possibility of an 

 alternative dominance of the one color over the other should not be lost 

 sight of, but the writer's experiments do not clearly indicate such a 

 relation. 



The relation of the black to the yellow character was tested by breed- 

 ing black mice to golden-agoutis. Each animal in this mating had the 

 chocolate pigment present in the hairs, and the union of the two 

 brought together all three of the pigment elements. Hence the cross 

 might be expected to produce gray animals, and perhaps those of other 

 colors as well, if the pigment characters undergo resolution. In the 

 course of the writer's experiments three black mice, sisters, were bred to 

 a golden-agouti male, their brother. The ancestry of these animals, so 

 far as known, was as follows : 



(J bl.-wh. 1 • 2 b. 9 wh. 



i bl. 92 9 gr. 91, 93, 97 



S gold.-ag. 225 9 bl. 221, 222, 223 



Three litters were obtained by this mating, giving a total of 7 gray 

 and 2 black mice. 



In a second case a golden-agouti male (485) was bred to an albino of 

 black parentage, so that the union of the pigment characters was simi- 

 lar to that in the previous case. The three young obtained from this 

 pair were all gray. Davenport (: 04) records a somewhat similar case, 

 in which a cross of a black with a yellow mouse resulted in a single gray 

 young. Bateson (: 03'') states, further, that Miss Durham by crossing 



