ALLEN. — THE HEREDITY OF COAT COLOR IN MICE. 149 



parent probably supplied a gamete with the chocolate-yellow character, 

 so that a golden-agouti offspring with chocolate recessive was produced. 

 A somewhat similar process may have taken place in the case of golden- 

 agouti 9 4G9. One parent was chocolate, the other gray. A resolution 

 of the gray character into black and yellow-chocolate may have taken 

 place, and a gamete of the latter pigment-character, uniting with one 

 from the chocolate female 276, would i)roduce a golden-agouti with the 

 chocolate character in double strength, i)erhap8 segregable. In any 

 event, it seems clear either that the two golden-agoutis here considered 

 produced gametes, some with the pigment character which they them- 

 selves showed and others with the chocolate character, or else that there 

 is no necessary dominance of either pigment character over the other, 

 but that sometimes one and sometimes the other dominates. 



A number of crosses were made between golden-agoutis and albinos, 

 the results of which varied according to the nature of the albinos used. 

 Four golden-agouti mice were bred to albinos descended from gray 

 house mice and the writer's original stock of albinos. In a total of 

 thirty-five pigmented offspring, two were black and the others gray. 

 The albino parent of the two black young produced also four gray mice 

 in the same litter. Her ancestry is as follows : 



$ wh. 9 house mouse 



$ gr. 51 9 wh. 



$ wh. 145 9 wh. 141 



$ wh. 286 



The black character probably came through the albino stock, which, 

 as was pointed out in discussing the cross of black mice with that stock, 

 seemed to produce about 25 per cent of gametes with the black char- 

 acter. Moreover, a segregation of pigment characters must also have 

 taken place in case of the golden-agouti female, probably into chocolate 

 and either yellow or yellow-chocolate, else the black young could hardly 

 have resulted. For any other combination of the pigments indicated 

 wouLl have given gray, not black. The latter color, then, probably 

 resulted fi'om the combination of a gamete havinir the black character 



