COAT CHARACTERS IN GUINEA-PIGS AND RABBITS. 



2.3 



tion whatever as to what color types will prevail in one as compared 

 with another, nor as to what proportion of the young will be devoid of 

 color, it would seem desirable, to avoid confusion, that the law be re- 

 named as something other than a law of heredity. 



ALBINISM AND SEXUAL PREPOTENCY. 



Galton ('97), on purely empirical grounds, was inclined to think 

 the male sex prepotent in the transmission of black spots in the case of 

 Basset hounds. Though I have elsewhere (Castle, : O3 b ) shown that 

 the conclusions which he drew from that study were probably erroneous 

 because they rested on false assumptions, it may be worth while in 

 this connection to test the idea of sexual prepotency in regard to 

 albinism. This may be done by comparing the results of reciprocal 

 matings, as shown in Table C, which contains a summary, as regards 

 the production of albino young, of most of the matings made up to this 

 time. Only matings between pigmented parents of undetermined 

 character as regards recessive albinism have been omitted from this 

 summary. These omitted matings produced several hundred young, all 

 pigmented, as was to be expected if either one or both pigmented parents 

 were free from recessive albinism. From Table C it is evident that, (i ) 

 when a mating is made between a hybrid pigmented and a pure pig- 

 mented animal the result is the same whether the hybrid be father or 

 mother; in every case the young are pigmented ; (2) when a mating 

 is made between a hybrid pigmented animal and an albino, hybrid 

 pigmented and albino young are produced in approximately equal 



TABLE C. Proportions of pigmented (p.) and albino (.) young- produced by 



matings of various sorts. 



numbers, viz, 120 pigmented to 116 albino young when the albino 

 parent was a male, 91 pigmented to 98 albino young when the albino 

 parent was a female. The deviations from equality are very slight 

 and unquestionably the result of chance. In the one case the deviation is 

 2 individuals in a total of 236 ; in the other, it is 3.5 in a total of 189 

 young. There is, accordingly, in this case no evidence of prepotency 

 in the transmission of albinism on the part of either sex. 



