MENDELISM AND SEX 149 



order as that we have just considered in the currant 

 moth. For Miss Durham's experiments seem to show 

 that while the male black-eyed canary* is pure with 

 regard to that character, the female is hybrid and 

 carries the pink-eye (or, in reality, the cinnamon 

 character)"!" recessive. It will be remembered {supra 

 page 147) that among moths the 7nale grossu- 

 lariata was similarly pure with regard to the lacticolor 

 character, while the feinale was hybrid. 



In canaries the existence of this remarkable 

 condition is shown by the different nature of the 

 offspring in the reciprocal crosses. For when male 

 " black eye " is crossed with female " pink eye," 

 all the offspring are black-eyed, both the males 

 and the females. But when male " pink-eye " is 

 crossed with female " black-eye," then among the 

 offspring all the males are black-eyed and all the 

 pink-eyed are females. I The result is thus one which 

 follows from a mating of the ordinary Mendelian 

 kind, namely, D R x R giving \ D R +1 R R (see 

 table of Mendelian matings, page 69). In this case 

 the female black-eyed bird is the D R, and the 

 pink-eyed male is the R R. The black colour of the 

 eye is dominant = D, and the pink-eye, or absence 

 of blackness, is the recessive = R. 



The new fact which these experiments reveal is 



* It does not matter whether the black-eyed canary is a " green " 

 or a yellow one. 'I'lie result is the same 



t In addition to the eye characters the cinnamon further differs 

 from green canaries in having light brown (cinnamon) markings 

 instead of black ones. This colour is due to chocolate pigment. 



I Four exceptions occurred in which the hens were black-eyed, 



