x] The Cinnamon Canary 179 



Miss Durham has begun a series of experiments 

 designed to investigate the problem constituted by these 

 facts, but the work has not yet gone far enough to provide 

 a complete solution. She finds (i 18) that, as stated, 



1 i ) Cinnamon $ x pure green $ gives all offspring of 

 both sexes black-eyed. 



(2) Green $ x Cinnamon $ gives in general F l cocks 

 black-eyed, and F^ hens pink-eyed. Two black-eyed hens 

 of unknown breeding mated to Cinnamon cocks have also 

 given, in addition, black-eyed hens as well as pink-eyed hens. 

 This result is exceptional. 



(3) Cinnamon $ x F l black-eyed $ gives all four types, 

 black-eyed cocks and hens, and pink-eyed cocks and hens. 



(4) Green $ x /\ black-eyed $ gives cocks all black- 

 eyed, and hens of both types, black-eyed and pink-eyed. 



The mating of F l black-eyed hens (from Cinnamon $ x 

 black-eyed $) x Cinnamon $ has not yet been made, but 

 there is little doubt that such a pair of birds will give the 

 same results that are obtained in mating (2). 



As regards the descent of the pink-eye there seems to 

 be no difference in result whether green or yellow black- 

 eyed birds are used. 



The general run of these experiments is now intelligible. 

 The case is evidently comparable with that of Abraxas 

 grossulariata and lacticolor. Were it not for the occasional 

 production of black-eyed hens from green $ x Cinnamon $ 

 the whole series of results could be represented in one 

 simple scheme. That exceptional occurrence proves of 

 course that there is some further element to be considered, 

 but neglecting that for the present, the scheme of descent is 

 as follows. As before, we take female as heterozygous, 

 femaleness being dominant, and we assume that there is 

 spurious allelomorphism between femaleness and the black- 

 eye factor. 



The allelomorphs are 



, , presence and absence of femaleness. 



B, b, presence and absence of the factor for black eye. 



The "pure" green hen is thus $$Bb, being, as experi- 



12 2 



