No. 631] COLOR CLASSES IN DOVES AND CANARIES 169 



rence of dark-eyed females, no mention is madt of their sfn-ilit/i 

 nor of the occurrence of Class b(3 . pink-eyed males, although 

 the lutt< r should liare appiared with approximately equal fre- 

 quency. "When one considers the amount of canary breeding 

 which has been done, and is still being continued and the fact 

 that breeders have long recognized the exceptional dark females, 

 the continued absence of the expected pink-eyed males becomes 

 a real objection to the acceptance of any hypothesis which calls 

 for their appearance. 



(c) Non-disjunction in the female: 



It will be noted that this type of non-disjunction fails, as it did 

 in doves, to account for the observed exceptional dark-eyed 

 females. 



Further if we now consider the reciprocal cross of dark-eyed 

 male X pink-eyed female, we shall find that the only type (ft) of 

 non-disjmietirm which is able to account for the exceptional color 

 class above recorded demands a type of result as yet not reported. 



o) If no non-disjunction 5 forms fppFFMm 



gametes PFM jpFMandpFm 



&) If non disjunction in the male; PPFFMMand) CpFMand 



forms gametes - J jpFM 



o) If non-disjunction in the female ; JppFFMm and 



forms gametes PFM j — 



The following classes of zygotes will be expected : 

 (a) If no non-disjunction : 



No exceptions have been recorded. 



