96 



THE AMERICAN NATURALIST 



[Vol. LII 



mated inter se, they are considered as being homozygous. 

 If crossed they invariably produce blues. 



These facts have led to the current view that the case 

 involves a single allelomorphic pair of characters. The 

 blacks and blue-splashed represent the homozygous con- 

 ditions, while the self blue is the heterozygote between 

 the two. When blues are interbred, blacks, blues, and 

 blue-splashed are produced in a ratio approximating 

 1:2:1 for these classes, respectively, which seems to cor- 

 roborate this view. 



Although the blacks and blue-splashed breed true for 

 color, they are not recognized by fanciers as breeds or 

 varieties, and it is doubtful whether they would continue 

 to exist if, much to the disgust of the breeders of blue 

 Andalusians, they did not continue to appear as " wast- 

 ers" among the progeny of blues. The blues, on the 

 other hand, are quite widely bred. They are officially 

 recognized by the American Poultry Association as a dis- 

 tinct breed and have their place in the American Standard 

 of Perfection. It is interesting in this connection to note 

 that the numbers of blues they throw on the Mendelian 

 expectation barely gets them into the Standard, since the 

 rules of the Association are that no breed can be officially 

 recognized as such unless a minimum of 50 per cent, of 

 the offspring come reasonably true to type (American 

 Poultry Association, 1910, p." 328, Constitution, Article 

 XI). 



The blues are quite uniformly bluish-gray throughout 

 the body, with certain exceptions in the males to be noted 

 later. Emphasis has usually been laid on their distinct- 

 ness from the black and the blue-splashed birds, but it 

 seems important to note their resemblance to these two 

 classes. In the first place, they are like the blacks in being 

 seZ/-colored, that is, all feathers in all parts of the body 

 are pigmented. In the second they resemble the blue- 

 splashed in that the color of the individual pigmented 

 feathers is blue rather than black, save in certain sections 

 of the males of both classes, where the feathers showing 



