THEORY OF EVOLUTION 45 



Another case of the same kind is known to 

 breeders of poultry. One of the most beautiful 

 of the domesticated breeds is known as the An- 



FIG. 15. Diagram illustrating a cross between special races 

 of white and black fowls, producing the blue (here gray) 

 Andalusian. 



dalusian. It is a slate blue bird shading into 

 blue-black on the neck and back. Breeders 

 know that these blue birds do not breed true 

 but produce white, black, and blue offspring. 



