APPLICATION OF PRINCIPLES OF BREEDING 519 



secured in both cases by the 

 application of the same prin- 

 ciple of special mating, 

 breeding not the Standard- 

 colored bird of either sex to 

 a mate of the other sex of the 

 same shade of color, but the 

 male to a female of the color 

 and breeding of his dam, and 

 the female to a male of the 

 color and breeding of her sire. 

 There is, however, this differ- 

 ence in the cases compared: 

 when sexual differences in 

 color are exaggerated by a 

 standard, the application of 

 the principle keeps apart the 

 lines of breeding, or subvari- 

 eties. When a standard seeks 

 to make the sex color types 

 identical, the application of the 

 principle of special matings 

 tends first to fix the types and 

 finally to fuse the lines. Allu- 

 sion was made to this in the 

 paragraph relating to modified 

 black-red types. Nowhere 

 is the evidence of prog- 

 ress toward fusion of sex 

 varieties as marked as 

 in the evolution of the 

 Barred Plymouth Rock.. 

 From within a few years 

 after they were estab- 

 lished, the two lines have 

 been steadily converging. 

 The dark females with 

 indistinct barring, once 

 used in the male line, and 

 the nearly white males 

 with just a suggestion of 

 barring, once used in the 

 female line, are rarely 

 seen now. Crosses of the 

 two lines are occasionally 



FIG. 537. Light Brahma cockerel, owned by 

 H. B. Robinson, Reading, Massachusetts 



FIG. 538. Same as Fig. 537. Note how the pose 

 changes the apparent shape 



