132 Experime7ital Zoology 



"The white Cochin has no sexual dimorphism in plumage color, 

 while the Tosa fowl is strongly dimorphic. Every one of the 

 first hybrids is dimorphic in plumage coloration, the two sexes 

 resembling, except for the white, respectively the female and the 

 male Tosa fowl. It is striking to see how from a germ-cell of 

 the male Tosa fowl either a bird colored Hke the male Tosa or a 

 bird colored hke the female Tosa may arise. The male germ- 

 cells contain the Anlagen not only of the male characteristic but 

 also of the female characteristic." 



In another case two races, both having sexual differences, were 

 crossed. These were the Tosa and the dark Brahmas. The 

 hybrids were also sexually different, showing the dominant color 

 of their respective sex. Thus the red wing- bar and white wing- 

 bar are found in the males, and the shafting and penciling of 

 females in the female hybrids. 



There are two races of fowls that have aberrant feathers. In 

 the Frizzled jowl (Fig. 13 ; 2) the contour feathers have a shaft con- 

 vex inward so that the feather is lifted up and even turned forward. 

 The primaries of the wings show groups of the barbs that are 

 twisted in corkscrew fashion. In the Silky fowl (Fig. 13;!) the 

 contour feathers are like down feathers, with a weak shaft, and 

 the barbs are subdivided, producing a fluffy effect. The quill 

 feathers of the wing and tail are less modified. The Silky fowls 

 used in the experiments were white, the Frizzle were dark (black, 

 red, and buff). 



Some of the hybrids were white (Fig. 13 ; 4) and some were dark 

 (77.4 per cent). Here the white is neither dominant nor reces- 

 sive, but the explanation of the result is not clear unless one or 

 both races are impure in their color inheritance. None of the 

 hybrids showed any silkiness, which is, therefore, seen to be reces- 

 sive to non-silkiness. Only 6 of the 10 hybrids were frizzled, the 

 other four having flat feathers. Davenport explains this ap- 

 proach to equal numbers on the ground that his frizzled animals 

 produced both frizzled and plain bearing germ-cells. 



In another cross the breed of black-breasted red Game 

 (Fig. 14; 2), in which the tail and rump are entirely absent, was 



