GENHRAL TOPICS IN INHERITANCE. 95 



the females (p. 21), and this is true not only in the first generation, but also 

 in the extracted whites of a later generation. 



IVhiic Leghorn and Rose-comb Black Minorca. — In the first generation the 

 male hybrids were almost without exception pure white ; the female hybrids 

 invariably show some black-speckled feathers. 



Tosa fowl and White Cochin Bantam. — In the first hybrid generation, as 

 stated, the males had all feathers of male Tosa coloration, but barred with 

 white. The females had the Tosa hen coloration, but with shafting broad- 

 ened. Here each sex inherits the corresponding characteristic plumage of 

 the Tosa fowl modified by the white of the Cochin, but in different fashion 

 for each sex. Barring or cuckoo marking seems, indeed, a prevailingly male 

 characteristic. Hurst (1905, p. 133), in crosses of White Leghorn and 

 Houdan, got, in addition to white hybrids, ri dark birds ; of these the 6 

 pullets were black ; the 5 cockerels were barred. 



In the F, generation I obtained extracted pure (?) male and female Tosa- 

 fowl plumage as well as pure whites (p. 49). 



Dark Brahma {female) and Tosa Jowl (male). — -Here both races are 

 dimorphic. The female hybrids closely resembled in coloration the female 

 Tosa fowl, except that the contour feathers were penciled as in the Brahma. 

 The male hybrids closely resembled in coloration the male Dark Brahma, 

 except that much more red and less white appeared on the wing bars and 

 wing bows. Both sexes inherit some qualities from the corresponding sex 

 of each of the parent species. Again, the males have a yellow foot like their 

 mother, whereas the females have a willow foot like their father. The hybrids 

 of either sex inherit foot-color from the opposite sex of their parents (p. 54). 



TRANSFER OF SEXUALLY DIMORPHIC CHAR ACTKRISTICS FROJI ONE SEX TO THE OTHER. 



Secondary sexual characters, such as have been referred to in the la.st .sec- 

 tion, seem indissolubly associated with their corresponding sex. The reason 

 for such an association is obscure, but it is known that it is not due to the 

 absence in the protoplasm of the characteristics of the opposite sex, for these 

 may develop in the individual when the germ glands are removed. The germ 

 glands, then, control the latency of the one set of characters and the patency 

 of the other set. In poultrj' the removal of the sex glands from a young 

 cock, in the process of caponizing, results in loss of the crowing instinct and 

 failure of comb, wattles, spurs, hackle, saddle, and .sickles to acquire the 

 size characteristic of a cock. If in the fowl the germ glands fail to develop, 

 the secondary sex characters are ambiguous. 



Despite this apparently physiological dependence of secondary characters 

 in the germ gland, it .seems improbable that the association is a necessary 

 one. Almost all characters can be dissociated ; why not also sex and second- 

 ary characters? There is reason to think much can be done in this way, 

 because something has already been accomplished. For example, the cereb- 



