Revision of the genus Gyinnorhina. 9 



the nest was, but the old birds took no notice of it. What 

 puzzles me in this case is breeding true to colour in such cross- 

 mating ? Had the colours been mixed, explanation would not be 

 difficult. What are we to call the offspring in such a case, pure- 

 breds or cross-breds 1 " 



If the case of the black and grey crows of the Old World is 

 one of dimorphism, this is one of polymorphism, because of the 

 bills and backs and dimensions other than those of sexual 

 characters. 



The position of the genus, as I see it, is represented by one 

 species only, G. leuconota, Gld., with one variety, namely, that 

 having a black back, at present known as G. tibicen. Lath. 

 Where the variety begins and ends with the series of specimens 

 exhibited, one cannot well say. 



