1 82 Geese of Europe and Asia 



birds together. The classification of birds, and of animals generally, still contains, how- 

 ever, much that is quite unintelligible. 



The swan-goose, under the name of the Chinese goose, is very widely spread in the 

 domesticated state, and is just as tame in this state as the ordinary domesticated grey goose. 

 Externally the swan-goose shows, however, a considerable difference in the structure of 

 the bill, the slight swelling at the base of the bill in the wild bird being converted in the 

 tame breed into a large round tubercle, of such a size that it quite changes the whole 

 outward appearance of the head, while at the same time the bill becomes shorter and 

 thicker. Pallas supposed that this development might be due to crossing with the mute 

 swan, but it is hardly needful to have recourse to such a hypothesis, as apparently the 

 rudiment of a gland in the wild swan-goose, under the influence of food and a different 

 mode of life, assumes abnormally large proportions. It is also a curious fact that in the 

 domesticated birds, which retain more or less the colour of their wild ancestors, the bill 

 remains black, while in the white breed the bill becomes red. The tame breed of this 

 species considerably exceeds the wild form in size, being sometimes of very large size 

 and weight. I think there is little doubt that it was large birds of this type, with the 

 colouring of their wild congeners, — perhaps a cross between wild and large tame birds, — 

 that were noticed by Gmelin and then described by Pallas under the name of A user 

 grandis, as it seems impossible to make this description fit any other known species of 

 goose. 



