Sushkin's Goose 79 



In some specimens, just as in A. segetum, is observable a slight admixture of white feathers 

 at the very root of the upper mandible." 



This comparatively short description is quite sufficient to indicate the main differences 

 in the plumage and the colouring of the bill of Sushkin's goose from its congeners — the 

 bean-goose and M. brachyrhynchus. But, regarding the structure of the bill, it will not be 

 superfluous to add the following details, as they will allow of the discrimination of this goose 

 from dry skins, the bills of which have lost their original colouring. Thus the bill of 

 Sushkin's goose is comparatively weak and narrow; from the bill of M. segehtm it is 

 distinguished by its far less depth at the base, and in particular by the feebler lower mandible, 

 of which the greatest thickness visible from without, when the beak is shut, varies between 

 6 and 6.5 mm. ( = 0.23-0.25 in.). In an adult M. neglectus and in a young female in first 

 plumage this dimension was only 5.5 mm. ( = 0.21 in.), while in all the specimens of 

 M. segetum examined the greatest depth of the lower mandible under the same conditions 

 varied between 7I- and 11 mm. ( = 0.29-0.43 in.). A still more marked difference is 

 presented by the shape and comparative size of the nail on the upper mandible; but to 

 describe this distinction is more difficult than to express it by a sketch, which I have 

 accordingly done. 



As to the number of teeth on the sides of the upper mandible (a feature on which I 

 laid great stress when I began to study the geese, but which I afterwards had to acknowledge 

 to be lacking in constancy), this varies in adults between 25 and 28, while in two young 

 specimens I found 23 and 24 of these teeth respectively, which again convinces me that the 

 number of teeth in geese increases up to a certain age. It is thus evident that, in freshly 

 killed birds, when the colouring of the soft-parts has not yet lost its true tint, Sushkin's 

 goose may be distinguished from all its nearest kin without any trouble, and if there exist a 

 resemblance, in the colouring of bill and legs, between this goose and M. brachyrhynchus, 

 the dimensions of the bill and different colouring of the wing-coverts of the latter will at 

 once afford a distinction. 



In his description of this goose, Dr. Sushkin mentions the fact that in certain 

 examples, "as in M. segetum, there is observed a slight sprinkling of white plumules at the 

 very base of the upper mandible." 



In the notice of M. segetum it is stated that I have personally never seen these white 

 feathers in specimens of this latter species ; but, as appears from the above remarks of Dr. 

 Sushkin, as well as from the observations of an individual fully competent to discriminate 

 between the bean-goose and the yellow-bill, whitish but not white or grey-white feathers 

 are sometimes to be met with at the base of the upper mandible in the bean-goose. 

 Although I have no right to doubt this statement, I must suppose that, if such white or 

 whitish plumules are to be met with in the bean-goose, it is only in a very limited number, 

 not comparable with what we see in the yellow-billed goose. I should, therefore, much like 

 to know to what extent these white feathers may sometimes manifest themselves in 

 Sushkin's goose, and to this point I may direct the attention of ornithologists and 

 sportsmen. 



As regards the disposition and depth of colour of the plumage in Sushkin's and the 

 bean-goose, I have been unable to find any distinctive differences ; the more so since the 

 bean-goose is subject to very considerable variations in colour. Some examples of the 

 latter species are, for instance, very dark, probably owing to age. 



