Eastern Bean-Goose 129 



accordingly the number of teeth (25) in the bean-goose (with vermilion band) killed by 

 Mr. Pike in Holland offered no obstacle to my assigning it to M. segetum. 



All this taken together removed any doubt as to assigning the Anadyr specimens 

 of bean-geese to the eastern M. segetum serrirostris ; and I arrived at the conviction that a 

 slight dimorphism (limited in this case to the colouring of the band on the bill), analogous 

 to that existing in the typical western M. segetum, occurs also in the eastern representative 

 of the species, M. segetum serrirostris, which beyond considerably larger dimensions 

 (especially of the bill) does not differ essentially from the former. 



Even the white patches at the mental angle, met with in the Anadyr examples 

 (in two of those brought by Sokolnikov), do not offer anything remarkable, since we have 

 seen that such occur also in typical bean -geese, as shown in Mr. Buturlin's collection 

 from Kolguev. The presence of white plumules, in greater or less number, in some 

 specimens both of the Western and the Eastern Siberian bean-geese is indeed a very 

 strong argument against the distinctness of yet another goose, namely, the thick-billed 

 Melanonyx mentalis of Oates. 



Indeed, once we are compelled to reject as worthless the character of " white chin" 

 in the thick-billed goose, we are left only one specific feature — the unusual massiveness 

 of the bill, which is mainly expressed by the great depth of the lower mandible. 



Not having, however, at present, the right to absolutely reject the specific distinctness 

 of the thick-billed goose, I pass on to record its alleged distinctive features and such 

 facts as are known concerning its distribution. 



