Genus Melanonyx, Buturlin (1901 



Before proceeding to describe the various species and races of geese for which Mr. S. A. 

 Buturlin in 1 90 1 established the genus Melanonyx (as a sub-genus), I consider it advisable 

 to discuss the validity of this group, and at the same time to give a short sketch of the 

 same, since it is impossible to do this when describing its individual members. This 

 is mainly owing to the fact that these geese have been so mixed up and confused, not only 

 by sportsmen, but by the majority of ornithologists of all countries, that it is now almost 

 impossible to unravel the entanglement; and to refer any of the recorded observations 

 to species with which they perhaps have nothing to do would be worse than to pass them 

 over. There are, of course, exceptions, and wherever it has been found possible to refer 

 with certainty observations to the proper species, the reader will find them in their place 

 in notices devoted to such species. 



First of all, I may state that I regard Melanonyx as rightly distinguished and 

 properly characterised by the author of Dikie gusi Rossiiskoi imperii, and, moreover, that 

 it is entitled to full generic rank. In one detail the definition of the genus given by the 

 author leaves room for emendation. Mr. Buturlin writes: "Anseris sub-genus novum, 

 rostro carneo aut flavescente aurantiaco, basi dertroque nigris, fronte fusco-grisea, albo 

 поп fasciata, abdomine griseo, nigro haud fasciato." 



The character I have underlined in this diagnosis is not applicable to the whole 

 genus, and even in the adult yellow-billed bean -goose the feathering at the root of the 

 upper mandible is almost always white, while in certain other species it is sometimes 

 white, either in the form of a more or less broad fringe, or white patches. As regards 

 the yellow-billed bean-goose, the white feathering on the forehead at the base of the 

 upper mandible sometimes attains a breadth of as much as 15 mm. (= 0.59 in.). 



Only in the first year or two, and again in very old age, in this species, are the 

 white plumules bordering the base of the bill ever completely absent, as has been 

 demonstrated by observations on specimens kept in captivity in the course of several 

 decades. Moreover, the white feathering either in the shape of separate plumules or in 

 the form of a definite patch of varying size, or occupying the mental angle, or even, 

 as an exception, the whole chin, is met with occasionally in Ж arvensis, M. segetum, 

 M. segetum serrirostris, M. mentalis, and probably some others. 



As to the black nails of both mandibles and the black base of the bill, in connection 

 with the coloured band on the bill and the absence of black patches on the under-parts, 

 these characters are quite constant, and sharply distinguish the group Melanonyx from 

 all other grey geese. Indeed, only in very old individuals of the yellow-billed bean- 

 goose is the whole bill to the base occasionally yellow-orange, and then only on the 

 culmen, between the nares, is a black longitudinal band retained. It should be added 



72 



