Genus Melanonyx 73 



that, in contradistinction to the representatives of the genus Anser, in the species 

 of the genus Melanonyx the teeth along the edges, in those spots where the mandibles 

 are coloured black, are of a dark instead of a light hue. 



In view of the similarity of colouring and arrangement of the pattern of the 

 colouring occurring in all the species of this genus, with the sole exception of the 

 short-billed goose [Melanonyx brachyrhynchus), it would sometimes be difficult, or even 

 impossible, to determine from skins alone to which species they belong, were it not 

 for the bill, which almost always permits us to decide with which goose we have to deal ; 

 and this, too, in spite of any alteration in colouring, which is the more important 

 seeing that the light areas of the bill rapidly change after death. 



The structure and form of the bill, the comparative size and shape of its nails, 

 and the number of teeth along the tomia of the upper mandible afford, for the most 

 part, such constant and decisive characters that, when taken together, they fully suffice to 

 discriminate the species and sub-genera of Melanonyx. I therefore discuss in great detail 

 — perhaps in too great detail — the bill of each representative of this genus under its 

 respective heading. To the importance of the bill distinguishing the species of this 

 group of geese I was led by the studies of Mr. Naumann, who with great care 

 analysed the various differences in the structure of the bills of the yellow -bill 

 (M. arvensis) and common bean -goose (M. segetum), so that I had only to verify his 

 investigations and deductions in relation to these two species and strive to apply them 

 to the other members of the group. In doing so, I succeeded in finding a few additional 

 characters which strongly confirm the truth of Naumann's deductions. 



Mr. Naumann's investigations are therefore of great importance, since it was owing 

 to these that it became possible to discover the connection which exists between certain 

 East Siberian and European geese of this group. It is true that one of the characters 

 given by Naumann, namely, the number of teeth along the edges of the upper mandible, 

 proved wanting in constancy when examining a large collection, but in the majority of 

 cases even this character may afford great assistance in discriminating species. 



Here it may be remarked as strange that, down to our own time, scarcely any 

 ornithologist has estimated at its true value the important difference in the bills of 

 the yellow-billed and the common bean-goose, pointed out by Naumann. Much con- 

 fusion in the literature on these birds would have been avoided, and our acquaintance 

 with the geographical distribution and mode of life of the members of the group would 

 have been increased, had this been known earlier. 



Despite all that has been written by Naumann on the bills of these two geese, 

 the majority of ornithologists seem to believe that the whole point of these distinctions 

 consisted in a different arrangement of the black and yellow-orange colour ; and as 

 colour alone here plays a secondary part (unless taken in connection with structural 

 characters), the confusion which Naumann had done so much to abolish was revived. 



Such a state of the " goose question" produced further unsatisfactory consequences ; 

 so that, for example, the late Mr. Seebohm latterly affirmed that M. brachyrhynchus was 

 nothing more than a slight variety of the bean-goose (M. segetum). Even the totally 

 different colouring of the whole bird, to say nothing of the bluish ashen-grey wing (recalling 

 rather the grey-lag than other representatives of the genus Melanonyx), did not save that 

 eminent ornithologist from a serious error. This view of Seebohm, to my astonishment, 

 was finally shared by other ornithologists, among them the late Mr. John Cordeaux. 



