1 1 2 Geese of Europe and Asia 



edging, into brown. Middle of wing similarly coloured ; axillaries and whole under-side of 

 wing dark black slate-grey with slightly lighter edges ; primary coverts, primaries, and 

 secondaries dark brown. Latter with narrow white edgings, widening towards the tips. 

 Legs and feet dingy yellowish or grey-yellow. 



Young in Down 



Scarcely known with certainty ; the sole undoubted example, which I had the oppor- 

 tunity of seeing later — when it was fully fledged — was caught, when without a sign of quills, 

 on July 30, 1 90 1, on Kusov Island, at the entry to the Kara Straits off Novaia Zemlia. 

 According to Mr. N. A. Smirnov, who brought this specimen, together with two others 

 (which I did not see), this bird had a predominant light grey colouring; the bill was wholly 

 blackish, and the feet a dead black with dark claws. A month later the feet began to lighten, 

 passing into a yellowish, and a yellow patch appeared on the apex of the culmen. 



These young in down were caught among stones on the seashore, and apparently 

 formed part of two united broods. The old birds were in full moult. 



So far as I can judge from the comparatively insignificant material at my disposal, 

 and from authentic published data (of which there are very few r ), the measurements of adult 

 bean-geese are as follows : — 



Wing. .......... 410-450 mm. (= 16. 10-17.70 in.). 



Culmen 57-63 mm. ( = 2.24-2.44 in.). 1 



Depth of bill at base 3 1-32 mm. (= 1. 22-1. 25 in.). 



Greatest depth of visible part of lower mandible with shut bill 7\~ l l mm - ( = - 2 9 -0 -43 m 0- 



Tarsus ........ . . 74-76 mm. ( = 2.90-3 in.). 



Length of median digit, claw included . . . . 80-85 mm. ( = 3.14-3.34 in.). 



Length of (median) claw ....... 10-12 mm. ( = 0.39-0.47 in.). 



Number of teeth on each side of upper mandible, in vast majority of cases, 20 to 21, but examples from 

 Kolguev showed a greater number, viz. from 20 to 24, of which more detail is given later. 



Bill 



I dwell at considerable length on the description of the bill of this species, since 

 it affords the best characters for distinguishing it from the yellow-billed goose. Naumann 

 first analysed in detail the difference in the structure of the bills of these two geese, 

 and, following his description, I have succeeded in finding another essential characteristic 

 which had escaped the attention of the German ornithologist, and so far, at any rate, 

 has proved very constant and, therefore, important. 



In the bean-goose the bill is absolutely and relatively smaller, shorter, and thicker 

 than in M. arvensis, and at the same, time of a more conical form, that is, its 

 sides meet at a more acute angle with the apex. The character which I found to be 

 very constant consists in the fact that, if the bill be looked at from above, the apparent 

 length of the nail in adult birds of M. segetum is contained in the total oilmen-length 

 not more than 3^ times, in younger birds between 3^ and 3^ times, while in M. arvensis 

 this same nail is contained in the culmen in adults up to 4^, and in young birds 

 4 times. 



To show this more clearly, I give drawings of the bills of adult birds of both species. 

 The importance of this character is indicated by the fact that the same relations 



1 The longest bill I have measured is 61 mm. ( = 2.40 in.), and belonged to a large full-grown specimen from Kolguev. 



