Key to Genera, Species, and Sub-Species с 



(adult), but, apparently as an exception, this colour sometimes 

 assumes on bill a red tinge. 



21 (24) Length of nail on upper mandible included in total length of 



culmen more than four times in fully adult birds, or four 

 times in younger specimens. 



22 (23) Culmen 55-72 mm. ( = 2.16-2.83 ln -) '> greatest depth (thickness) 



of visible portion of lower mandible, with bill shut, 6-8^ mm. 

 ( = .23-33 xn ')- Prevailing colour on bill (in adults) yellow 

 (or orange), in young birds black. 

 Around base of upper mandible on feathering lies a white 



band, absent only in young and very old individuals. M. arvensis, Brehm. 



23 (22) Culmen 74-83 mm. ( = 2.91-3.26 in.); greatest depth (thickness) 



of visible portion of lower mandible, with bill shut, 9-12 mm. 

 ( — .35—47 in.). Yellow (orange) colouring concentrated on ter- 

 minal portion of bill in form of ring embracing both mandibles. 

 Around base of upper mandible no white feathering. M. arvensis sibiricus, Alpheraky. 



24 (21) Length of nail of upper mandible included in total length of 



culmen considerably less than four times. 



25 (28) Yellow (orange) colouring concentrated on anterior half of bill ; 



no white feathering along base of upper mandible ; sometimes 

 white patch occurs on chin, or even whole chin is white. 



26 (27) Culmen 48-61 mm. (=1.88-2.40 in.); greatest depth of lower 



mandible, with shut bill, 7J-11 mm. ( = .29-43 in.) ; wing 



425-450 mm. (= 16.70-17.70 in.). M. segetum, Gmelin. 



27 (26) Culmen 62-72 mm. ( = 2.44-2.83 in.); greatest depth (thickness) 



of lower mandible, visible with shut bill, 10-12 mm. ( = .39- 



.47 in.) ; wing 450-475 mm. (= 17.7-18.7 in.). M. segetum serrirostris, Swinhoe, 



28 (25) Yellow colouring extends from terminal portion of bill under 



nares and along edge of upper mandible in irregular patches. 

 Length of bill 68-78 mm. ( = 2.67-2.95 in.); greatest depth of 

 lower mandible, with bill shut, 13-16 mm. ( = .51-63 in.). 

 Wing 495-516 mm. ( = 19.40-20.30 in.). M. segetum mentalis, Oates. 1 



29 (16) Colouring of light portions of bill and legs unlike ; on bill, pink 



(red?), on legs, orange. Culmen 64 mm. ( = 2.51 in.). 



(Doubtful species.) M. ? carneirostris, Buturlin 



30 (9) Prevailing colouring of head white. Along each side of dark (species dubia). 



neck stretches a broad white band. Bill weak, entirely light 



except black nails, of which upper included in total length of 



culmen not less than four times. Genus Eulabeia, Reichenbach (1852). 



Prevailing colour of head white, with two black transverse 



bars, anterior one of which reaches to eyes (adult birds), or 



with dark brown occiput and nape (young birds). General 



colouring ochreous light grey ; rump bluish cinereous grey. 

 Culmen 48I-58J mm. (= 1.9-2.4 in.). E. indica, Latham. 



31 (2) Feathering of forehead projects into base of bill in an abrupt arc 



or promontory. Legs at all ages black (of varying intensity) ; 

 bill entirely black. Feathering at sides of neck forms scarcely 

 any sharply defined longitudinal tufts, or latter feebly expressed. 



1 I now no longer doubt that the A, mentalis described by Oates is founded on very large old specimens of the eastern variety 

 of the bean-goose. 



