THE GREAT NORTHERN DIVER. I6 9 



The adult male in breeding dress has the bill black, the upper mandible 

 arched. Head and neck black, glossed with purplish on the crown, with purplish- 

 blue on the chin and on the lowest portion of the black neck, and with greenish 

 on the rest. Across the upper throat in front a band formed of about a dozen 

 short white lines, and on each side of the neck a row of about twenty longer 

 white streaks, forming bauds which nearly meet, and attain their greatest width 

 at the back. Lowest part of the fore-neck, breast and belly white ; sides of the 

 lowest part of the neck and of the upper breast streaked black and white ; sides 

 of the body and the flanks black, marked with white. Across the region of the 

 vent a dark line ; under tail-coverts black, tipped with white ; under wing-coverts 

 and axillaries white ; the larger coverts dusky down the centres ; the axillaries 

 with narrower and darker marks ; wings and tail quills blackish ; back and upper 

 parts generally, black glossed with bluish (the feathers of the mantle and scapulars 

 squarish at the ends), spotted with white; the spots on the middle of the back 

 arc square, those on and about the scapulars square and larger, those on the wing- 

 coverts and rump quite small and round or oval ; these spots are fewest on the 

 lower part of the back above the rump, and absent from the tail-coverts. The 

 black and white lines on the neck are corrugated to the eye and touch ; the 

 feathers forming them are curved, with raised stiff edges, the middle of the feathers 

 black, the edges white. Tarsi and toes black, paler on the inside of the former 

 and upper side of the latter. Total length from 3O'oo to 36'oo inches ; wing 

 from i2'5 to i5'oo inches. The female is smaller than the male. 



In winter the bill is light bluish horn colour, with the edges of the mandibles 

 darker and the culmen dark brownish horn ; irides warm brown, or reddish-brown ; 

 lores and sides of the face and head brownish, slightly mixed with white ; crown, 

 hind neck, back and upper parts generally, blackish-brown, slightly glossed with 

 green, the feathers below the neck (except on the lowest part of the back and the 

 rump) edged with grey ; primaries and tail brownish-black, the former browner 

 and paler on the inner webs, and the latter tipped with dirty white ; chin, throat, 

 sides of the lower part of the face, fore-neck, breast and belly white ; lower throat, 

 particularly on the sides, freckled with brown ; sides of the neck and of the upper 

 breast blackish-brown, with white margins to the feathers ; sides of the body aud 

 flanks blackish-brown, mixed with white. Thighs and band across the region of 

 the vent dusky ; feathers of the lowest part of the belly marked with brown ; tarsi 

 aud toes pale bluish-grey on the inner side and the upper or inner side of the 

 closed foot, dark brown on the outer and lower side. 



The ordinary winter dress of the full}' adult bird does not seem to be satis- 

 factorily determined. Seebohm stated that after the autumn moult a plumage was 



VOL VI. 2 C 



