grkat northern diver. 
179 
Adult Male. — General colour above glossy black, spotted 
with white, the feathers being square at the tip, and orna- 
mented with twin sub-terminal spots of white, larger and 
more conspicuous on the scapulars ; wing-covcrts like the 
back, but more feebly spotted with white, the spots being 
rounder and sometimes two in number near the end of the 
outer web ; lower back and rump more distinctly greenish- 
black, minutely spotted with white; bastard-wing, primary- 
coverts and quills black, browner on the inner webs ; upper 
tail -coverts and tail-feathers black; head black, with a 
purplish shade on the crown, changing to dull green on 
the sides of the head and neck ; the sides of the hind-neck 
more distinctly purplish-blue ; sides of face and tbroat black, 
with a purple gloss on the chin, and the throat itself decidedly 
more green till it reaches an abrupt line, where it changes to a 
beautiful purple like the sides of the neck ; across the middle 
of the throat a band of white feathers striped with black ; a 
similar, but larger, band on each side of the neck ; remainder 
of under surface, from the fore-neck downwards, white, the 
sides of the fore-neck and chest streaked with black, the sides 
of body and flanks black, with small white spots ; across the 
line of the vent a narrow band of black ; utider tail-coverts 
black tipped with white spots ; under wing-coverts and 
axillaries white, the latter narrowly streaked with black ; the 
lower primary-coverts produced for half the length of the 
wings, white, broadly streaked with ashy-brown down the 
middle ; quill-lining ashy-grey ; bill black ; legs and feet 
greenish-black; iris crimson. Total length, aS'o inches; 
culmen, 3-2 ; wing, 14-0 ; tail, 2‘5 ; tarsus, 3.35. 
Winter Plumage. — Brown above, with a slight greenish gloss, 
the feathers sub-terminally dark in the centre and margined 
with ashy-grey, less distinctly on the lower back and rump, 
which are consequently more uniform ; wing-coverts like the 
back, as also the inner secondaries ; quills and tail blackish- 
brown ; head and neck brown with a slight greenish gloss ; the 
lores and sides of face brown ; cheeks and under surface of 
body white, shaded with brown on the lower throat ; sides of 
the neck brown with white edges to the feathers, producing a 
streaked appearance, the centre of the feathers darke^brown , 
