COLYMBIDA—DIVERS. 307 
head is glossed with green and the lower neck with purple ; 
the white scapular spots are larger ; the streaks upon the upper 
throat-band are,only six in number, and on the lower one ten; 
the 422/ is yellowish-white at all seasons and deeper. 
In the changes of its plumage it does not differ from C. 
glacialis. 
Distribution: Inhabits the Circumpolar regions, having 
occurred in winter as far south as the British Islands and 
Japan. 
Habitat: Similar to that of C. glacialis. 
BLACK-THROATED DIVER. 
Colymbus arcticus Linz. 
Adult (Summer): Cvown and nape greyish-brown ; 
scapulars with 12 or 13 transverse white bars ; wing-coverts 
speckled with white, rump and back otherwise deep black ; 
throat black, crossed by a band of black and white streaks ; 
chest and sides of neck longitudinally banded. with black and 
white ; under parts below chest white, the flanks black ; bill 
black ; legs and feet dark brown ; irides crimson. Length 26 
inches ; culmen 2°6; depth of bill at nostrils o°7 to o'8 ; wing 
2175 ; tarsus 2°09. 
Adult (Winter): Closely resembles the last species, but 
is usually smaller and has a more slender bill. 
Young in first plumage: Are smaller than those of C. 
glacialis, otherwise similar. 
Distribution: Breeds in Scotland and in North-eastern 
Europe down to the Baltic. Ranges also across Siberia to the 
Pacific and to the fur countries of North America. Occurs 
during winter down to the Mediterranean. 
Habitat : Similar to that of C. glacialis. 
RED-THROATED DIVER. 
Colymbus septentrionalis Zeun. 
Adult (Summer): Crown, nape and back of neck longi- 
tudinally streaked with black and white; rest of upper parts 
dusky-brown, more or less marked about the back wth oval 
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