506 COLYMBIDAs 
clossed with green ; sides of the upper breast, streaked with 
black and white and glossed with green; breast and 
abdomen, white; under tail-coverts, chiefly brownish. 
Adult female nuptial.—Similar in plumage to the male. 
Adult winter, male and female-—The neck-bands dis- 
appear and the ground-colour of the head and _ neck 
becomes brownish-black; the spots on the back, scapulars, 
and wings, are ash-grey on a dark brown ground-colour 
not so pure as in the nuptial plumage; throat, fore-neck, 
breast, and abdomen, white. 
Immature, male and female. — Resembles the adult 
winter-plumage except that the back, scapulars, wings, 
and hind-neck, are dark greyish-black ; breast and abdomen, 
impure white. 
Beak. Blackish-brown, tip lighter ; powerful and 
dagger-like. 
Fret. Greenish-black. 
TrR1DES. Crimson. 
AVERAGE MEASUREMENTS. 
TOTAL LENGTH ... ... 81 in. Female smaller. 
WING 7 ey Pe a 
BEAK ote aoe eet io Dia 
TTARSO-METATARSUS ae Cle 
Eee Pe bs NDP So. CrOMilie 
WHITE-BILLED NORTHERN DIVER. Colymbus adamsi 
(G. R. Gray). 
Coloured Figures.—Dresser, ‘ Birds of Europe,’ vol. ix, pl. 722; 
Lilford, ‘ Coloured Figures,’ vol. vi, pl. 45; ‘Ibis,’ 1894, 
pl. 8. 
This species, the Arctic form of the Great Northern 
Diver, is a very rare visitor to British waters. An example 
was shot at Pakefield, near Lowestoft, in the spring of 
1852; it is now in the collection of Mr. J. H. Gurney. An 
immature specimen, supposed to have been taken in Suffolk 
at a later date, is figured by Babington (‘ Birds of Suffolk’). 
Another was obtained on the coast of Northumberland, and 
