WHITE-BILLED NORTHERN D1VEE 507 



is now in the Museum at Newcastle. A fourth was 

 obtained, December 1872, on Bidding Broad, Norfolk, by 

 the late Mr. E. F. Booth (Norf. and Nor. Nat. Hist. Soc.). 

 A fifth was procured in the winter of 1895-6 in Hamp- 

 shire, as stated by the Rev. J. E. Kelsall. A sixth (an 

 immature bird), shot on Loch Fyne, autumn, 1893, was 

 identified by Dr. E. Bowdler Sharpe, in the collection of Mr. 

 Bulkley Allen, of Altrincham. 



DESCRIPTIVE CHAR1CTERS. 



PLUMAGE. Adult male nuptial. This Diver in nuptial 

 plumage may be distinguished from C. glacialis as follows : 

 " The head and upper neck are glossed with green, while 

 the lower neck is tinged with purple (the reverse of the 

 arrangement in the Great Northern Diver) ; the white 

 streaks of the transverse band on the throat are not more 

 than eight in number, with fewer than ten on the lower 

 neck ; the white spots on the scapulars are decidedly longer 

 than broad ; while those on the flanks and upper tail- 

 coverts 1 are smaller than in the Sub-arctic species; and 

 finally, this high northern form is superior in size. Some 

 of these distinctive features had attracted the attention of 

 the late Sir James Clark Ross, who virtually discovered 

 this bird on Boothia in 1830, though it was only named 

 in 1859 by G. R. Gray ; but until Seebohm worked out and 

 summarised the points of difference (Zool., 1885, p. 144), 

 its claims to recognition were somewhat coldly received " 

 (Saunders, Man. Brit. Birds, '2nd Edit., p. 711). 



Adult female nuptial. Similar to the male plumage. 



Adult winter, male and female. Similar to the winter- 

 plumage of C. glacialis. 



Immature, male and female. Resembles the adult winter- 

 plumage. 



BEAK. Yellowish-white at all seasons; under segment 

 sharply upcurved from the angle, upper border of upper 

 segment straight from the forehead to the tip, deeper and 

 stouter than that of C. glacialis. 



FEET. Brownish-black. 



IBIDES. Reddish. 



EGGS. Resemble those of C. glacialis. 



1 In this species the tail consists of eighteen feathers, whereas 

 in C. glacialis there are twenty (W. R. Ogilvie-Grant, Cat. Birds Brit. 

 Mus., vol. xxvi, p. 501). 



