WHITE-BILLED DIVER. 1 83 
Total length, 29 inches ; culmen, 37 ; wing, 15-2 ; tail, 2-95 ; 
tarsus, 3 '3. 
Winter Plumage. — Similar to that of C. glacialis, but dis- 
tinguished by the ivory white bill. Upper surface brown, the 
feathers darker brown before the edges, which are light ashy- 
grey and very broad ; lower back and rump uniform brown ; 
wing-covcrts like the back, but not quite so distinctly mar- 
gined; quills and tail-feathers dark brown, the latter edged 
with ashy-grey like the upper tail-coverts ; inner secondaries 
edged with ashy-grey like the scainilars ; crown of head and 
neck dark ashy-brown ; lores and sides of face white, like the 
under surface of the body, the sides of which are brown with 
ashy-w’hitish margins to the feathers. 
Characters. — Professor Collett has given an excellent account 
of the sequence of plumage in the White-billed Diver, in the 
“Ibis” for 1894 (pp. 269-283, pl.viii.). This paper is especially 
to be commended to the notice of those ornithologists who 
imagine that there are few facts remaining to be discovered in 
the economy of European birds. It is a matter of regret to me 
that space prevents my reproducing his remarks ex/efisa. 
Professor Collett point out that the jw/ng birds of the year 
have rounded or almost pointed feathers, instead of the square- 
tipped plumes of the old birds. In the following year the grey 
plumage is retained, and the worn winter feathering is still 
found in the ensuing June. After the next autumn moult the 
back is still grey, but the feathers are more square-cut, showin<r 
an approach to the adult form. The bill is white, like that of 
the old birds. When the birds are two years old the adult 
plumage is assumed, but it seems probable that, as is the case 
with ( 7 . glacialis^ the birds do not breed in their first nuptial 
dress. Professor Collett has found that, in addition to fresh- 
moulted feathers, some of the adult plumes are donned by a 
recoloration of the actual feather. For further details of the 
characters of C. adamsi the reader is referred to the paper 
itself. 
Range in Great Britain. — That C. adamsi occurs more fre- 
quently off the British coasts than is usually supposed, is very 
probable, and now that attention has been called to the species, 
it will doubtless be found that many examples exist in collec- 
