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dacti/lus of Gmelin, the Tarrock Gull of 
Latham, and Kittiwake of Pennant's Arc- 
tic Zoology. 
The mature bird, in complete winter 
plumage, has the summit of the head, 
back of the head and neck, and a part of 
the sides of the neck of an uniform bluish 
ash-colour ; very fine streaks of black in 
front of the eyes ; forehead, parts about 
the eyes, all the under parts, rump, and 
tail of a perfect white ; back, wings, and 
quills of a pure bluish ash-colour ; the ex- 
terior quill-feather bordered with black, 
the four exterior ones terminated with 
black ; three of them have a very small 
white spot at their ends ; the fifth quill has 
a black band towards its extremity, and is 
terminated with white ; beak of a greenish 
yellow ; mouth, and circle round the eyes 
of a fine red ; irides brown > feet of a deep 
olive brown. 
In the breeding season the old birds have 
all the head and neck of a perfect white, 
without any appearance of bluish ash- 
colour in the back of the neck, or of fine 
dusky streaks in front of the eyes ; the 
