SABINE'S GULL. 577 



blotches and scrawls at the larger end; measurements 1'7 by 

 1-8 in. 



The adult in summer plumage has the bill one inch long, 

 the base of both mandibles black, as far as the angular pro- 

 jection of the lower mandible, the remainder yellow ; the 

 inside of the mouth bright vermilion. The irides dark, sur- 

 rounded by a naked circle of the same colour as the inside 

 of the mouth ; a small white speck beneath the eye scarcely 

 perceptible. The whole of the head and upper part of the 

 neck a dark lead-colour, terminating in a narrow black 

 collar ; the remainder of the neck behind and before, as well 

 as the breast and belly, pure white. The back, scapulars, 

 and wing-coverts are ash-coloured, much lighter than the 

 head; the lower ends of the scapulars are tipped with white. 

 The shafts and outer webs of the first five primary quill- 

 feathers are black, the edge of their inner webs white to 

 within an inch and a half of the tips, the white sometimes 

 continued to the tip ; the tips of the first and second of these 

 quill-feathers white in old birds ; the tips of the third, fourth, 

 and fifth white, giving the wing when closed a spotted appear- 

 ance ; the sixth primary has the web principally white ; the 

 upper primaries, secondaries, and the whole under parts of 

 the wings, white. The legs, feet, and claws reddish-black ; 

 the thigh feathered to within three-eighths of an inch of the 

 knee : the tail with its upper and under coverts white ; the 

 outer tail-feathers narrower and about one inch longer than 

 those in the middle. Total length thirteen inches ; wing, 

 from the wrist ten inches and three-quarters. 



Two examples in their second year obtained in Callao 

 Bay, Peru, in December 1881, have the forehead and crown 

 white ; an irregular and rather broad dark band or patch on 

 the nape where the collar joins the hood in the adult ; the 

 white tips of the primaries are abruptly abraded, as if cut off 

 with scissors, giving the lower part of the wing a uniform 

 black appearance ; legs and feet clay-brown ; mantle, tail, 

 under-parts and bill, as in the adult. 



Thompson's description of the autumnal plumage of the 

 young bird of the first year is, " the forehead, space imme- 



VOL. in. 4 E 



