GREEN-BILLED GULL. 577 



The plumage is full, soft, and elastic, generally blended, 

 on the back and wings rather compact. The wings are very 

 long, rather narrow, pointed, and exceed the tail by about two 

 inches ; the primaries very long, tapering, and rounded ; the 

 secondaries twenty, a little incurved, rather narrowly rounded. 

 The tail is almost even, the middle feathers exceeding the 

 lateral by only a quarter of an inch. 



The bill is of a uniform greyish-green tint, shaded at the 

 end with ochre-yellow ; the basal margins and mouth orange ; 

 the edges of the eyelids dull reddish ; the iris brown. The 

 feet deep greenish-grey ; the claws black. The head, neck, 

 lower parts, rump, and tail, are white ; but the upper 

 part of the head, the cheeks, the hind part, sides, and lower 

 part of the neck, are marked with oblong or roundish spots 

 of dark brownish-grey. On the outer five quills is a band 

 of greyish-black, largest on the outer, gradually diminishing, 

 and on the fifth reduced to a broad band near the tip. The 

 first quill is white at the end for nearly three inches, with a 

 black spot on the inner web at the end ; the second has a 

 white space of an inch and a half, with a band of black, and 

 the tip white ; on the third is a white spot near the end ; the 

 tips of all the quills Avhite, that colour more extended on the 

 secondaries. There is a semicircle of blackish-bristly feathers 

 before the eye. The back and wings are light greyish-blue ; 

 the shafts of the primaries of the colour of the webs, the 

 outer two being black nearly in their whole length. 



Length to end of tail 18 inches; extent of wings 36; 

 wing from flexure 14| ; tail 5 ^; bill along the ridge 1^ ; 

 along the edge of lower mandible 2 ; tarsus 2 ; first toe -^, 

 its claw -^ ; second toe ly'y, its claw -^ ; third toe 1^, its 

 claw -^ ; fourth toe \^, its claw ^. 



Female in Winter. — Similar to the male, but somewhat 

 smaller. 



Variations. — Considerable differences are observed as to 

 size, the thickness of the bill, and the length of the tarsus. 

 Variations also occur in the markings of the outer primaries, 

 just as in Larus argentatus. 



VOL. V. ^ p 



