316 GREAT BLACK-BACKED GULL. 



quill longest, the second scarcely shorter, the rest of the primaries rather 

 rapidly graduated ; secondaries broad and rounded, the inner narrower. 

 Tail of moderate length, even, of twelve rounded feathers. 



Bill gamboge-yellow, the lower mandible bright carmine towards the 

 end. Edges of eyelids bright carmine, iris silvery. Feet yellow, claws 

 black. The head, neck, and all the lower parts, pure white ; back and 

 wings deep blackish-grey tinged with purple, or dark slate-colour ; the 

 rump and tail white, as are the edges of the vnng, and a large portion of 

 the extremities of all the quills ; the second, third, fourth, and fifth pri- 

 maries have a broad band of black across their ends, the inner web only 

 of the second being so marked, in some specimens however both webs. 

 The oesophagus is very large, the gizzard small, the intestine four feet 

 long, and about the thickness of a goose quill. 



Length to end of tail 29 J inches, to end of Avings 31^, to end of 

 claws 29 J ; extent of wings 67 ; wing from flexure 20 ; tail 9 ; bill along 

 the ridge 2i§, along the edge of lower mandible 8/5 ; its depth at the 

 angle 1, at the base {^ ; tarsus Sj% ; middle toe 2|, its claw ^. Weight 

 3 1b. 



The Female is similar to the Male, but considerably less. 



The Young when fledged have the bill brownish-black, the iris dark 

 brown, the feet as in the adult. The head and neck are greyish-white, 

 streaked with pale brownish-grey ; the upper parts mottled with brown- 

 ish-black, brownish-grey, and dull white, the rump paler. The primary 

 quills blackish-brown, slightly tipped with brownish-white; the tail-fea- 

 thers white, with a large brownish-black patch towards the end, larger on 

 the middle feathers, which are also barred towards the base with dusky. 

 The lower parts are greyish -white, the sides and lower tail- coverts ob- 

 scurely mottled with greyish-brown. ^ 



