GREAT BLACK-BACKED GULL. o29 



orange-red patch near the end ; the edges of the eyehds 

 orange-red, the iris pale yellow ; the feet flesh-coloured, the 

 claws dusky. The head, neck, lower parts, upper tail-coverts, 

 and tail are white ; but the head and hind neck are longi-' 

 tudinally streaked with greyish-brown. The back and wings 

 are of a deep slate-colour, or greyish-black tinged with purple. 

 The edge of the wing is white. The outer five priinaries 

 become deep black toward the end ; all the qviills are largely 

 tipped with white ; that on the end of the first quill is two 

 inches and a quarter in length ; on the second an inch and 

 nine-twelfths, but crossed by a black band ; on the third half 

 an inch. 



Length to end of tail 29 inches ; extent of wings 64 ; bill 

 along the ridge 2-j^, along the edge of lower mandible oj\, 

 its height at the angle 1 ; wing from flexure 19|^ ; tail 7-^ ; 

 tarsus 2]^ ; first toe ^Vj ^^^ claw -f^ I second toe l^f , its 

 claw-^; third toe 2^, its claw -fj; fourth toe 2^, its 

 claw yV. 



Female in Winter. — The female resembles the male, 

 being only smaller. 



Length to end of tail 27 inches ; extent of wings 60 ; bill 

 along the ridge 2j ; wing from flexure 19 ; tail 7^ ; tarsus 

 2|f ; middle toe 2^, its claw y\. 



Variations. — The dark tint of the back and wings varies 

 a little ; the streaks on the head and neck are more or less 

 numerous, darker or lighter ; and the markings on the outer 

 primaries difier a little. Sometimes there is a band on the 

 white space of the first ; that of the second is generally on 

 both webs, sometimes on the inner only ; and sometimes the 

 sixth has a black band or spot close to the white tip. Indi- 

 viduals vary considerably in size. The largest that I have seen 

 was oO inches in length, the smallest 26 ; sometimes the bill 

 measures 3 inches along the ridge, and the tarsus 8, or even 

 S-^ inches. 



Male in Summer. — The bill is pure yellow, with the 

 patch bright carmine ; the edges of the eyelids of the latter 

 VOL. v. 2 M 



