546 LARUS ARGENTATUS. 



The bill is pure yellow ; the lower mandible with an 

 orange-red patch toward the end ; the edges of the eyelids 

 yellow ; the iris pale-yellow ; the feet flesh-coloured ; the 

 claws brownish-black. The head, neck, lower parts, upper 

 tail-coverts, and tail, are white ; but the head and neck, the 

 throat excepted, are longitudinally streaked with very pale 

 brown. The back and wings are light bluish-grey. The 

 edge of the wing is white, the outer six primaries are deep 

 greyish-black toward the end, the outermost nearly to the 

 base, the sixth only for a very short space ; all the quills 

 largely tipped with white, the outer Mith an additional Avhite 

 patch. 



Length to end of tail 2o inches ; extent of Avings 54 ; 

 •wing from flexure 18 ; tail 7 ; bill along the ridge 2^ ; 

 along the edge of lower mandible 2f ; its height at the angle 

 -j^ ; tarsus 2^ ; hind toe and claw -^ ; second toe l-^^, its 

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

 claw -^2- 



Female in Summer. — The female resembles the male, 

 being only somewhat smaller. 



Length to end of tail 22 inches ; extent of wings 53 ; 

 wing from flexure 17-^; tail 7 ; bill along the ridge 2^ ; its 

 height at the angle -/^ ; tarsus 2-^ ; middle toe 2\, its 

 claw -j^. 



Variations. — Individuals vary considerably in size, and 

 more especially in the length and height of the bill ; but the 

 colours exhibit little difterence, unless on the outer quills. 

 In one individual the first quill is white at the end to the 

 length of two inches and a third, the second white for four- 

 and-a-half-twelfths, with a round spot on both webs. In 

 another the tip of the first quill is white for half an inch, 

 with a large white band, Avhile the second has a w'hite spot 

 on both webs. In a tliird the first quill has a round Avhite 

 spot on both webs, and the tip white, while the second has a 

 white spot on the inner ■\veb only. A fourth has a white spot 

 on the inner web of the first quill, and none on either web of 

 the second. It is in very old individuals that there is a large 



