28 NORTH AMERICAN BIRDS. 



irregular spots of blackish, the principal of which are 

 two on the crown (one behind the other), four across 

 the occiput, about three (small ones) on lores, the rest 

 irregularly distributed. Length 28.00-31.00, wing 

 17.60-19.50, culmen 2.40-2.60, depth of bill through 

 angle .98-1.05, tarsus 2.70-3.10, middle toe 2.10-2.50. 

 Eggs 3.05 X 2.12, the ground-color averaging deeper 

 brownish and the spots larger than in L. glaucus. 

 Hab. Coasts of the North Atlantic ; in America, south, 

 in winter, to Long Island. 



47. L. marinus LINN. Great Black-backed Gull. 

 e 2 . Shafts of primaries black, except within the white spaces. 

 f 1 . Two outer primaries without distinct gray " wedges" on 



inner webs. 



g 1 . Angle of lower mandible very prominent, the depth 

 of the bill through the angle being decidedly 

 greater than at base ; middle toe, with claw, as 

 long as tarsus. Summer adult : Mantle deep plum- 

 beous. Winter adult : Top of head and hind-neck 

 streaked with dusky; otherwise as in summer. 

 Young : Above brownish slate, irregularly varied 

 with grayish white ; quills and tail-feathers uni- 

 form dull black, narrowly tipped with white; 

 lower parts brownish gray, clouded or irregularly 

 spotted with grayish white, the breast and belly 

 nearly uniform grayish. Downy young : Grayish 

 buffy white, the head with distinct black blotches 

 of indefinite arrangement ; upper parts clouded or 

 irregularly blotched with brownish dusky ; lower 

 parts, except throat, immaculate. Length 24.00- 

 27.00, wing 15.75-17.00, culmen 2.00-2.35, depth 

 of bill at angle .85-.9S, tarsus 2.45-2.65, middle toe 

 (without claw) 2.00-2.45. jE^s 2.87 X 1-94. Hab. 

 Pacific coast of United States, south to Cape St. 

 Lucas... 49. L. occidentalis ATJD. Western Gull. 

 g*. Angle of lower mandible not very prominent, the depth 

 of the bill at angle being little if any greater than 

 through base. In plumage not essentially different 

 from L. occidentalis, but feet yellow, instead of flesh- 

 colored, in life ; wing 16.00-17.00, culmen 2.00-2.10, 

 depth of bill through angle .60-.68, through base 

 .60-.72, tarsus 2.18-2.68, middle toe 1.65-1.95. Hab. 

 Northern Europe, south, in winter, to Africa. 



L. fuscus LINN. Lesser Black-backed Gull. 1 



1 Larus fuscus LINN., S. N. ed. 10, i. 1758, 136. 



