‘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 Z. glaucus. 
Hab. Coasts of the North Atlantic; in America, south, 
in winter, to Virginia or beyond. 
47, L. marinus Linn. Great Black-backed Gull. 
é&. Shafts of primaries black, except within the white spaces. 
f!. Two outer primaries without distinct gray “ wedges” on 
inner webs. 
g'. 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-.95, tarsus 2.45-2.65, middle toe 
(without claw) 2.00-2.45. Hggs 2.87 x 1.94. Hab. 
Pacific coast of United States, south to Cape St. 
Lucas... 49. L. occidentalis Aup. 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 
.€0-.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 Larus fuscus Linn., 8. N. ed. 10, i. 1758, 136, 
