KEY TO FAMILIES 
119 
very long and pointed, the outer feathers being much the longest; 
toes webbed. Adult Gulls and Terns are usually pearl-gray above, 
white below; Jaegers and most young Gulls are dark. 
A. Bill hooked and hawklike. 
a. Bill with a naillike hook, its base with a scaly shield; plumage 
dark; central tail-feathers longest. (Fig. 23, a). . . . Family 
Stercorariidce: Skuas and Jaegers, p. 150. 
b. Hook continuous with bill, no scaly shield, tail-feathers usually 
of about equal length (Fig. 23, b) ... . Subfamily Larina: 
Gulls, p. 152, 
x 
Fig. 24. Fig. 25. 
B. Bill not hooked. 
a . Bill straight, usually slender and sharply pointed; tail usually 
more or less forked. . . . Subfamily Sternince: Terns (Fig. 24) , 
p. 162. 
b . Bill thin and bladelike, the lower mandible longer than the 
upper (Fig. 25). . . . Family Rynchopidce: Skimmers, p. 172. 
Order III. Tubinares. — Albatrosses, Petrels, and Fulmars. 
Gray, sooty, or black and white sea-birds; living, except when nesting, 
well off shore; flying low, often skimming the waves. Nostril-openings 
tubelike; bill hawklike, its ‘hook’ often prominent; front-toes webbed, 
hind-toe small or absent ; wings long and pointed ; tail short. 
A. Size very large, nostril- tubes separated, on sides of bill (Fig. 26, a ) . 
... Family Diomedeidce: Albatrosses, p. 172. 
B. Size smaller, nostril-tubes joined on top of bill (Fig. 26, b). . . . 
Family Procellariidce: Petrels, Fulmars, Shearwaters, p. 173. 
