i 
' 
: 
LARIDH, TERNS.—GEN. 287-8. 317 
inch. Arctic America, apparently very rare; I have never seen a specimen, 
and do not know of any in this country. Rron., F. B.-A. ii, 427; Nurt., 
li, 295; Aup., vii, 130; Lawr. in Bp., 856; Couns, /.c. 311. . ROSEA. 
287-8. Genus XEMA Leach. 
Fork-tailed Gull. Adult: white, including inner primaries, most of 
secondaries, and greater coverts; head enveloped in a slate-colored hood, 
succeeded by a velvety-black collar; mantle slaty-blue, extending quite to 
the tips of the tertiaries; whole edge of the wing, and first 5 primaries, 
black, their extreme tips, and the outer half of their inner webs to near the 
end, white; bill black, tipped with yellow; feet black; length 15-14; wing 
10-11; bill 1; tarsus 14; tail 5, forked an inch or more. The changes of 
plumage are correspondent with those of L. philadelphia; in the young the 
tail is often simply emarginate. Arctic America, both coastwise and in the 
interior, common, but still rare in collections; in winter, S. occasionally to 
New York (Audubon) and Utah (Allen). Ricu., F. B.-A. ii, 428; Nurv., ii, 
296; AuD., vii, 127, pl. 441; Lawn. in Bp., 857; Couns, /.c.311. SABINET. 
Swallow-tailed Gull. Head and nearly all the neck grayish-brown; a 
white spot on each side of the forehead; mantle grayish-white ; lesser wing 
coverts white, greater slate, white-bordered ; bill black at the base, white at 
the end, much bent; eyes and feet red; eyelids orange; claws black; tail 
white, very much forked. Length about 2 feet. 
“California.” This bird appears to be exceedingly 
rare; no one in this country has seen it. The de- 
scription is compiled from the original account. 
Larus furcatus Nesoux, Rev. Zool. 1840, 290; 
Prevost and Des Murs, Voy. Venus, pl. 10; 
Creagrus furcatus Bonar.; Lawr. in Bp., 857; 
Counswiewole weer ees |) | | L FURCATUM. 
Subfamily STERNIN A. Terns. 
Covering of bill continuous (no cere), hard and horny 
throughout; bill paraynathous, relatively longer and 
slenderer than in the gulls, very acute, the commissure 
straight or nearly so to the very end; nostrils generally linear. Tail never square, 
almost invariably forked (often deeply forficate), in one group double-rounded. 
Wings extremely long, thin and pointed. Feet small, weak, scarcely ambulatorial. 
The terns are not distinguished from the gulls by any strong structural pecu- 
liarities, but they invariably show a special contour, in the production of which the 
longer, slenderer and acutely paragnathous bill is a conspicuous element. Only one 
species has the bill in any noticeable degree like that of a gull. A few of the terns 
are as large as middle-sized gulls, but the normal stature is much less; and they 
are invariably of a slenderer build, more trim in shape, with smoother, closer-fitting 
plumage. The great length and sharpness of the wing relative to the bulk of the 
body confer a dash and buoyancy of flight wanting in the gulls; in flying over 
the water in search of food, they hold the bill pointing straight downward, 
which makes them look curiously like colossal mosquitoes; and they secure their 
Fic. 201. Roseate Tern. 
