SABINE'S GULL. 
41 
THE FORK-TAILED GULLS. GENUS XEMA. 
Xenia, I.each in T. Rosses Voy. Baffin’s Bay, App. ii. p. 57 
(1819). 
Type X. sabinii (J. Sabine). 
In this genus the tail is considerably forked, and the wings 
long, the hind-toe being free and very small. 
Only two species of Fork -tailed Gull are known, the 
Arctic X. sabinii, and X. furcata of the Galapagos Islands, 
which seems to wander down the Pacific coast of South 
America, as it has been found at Faracas Bay, in Peru. 
I. Sabine’s gull, xema sabinii. 
Larus sabinii, J. Sabine, Trans. Linn. Soc. xii. p. 520, pi. 29 
(1818); Seebohm, Hist. Brit. B. in. p. 298 (1885); 
Lilford, Col. Fig. Brit. B. part xx. (1891). 
Gavia sabinii, Macgill. Brit. B. v. p. 607 (1852.) 
Xema sabinii, Dresser, B. Eur. viii. p. 337, pi. 593(1874); 
B O. U. List. Brit. B. p. 193 (1883); Saunders ed. 
Yarrell’s Brit. B. iii. p. 573 (1884); id. Man. Brit. B. 
p. 641 (1889) ; id. Cat. B. Mus. xxv. p. 162 (1896). 
{Plate XCVIII.) 
Adult Male in Breeding Plumage.— General colour above light 
ashy-c^rey, including the wing-coverts and inner secondaries, 
the latter as well as the greater wing- coverts being tipped with 
white, the latter very broadly, so that nearly the terminal half 
of the external greater wing-coverts is white ; exterior lesser 
coverts, bastard-wing, primary-coverts, and primaries black, 
the latter tipped with white, and having the inner half of the 
inner web longitudinally white, but this not reaching to the end 
of the quill on the first five primaries the blacky much 
diminished on the next two primaries, the inner primaries and 
the secondaries being white ; the innermost secondaries light 
ashy-grey, white at their ends; lower rump, upper tail- coverts, 
and tail white, the latter conspicuously forked ; head, sides of 
face, and throat dark slaty-grey ; the hind-neck, sides of neck, 
and under surface of body, from the lower throat downwards, 
