512 GULL TRIBE. 
genus of the subfamily is represented by three species, of which the black skimmer 
(Rhynchops nigra), distinguished by its dark beak, is North American, while the 
yellow-beaked skimmer (R. albicollzs) is Indian, the third species inhabiting the 
Nile and Red Sea littoral. The American species has been observed flying close 
to the water, with the lower half of the beak immersed beneath the surface, 
doubtless searching for food. 
The gulls proper, as distinguished from the other members of 
the order, form the third subfamily (Lavine) of the typical family ; 
the great majority of them belonging to the genus Larus, although the kittiwake 
and an allied species from the North Pacitic are separated as Rissa ; while Sabine’s 
gull and a kindred but very rare form from the Galapagos Islands constitute the 
genus Xema; and Ross's gull (Rhodostethia rossi). and the ivory gull (Pagophila 
eburnea) respectively represent distinct generic types. As a subfamily, the gulls 
are characterised by the upper mandible of the beak being longer than the 
lower one, over which its tip is bent down; while the tail is usually squared, 
although in one genus it is forked, and in a second wedge-shaped. Some of the 
smaller gulls, like so many of the terns, assume a dark head and neck in the 
summer-plumage. 
Fork-Tailed Sabine’s gull (Nema sabinei), together with the Galapagos 
Gulls: forked-tailed gull (X. furcatwm), may be at once distinguished by 
the forking of the tail,—a character in which they agree with the great majority 
of the terns, as they also do in the assumption of a dark head during the breeding- 
season. Not a very uncommon straggler—especially in the immature state—to 
the British Islands, Sabine’s gull breeds in Arctic America and Siberia, generally 
in company with the Arctic tern; two eggs being laid by the female on the bare 
ground. Of the second and larger species but little is known, only a few examples 
having found their way into European collections. 
As the forked tail serves to distinguish the members of the last 
genus, so the single representative (Rhodostethia rossi) of the 
present one is equally well demarcated by the wedge-like contour of the same 
appendage. It is likewise characterised by its small dove-like beak: while the 
delicate pink hue of its plumage is also a striking feature, although one shared by 
some other members of the subfamily. Formerly rare in collections, this gull has 
more recently been obtained abundantly off Point Barron; but its true polar 
haunts appear to be as yet undiscovered, although it has been seen in summer 
in Boothia Felix and Franz-Josef Land. 
Represented by nearly half a hundred species, the typical gulls 
of the genus Larus differ from both the preceding by the squared 
tail, while they are further characterised by the full development of the first or 
hind-toe. The genus includes both the largest and the smallest representatives of 
the subfamily ; and while some species assume a dark head in the breeding-season, 
others lose all trace of dark tints in this region when adult. The smallest of the 
dark-headed species visiting the British Islands is the little gull (Z. minutus), easily 
recognised by its diminutive size, and, when in flight, by the slaty black under 
surface of the wings. A straggler to Southern Norway, this gull is common in the 
Mediterranean countries, ranging eastwards to the Caucasus, and thence northwards 
Gulls. 
Ross’s Gull. 
Typical Gulls. 
