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Subfamily LABINM 



Genus XEMA. 



Larus apud Sabine, Trans. Linn. Soc. xii. p. 522 (1818). 

 Xema, J. Ross in Ross's Voyage, 8vo ed. ii. p. 164 (1819). 

 Gavia apud Macgillivray, Man. Brit. B. ii. p. 241 (1842). 



This genus contains only two species : — Xema sabini, which inhabits the boreal portions of the 

 Nearctic and Palsearctic Regions; and Xema furcatum, which inhabits the Nearctic Region. In 

 general appearance, and especially in the form of the tail, these birds somewhat resemble the 

 Terns, and form as it were a link between them and the Gulls. They are said to resemble 

 the Black-headed Gulls somewhat in habits, and, like them, feed on various kinds of marine 

 insects, small fish, Crustacea, &c. They have a light and easy flight, and walk with tolerable 

 ease. They breed in the Arctic regions of both the Old and the New World, their nests being 

 a mere depression in the moss, lined with a few dry grass-bents; and their eggs are dull 

 brownish olivaceous blotched with dull brown. 



Xema sabini, the type of the genus, has the bill about as long as the head, moderately stout, 

 the upper mandible straight to beyond the nostrils, then sharply decurved to the tip, which is 

 attenuated, but rounded and sharp-edged ; nostrils basal, linear ; wings long, pointed, the first 

 quill longest ; tail moderately long, forked ; legs moderately long, the tibia bare for some 

 distance, tarsus tolerably strong, anteriorly scutellate, posteriorly and laterally covered with small 

 roundish or rectangular scales ; hind toe very small, elevated ; anterior toes moderately long, 

 scutellate, connected by reticulated membranes ; claws short, stout, slightly curved, slightly 

 sharp, that on the middle toe with the inner edge dilated. 



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