BIEDS — LARIDAE — XEMA SABINII. i!57 



Sp. Cii.— " Color. Scapulars, interscapulars, and both surfaces of the wings, clear pearl gray ; outer web of the first quill 

 blackish brown to \U tip, which is gray ; tips of the scapulars and lesser quills whitish ; some small feathers near the eye and a 

 collar round the middle of the neck pitch black ; rest of tlie plumage white. The neck above and the whole under plumage 

 deeply tinged with peach-blossom red in recent specimens. Bill black ; its rictus and the edges of the eyelids reddish orange. 

 Legs and feet vermilion red ; nails blackish." 



" Length, 14 inches ; wing, 10|; tail, 5J ; bill, J ; tarsus, 1.1-12." 



Described as above in the Fauna Boreala-Americana. 



Hub. — Arctic seas. 



No specimens are in the collection. 



CREAGRUS, Bonaparte. 



Creagrus, Bon. 1854. 

 Ch. — Bill strong and much curved ; tail strong and very deeply forked. 



But one species iu this genus, from the coast of California ; it is remarkable for its deeply 

 forked tail, an unusual form among the gulls. 



CREAGRUS FURCATUS, Neboux. 



Tlic Swallow-tailed GlUl. 



Mouette a queue fourclme, Neboux, Rev. Zool. 1840, 290. 

 Larusfurcattts, Neb. Voy. Venus, Zool. pi. x. 

 Creagrus furcatus, Bruch, Cab. Jour. 1855, 292. 

 Sr. Ch. — Mult. Head and nearly all of the neck grayish brown ; two small rounded wliite spot^, embracing symmetrically 

 the base of the upper mandible ; mantle grayish white ; breast, abdomen, and under wing coverts, white ; wings extend beyond 

 the tail ; primaries black on their outer and inner edges ; the smaller wing coverts white ; the greater slate color bordered with 

 white; tail very much forked and white ; the two outer tail feathers much longer than is usual in this class of birds; bill very 

 much bent, black at the base and white at the extremity ; iris red ; eyelids orange ; tarsi and feet red ; claws black. 

 Total length, GO centimetres. 

 Hah. — California 



No specimen in the collection. 



XEMA, Leach. 



Xema, Leach, Linn. Trans. XII, 1818. 



Ch. — Bill short, rather slender and compressed ; upper mandible straight at the base, curved at the end ; nostrils lateral and 

 linear; wings lengthened and pointed ; tail forked ; tarsi rather strong ; toes united by a full web ; hind toe short. 



This genus has but one species, which inhabits the Arctic regions, seldom coming far to the 

 south. Small in size. 



XEMA SABINII, Sabine. 



Tlie Fork-tailed GuU. 



Larussabinii, J. Sabine, Lin. Trans. XII, 1818, 520 ; pi. xxix.— Rich. & Sw. F. B. A. II, 1831, 428 — Nmr. Man. 



II, 1834, 296.— AuD. Birds Am. VII, 1844, 127; pi. ccccxh. 

 Xema sahinii, Brdch, Cab. Jour. 1855, 292. 



Sp. Ch. — Adult. Head and upper part of neck blackish gray, terminated below by a ring of deep black; the rest of the 

 neck, under plumage, the upper tail coverts, and the tail, pure white ; the back and upper surface of the wings bluish gray ; the 

 edge of the wing from the flexure black ; the first five primaries black, with their tips white ; secondaries largely tipped with 

 white; bill black at base for more than half its length, then yellow to the point ; interior and angles of the mouth and edges of 

 eyelids vermilion ; feet black. 



Length, 13^ inches; wing, 11; tail, 5; bill, 1; tarsus, 1.4-12. 



Hab.— Nova. Scotia, northward; Arctic seas. 



There are no specimens in the collection. 

 August 27, 1858. 



108 b 



