DESCRIPTION AND TECHNICAL OBSERVATIONS.
Genus Thalassidroma. Vigors. Zool. Jour. II., p. 405. (1825.)
Size small; bill rather wide at base, compressed towards the end, and abruptly hooked; lower mandible shorter; nostril elevated, tubular; wings long, pointed, second quill usually longest; tail moderate, rather wide, usually emarginate or forked; legs long, slender; tibiæ more or less naked above the joint with the tarsi; toes rather short, fully webbed. A genus comprising about twelve species, all of which are strictly marine, and inhabit the various oceans of the world.
Thalassidroma furcata. (Gmelin.) Procellaria furcata. Gm. Syst. Nat. I., p. 561. (1788.) Procellaria orientalis. Pallas. Zoog. Ross. As. II., p. 315. (1831.) Thalassidroma cinerea. Gould.
Form. Wing long; second quill longest; tail forked; legs shorter than usual in this genus; under coverts of the tail long.
Dimensions. Total length (of skin) about 8 inches; wing 6; tail 4 inches.
Colors. Entire plumage light cinereous or lead color; lighter, and in some specimens, nearly white on the abdomen and under tail coverts; lesser wing coverts darker; in some specimens nearly black; quills and tail slightly tinged with brown; greater wing coverts and secondaries pale on their outer edges; primaries nearly white on their inner edges; bill and feet black.
Hab. Coasts of Oregon, Russian America, Northeastern Asia, and the Pacific Ocean. Spec. in Nat. Mus., Washington, and Mus. Acad., Philad.
This bird belongs to a group of the genus Thalassidroma, of which T. marina is the best known species, an inhabitant of the Southern Pacific Ocean, and figured by Mr. Gould as a bird of Australia.
All the species of this group are characterised by cinereous plumage, a strong distinctive character from the greater part of the birds of this genus, which are of dark colors, and in some species nearly black. The present bird does not, in any considerable degree, resemble any other American species, and may be easily recognised.