764 SYSTEM A TIC SYNOPSIS. — L ONGIPENNES — GA VI^. 



bill black at base, white at end ; eyes and feet red ; eyelids <^)range ; claws black. Length 

 about 2 feet. " California " (?) The foregoing is compiled from the original description. 

 Only three specimens of this excessively rare gull are known : one ascribed to Monterey, Cali- 

 fornia; another, adult, from Chatham island, one of the Galapagoes. The latter, in the 

 liritish Museum, is thus described: "Head, neck, and throat, of a sootier color than in X. 

 sabinii) darkening toward the base of the hood, but not forming a distinct black collar, as in 

 this species; a white frontal band; under parts and tail pure white, the latter more deeply 

 forked than in sabinii ; mantle pale pearl-gray, somewhat darker on the wing-coverts; prima- 

 ries blackish-browu on outer webs and continuation of inner webs, thence white, except at ti]); 

 secondaries white, tinged with gray at their tips ; bill blackish, tipped with horn-yellow from 

 the angle. Wing 16.50 inches; tarsi nearly 2 inches; middle toe the same; hind toe very 

 small, but bearing a well-developed claw." A third has lately been announced from Paracas* 

 Bay, Peru ; this is a young one, with black bill, reddish feet, the mantle spotted and the tail 

 barred with blackish. Adult and young are figured by Saunders, P. Z. S., 1882, p. 523, pi. 

 34; see also P. Z. S., 1878, p. 210. The species is very questionably N. Am. 



72. Subfamily STERN I N>E: Terns. 



Covering of bill continuous (no cere), hard and horny 

 throughout. Bill paragnathous, relatively longer and slenderer 

 than in the gulls, very acute, the commissure straight or nearly 

 so to the very end. Curve of culmen gentle and gradual from 

 base to apex. Symphysis of inferior mandibular rami much 

 more extensive than in Lestridince or Larince, but the erainentia 

 symphysis less marked. InteiTamal space narrow. Encroach- 

 ment of feathers on the bill as in Larince. Nostrils hnear- 

 oblong, lateral, direct, pervious, varying with genera as regards 

 degree of approximation to the base of the bill. Wings ex- 

 tremely lengthened, narrow, and acute, the first primary much 

 the longest, the rest rapidly graduated. Secondaries short and 

 inconspicuous. Tail usually much elongated and deeply forked, 

 Fig. 511. —Roseate Tern. (From the lateral feathers being more or less attenuated and filiform; 

 Tenney, after Audubon.) only occasionally short and broad (Gelochelidon) , or graduated 



(Anoiis, etc.). Legs placed rather further back, and less decidedly ambuUitorial than in 

 LariiKB. Tibia denuded for a varying distance. Tarsi short and usually slender ; scutellate 

 and reticulate, as in Larince. Toes of moderate length, and of the usual relative proportions. 

 Webs rather narrow, and (except in Anoiis, etc.) more or less incised. Claws small, com- 

 pressed, but much curved and acute. Size inoderate, or very small. General form slender 

 and delicate. Plumage as in other subfamilies, but the pterylse narrow; the sexes hardly 

 differing in coloration, but the variations with age and season very great. 



The terns are not distinguished from the gulls by any strong structural peculiarities, but 

 they invariably show a special contour, in the production of which the longer, slenderer, and 

 acutely paragnathous bill is a conspicuous element. Only one species has the bill in any no- 

 ticeable degree like that of a gull. A few of the terns are as large as middle-sized guUs, but 

 the normal stature is much less ; and they are invariably of a slenderer build, more trim in 

 shape, with smoother, closer-fitting plumage. The great length and sharpness of the wing 

 relative to the bulk of the body confer a dash and buoyancy of flight wanting in the gulls; in 

 flying over the water in search of food, they hold the bill pointing straight downward, which 

 makes them look curiously like colossal mosquitoes ; and they secure their prey by darting 

 impetuously upon it, when they are usually submerged for a moment. The larger kinds feed 

 principally upon little fish, procured in this way; but most of the smaller ones are insectivo- 



