662 STEENIN^, TEENS. 



coverts white ; greater coverts slaty-gray [_ardoi8ee'], bordered with white. Tail deeply 

 loi kcd ; the external pair of rectrices having an elongation not met with in any other 

 species of the subfamily. 



I regret exceedingly that I have had no opportnnity of examining a specimen of this 

 rare and remarkable Gull. The Smithsonian has never received an example, and I am 

 not aware of the existence of one in any American collection. This is the more to be 

 regretted since the original description by Neboux, which has served uh the basis of 

 nearly all subsequent accounts, both of American and European ornithologists, is brief, 

 deficient, and unsatisfactory. Fortunately, however, the species is one presenting such 

 peculiar features, that no confusion has arisen concerning it. I have taken my diag- 

 nosis from the Zoology of the Voyage of the Venus, and compiled the above outline 

 description from Neboux's original account. I transcribe the further remarks of MM. 

 Provost and Des Murs : 



" In spite of the great diflSculty usually experienced in determining the species com- 

 posing the genus Zants, on account of their close resemblance to each other, and the 

 many variations in colors which each presents, the one in question may bo distinguished 

 at a glance by its orange eyelids and red legs and webs, and y)articularly by the two 

 white spots which ornament the forehead at the upper mandible ; though the red feet 

 are indeed shared by several other species, e. </., L. hcematorhjnehus King, and bonapartei 

 Eichardson. We lay no stress upon the semicircular white spot on the under eyelid, 

 )>ecause this also exists in the franklini and bonapartei of Eichardson. The two other 

 most striking and remarkable features of the species lie in the deeurved bill, which is 

 a little like that of Larua modestm Tschndi ; and in the deeply forked shape of the tail, 

 which is elsewhere only found among typical Stemimw." 



Bibliography. — The species was first introduced by Neboux, as above, in 1840, under 

 the appellation of " La mouette S. queue fourchue," no Latin binomial designation 

 being given. Upon this name and description MM. Provost and Des Murs founded 

 in ly'jfj their Larus furcutus. In conseciuence, doubtless, of its forked tail, it was in 

 Ihii'.i referred by Bmch to the genus Xema. A distinct genus was first framed for it by 

 Bonaparte in 1854. 



Since the foregoing was penned I have been favored, through the courtesy of Howard 

 Saunders, esq., with an original description of a specimen in the British Museum. 

 Under date of March 6, 1873, Mr. Saunders writes me that the bird is a true Xema, and 

 has the appearance of being an Arctic species. " Head, neck, and throat, of a sootier 

 color than in X. sabinei, darkening toward the base of the hood, but not forming a dis- 

 tinct black collar, as in this species ; a white frontal band ; under jiarts and tail pure 

 white, the latter more deeply forked than in sabinei; mantle jtale pearl-gray, somewhat 

 darker on the wing-coverts; primaries blackish-brown on outer webs and continuation 

 of inner webs, thence white, except at tip; secondaries white, tinged with gray at 

 their tips ; bill blackish, tipped with horn-yellow from the angle. Wing, 16.50 inches ; 

 tarsi, nearly -Z inches ; middle toe the same ; hind toe very small, but bearing a well- 

 developed claw." 



Subfamily Steeninje. 



DiAG. Laridoe rostro integro, paragnatho. 



C'h. Bill entire, its upper and under mandible of equal length ; always compressed, 

 and higher than broad. Curve of culnien gentle and gradual from base to apex. 

 Commissure gently declinato-convex, sometimes slightly sinuate at base. Symphysis 

 of inferior mandibular rami much more extensive than in LmlrUJinm or Lorince, V)utthe 

 eminentia symphysis lesi marked. Intenamal space narrow. Encroachment of feath- 

 ers on the bill as in Larina. Xostrils linear-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 ranch elongated 

 and deeply forked, the lateral feathers being more or less att<;nuated and filiform ; only 

 occasionally short and broad (Gelochelidon), or graduated (Anous, iSui.). Legs placed 

 rather further back, and less decidedly ambulatorial than in Larino). Tibia denuded 

 for a varying distance. Tarsi short and usually slender ; scutellate and reticulate, as 

 in Larinw. Toes of moderate length, and of the usual relative x>roportions. Webs 

 rather narrow, and (except in AnouH, &c.) more or less excised. Claws small, com- 

 pressed, but mflch curved and acute. Size moderate, or very small. General form 

 .slender and delicate. Plumage as in other subfamilies, but the pterylai narrow, the 

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



For anatomical peculiarities of the subfamily, see under head of Sterna hirimtUt. 



The generic and subgenerie groups of the Stemince are rather better rnarkeil than 

 those of the Larince. They are in number about thirteen. Of these more than half 

 (seven) are represented in North America. PhcBthum, (xDgin, and several subgenera near 

 Anoun are extralimital. The Xorth American forms may readily Ije distinguished by the 

 following analysis, ffydrochdidon and Anous may be regarded as genera, the remainder 

 being subgenera of Sterna. 



