

696 SIEENA ALEUTICA, ALEUTIAN TERN. 



ground color varies froai clear, pale greeiiisb-wbite to pale dull drab or 

 olivaceous. The markings are numerous, aud generally distributed, 

 though they frequently tend to wreathe around the large end, especially 

 when they are of large sizej they consist of small splashes, irregular 

 spots, and mere dots of clear brown of several shades, together with 

 numerous pale, ill-defined lilac or gray shell-markings. 



STEENA ALEUTICA, Bd.^ 

 Aleutian Tern. 



Sterna aleutica, Bd., Tr. Chic. Acad, i, 1869, 321, pi. 3t, f. 1.— Dall & Bann., ibid. 307 



(Kodiak).— Codes, Key, 1873, 322. 

 Sterna " camtscliatica, Pall.," Finsch, Abh. Nat. iii, 1872, 85 (Alaska). 



DiAG. S. rostro, pedibus, vertice, nuehd, et fascia transoculari, nigris ; lunula frontali, gwld, 

 genis ctcaudd, albis ; corpora griseo-plumbeo, subtus dilutiore, magis perlaceo ; magnitudine 

 cireiter S. macruros. 



Hab. — Aleutian Islands. (Kodiak.) 



Adult.— {TSo. 52517, Mas. Sniitlis. ; Kodiak, June 12, 1868. The type of the species.) 

 The hill has the usual sh.ape, as in hirmtdo, niaa-ura, ic. It is entirely black. The feet 

 are small, as in the species just named, but depart somewhat from the typical condi- 

 tion of this genus in having the webs more deeply incised. The emargination is not so 

 great, however, as in the genus Sydrochelidon. It is much as in JBaliptana. The tibiae 

 are bare to the usual extent. The wiugs and tail are exactly as in Sterna proper, the 

 latter, in its length aud depth of fork, recalling macrura and forsteri. The crown and 

 nape are black ; there is a large white frontal crescent, the horns of which reach to the 

 posterior border of the eyes, the convexity of which extends into the nasal fossas, the 

 concavity of which is opposite the anterior border of the eyes. It is thus seen to ho 

 broader than in most species similarly marked. The black vertex sends through the 

 eye a band that crosses the cheeks and reaches the bill just posterior to the point of 

 greatest extension of the feathers on the latter. The chin, auriculars, and other parts 

 of the he.ad bordering this vitta below, .are pure white, presently deepening iuseosibly 

 into the hue of the under parts. The tail is wholly pure white ; no pearly wash on 

 either vane of any of the feathers. The upper parts at large are of a dark pearl-gray, 

 with a dull leaden hue, different from the clear pearly of rnacrura, &c., yet not of the 

 smoky cast oi panaycnsis, &c. ; it is a tint intermediate between these, that I find diffi- 

 cult to name satisfactorily. The whole under parts, from the white of the chin, 

 just noticed, to the under tail-coverts, are of a paler and more decidedly pearly tint 

 of the same color, more nearly as in fuU-plumaged macrnra, yet more grayish. Both 

 under and upper tail-coverts are, like the tail, white. The color of the b.aok mounts 

 on the neck behind to the black of the nape without intervention of white. The under 

 wing-coverts and the edge of the wing are pure white ; so also are all the sh.afts of the 

 primaries. The primaries are blackish lead-color, with silvery hoarlness, and each with 

 a large white space on the inner web. This white space on the first primary occupies 

 at the base the whole width of the inner web, but grows narrower toward the tip of 

 the feather, ending about an inch from the tip, which is wholly blackish. le.ad-color, 

 a.s just described, this color funning down as a narrow margining of the inner vane for 

 two inches or more. On the other prim.aries successively this white space diminishes 

 an size, and is also less distinctly deiined. The secondaries are colored much like the 

 back, hut the greater part of the iuner web of all is white, and there is a narrow 

 oblique touch of white on the outer web near its end, which forms a bar .across the 

 wing when closed. 



' Divieiisions. — Bill along culmen, 1.40; along gape, 1.70; height at base, 0.30; length 

 of gonys, 0.80; wing, 9.75; tail, 6.50: depth ot fork, about 2.40; tarsus, 0.60; middle 

 toe alone, 0.80 ; its claw, nearly 0.30. 



No special comparison with any other known species is required. 



This Tern, recently described (as above), is interesting in several respects. It is 

 singular that so strongly marked a species should have remained so long unnoticed, 

 but. we find no indication of it in the names or descriptions of previous writers. It 

 gives us a new style of coloration for North American species. At first sight it sug- 

 gests species of Haliplana, without, however, presenting anything like the special 

 coloration of the type of that subgenus, fuUginosa. It more nearly resembles the-paler- 

 colored species of the genus, as panayensis for example ; and, again, comes nearer still 

 to certain southern forms of what are usually rated as Sterna proper ; for instance, <S. 

 lunald, Peale. The black bill and feet, white frontal lunula, dullness of the upper 

 pairts, &c., which suggest RaUplana, are supplemented by an approach to that genus 



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