768 SYSTEMATIC SYNOPSIS. — LONGIPENNES— GA VIJE. 
Fig. 517. 
much reduced 
Aleutian Tern, 
South America, questionably occurring in N. Am. ; New Jersey and Long Island " (Audu- 
bon). 
803. S. aleu'tica. (Of the Aleutian Isles. Fig. 517.) Aleutian Tern. Adult : Bill of ordinary 
shape, as in hirundo, macrura, etc., entirely black. Feet small, as in the species just named, 
but the webs more deeply incised ; emargination not so great, however, as in Hydrochelidon ; 
much as in Haliplana. Tibiae bare to the usual extent. Wings 
and tail exactly as in Sterna proper, the latter, in its length and 
depth of fork, recalling mao'ura and forsteri. Crown and nape 
black ; 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 fossae, the concavity of which is opposite the anterior 
border of the eyes ; thus 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 head bordering this vitta below, are pure white, 
presently deepening insensibly into the hue of the under parts. Tail wholly pure white ; no 
pearly wash on either vane of any of the feathers. Upper parts at large dark pearl-gray, with 
a dull leaden hue, different from the clear pearly of macrura, etc., yet not of the smoky cast 
of panayensis, etc. ; it is a tint intermediate between these, that I find difficult to name satis- 
factorily. The whole under parts, from the white of the chin, just noticed, to the under tail- 
coverts, paler and more decidedly pearly, more nearly as in fuU-pluraaged macrura, yet more 
grayish. Both under and upper tail-coverts, like the tail, white. The color of the back 
mounts on the neck behind to the 
black of the nape Mdthout interven- 
tion of white. Under wing-coverts 
and edge of wing pure white ; as are 
all the shafts of the primaries. Pri- 
maries blackish lead-color, with 
silvery hoariness, and each with a 
large white space on inner web ; this 
white space on the first primary oc- 
cupies at the base the whole width 
of the inner web, but grows nar- 
rower toward the tip of the feather, 
ending about an inch from the tip, 
which is wholly blackish lead-color, 
this color running down as a narrow 
margining of the inner vane for two 
inches or more. On the other pri- 
maries successively this white space 
diminishes in size, and is also less 
distinctly defined. Secondaries colored much like the back, but the greater part of the inner 
web of all white, and a narrow oblique touch of white on outer web near its end, which forms 
a bar across the wing when closed. 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 of fork 2.40; tarsus 0.60; middle 
toe alone 0.80; its claw nearly 0.30. Alaska and Aleutian Islands ; a notable late discovery, 
coming between the species of Sterna proper and the sooty tern group ; related to S. lunata. 
804. S. fuligino'sa. (Lat. fiiligmosa, sooty. Fig. 518.) Sooty Tern. Representing a small 
group apart from any of the foregoing, named Haliplana by some; approaching the noddies 
slightly. Bill as long as head, scarcely exceeded by whole foot, straight, stout at base, taper- 
FlG. 518. — Foot of Sooty 
Tern, nat. size. (From Saunders.) 
Fig. 519. — Foot of Bridled 
Tern, nat. size. (From Saunders.) 
