STERNA FULIGINOSA, SOOTY TEEN. 699 



Casual in Europe (as above). Ascension Island (Collingwood, Zool. 980; Sperling, Iliis, 

 18(jB, 286). South America to Cliili {Fliil. & Landh.). Middle America and various West 

 Indian islands. Pacific coast of Mexico (Socorro, Graysoii). In North America on the 

 South Atlantic and Gulf coast; north regularly only to the Carolinas; casu.iUy to Penn- 

 sylvania (Chester County, Barnard, in lit, Baird) ; extension to New England denied. 



Adult in spring plumage. — With the form, &c., as already detailed under head of the 

 subgenus. Bill black. Legs and feet black. Claws black. Iris dull red. On the fore- 

 head is a broad lunula of white, the cornua of which extend baekw.ard over tbe eye to 

 about opposite its middle ; its convex borders separated from the white of the lower 

 part of the cheeks by a straight rather broad band of brownish-black, which extends 

 from the eye obliquely downward and forward to the bill. The entire upper parts are 

 black, deep and uniform, with considerable of a greenish gloss, specially noticeable on 

 the crown. Entire under parts from chin to end of inferior tail-coverts, sides of the 

 head below the eye, sides of the neck more than half way around, with inferior alar 

 teotrices, pure white. Primaries deep brownish-black, lighter on the inner Avebs ; their 

 shafts superiorly light brown, inferiorly white. Secondaries like the primaries, but 

 the greater part of their inner webs whitish. Tail glossy brownish-black above, duller 

 below ; the elongated exterior rectrices white, with white shafts, deepening into black- 

 ish toward the extremities, priucip.ally of their inner webs. 



Young-of-thc-year. — Smaller than the adults, tbe bill especially much smaller and 

 weaker. Upper mandible black ; the under dull reddish, deeper toward the tip ; eyes 

 and feet dull reddish. The entire plumage is of a nearly uniform brownish or grayish 

 fuliginous ; darker on the upper parts ; still deeper on the primaries, where it is almost 

 black; lighter on the under j)arts, so much so as to fade on the abdomen into grayish- 

 white. The superior alar tectrices and the scapulars are all broadly tipped with white, 

 which gives a very peculiar spotted aspect to the parts. The feathejs of the back, 

 rump, and upper tail-coverts, are all margined and tipped with dull rufous, which 

 causes these parts to present a remarkable transversely-waved appearance. The i.ail 

 is uniformly of much the same color as the wings, all the rectrices fading toward their 

 apices into dull brownish. It is simply emargiuate, instead of being deeply forked 

 the lateral rectrices having but a slight elongation. 



Dimensions of (lie adult. — Average length, about 16..50; extent of wings, 33 to 35. Wing 

 from the carpus, 12; tail, 7 to 7.50 ; depth of fork, 3. to 3.50. Bill along culmen, ].80j 

 along commissure, 2.50 ; from feathers on side of lower mandible, 1.90 ; height at base 

 0.50. Tibize bare, 0.70 ; tarsus, 1 ; middle toe and claw, 1.20 ; outer ditto, 1.05 ; inner 

 ditto, 0.75 ; hallux and its claw, 0.30. 



This species is too well known, and too distinct from any other of North America, to 

 require any further description or comparison. The plumage of the young, above de- 

 tailed, is very peculiar, and interesting as being a state upon which one or two nominal 

 species have been founded. It is very difterent from that of the adults. As the bird 

 in this condition grows older the abdomen .ind under parts generally become lighter 

 at the same time that the upper portions of the body deepen in color. The rufous 

 margins of the feathers of the laack and the white tips of the alar tectrices gradually 

 disappear, and the white front begins to make its appearance. The lateral feathers of 

 the tail acquire length and tenuity and become whitish. While the bird is undergo- 

 ing these changes it has also been characterized by some authors as a distinct species. 



A specimen from Socorro (No. 50861, A. J. Grayson), and another from Isabella 

 Island, are different in some respects from any others I have seen. The under parts 

 from the middle of the belly backward, including the tail-coverts, are distinctly washed 

 over with clear, pale slate-gray, which appears in striking contrast to the pure white 

 of the rest of the under parts. The line of demarcation of the two colors is evident. I 

 have not specimens enough to say whether this is a constant feature of the birds from 

 that locality. This is the form named var. o-issalis, as above. 



A large suite of specimens from various Pacific localities, in the Smithsonian, col- 

 lected by the United States Dxploring Expedition, shows me no characters by which a 

 second species may be distinguished iiom fidiginosa. 



Anatomical characters. — The mouth presents but slight variations from the ordinary 

 type. Median ridge commences an inch and a quarter from the tip; is broad and not 

 very prominent ; small obtuse papillie are thinly scattered over its whole surface. 

 Lateral ridges are somewhat sinuate, and extend backward hardly beyond the termina- 

 tion of the median ridge. They are thickly papillate. Opening of posterior nares 

 three-fourths of an inch long. Palate posteriorly considerably vaulted ; the oval aper- 

 ture at its extremity short ; the oblique fringe of papillse that proceed on uitlu-r side 

 short and slightly developed. This portion of the mouth is marked with delicate 

 oblique striae. There are several folds of mucous membrane at the angle of the mouth. 

 Tongue one and a quarter inches long ; very acute, corneous on its anterior two-thirds ; 

 its posterior extremity obtusely emargiuate, thickly papillate. Eima glottic! is one- fourth 

 long; situate rather mora than this distance from the base of the toDgue ; its edges 

 smooth, terminally papillate, and these papillin extend for some distance on either side. 



(Esophagus between five and six inches long, including the proventriculus ; present- 



