308 



LONG-WINGED SWIMMERS — LONGIPENNES. 



parts decidedly more buffy, the dark marblings coarser and more distinct ; tbe whole anterior por- 

 tion of the crown, for the space of about half an inch, together with the superciliary region, is 

 immaculate brownish bulF ; the throat is rather lighter sooty, the sides, etc., paler grayish. From 

 the downy young of S. imnuliscta, the above described specimens may be distinguished by the 

 much less fulvous coloring of the upper parts, and much darker as well as decidedly more gray 

 color of the sides and posterior lower parts. In short, while the general coloration is bright tawny 

 buff in paradiscea, the general aspect is decidedly sooty in aleutica. Young, first plumage: 

 Forehead, lores, crown, and entire nape smoky grayish brown, darkening on the occiput into 

 fuliginous-dusky, this color extending anteriorly on each side nearly or quite to the eye ; the 

 smoke-color of the nape extending over the sides of the neck to the sides of the breast, sometimes 

 even tinging the jugulum and foreneck. Back, scapulars, inner wing-coverts, and tertials dull 

 slate-black, broadly and sharply bordered, especially terminally, with deep yellowish ochraceous ; 

 remainder of the wing plumbeous, the greater coverts and secondaries tipped with white ; prima- 

 ries as in the adult ; upper part of the rump dark brownish slate, the feathers narrowly tipped 



with pale fulvous, this preceded by a dusky subterminal bar ; lower part of rump and upper tail- 

 coverts plumbeous-gray, the lateral coverts nearly white, and the longer tipped with buff; tail 

 pale bluish gray, the feathers growing dusky subterminally, and tipped with deep ochraceous-buff ; 

 inner webs of the rectrices paler than the outer, or nearly white ; outer web of exterior featlier 

 almost entirely pure white. Lower parts entirely white, the under side of the head and neck, as 

 well as the sides of the breast, more or less stained or clouded with smoke-brown. Maxilla 

 dusky ; mandible light reddish (brownish in dried skin), the terminal third or fourth black ; legs 

 and feet clear light reddish. 



Total length, 13.25 to 14.75 inches ; extent, 30.00 to 31.00 ; wing, 9.75-10.75 ; tail, 6.50-7.00 ; 

 depth of its fork, 2.40-3.75 ; culmen, 1.25-1.40 ; depth of lull through base, .38 ; tarsus, .60-.75 ; 

 middle toe, without claw, .80-.85. 



The young of Sterna aleutica may be A^ery easily distinguished from that of S. j^aradiseta — the 

 only other Tern found in any part of Alaska — by the following differences of coloration : (1) The 

 distinctly cinereous rump and upper tail-coverts ; (2) the pure white, instead of uniform blackish, 

 outer webs of the lateral rectrices ; (3) the deep smoke-brown hue of the forehead, crown, nape, 

 and sides of the breast ; (4) the broad white anterior border to the forearm ; (5) the dusky stripe 

 near the edge of the inner webs of the primaries ; and ((i) the much darker general coloration, 

 and es[)ccially the blackish dorsal region, with wide deep ochraceous borders to the feathers. 



The adult needs no comparison with any other species of the genus. 



Our information in regard to the specific habits of tliis newly discovered species 

 and the extent of its geographical distribution is still quite meagre. It is not prob- 

 able tliat its habits vary greatly from those of other Terns, Avhich in all the members 

 of this family are quite similar. The species was first met with, and its eggs pro- 

 cured at the same time, by Mr. BischofF at Kadiak ; and examples of the birds and 



