994 SYSTEMATIC SYNOPSIS. — LONGIPENNES. 



the tip has also a iniDUte gray spot; 4th wholly bluish-gray to within 1.50 of the tip, which 

 has a larger gray spot than has the 3d, so that the black is less than 1.50 long; 5th, the gray 

 extending so far that it is separated from the well-defined white apical spot by a band of blacit 

 less than 1.50 wide ; 6th gray, fading into white at tip, and with the black reduced to a small 

 subapical spot on one or both webs ; other primaries like Gth, minus the black spot. (This 

 "gray " of the primaries is the color of the mantle.) Feet coral-red, especially toes and webs 

 (tarsi not quite so bright), drying yellow; claws black. Adults in winter: As before, but 

 <;ervi.\: and auriculars overlaid with plumbeous. Young: Similar, but cervical collar better 

 marked and darker, and mantle variegated with grayish-white tips of the feathers ; more dark 

 color about eyes, but no black on wing-coverts, inner secondaries, or tail : bill and feet ob- 

 scured. Nestlings covered with white down, with whitish bill and feet. Length 14.00-16.00 ; 

 wing 13.00; tail 5.00; culmen 1.20; rictus 1.70; from nostril to tip 0.60; depth at base 0.50; 

 width 0.42; depth at angle 0.42; tarsus 1.25; middle toe and claw nearly 2.00. A beautiful 

 aud very distinct species, swarming by thousands on rocky coasts and islands of Bering's Sea, 

 vi^here it is a permanent resident; nests on shelves of the most inaccessible crags, building a 

 substantial structure of grass, moss, and seaweeds, mixed with mud; eggs 2-3, 2.25 X 1-65, 

 of the usual pattern of coloration : June, July. 



PAGOPH'ILA. (Gr. wdyos, pcigos, ice ; (/)tXo9, j^hilos, loving.) Ice Gulls. Bill much 

 shorter than head, about equal to tarsus, very stout, little compressed ; nasal fossae deep, the 

 nostrils place<l far forward. Culmen straight to nostrils, then regularly convex ; commissure 

 gently curved to tip, where it is considerably decurved; gonys straight to near angle, which is 

 well defined, the outline from angle to tip perfectly straight. Feathers extending between 

 rami nearly to angle. Wings long and pointed, reaching beyond tail. Feet very short and 

 stout; scales of tarsus and toes large and rough. Tibiae feathered to near joint; tarsus about 

 as long as middle toe without claw ; claws large, much curved ; M-ebs narrow and much in- 

 cised ; a slight connection of hind with inner toe. Size moderate ; form stout; color entirely 

 white. One species. (Gavia Boie, 1822, of A. 0. U. Lists, 1886-95. Pagophila Kaup, 

 1829, A. 0. U. Suppl. List, Auk, Jan. 1899, p. 98. 



P. al'ba. (Lat. aZ&a, white.) Ivory GuLL. Snow Gull. Adult ^ 9^ breeding plumage : 

 Entirely pure white ; shafts of primaries straw-yellow. Bill greenish-gray, yellow at tip 

 and along cutting edges ; feet black ; eyes brown ; edges of eyelids red. Young : Front and 

 sides of head dusky gray; upper part of neck, all round, irregularly spotted with the same. 

 Scapulars, and upper and under wing-coverts, with brownish-black spots, most numerous along 

 lesser coverts. Tips of primaries and tail-feathers with dusky spots. Nestlings covered with 

 white down; fledglings gray. Length 16.00-19.00; extent 41.00; wing 13.25; bill above 

 1.40; along gape 2.10; height at nostrils 0.45; tarsus 1.45; middle toe and claw 1.75. Cir- 

 cumpolar regions, breeding only in very high latitudes, S. rarely to the U. S. in winter; New 

 Brunswick casually. The bird abounds in summer in its Arctic breeding resorts, where it 

 usually nests on cliffs like a Kittiwake, sometimes on low ground. Eggs 2-4, 2.25-2.45 X 

 about 1.70, olivaceous-bufi", marked with different shades of brown and gray; laid late in June 

 and in July. P. eburnea of former editions of the Key, as of most authors, after Larus ebur- 

 neus Phipps, 1774, antedated by L. albus Gunn. 1767, whence P. alba CouES, Auk, July, 

 1897, p. 313. A. 0. U. Suppl. List, 1899, p. 99. 



CHROICOCEPH'ALUS. (Gr. ^P^tKo'?, c7wwJtos, colored ; Kecf)aXrj, kephale, head.) Hooded 

 Gulls. Rosy Gulls. Form as in Larus, but usually less robust; size averaging smaller; 

 bill usually slenderer, more acute, and less hooked. Head enveloped in a dark hood in the 

 breeding season, when white of under parts usually blushes pink or rosy. Markings of prima- 

 ries varying with the species, but different from that of the larger Gulls. Tail square, or nearly 

 so. There are no marked peculiarities of form of this genus, pattern of coloration being mainly 

 its basis. The numerous species average much under those of Larus in size (though one, C. icli- 



