BIRDS OF NORTH AND MIDDLE AMERICA. 783 
by a backward prolongation of the culmen, the posterior end of 
which meets the upper portion of the basal lamina, the posterior 
half of which is minutely punctulated; a conspicuous tumid rosette 
surrounding rictus; eyelids with deciduous horny plates, that on 
upper eyelid in one species erect, hornlike. Wing moderate, the 
longest primary (outermost) exceeding distal secondaries by slightly 
more than half the length of wing. Tail less than one-third (but 
more than three-sevenths) as long as wing, very slightly rounded; 
rectrices 16. Tarsus much shorter than middle toe without claw, 
the acrotarsium with a narrow series of small transverse scutella 
on lower half or more; outer toe (without claw) slightly shorter 
than middle toe (without claw), the inner toe (without claw) slightly 
shorter than first two phalanges of middle toe, its claw conspicu- 
ously larger, more strongly curved, and more acute than other claws. 
Nuptial ornaments.—Basal portion of bill with eleven deciduous 
pieces, which are shed after the breeding season,’ as are also the 
horny appendages to the eyelids and the tumid rictal rosette. 
Plumage and coloration.—No ornamental head plumes. Upper 
parts, together with a band across foreneck, uniform black, the 
pileum grayish brown; sides of head grayish or white (blackish 
anteriorly in winter); under parts of body immaculate white. 
Range.—Circumpolar regions, south in winter to Massachusetts, 
Canary Islands, Queen Charlotte Islands, and Kuril Islands. (Two 
species. ) 
KEY TO THE SPECIES AND SUBSPECIES OF FRATERCULA. 
a. Deciduous nasal cuirass occupying less than basal half of bill; grooves on sides of 
maxilla and mandible very oblique, broad, and distinct; process on upper eye- 
lid short, subconical; nuptial plumage with upper throat gray (whitish gray 
posteriorly, light mouse gray anteriorly and laterally) and sides of head light 
gray posteriorly; tail shorter (42-53 mm.). (Fratercula arctica.) 
b. Smaller, with relatively smaller and narrower bill; averaging wing, 162.9; tail, 
48.4; culmen, 48.9; greatest depth of bill, 36.3; tarsus, 26.4; middle toe, 37.4. 
(Coasts and islands of northern Atlantic Ocean, including Iceland and 
southern Greenland, south in winter to Massachusetts, Portugal, Canary 
Telands, 6tC:) ..-.ccccc.0c0teu tte eettan eases -Fratercula arctica arctica (p. 784). 
bb. Larger, with relatively larger and deeper bill; averaging wing, 176; tail, 52.2; 
culmen, 53.7; greatest depth of bill, 44.7; tarsus, 28.5; middle toe, 42.5. 
(Islands of Arctic Ocean, from northern Greenland to Spitzbergen.) 
Fratercula arctica naumanni (p. 788). 
aa, Deciduous nasal cuirass occupying much more than basal half of bill; grooves on 
sides of maxilla and mandible nearly vertical, narrow and indistinct; process 
on upper eyelid elongated, hornlike; nuptial plumage with whole throat 
blackish, the chin, only, gray; sides of head white; tail longer (60-68 mm.). 
(Shores and islands of northern Pacific Ocean’ and Bering Sea, from British 
Columbia to Kuril Islands)............-....-. Fratercula corniculata (p. 789). 
@ See Bureau, Bull. Soc. Zool, de France, ii, 1877 (1878), 1-21, pls. 4, 5; Stejneger, 
Bull. U. 8. Nat. Mus., no. 29, 1885, 48-51, the latter with special reference, however, 
to Lunda cirrhata. 
