LARID^ — LAMINA : GULLS. 
747 
dusky ; darkest on the latter ; all with light edgings. Primaries uniform brownish-black, 
without white spots, tips, or lighter bases. Tail almost entirely brownish-black, with a 
narrow border of white. Young in August : Bill and legs as in the preceding. Everywhere 
whitish-gray ; of the under parts appearing as mottling, and the blue of the upper 
parts as irregular patches. Dimensions: length 17.50; extent 42.00; wing 13.75; bill 
above 1.40; gape 2.00; width at nostrils 0.25; height 0.35, height at angle 0.35; tarsus, 
and middle toe with claw, 1.80. Interior of Arctic America, and Pacific coast generally. Not 
authenticated as occurring on the Atlantic coast. The American representative of L. canus. 
781. L. heer/manni. (To Dr. A. L. Heermann. Fig. 509.) White-headed Gull. Very different 
from any of the foregoing, belonging to a different section of the genus (Blasipus). Bill shorter 
than head or tarsus, rather slender, moderately compressed, the tip rather acute; its color red in 
part in the adult. Folded wings reaching beyond the tail. Tail of moderate length, even, slightly 
emarginate in the young. Feet rather large. Tarsus equal to the middle toe and claw. Gen- 
eral colors dark ; tail mostly blackish. Adult, breeding plumage : Bill bright vermilion red, 
black for its terminal third, sometimes wholly red ; a red ring around eye. Head white ; this 
color gradually merging on the neck into plumbeous-ash, which extends over the whole under 
parts, being lighter on the abdomen and under tail-coverts than elsewhere. The back is deep 
plumbeous-slate, lighter on 
the rump. Upper tail-cov- 
erts clear ashy. Upper sur- 
faces of wings like the back ; 
the primaries black ; the tips 
of all, except the two or 
three outer ones, narrowly 
white. Tail black, nar- 
rowly tipped with white. 
Legs and feet reddish-black. 
Young-of-the-year : Smaller 
than the adult. Bill and feet brownish -black. Entire plumage deep sooty or fuHginous- 
blackish ; all the feathers, but especially those of the back and upper wing-coverts, edged 
with grayish-white. Primaries and secondaries black, as in the adults, with only traces of 
white tips on the former. Tail black, very narrowly tipped with dull white. Immature : 
Bill as in the adult. Head all round, and the throat, mottled with brownish -black and dull 
white, the latter color predominating on the forehead and throat. Upper tail-coverts lighter 
than in the adult, and the white tips of the tail-feathers broader; otherwise generally as in the 
adult, but with all the colors rather deeper. Dimensions: ''length about 17.50 ; w^ing 13.50; 
tail 5.50"; length of skin 18.50; wing 14.00; tail 5.75; bill along culmen 1.80; along gape 
2.40; depth at base 0.55; at angle, about the same ; tarsus 2.20; middle toe and claw a little 
less. Young: wing 12.25; tail 4.75; bill along culmen 1.00; depth at base 0.50; at angle 
0.45 ; tarsus 1.90. Length of some skins up to about 20 inches. Pacific coast of N. Am., from 
British Columbia to Guatemala ; singular among all our species in dark lead-color with white 
head and red bill ; common on the California coast. 
309. BIS'SA. (Icelandic name, rissa or ritsa.) Kittiwakes. Bill stout, rather short, little com- 
pressed at the base, shorter than the head, equal to middle toe without claw, longer than tarsus ; 
tip decurved and attenuated ; convexity of culmen regular and gradual from base to tip ; gonys 
concave, in consequence of the great deflection of the apex of lower mandible; outline of rami 
slightly concave ; eminentia symphysis well marked and acute, but not large. Wings very 
long, pointed, reaching beyond the tail ; the primaries pointed, first longest. Tail moderately 
long, even or (in young) emarginate. Legs stout and short. Tarsus remarkably short, less 
than middle toe alone ; anterior toes all long, and united by broad, full webs with unincised mar- 
