OIDEMIA. 111 
6}. Nail of bill much flattened, scarcely hooked at tip. Adult male: Bill black, 
with a yellow or orange spot on culmen immediately in front of the 
basal knob. Adult female: Above sooty brown, beneath paler, inclining 
to light grayish brown on breast and belly; bill wholly dusky, the basal 
half of the culmen level, or scarcely if at all elevated at base. Wing 
8.00-9.20, culmen 1,90, depth of upper mandible at base .98-1.00 in male, 
.50 in female, tarsus 1.50-1.60. Hab. Northern portions of eastern hemi- 
sphere. 
O. nigra (Liny.). European Scoter.! 
b%. Nail of bill distinctly arched, and decidedly hooked at tip. Adult male: 
Basal half of upper mandible, including whole of knob, yellow or 
orange; rest, including entire edge, black. Adult female: Above dusky 
grayish brown, the feathers of dorsal region with paler tips; lower 
parts paler grayish brown, the lighter tips broader, though want- 
ing on the posterior portions; lateral and under-parts of head nearly 
uniform light grayish brown, in decided contrast with dark brown of 
pileum and nape; bill uniform blackish. Young: Much like adult 
female, but lighter beneath, where indistinctly barred (mostly beneath 
the surface) with grayish brown. Length 17.00-21.50, wing 8.75-9.50, 
culmen 1.65-1.80, depth of upper mandible at base .85-.95 in male, .70 
in female, tarsus 1.65-2.00. Zggs 2.55 x 1.80; pale dull buff or pale 
brownish buff. Hab. North America, breeding northward; in winter, 
south to New Jersey, the Great Lakes, and California. 
163. O. americana Sw. & Ricw. American Scoter. 
a’, Length of commissure much more than length of inner toe without claw. 
b'*. Feathering of head advancing nearly or quite as far on lores as on fore- 
head; sides of upper mandible at lower portion of base sunken; wing 
with a white speculum. (Subgenus Melanitta Botz.) 
ce. Loral feathers separated from nostril by a space nearly or quite 
equal to length of nostril; male with lower part of swollen basal 
portion of upper mandible, on sides, unfeathered; sides of bill 
orange-yellow in life; basal portion of culmen elevated but not 
forming an abrupt knob; plumage uniform black, or brownish 
black, relieved by a white wing-speculum and a white patch be- 
neath and behind eye. Adult female: Sooty grayish, or dusky 
grayish brown, darker above; wing with a white speculum, but no 
white on head; bill wholly dusky. Downy young: ‘‘ Crown, nape, 
hind-neck, and sides of the head to a line from the base of the 
lower mandible deep brown; a small white spot below the eye; 
upper parts uniform dark brown with an olivaceous tinge ; & small 
white patch of down on the wings; under-parts white, the upper 
breast crossed by a dull brown band.” (Drzsszr.) Length about 
21.00, wing 10.65-11.40, culmen 1.40-1.70, depth of upper mandible 
1 Anas nigra Linx., S. N. ed. 10, i. 1758, 123. Oidemia nigra Fiem., Brit. Anim. 1828, 119. 
