ANATID.E— THE SWANS, GEESE, AND DUCKS. 179 



■winp-ooverts, rpniipos, and tail plain duslcy; upper tail-coverts and lower parts barred 

 ■with pale fulvous and dusicy, the abdomen nearly plain erayish brown. "Bill pale green- 

 ish (Tray; iris dull yellow; feet dull ochre" (Audubon). Young female: Similar to the 

 younc male, but head and nofk srayish-bulT, finely streaked with dusky. 



Total length, about 20.00-25.00 inches; wine, 10..J0-11.2J; bill, from base of frontal lobe to 

 tip, in the male. 1.20-1.30; tai-sus, 1.80-1.86; middle toe, 2.20, 



The female of this species may be easily distinguished from 

 that of S. dresseri by the very different outline of the feathering 

 at the base of the bill, as explained, page 176. 



This is the only one of the Eiders the range of which extends com- 

 pletely across the northern portion of the northern hemisphere. 

 Its habits are essentially the same as those of the other species of 

 the same genus. It migrates south in winter to a greater or less 

 distance, but in varying numbers, according to the character 

 of the season. It breeds in the arctic regions. 



Genus OIDEMIA Fleming. 



Oidemia Flem. Philos. Zool. ii, 1822,260, Type, by elimination. Anas nigra LiNN. 



Gen. Chae. Distance from posterior border of nostril to angle of mouth equal to or 

 greater than distance from anterior end of nostril to tip of upper mandible. Adult males 

 uniform black, with or without white speculum, and with or without white patches on head; 

 bill brightly colored in life with tints of yellow, orange, or red, but partly Dlack. Adult fe- 

 males plain brownish, lighter and more grayish beneath, the white head-markings of the 

 male (if any) indistinctly indicated. 



This genus includes three subgenera, with the following char- 

 acters : 



A. Length of commissure much less than inner toe, without claw; adult males entirely 

 uniform black; bill of adult male much swollen on top at base; distance from anterior 

 end of nostril to nearest feathers of forehead greater than distance from same point to 

 tip of bill. 



1. Oidemia. 



B. Length of commissure much more than length of inner toe without claw. 



a. Feathering of head advancing nearly or quite as far forward on lores as on forehead; 



wing with a white "speculum." 



2. Melanitta. 



b. Feathering of head advancing much farther forward on forehead than on lores; mug 



without white "speculum." 



3. Pelionetta. 



Subgenus OIDEMIA FLE>fiNG. 



Oidemia Flem. Philos. Zool. Ii, 1822,2G0. Type, by elimination. Anas nigra Lixv. 



SuBOEN. Ch.vb. Feathers at the base of the maxilla forming a nearly straight oblique 

 hne from the forehead back to the rictus, advancing scarcely, if at all, on the forehead; bill 

 very deep through the base, where sometimes elevated into a roundish knob, and much de- 



