BIRDS—MERGINAE—MERGUS AMERICANUS. 813 
MERGUS, Linnaeus. 
Mergus, Linnarvs, Syst. Nat. 1735. Type M. castor, L. 
Cu.—Bill longer than the head, mostly red; serrations conical, acute, recurved. Crest occipital, pointed, or depressed. 
Tarsus about two-thirds the middle toe. Tail about half the length of wings. 
The two North American species of this genus are very differently marked, though the females 
are quite similar. In external form they differ considerably from Lophodytes cucullatus, and 
to a less extent among themselves. The difference is chiefly in the position of the nostril, and 
the outline of the feathers at the base of the bill, as well as in the shape of the crest. 
The species may be briefly characterized as follows: 
Nostril near the middle of the bill; the frontal feathers extending much beyond the lateral. 
Head without conspicuous crest. Head and neck green. Beneath salmon colored. Sides 
without transverse bars. Wing white from the extreme bend, crossed by one black bar. 
M. americanus. 
Nostril towards the base of bill. Lateral feathers extending beyond the frontal. Head with 
pointed occipital crest. Head and upper part of neck green; jugulum light reddish brown, 
streaked with black; feathers in front of elbow white, margined with black. Sides finely 
barred transversely with black. Edge of wing brown; its white crossed by two black bars. 
M., serrator. 
MERGUS AMERICANUS, Cassin. 
Goosander; Sheldrake; Fish Duek. 
Mergus merganser, Wits. Am. Orn. VIII, 1814, 68; pl. Ixviii. Not of Linnaeus—Bon. Obs. Wils. 1825, 248.— 
Dovenry, Cab. I, 1830, 109 ; pl. x.—Sw. F. Bor. Am. II, 1831, 461.—Nurr. Man. II, 1834, 
460.—Auvp. Orn. Biog. IV, 1838, 261; pl. 331.—Is. Syn. 1839, 297.—Is. Birds Amer. VI, 1843, 
387; pl. 411. 
Mergus americanus, Cassin, Pr. A. N. Sc. VI, 1853, 187. 
Merganser custor, var. A. americanus, Bon. Comptes Rendus XLII, 1856. 
. 
Spe. Cu.—Feathers of the forehead extending on the bill in an acute angle for half the distance between those on the sides 
and the nostril ; outline of those on the sides nearly vertical and reaching but little beyond the beginning of lower edge of bill, 
but as far as those on the side of lower jaw. Nostril large, far forward, its middle opposite the middle of the commissure. 
Male. Head without conspicuous crest. Head and neck green. Fore part of back black ; beneath salmon color. Wings 
mostly white, crossed by one band of black. Sides scarcely barred transversely. 
Female. Head with a compressed occipital crest- Head and neck chestnut. Above ashy; beneath salmon colored. White 
of greater coverts with a terminal bar of ashy, (sometimes wanting ;) the black of base of secondaries entirely concealed. 
Outer tertials ash. 
Length, 26.50; wing, 11.00; tarsus, 1.84 ; commissure, 2.90. 
Hab.-—Whole of North America. 
Head without conspicuous crest, though one is visible in life. Head and most of neck all 
round very dark green; rest of neck and the body generally, except the upper part, creamy 
white, deepening to salmon red beneath. Lower part of back, rump, and tail feathers, 
plumbeous. Fore part of back, interscapular region, and inner scapulars, black. Avxillars, 
inside of wings, coverts, most of secondaries, and tertials, with the outer scapulars, creamy 
white; the greater coverts black at the base, forming a black bar and the tertials narrowly 
