MEGG V—MERGANSER 543 
described,’ and so often repeated by other writers, as to be very 
commonly known, and here there seems no necessity to enter into 
further details concerning it. 
MEGGY, properly an abbreviation of Margaret, a nickname of 
the WHITETHROAT ; but perhaps a corruption of Muaey. 
MEGISTANES, Vieillot’s name in 1816 (Analyse, p. 53) for a 
group containing the four genera of Ratite birds then known, 
Struthio, Rhea, Casuarius, and Dromexus, and since applied (Ann. 
& Mag. N. H. ser. 4, xx. p. 500) to the Order composed of the two 
last (CASSOWARY, EMEU). 
MELANISM (adj. melanistic) the abnormal occurrence of 
black or very dark coloured plumage (see CoLouR, p. 99, and 
HETEROCHROSIS, p. 420). 
MERGANSER, a word originating with Gesner (Hist. Anim. 
iii. p. 129) in 1555, and for a long while used in English as the 
general name of a group of fish-eating Ducks which possess great 
diving powers, and form the genus Mergus of Linneeus, now regarded 
by ornithologists as a subfamily, 
Mergine, of the Family Anatide. 
They have a long, narrow bill, with 
a small but evident hook at the tip, 
and the edges of both mandibles beset 
by numerous horny denticulations, Br or Mercvs. (After Swainson.) 
whence the name of “Saw-bill” is 
frequently applied to them. Otherwise their structure does not much 
depart from the Anatine or rather Fuliguline type. All the species 
bear a more or less developed crest or tuft on the head. Three of 
them, Mergus merganser or custor, M. serrator, and M. albellus, are found 
over the northern parts of the Old World, and of these the first two 
also inhabit North America, which has besides a fourth species, J/. 
- cucullatus, said to have occasionally visited Britain. J2 merganser, 
the GOOSANDER, is the largest species, being nearly as big as the 
smaller Geese, and the adult male in breeding-attire is a very beautiful 
bird, conspicuous with his dark glossy-green head, rich salmon- 
coloured breast, and the upper part of the body and wings black 
and white. This full plumage is not assumed till the second year, 
and in the meantime, as well as in the postnuptial dress, he much 
resembles the female, having, like her, a reddish-brown head, the 
upper parts greyish-brown, and the lower dull white. In this con- 
dition the bird is often known as the “Dun Diver.” This species 
1 See Gould, Handb. B. Austral. ii. pp. 152-175; G. R. Gray, Proc. Zool. 
Soc. 1861, pp. 292-296 ; Wallace, Malay Archipelago, i. pp. 415-419; ii. pp. 
147-149 ; Guillemard, Crwise of the ‘ Marchesa,’ ii. pp. 193-197 with fig. ; Hick- 
son, Naturalist in North Celebes, pp. 94, 95. 
