[Case 37. ] 
[Case 37. | 
[Case 38. | 
64. BIRD GALLERY. 
Torrent-Duck (M. armata) (688), frequents the high mountain torrents 
of the Andes, and forms a link between the true Mergansers and the 
stiff-tailed Diving-Ducks, but differs from the former in having no teeth 
on the edges of the mandibles and in having the bend of the wing armed 
with astrong spur. The New Zealand Soft-billed Duck (Hymenolemus 
malacorhynchus) (689) is worthy of special notice on account of its 
remarkable bill with a dependent membrane, suited for the capture of 
insect larve on which it principally feeds. 
The Stiff-tailed Ducks, so-called from tieir rather long, narrow, rigid 
tail-feathers which are often carried erect when the bird is swimming, 
include several genera of which representatives will be found in the 
White-headed and Australian species of Hrismatura (690, 691), 
the American Masked form (Nomonyx) (698), and the Musk-Duck 
(Biziura lobata) (692). The latter, whose name is derived from the 
strong musky odour of the sitting female, frequents the seas as well as 
the lakes of Australia and Tasmania. It is much the largest species of 
the group, and remarkable on account of the leathery chin-pouch found 
in both sexes. The appendage opens under the tongue and is largest 
in the male, giving the bird a very peculiar appearance. Like its 
allies it is an expert diver and can remain for a long time submerged. 
It seldom, if ever, flies in the daytime, but will do so at night. The 
nest is placed in aswamp or in a bank, and contains two or three olive- 
coloured eggs. 
Of Sea-Ducks we may first mention the Eiders, which are all in- 
habitants of northern waters, and are represented by Steller’s Eider 
(Heniconetta stelleri) (694) and the King- and Common Eiders (Somateria 
spectabilis (695) and S. mollissima (696)), all of which are included in 
the British List. Their nests supply the “ Eider down ” which forms an 
important article of export in countries such as Norway, where the 
common species is protected by law and consequently exceedingly 
numerous. It will be noted that the series exhibited shows the 
changes from summer- to winter-plumage in both the old and young 
drakes, the ‘eclipse ” or intermediate autumn-plumage being specially 
interesting. 
The South-American Rosy-billed Duck (Metopiana) (697) is often 
kept on ornamental waters in this country. The Pochards (Netta 
and Nyroca) include the Red-crested (698) and Ferruginous (701) 
species, both of which occur in Great Britain as occasional stragglers, as 
well as the Common Pochard (699) and the Canvas-Back (700) from 
North America, famous for its excellent qualities as a bird for the table. 
The Tufted Duck (Fuligula) (103) breeds plentifully on the lochs and 
ponds of Great Britain and Ireland, and is easily recognised by the 
long droopmg occipital crest developed in both sexes; the Scaup 
