ANATIDiE — THE SWANS. 
421 
1. Sthenelus, Stejneger, 1882. 
c 2 . Inner webs of outer three primaries and outer webs of the second, third, and fourth 
sinuated; the young with the down on the sides of the bill terminating far back of 
the nostrils ; webs of the feet straight, not scalloped. 
2. Cygnus, Bechst., 1803. 
b 2 . Tail rounded ; the young with the down on the sides of the bill forming very distinct loral 
antia;. 
3. Olor, Wagl., 1832. 
a 2 . Predominant color of the adults blackish ; the young with naked lores ; tertiaries and scapu- 
lars crisp ; tail shorter than the middle toe with claw. 
4. Chenopis, Wagl. 1832. 
“ Geographical Distribution. 
“ The Cygnince appear both in the northern and the southern hemispheres as extra-tropical birds, 
no representatives of these large Lamellirostres being found within the tropics. They are conse- 
quently wanting both in the Indo-African Tropical — they do not at all breed in Africa — and in 
the American Tropical Region, only one species being met with in the South American Temperate 
and one in the Australian Region. The remaining seven species occur in the Arctic and the 
North Temperate Regions, the greatest number, viz., iive, being found in the Old World, and here 
they only extend their winter migrations to the two southern provinces, the Mediterranean and 
the Manchurian, without breeding there. The two North American species only breed within the 
American division of the Arctic Region. 
“ The following table gives a synopsis of their distribution : — 
Name of species. 
Arctic reg. 
North temp. reg. 
ft 
1 
u 
1 
< 
Indo-Afr. trop. reg. 
South Amer. temp. reg. 
African temp. reg. 
Antarctic reg. 
1 Australian reg. 
'd 
U 
o 
pE 
2 
o 
i 
I 
& 
<u 
'PI' l0 AV P10 
New World. 
Sthenelus melancorypha . 
X 
Cygnus gibbus 
— 
— 
X 
— 
— 
— 
— 
— 
— 
— 
imrnutabilis . 
— 
— 
X 
— 
— 
— 
— 
— 
— 
— 
TJnwini .... 
— 
— 
X 
— 
— 
— 
— 
— 
— 
— 
Olor cygnus 
X 
— 
X 
— 
— 
— 
— 
— 
— 
— 
Bewickii 
X 
— 
— 
— 
— 
— 
— 
— 
— 
— 
colum.bianus .... 
— 
X 
— 
X 
— 
— 
— 
— 
— 
— 
buccinator .... 
— 
X 
— 
X 
— 
— 
— 
— 
— 
— 
Chenopis atratus .... 
— 
— 
— 
— 
— 
— 
— 
— 
X 
Of the genera, as defined above, only the third (Olor) belongs to North America, the remainder 
being distributed as follows : — 
The first, Sthenelus (new genus, Pr. U. S. Nat. Mus., Vol. 5, July 25, 1882, p. 183), includes 
only the Black-necked Swan (Anas melancorypha, Mol., Cygnus nigricollis, Auct. ex Gmel.) of 
Chili and other parts of Southern South America ; Cygnus proper contains three species (one of 
them the common domestic species), all of them peculiar to the Paltearctic Region ; Chenopis, in- 
cluding only the Black Swan of Australia {Anas atrata, Lath., Cygnus atratus, Auct.), is confined 
to Southern Australia. 
As before remarked, the Coscoroba Swan (Anas coscoroba, Mol., Cygnus coscoroba, Auct., Anser 
candiclus, Vieill., Coscoroba Candida, Stejn.) of South America, while resembling the true Swans 
in its large size and pure white color, agrees in structure with the Ducks, and can properly be 
considered only as a gigantic member of that sub-family. 
