Swan. NATATORES. CYGNUS. 287 
ridge of the keel, instead of narrowing downwards as in the 
other species, gains breadth as it approaches to the posterior 
extremity of the keel, or where the cavity widens and occu- 
pies a lateral portion of the sternum. In its habits the pre- 
sent bird resembles the Whistling Swan, and is, like it, a na- 
tive of the Arctic Regions of Europe, Asia, and America, as it 
would appear to be the Lesser Swan mentioned by Hearne 
(in his “ Journey to the Northern Ocean”) as visiting Hud- 
son’s Bay in summer.—It feeds upon aquatic vegetables and 
seeds. As might be expected from the form of the lower 
larynx, and that part of the trachea adjoining it, its voice is 
much weaker than that of the preceding species. 
Prats 4'7.* Represents the Cyg. Bewickit of nearly one-half 
the natural size. 
Bill, as far as the nostrils, black ; the base orange-yellow; 
and the upper mandible having a tubercle or knob, 
varying in size according to the age of the bird. Fore- 
head and region of the eyes with numerous specks of a 
pale orange-yellow. In adults, the rest of the body 
pure white, and in the young pale-grey. Tail wedge- 
shaped, and consisting of eighteen feathers. Legs black. 
SuBFAMILY ANATINA. 
Genus TADORNA, Freu. SHIELDRAKE. 
GENERIC CHARACTERS. 
Bill shorter than the head, higher than broad at the base, 
depressed or concave in the middle, with the tip flattened and 
turning upwards, nearly of the same breadth throughout ; 
dertrum, or nail, abruptly hooked. Upper mandible laterally 
grooved near the tip; under mandible much narrower than 
the upper one, and, when closed, hidden by the deflected 
2 
Food. 
General 
descrip- 
tion. 
