480 ORNITHOLOGY AND OOLOGY. 



SUB-ORDER ANSERES. 



Family ANATID^. 



The two jaws with transverse lamellae, alternating and fitting in each other; 

 upper mandible ending in an obtuse rounded nail; a groove running along both 

 jaws to the nail; the feathers of the forehead extend forward on the culmen in a 

 rounded or acute outline; those on the side of lower jaw and on the chin extend 

 (brward in a similar manner; commissure straight; legs short. 



Sub-Family Ctgnin.e. — The Swans. 

 CYGNUS, LixN.EUS. 



Cygnus, Lixn.eus, Syst. Nat. (1835). (Type Anas olor, Gra.) Gray. 



Neck very long; bill longer than the head (commissure longer than the tarsus), 

 the basal portion covered by a soft skin extending to the anterior half of the 

 eye; the plane of the upper outline from eye to eye horizontal; the lateral outline 

 extending nearly straight to the commissure, or even sometimes widening slightly; 

 not half the width of the bill at tip; nostrils situated in the middle portion of 

 the bill; lower portion of tibia bare; the tarsus much shorter than the foot, much 

 compressed, covered with hexagonal scales, which become smaller on the sides and 

 behind; hind toe small, much elevated; the lobe narrow; tail of twenty or more 

 feathers, rounded or wedge-shaped; sexes similarly colored. 



CYGNUS AMERICANUS. —Sharpless. 



The American Swan. 



Oygnm Americnmis, Sharpless. Doughty's Cab. N. H., L (1830) 185. Aud. Cm. 

 Biog., V. (1839) 133. lb., Birds Am., VI. (1843) 226. 

 Cygnus fervs, Nuttall. Man., II. (1834) 368. 



Description. 



Bill as long as the head, broad, high at the base; the feathers ending on the fore- 

 head in a semicircular outline; nostrils far forward, the anterior extremity consider- 

 ably more forward than half the commissure; tail of twenty feathers. 



Adult pure-white; bill and legs black; the former with an orange or yellowish 

 spot in front of the eye; less mature specimens with the head above tinged with 

 reddish-brown ; iris brown. 



Length, fifty-five inches; wing, twenty-two; tarsus, four and twenty-five one- 

 hundredths; bill, above, four and twenty one-hundredths inches. 



Bab — Continent of North America. 



