304 NATATORES. ANAS. 
Genus ANAS, Zivw. DUCK. 
GENERIC CHARACTERS. 
Bill longer than the head, depressed through its whole 
length, broad, strait from before the nostrils to the tip, nearly 
equally broad throughout. Mandibles dentato-laminate, 
with the lamine of the upper mandible scarcely projecting 
beyond the margin. Nostrils lateral, oval, situated near the 
base of the bill. Wings of mean length, acuminate. Tail 
short, slightly wedge-shaped ; with the middle feathers curl- 
ing upwards in some species. 
Feet with four toes, three before and one behind ; the 
front ones webbed, the hind toe small and free. 
The birds of this genus, of which the Common Wild 
Duck niay be considered the representative, differ from the 
Shovellers in the general form of the bill, which is not ex- 
panded near the tip, and in the shortness of the laminz of 
the upper mandible, which do not project beyond its mar- 
gins. In this latter respect they also differ from the Gad- 
walls. They possess a wide range, being met with in most 
parts of the globe ; and it is from the common species (Anas 
Boschas) that we have obtained our useful domestic Duck, 
now expanded into so many varieties. 
