300 NATATORES. CHAULIODUS. 
Genus CHAULIODUS, Swarnson. GADWALL. 
GENERIC CHARACTERS. 
Bill as short as the head, depressed throughout its length, 
as broad as high at the base, rather narrowing towards the 
tip, which has a small dertrum or nail. Both mandibles la- 
minated ; the lamin of the upper one projecting beyond 
the margins of the bill. 
Nostrils lateral, near the base of the bill, oval and per- 
vious. | 
Wings long and acuminate. Tail wedge-shaped. 
Feet with four toes; three before and one behind; the 
front ones webbed ; the hind toe small and free. 
The form of the bill, and the great development of its la- 
minated structure (as shewn in the proportionate size of the 
laminz of the upper mandible), combined with the peculiar 
habits, and comparatively sombre plumage of the species, 
has induced me to separate the Gadwalls from the succeed- 
ing genera, comprising the Ducks, the Teals, and the 
Widgeons. In this, however, I only adopt the views of a 
more able ornithologist, for Mr Swainson, in the second 
volume of the Northern Zoology, and also in a paper upon 
the typical perfection of the Anatide (published in the Jour- 
nal of the Royal Institution), has made it a subgenus of his 
genus Anas (of which he considers the Shoveller as the type), 
and which term is precisely of the same import as that of 
genus in the systematic arrangement I have adopted, being 
the denomination of the lowest group of species. Although 
the form of the bill differs much from that of the Shovellers, 
having lost the dilatation of its extremity, so conspicuous in 
the other, and assumed in a great measure the proportions 
of the next genus (Anas), the Gadwalls still shew a near af- 
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