ANSEE. 
61 
in several of the species continued, and we see 
in them the greatest perfection in the structure of 
the bill. In the Fuligulina?, or scaups and po- 
chards, &c. wc see the time spent almost entirely 
on the waters, the powers of swimming and div- 
ing augmented, while the wings in many are pro- 
portionally short ; and in the last sub-family, or 
the Mergansers, the habits are more aquatic still, 
their progress when upon land, which is only during 
the time of breeding, more constrained, and their 
food composed almost entirely of fishes, for the 
holding fast of which their bill is strongly toothed 
or serrated. In the males of most of the species 
there is a dilatation or bony labyrinth in the wind- 
pipe or trachea, the use of which seems scarcely to 
be understood, while in others, as the swans, it 
performs a doubling or a convolution in the interior 
of the sternum. In all the species we have exa- 
mined, this structure is different in each, and pre- 
sents a distinguishing mark where they are closely 
allied. Tire geese of the Kasorial form is charac- 
terised in 
Ansee, Brisson. — Generic characters. — Bill 
somewhat conical in shape, narrower than the 
head, elevated at the base ; lateral laminae in 
the form of blunt teeth, slightly developed, 
and apparent exteriorly ; nostrils central, rather 
large, pierced entirely through ; wings pointed, 
ample, tuberculated ; legs placed under the 
centre of the body, tarsi rather long, hallux 
