26 ELEMENTS OF ORNITHOLOGY. 
bassana), we meet once more with an Oceanic form. It may 
serve as the type of a very small group of Marine Birds widely 
distributed in the Tropics. 
The Gannet is a somewhat ungainly Bird, a little smaller 
than a Goose, and awkward in its movements on the land. 
Not only is it a perfect swimmer, but it is also remarkable 
for its wonderful powers of flight, soaring to great heights 

The Darter (Plotus anhinga). 
and traversing a hundred miles or more of aérial space in 
one day. Though not possessed of the powers of diving which 
Darters and Divers enjoy, the Gannet, large and heavy bird 
though it be, will suddenly descend and plunge directly down- 
wards to catch the fish on which it feeds most greedily. It is 
very local as to its breeding-places, there being but few such in 
