66 ON THE GEOGRAPHY OF ANIMALS. 
-wood ibis, in form at least, 
seems to represent the glossy 
ibis, so common in the south of 
Europe. The herons of Caro- 
lina and Florida are numerous, 
and comprise several large and 
beautiful species. The magni- 
ficent scarlet ibis, also, is there 
not uncommon: yet few of 
these elegant wading birds ex- 
tend to the northern parts of 
the United States. Among the 
ducks and other swimming 
tribes, there is a general simi- 
larity in the species to those of 
Arctic America, two or three 
only being restricted to the 
warmer sheres of the southern 
provinces. The chief of these 
is the splendid Dendronessa 
sponsa Sw., called there the summer or tree duck of 
South Carolina. The Sela aac: duck (Fuligula 
Vallisneria Bon., fig. 
24..) is chiefly found 
in temperate Ame- 
rica, and is prized 
as a delicious food. 
- Nearly all the rest 
* of the duck tribe 
occur in fhe northern regions, which they quit for the 
United States during severe winters, and return to 
breed in the spring. America, like Europe, thus pre- 
sents us with a double migration, and both for the same 
purposes; namely, to avoid cold, to procure sustenance, 
and to rear their young. 
(93.) The fish of the Ohio, and the other great rivers, 
are stated to be peculiarly abundant, both in number and 
in species; yet none appear to resemble those of Europe. 
The famous fishing-banks for cod, on the coast of New- 
