e abundant. There is therefore no doubt as to Mexico forming part of this
region, although it is comparatively poor, and exhibits the intermingling
of temperate and tropical forms.

The West Indies are less clearly Neotropical, their poverty in mammals as
well as in most other groups being extreme, while great numbers of North
American birds migrate there in winter. The resident birds, however,
comprise trogons, sugar-birds, chatterers, with many humming-birds and
parrots, representing eighteen peculiar Neotropical genera; a fact which
decides the region to which the islands belong.

South temperate America is also very poor as compared with the tropical
parts of the region, and its insects contain a considerable proportion of
north temperate forms. But it contains armadillos, cavies and opossums; and
its birds all belong to American groups, though, owing to the inferior
climate and deficiency of forests, a number of the families of birds
peculiar to tropical America are wanting. Thus there are no manakins,
chatterers, toucans, trogons, or motmots; but there are abundance of
hang-nests, tyrant-birds, ant-thrushes, tree-creepers, and a fair {54}
proportion of humming-birds, tanagers and parrots. The zoology is therefore
thoroughly Neotropical, although somewhat poor; and it has a number of
peculiar forms of strictly Neotropical types--as the chinchillas, alpacas,
&c., which are not found in the tropical regions except in the high Andes.

_Comparison of Zoological Regions with the Geographical Divisions of the
Globe._--Having now completed our survey of the great zoological regions of
the globe, we find that they do not differ so much from the old
geographical divisions as our first example might have led us to suppose.
Europe, Asia, Africa, Australia, North America, and South America, really
correspond, each to a zoological region, but their boundaries require to be
modified more or less considerably; and if we remember this, and keep their
extensions or limitations always in our mind, we may use the terms "South
American" or "North American," as being equivalent to Neotropical and
Nearctic, without much inconvenience, while "African" and "Australian"
equally well serve to express the zoological type of the Ethiopian and
Australian regions. Europe and Asia require more important modifications.
The European fauna does indeed well represent the Palaearctic in all its
main features, and if instead of Asia we say tropical As