GENERAL CHARACTERISTICS. 
3°3 
by which they are inhabited. For instance, while the Palsearctic region, that is to 
say, the greater part of Europe and Asia north of the line of the Himalaya, is 
characterised by the sole possession of the capercaillie, and its abundance of grouse, 
buntings, etc., North America is the sole home of the turkey, while humming-birds 
are mainly characteristic of South and Central America, as are birds of paradise, 
lyre-birds, and cockatoos of the Australasian region. Many birds, especially some 
of the humming-birds, have indeed a very local distribution; and, as might have 
been expected, the various groups of flightless Birds are now respectively confined 
to particular continents and islands. It would be impossible to pursue the subject 
further in the space available, but the reader will be enabled to gather many of 
the leading facts of avian distribution in the course of our description of the various 
groups. 
As regards their geological distribution, it may be mentioned that most of the 
birds from the Tertiary formations are more or less closely allied to existing types. 
When, however, we reach the antecedent Cretaceous (chalk) epoch, we find that at 
least several of the birds were furnished with teeth; while in the still older Jurassic 
or Oolitic epoch the one definitely known bird ( ArchcnoRteryx ) was not only 
furnished with teeth, but had a long tapering tail, and exhibited several other 
features indicative of reptilian affinity. While Birds present no sort of relationship 
to Mammals, they show manifest indications of being nearly allied to certain 
extinct groups of Reptiles; but the nature of that relationship can be best indicated 
in our consideration of those groups. 
On no subject is there greater diversity of views among zoologists 
than with regard to the classification of Birds; scarcely any two 
ornithologists being in accord on this point. To a great extent this is owing to 
that structural uniformity among the members of the class to which reference has 
been already made, which renders it almost impossible to determine what features 
should be regarded as of primary importance. With such conflicting views it is 
inevitable that schemes of classification are to be counted almost by the dozen, and 
scarcely a year passes without one or more new ones being proposed. As it is 
unlikely that any one of these latter classifications will be permanently accepted, 
it has been thought advisable, in a popular work of the present nature, to revert to 
a modification of a scheme proposed some years ago by Dr. Sclater. Including 
certain extinct groups, the class, according to this scheme, may be divided into the 
following twenty-four groups, of which the first twenty-one may be reckoned 
orders—such orders, be it understood, being for the most part far less distinct from 
one another than are those of Mammals. 
Classification. 
Orders of Birds. 
1. 
2 . 
Passeres —Perching Birds. 
Picarle —Woodpeckers, Cuckoos, Hornbills, etc. 
3. Psittaci —Parrots. 
4. Striges —Owls. 
5. Pandiones —Ospreys. 
6. Accipitres— Eagles, Falcons, Vultures, etc. 
