GENERAL CHARACTERISTICS. 303 



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 arc 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 

 g 1 mips. 



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 antecedenl < Iretaceous (chalk 1 epoch, we find that at 

 least Beveral of the birds were furnished with teeth: while in the still older Jurassic 

 or Oolitic epoch the one definitely known bird (Archceopteryx) was not only 

 furnished with teeth, but had a lone- 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. 



Orders of Birds. 



1. PASSERES — Perching Birds. 



2. PlCAREE — Woodpeckers, Cuckoos. Hornbills, etc. 



3. PsiTTACi — Parrots. 



4. Striges — Owls. 



5. Pandiones — Ospreys. 



G. Accipitres — Eagles, Falcons. Vultures, etc. 



