CHAP. XIV.] 
THE NEOTROPICAL REGION. 
9 
highly specialized forms out of some ancestral swift-like type ■ 
how complete and long continued the isolation of their birth- 
place to have allowed of their modification and adaptation to 
such divergent climates and conditions, yet never to have per- 
mitted them to establish themselves in the other continents. 
No naturalist can study in detail this single family of birds, 
without being profoundly impressed with the vast antiquity of 
the South American continent, its long isolation from the rest of 
the land surface of the globe, and the persistence through countless 
ages of all the conditions requisite for the development and 
increase of varied forms of animal life. 
Passing on to the parrot tribe, we find the peculiar family of the 
Conuridse, of which the macaws are the highest development, very 
largely represented. It is in the gallinaceous birds however that 
we again meet with wholly isolated groups. The Cracidee, in- 
cluding the curassows and guans, have no immediate relations 
with any of the Old World families. Professor Huxley considers 
them to approach nearest to (though still very remote from) the 
Australia n megapodes ; and here, as in the case of the marsu- 
pials, we probably have divergent modifications of an ancient 
type once widely distributed, not a direct communication between 
the southern continents. The Tinamidse or tinamous, point to a 
still more remote antiquity, since their nearest allies are believed 
to be the Struthiones or ostrich tribe, of which a few repre- 
sentatives are scattered widely over the globe. The hoazin of 
Guiana (Opisthocomus) is another isolated form, not only the 
type of a family, but perhaps of an extinct order of birds. Pass- 
ing on to the waders, we have a number of peculiar family types, 
all indicative of antiquity and isolation. The Cariama of the 
plains of Brazil, a bird somewhat intermediate between a bustard 
and a hawk, is one of these ; the elegant Psophia or trumpeter of 
the Amazonian forests ; the beautiful little sun-bittern of the 
river banks (. Eurypyga ) ; and the horned screamers ( [Palamedea ), 
all form distinct and isolated families of birds, to which the Old 
World offers nothing directly comparable. 
Reptiles . — The Neotropical region is very rich in varied forms 
of reptile life, and the species are very abundant. It has six 
