78 DISTRIBUTION OF ANIMALS. [PART I. 
of a single representative of a unique order of reptiles, is, as 
before remarked, of the same character as the preservation of 
the Proteus in the caverns of Carniola ; and can give the locality 
where it happens to have survived no claim to form a primary 
Zoological region, unless supported by a tolerably varied and 
distinctly characterized fauna, such as never exists in a very 
restricted and insular area. 
Neotropical Region—My. Sclater’s original name for this 
region is preserved, because change of nomenclature is always 
an evil; and neither Professor Huxley’s suggested alteration 
“ Austro-Columbia,” nor Mr. Sclater’s new term “Dendrogea,” 
appear to be improvements. The region is essentially a tropical 
one, and the extra-tropical portion of it is not important 
enough to make the name inappropriate. That proposed by 
Professor Huxley is not free from the same kind of criticism, 
since it would imply that the region was exclusively South 
American, whereas a considerable tract’ of North America 
belongs to it. This region includes South America, the 
Antilles and tropical North America; and it possesses more 
peculiar families of vertebrates and genera of birds and mam- 
malia than any other region. 
Subdivisions of the Neotropical Region—The great central 
mass of South America, from the shores of Venezuela to Paraguay 
and Eastern Peru, constitutes the chief division, and may be 
termed the Brazilian sub-region. It is on the whole a forest 
country; its most remarkable forms are highly developed 
arboreal types; and it exhibits all the characteristics of this rich 
and varied continent in their highest development. 
The second, or Chilian sub-region, consists of the open plains, 
pampas, and mountains of the southern extremity of the con- 
tinent ; and we must include in it the west side of the Andes as 
far as the limits of the forest near Payta, and the whole of the 
high Andean plateaus as far as 4° of south latitude; which 
makes it coincide with the range of the Camelide and Chin- 
chillide. 
The third, or Mexican sub-region, consists of Central America 
and Southern Mexico, but it has no distinguishing character- 
