GEOGRAPHICAL RELATIONS OF BIRDS. 241 
It is made up of six subregions, very imperfectly defined as 
yet :— 
I. The Patagonian subregion, or Tierra del Fuego and the 
Continent thence northwards to a little north of Bahia Blanca 
on the East coast, and a line running thence north-west, east of 
Mendoza to the Andes ; also all the higher slopes of the Andes 
to north of the Equator, and the land west of the Andes from 
about Truxillo southwards, including the island of Chiloe and 
the other islands back to Tierra del Fuego. 
II. The Brazilian subregion, or the Continent east of the last 
subregion to Potosi, and thence north-east, south and east of 
the watershed of the Amazons, to the mouth of the Paranahyba. 
III. The Amazonian subregion includes the basin of the 
Amazons as far west as the tributary of it named the Huallaga, 
from the mouth of which its boundary passes obliquely and 
irregularly to the mouth of the Orinoco. 
IV. The Peruvian region, consisting of the lands intervening 
between the Andes and the Brazilian and Amazonian regions, 
together with the rest of the Continent north of Truxillo 
and the Orinoco, the Galapogos Islands and those of Trinidad 
and Tobago. 
V. The Central-American subregion, or the region from the 
Isthmus of Panama to the boundaries of the Nearctic region. 
VI. The Antillean region, or the West Indies excluding 
Trinidad and Tobago. 
The AUSTRALIAN region is made up of Australia, Tas- 
mania, and New Zealand, with the Moluccan Archipelago, up 
to and including the island of Lombock, with Celebes and the 
islands of the Pacific to the Sandwich Islands in the north. 
It is divisible into four subregions :— 
I. The Papuan subregion, or New Guinea and all the islands 
belonging to this region, as far as and including Celebes, 
New Ireland, and the Solomon Islands. 
Il. The Proper Australian subregion, or Australia and Tas- 
mania. 
IU. The Polynesian subregion, or the islands from New Cale- 
donia, Fiji, and the New Hebrides to the Society and Sandwich 
Islands. 
IV. The New-Zealand subregion, or New Zealand with the 
Norfolk, Chatham, Auckland, and Macquarie Islands. 
The number of species which migrate and the extent of their 
migrations may appear to oppose a great difficulty to the group- 
R 
