CHAP. XIII. ] THE AUSTRALIAN REGION. ~~ 889 
a geological sense) been separated from it. In the next rank come 
the large islands of the Moluccas on the west, and the range 
terminating in the Solomon Islands on the east, both of which 
groups possess a clearly Papuan fauna, although deficient in 
many of the most remarkable Papuan types. 
All these islands agree closely with New Guinea itself in 
being very mountainous, and covered with a luxuriant forest 
vegetation ; but to the south-west we find a set of islands ex- 
tending from Timor to Lombock, which agree more nearly with 
Australia, both in climate and vegetation; being arid and 
abounding in eucalypti, acacias, and thickets of thorny shrubs. 
These, like the Moluccas, are surrounded by deep sea, and it is 
doubtful whether they have either of them been actually con- 
nected with New Guinea or Australia in recent geological times; 
but the general features of their zoology oblige us to unite all 
these islands with New Guinea as forming the Austro-Malay 
sub-division of the Australian region. Still further west how- 
ever, we have the large island of Celebes, whose position is very 
difficult to determine. It is mountainous, but has also extensive 
plains and low lands. Its climate is somewhat arid in the south, 
where the woods are often scattered and thorny, while in the 
north it is moister, and the forests are luxuriant. It is surrounded 
by deep seas, but also by coralline and volcanic islets, indicating 
former elevations and subsidences. Its fauna presents the most 
puzzling relations, showing affinities to Java, to the Philippines, 
to the Moluccas, to New Guinea, to continental India, and even to 
Africa; so that it is almost impossible to decide whether to place 
it in the Oriental or the Australian region. On the whole the - 
preponderance of its relations appears to be with the latter, 
though it is undoubtedly very anomalous, and may, with almost 
as much propriety, be classed with the former. This will be 
better understood when we come to discuss its zoological pecu- 
harities. 
The next sub-region consists of the extensive series of islands 
scattered over the Pacific, the principal groups being the Sand- 
wich Islands, the Marquesas and Society Islands, the Naviga- 
tors’, Friendly, and Fiji Islands. New Caledonia and the New 
