INTRODUCTION. 
The first volume of this work contains an Index of the 
ichthyological papers of P. BLEEKER, as these are indispen- 
sable to everyone, who studies tropical Indo-Pacific fishes. 
In the following volumes the authors will endeavour to give 
a concise description of all the fishes at this moment known 
to inhabit the Indo-Australian Archipelago. 
This work aims, in the first place, to be a faunistical one. 
Thus our first task must be, to give a definition of this region. 
We followed P. and F. SARASIN, MAX WEBER, P. N. VAN 
KAMPEN and others in calling it “/ndo-Australian Archipelago”, 
as this region includes the many islands between Sumatra and 
New Guinea and thus connects the utterly different faunas of 
India and Australia. The western islands of the Archipelago 
derive part of their fauna from India, the eastern islands from 
Australia. This dualism is expressed in the name Indo-Australian 
Archipelago. But just because of this Archipelago forming a 
link between two continents without strongly marked boundaries, 
it is necessary to call to aid artificial boundaries. Political 
boundaries are useless in this respect. For instance Borneo, 
Timor, New Guinea, each of which belongs to more than one 
colonial power, certainly form part of the Archipelago. 
As it reaches westwards to the Asiatic Continent, we have 
included for our purpose the island Singapore, all the more 
so as this island forms a continuation of the Rio and Linga 
Archipelago. Eastwards our region terminates with New Guinea. 
This large island at the same time defines the southern boundary 
in the east, Australia being therefore excluded. This appears 
to us to be logical. For, although Australia has many faunis- 
tical points in common with New Guinea and the Aru Islands, 
and although the littoral fauna of its tropical part is closely 
connected with that of the Indo-Australian Archipelago, the 
mere fact that Australia reaches far beyond the southern tropic 
into the temperate zone, gives to this large part of the world 
its own characteristic fauna. 
