INTRODUCTION’. 
formed by the high mountain ranges of the interior the general strike 
of which is in a north-east and south-west direction 1 - In some species, 
a race found east and south of these mountains is separable from that 
found, broadly speaking, in Sarawak, In many other cases races 
are distributed, broadly, as above but meet on the northern (' ‘north- 
western’ ') coast in the neighbourhood of Baram where there is a most 
important faunal boundary. Occasionally, a northern race thus cut 
off extends only a short distance down the east coast. 
Within the major divisions given above there are also tendencies 
for areas of faunal distinction to separate in the lowlands of south, 
and of west Borneo. Certain rivers running west and east act as 
boundaries in the case of some mammals. 
A slight Javan influence is apparent in the south of Borneo. 
Turning to the mountains we find that, within the island, the 
great massif of Mt. Kinabalu in the north has far fewer peculiar forms 
than was formerly thought, for recent collecting has shewn that it 
shares most of its birds with other high peaks in North Sarawak. 
On the neighbouring Mt. Dulit there are signs of independent speciali- 
zation although these are not so numerous as some recent authors 
would have us believe. It is interesting to note that a few montane 
species also occur on the isolated peaks of Foi and Penrissen in the 
north-west comer of the island : the form is usually that found on the 
northern mountains, but in one or two cases, distinctive subspecies 
have been developed. 
The islands off the north-west coast of Borneo call for little com- 
ment beyond mention of an indigenous race of a small owl on 
Mantanani. 
Mallewall£, Banguey and Balambangan, situated off the northern 
extremity of Borneo, outside the ten fathom line, hut on a bank of 
less than twenty fathoms, have an avifauna almost entirely Bornean 
but with slight indications of internal differentiation, and there is also 
a small non-Bornean element, derived from the adjacent Palawan 
group of islands. 
Maratua island, off the east coast, in the Celebes Sea, has also 
produced a few subspecies : on it there is, too, a Phillippine 
influence unknown on the mainland of Borneo or in the Banguey 
group. 
In some respects the avifauna of the Karim ata Islands, off the 
west coast, is closer to that of Sumatra than of Borneo : some of the 
species merely tend to large size as on other islands in the South 
China Sea, but within the group two birds seem to be represented by 
j See a map and paper by E. Banks in Proc Zook Sac 1933, P- 273 : 
and the same author’s detailed study of the distribution of Scturus 
prevosti in Borneo, op.cii.. 1931, p. 1336, which also has a useful map. 
