Introduction: Wallace’s line. 
81 
restrict ourselves to the ornithological facts at our disposal, taking the Avifauna 
of Celebes as the basis for this purpose. Conclusions which may be drawn from 
ornithological facts alone must, however, be weighed very carefully, as birds 
have their own modes of dispersal. We shall then see in how far these con- 
clusions differ from those arrived at by other means. 
Wallace’s line. 
As is generally known Mr. Wallace drew a line to the west of Celebes 
by which the Archipelago was divided into two widely differing halves. This 
division was welcomed with much approbation on account of the fascinating 
speculations of its inventor, though these speculations were more suggestive 
than substantially founded upon and backed by facts, some of which were not 
taken into consideration, and others were not available with our defective know- 
ledge of 20 or 30 years ago, nor indeed are they available to-day. 
Mr. Wallace has, however, in the course of his later studies modified his 
views in some respects. At first, as in the “Malay Archipelago” (1869) and in 
the “Geographical Distribution of Animals” (1876) — not to mention earlier 
writings^) — the line passes between Bali and Lombok, through the Macassar 
Strait west of Celebes, turning to the east between Mindanao and Halmahera; 
while he adds in “Island Life” (1880, 431) “that the present land of Celebes 
has never (in Tertiary times; been united to the Asiatic continent, but has re- 
ceived its population of Asiatic forms by migration across narrow straits and 
intervening islands”. He draws in the latter work (p. 434) the following con- 
clusion; “We have in this island a fragment of the great eastern continent 
which has preserved to us, perhaps from Miocene times, some remnants of its 
ancient animal forms”; and (p. 509): “I now look upon Celebes as an outlying 
portion of the great Asiatic continent of Miocene times, which either by sub- 
mergence or some other cause had lost the greater portion of its animal inhabi- 
tants and since then has remained more or less completely isolated from every 
other land. It has thus preserved a fragment of a very ancient fauna along 
with a number of later types which have reached it from surrounding islands 
by the ordinary means of dispersal”. He further says in his “Australasia” (ed. 
by Dr. Guillemard 1894, p. 287): “The peculiarities of the animal life of 
Celebes may be best explained by supposing it to be an outlying portion of 
that Miocene continent, which became detached from it, and has since never 
been actually joined to any Asiatic or Australian land. It has thus preserved 
to us some descendants of ancient types, and these have become intermingled 
with such immigrants from both east and west as were enabled to establish 
Florenreiche der Erde, Petermann’s Erg. Heft Nr. 74 1884, Atlas der Pflanzenverbreitung 1887, Handbuch der 
Pflanzengeographie 1890), Warburg (Die Flora des asiatischen Monsungebietes : Verb. Ges. Deutscber Naturf. 
Allg. Theil 1890, especially concerning South Celebes), etc. 
1) These earlier writings are to be found in the Ibis IS.'iO, 450; J. of the Proc. Linn. Soc., Zool., I860, 
IV, 172; P. Z. S. 186:1, 481; J. K. Geogr. Soc., 1863, XXXIII, 217; Edinburgh Philos. Journ., new ser., 1864, 
XIX, Nr. 1, etc. 
Meyer & Wigleswortli, Birds of Celebes (May 5thj 1898). 
11 
