114 
Introduction; Geographical Disti-ibutibn. 
17. Zosterops anomala M. & Wg. 20. Ptildpus Jischeri Briigg. 
18. Trichostoma celebense Strickl. 21. — gidaris (Q. G.) 
19. Basileornis celebensis G. E.. Gray 22. Carpophaga forsteni (Bp.) 
There are about 45 species in Celebes which may be relegated to the 
III. Class, differing from one another about as much as Corvus corone L. from 
Corvus cornix L., and for the most part geographical species. They need not 
be tabulated again here, but in the following table these III. Class species have 
been taken as the unit in computing the relationship of the avifauna of Celebes 
with those of the neighbouring countries. We have adopted the following scale: 
One III. Class species, or V.(!) Class genus 1 
One II. Class species, or IV. Class genus — 2 
One I. Class species, or III. Class genus = 4 
One II. Class genus = 8 
One . I. Class genus = 16 
Species of lower value than the III. Class, and first class subspecies are 
valued at -50; less pronounced races at -25. We have not troubled to make 
finer estimations than these last'). 
In attaching a value in this manner to species or genera, room for error 
due to the “personal equation” must be allowed for, but the method is obviously 
better than the usual addition and substraction of genera and species as if they 
were, respectively, units of equal worth. It is very evident, for instance, that 
Megacephalon suggests much more about ancient Celebes than does Gazzola, but 
it is another question whether the value of the former (four times as great as 
the latter) is correctly estimated. 
') Besides the peculiar species of Celebes and the neighbouring islands, there are about 200 other 
Celebesian species which are either migratory or extend their range beyond the bounds of the area. They 
may be tabulated as follows, with the premonition that there is great uncertainty as to whether some species 
should be termed migratory or not: 
Species occurring both in tlie Oriental and Australasian Regions (often migratory) c. 60 
Asiatic migrants c. 64 
Australian migrants c. 5 
Asiatic non-migrants o. 38 
Australian non-migrants c. 34 
It is sufficiently obvious that these species have nothing to say about the former distribution of land and water 
in the East Indies, and they should not be taken into consideration in questions of Geographical Distribution. 
