23, i Merrill: Distribution of Dipterocarpaceae 25 



Bornean elements to enter the Balabac-Palawan-Calamian group 

 to the north and the Sulu Archipelago and perhaps the Zam- 

 boanga Peninsula of Mindanao to the south. It is significant 

 that the ornithologists and zoologists wish to derive the Palawan 

 avifauna and mammalian fauna wholly or largely from Borneo, 

 and the herpetologists and some entomologists are apparently 

 like minded in reference to their respective groups. Everett 27 

 claims that there has been no land connection between the 

 Palawan-Calamian group and the Philippines proper since 

 Palawan received its present fauna. Pagenstecher, 28 however, 

 states that, of the two hundred thirty-five species of Lepidoptera 

 that occur in Palawan, one hundred thirty are found in the 

 Philippines proper and one hundred twenty in Borneo, and 

 sixty-five are common to the three regions. In respect to 

 the lepidopterous fauna Palawan is evidently as much Philippine 

 as it is Bornean. The Palawan flora is definitely about as much 

 Philippine as it is Bornean, and the Bornean elements in its 

 flora are relatively very weak when compared with the mani- 

 festly very strong Bornean zoological elements found there. 



We have already seen that direct land connections between 

 Borneo and Celebes have not existed since early Tertiary. There 

 were probably indirect connections via eastern Java and Celebes 

 through what are now intervening islands, but these connections 

 could not have been very extensive nor very long continued. 

 There were definite connections between Mindanao and Celebes 

 via the Sangi Islands, and possibly between Mindanao and 

 Gilolo and, in turn, with New Guinea via Talaut Island, and 

 these connections existed some time during the Tertiary; prob- 

 ably they existed at different times, having been more or less 

 intermittent, for depressions and elevations have been character- 

 istic of the entire region throughout the Tertiary and Quarter- 

 nary ages. The Celebes-Mindanao connections were not 

 necessarily in existence at the same time that a land bridge 

 existed between Borneo and Mindanao. The evidence seems to 

 be that the connections between the Philippines and Borneo were 

 earlier, more extensive, and longer continued than were the 

 connections between Mindanao and the islands to the south and 

 east. Thus the dominant dipterocarps were permitted to enter 



27 Everett, A. H., Remarks on the zoogeographical relationships of the 

 island of Palawan and some adjacent islands, Proc. Zool. Soc. London 

 (1889) 220-228, map. 



» Pagenstecher, A., Die geographische Verbreitung der Schmetterhnge 

 (1909) 1-451 (p. 237). 



