130 Prof. Dr. Max Weber on the 



found there. These belong to the Oriental region. Indi- 

 genous forms do not occur (for Haplochilus celebensis cannot 

 be considered such), nor Ceratodus and Osteoglossum, which 

 belong to the tropical region of Australia, the latter being 

 found also in the great Sunda Islands. From this we receive 

 the impression that the entire area of fresh water, poor in 

 freshwater forms, was gradually peopled from the sea. 



How is this dearth to be explained, since it is not occasioned 

 by the present hydrographical condition of Celebes ? 



Further, how is the qualitative difference in the fish-fauna 

 of Celebes to be explained as compared with that of the large 

 Sunda Islands? 



The answer to the first question would be that the present 

 hydrographical conditions were not necessarily those of the 

 past. There are geological proofs that the shape of Celebes 

 was formerly different from what it is to-day, and we are 

 indebted to A. Wichmann for this important information. 

 He shows that South Celebes (which is of special importance 

 to us, as containing the system of the Tjenrana River specially 

 in question) consisted in the second half of the Tertiary period 

 (Neogen) of a number of small separate portions, rising like 

 islands above the surface of the sea *. " In consequence of 

 the negative elevation, which began at the end of the Neogen 

 and continues to this day, the island of South Celebes was 

 uplifted to form a peninsula through junction with the central 

 mass of the island, while at the same time the surrounding- 

 coral-islands were raised and the sandstone-beds in the east 

 rose from the sea as eroded surfaces " f . 



From a geological point of view it is also probable that 

 the connexion between North and South Celebes is compara- 

 tively recent. In a former article \ I pointed out the peculiar 

 differences in the mammalian fauna of North and South 

 Celebes. In South Celebes Paradoxurus 3/usschenbroekii, 

 Schl., Babirussa alfurus, Less., Cynopithecus niger, Desm., 

 Sciurus murinus, Mull. & Schleg., Sciurus rubriventer, Mull. 

 & Schleg., Sciurus leucomus, Miill. & Schleg., Sciurus Pre- 

 vosti, Desm. ; which up to the present have only been recorded 

 from North Celebes, are absent. On the other hand, Ma- 

 cacus maurus, Cuv., Sciurus notatus, Boddaert, Sciurus 

 Weberij Jentink, are peculiar to South Celebes. 



* A. Wichmann, u Bericht ub. eine im Jahre 1888-89 ausgefukrte 

 Reise nach d. Ind. Archipel," Th. i. p. 74, in Tijdschr. v. h. Nederl. 

 Aardrijkskdg. Genootschap, Jaargang 1890. 



t A. Wichmann, " Die Binnenseen von Celebes," Peterin. Mitth. 1893, 

 Heft, x., xi., and xii. p. 18 des sep. Abdruckes. 



X Max Weber, Zoolog. Ergebnisse, Bd. i. 1890-91, pp. 103, 110, 113. 



