Dammerman: Fauna of the Krakataii Islands. 79 



The soil and surface fauna from different localities has been studied 

 in this manner for a long period and I hope to publish later the results 

 of this research in full. 



In the table on the following pages are listed the species and individuals 

 found on 1 M- of different localities on Krakatau, Verlaten I. and Sebesy. 



The localities are distinguished by the vegetation. First of all there is 

 the littoral zone, composed of beach plants. Behind this formation is usually 

 a fringe of Casuarina-forest, consisting chiefly of Casuarina-trees mixed 

 with a few other plants. The third zone is formed by the jungle proper 

 composed of numerous species of trees so characteristic of a tropical wood. 



In the littoral zone one finds as a rule the decaying leaves immediately 

 on the barren sand ; in the Casuarina-forest the soil is covered by a rather 

 thick and firm layer of needles, whereas in the virgin forest the surface 

 layer consists of dead leaves and mould which varies in thickness. The 

 layer of leaves and mould in the tropics is, contrary to what one would 

 expect, remarkably thin, as appears from the figures in the table. Certainly 

 this is due to the fact that tropical trees shed their leaves as a rule the 

 whole year round and decay being so much quicker here. 



The altitude of the locality given as M. in the list means at sea level 

 or at least beneath 50 M. 



If we look at the list on the following pages the results prove to be of 

 great divergence, so it is hard to deduce an exact average from the figures 

 especially as to the number of specimens. 



On Krakatau 1 found for the littoral zone 14 species on 1 M^; on 

 Sebesy an average of 14.5. The mean figure for the Casuarina-forest on 

 Krakatau is 14, on Verlaten 1. 7.8, on Sebesy 18.2. For virgin forest be- 

 neath 50 M. the figures are: — on Krakatau 20.4, on Verlaten I. 17, and on 

 Sebesy 20.5 species on 1 M^ 



With regard to the number of individuals on 1 M^, the figures vary 

 too much to give an average, but such high numbers as observed on 

 Verlaten 1. North are evidently never noticed on Krakatau or Sebesy. 



The conclusions to be drawn from this study of the surface fauna 

 are the following: — Between the surface fauna of Krakatau and Sebesy there 

 is only a slight difference, but on Verlaten I. North species are far less 

 abundant whereas individuals are more plentiful. Verlaten I. North being 

 more recent land has a newer fauna than Krakatau and Sebesy. 



From Appendix A it appears that on Verlaten I. the total number of 

 animals is about half that of Krakatau or Sebesy, The same relation exists 

 in regard to the flora; DOCTERS VAN LEEUWEN collected 145 species of 

 Phanerogams on Krakatau in 1919, and only 62 on Verlaten I. 



The above mentioned research proves also that the fauna of Krakatau and 

 Sebesy are both to be considered as still abnormal. Generally we may say the 

 fauna of Sebesy is somewhat richer than that of Krakatau and seems to be 

 in a more advanced stage of restoration. However, the total number of animals 



