DammerMAN: Fauna of the Krakatau Islands. 63 



Also at the west side of Zw. Hoek a fringing reef existed of 1 M. in 

 breadth and 2 dM. in thickness, built up by Madrepora nobilis {DANA) and 

 a few Por if es micronata (Dana) and Favia af finis (M. Edw.). 



\n 1889 this reef, for the greater part, was destroyed again by blocks 

 of basalt which fell from the steep rocks at this end of the island. In the 

 bay big pumicestones were found grown over by corals {Madrepora and 

 Porites); and Seriatopora elegans (M. EDW.) was observed forming "schon 

 ganze Korallenwäldchen", Compact corals like Fungia, Astrea a.o. were not 

 represented, but the other corals were growing over the whole bay, and 

 Sluiter expected that it would be filled up by the coral reef simultaneously, 

 and that later on a barrier reef would arise which would increase at the 

 ocean side. 



hi April 1921 the author, together with Dr. H. BOSCHMA, had an 

 opportunity to search after these coral formations at Zwarte Hoek, but none 

 of the coral species mentioned by SLUITER could be retraced and in the bay 

 no corals existed, apparently the oceanbreakers having destroyed all again. 

 At the west side of Zwarte Hoek the former coralreef must have disappeared 

 altogether because the coastline here has changed very much, (see Map Fig. 1). 

 A big piece of land built up during the eruption of pumicestones and ashes 

 has been washed away, the full ocean swelling breaking on the coast at 

 this point of the island. But at the northern end of Krakatau, however, we 

 found corals growing on the blocks of basalt at the foot of the steep rocks, 

 Porites, Madrepora and the ramified Pocillopora of dark rose colour were 

 observed at this place by Dr. BOSCHMA. 



After Sluiter no zoologist seems to have visited the islands until 

 1908. The botanist ERNST, who made a trip to Krakatau in April 1906, 

 communicates a few observations on land animals, but his remarks are too 

 vague to be of much importance. It was in May 1908 that for the first time 

 a more thorough survey of the fauna of Krakatau was made. Mr. JACOBSON 

 visited all three islands at that time and has given a complete list of the 

 animals found by him. As far as the species have been worked out by 

 specialists, they are listed in Appendix B. Unfortunately the greater part of 

 the species collected by him are still unidentified. The work of JACOBSON 

 will be discussed at length below, but we will first mention the other 

 zoologists who have been on the islands after him. 



Five years after JACOBSON, in October 1913, Dr. KONINGSBERGER 

 paid a very short visit to Krakatau, but probably time was too short 

 for collecting as no further details are known. On the occasion of the 

 first "Ned. Indisch Natuurwetenschappelijk Congres", in 1919, a trip to 

 Krakatau and Verlaten 1. was to be made. Therefore in April of that year 

 Dr. DOCTERS VAN LEEUWEN, Director of the Botanical Gardens at Bui- 

 tenzorg, visited the islands, Along with him were Mr. BARTELS, the wellknown 

 ornithologist, and Dr. SUNIER, Chief of the Laboratory for Marine Inves- 

 tigations at Batavia. Mr. BARTELS collected many birds new to the islands; 



