War Lumu-Lumu Island, Stat. 78, a coral island that rises to the surface of the sea 

 from the Borneo-bank in the Makassar Straits, the Siboga anchored for a couplé of days. 

 Durin» our stay on the Borneo bank our little dredge was often thrown out behind the ship 

 and hauled up at ber forecastle and every time it came up filled with various species of 

 Lithothamni miolithon Reinboldi coming up oftenest. All along the east-side of Borneo 



and in the Sulu Archipelago we met Lithothamnia in such quantities, that they formed a 

 conspicuous character of the reets. It was also here that I found for the first time Archaeo- 

 lithothamni ; its thick branches and beautiful soft pink colour were fascinating to the 



ivhile the knowledge, that representatives oi this genus were described by Rothpletz from 

 the furassic and Pliocene periods, made it doubly interesting to the mimi. 



in shallow channels near Tual, Stat. 258, of Low-Key Island the dredge was filled with 

 Lithothamnion australe f. tualensis. We were at work for hours with the steam-launch and 

 constantly the dredge brought np Lithothamnia even to the vexation of our zoologists. For 

 though Lithothamnia will give shelter as a rule to a great number of quite different animals, 

 which adapt themselves outwardly in form and colour in a striking manner to the plants on 

 which they live, this is not always the case. The Lithothamnia of Tual were not favourable 

 to the maintenance of animal life, being small with widely spreading branches and thus affording 

 but a had shelter to snails, worms, star-fish and other animals. 



The most remarkable bank was one south of the Island Saleyer, Stat. 66, mentioned 

 on the charts as a "coral bank" and extendine; between the islands of Bahuluwangr and 

 Tambolungan. The Siboga had vainly tried to find a good anchorage on the east-side of 

 Saleyer: the night advanced rapidly and therefore Commander Tvdeman resolved to anchor 

 for the night on the above named coral bank, where he was sure to find from 8 — 10 m. 

 water. How great was our astonishment the next morning when coming on deck, we saw a 

 distinct red colour at the bottom of the sea regularly interrupted by narrow white bands. It 

 was nu coral bank on which we were lying but an enormous bank oi Lithothamnia. that g'ave 

 a red colour to the bottom of the sea, and the white bands we remarked consisted of heaped 

 up dead joints of Halimeda. 



Weber x ) examined the whole bank and his view of Lithothamnion-ba.iiks, the conditions 

 under which they develop themselves and expecially of this particular bank may well be 

 recapitulated here. 



For the development oi Lithothamnia the bottom upon which the roundish knolls grow 

 must be more or less flat. A current must be running over it, which turns the knolls liphtly 

 over, for the knolls want light and sea-water on every side or they would soon lose their 

 colour, which means death to them. We observed this on the bank of Haingsisi where 

 half-buried knolls were quite white on their underside. But the current must not be too strong. 

 When- Lithothamnia throve best many tiny Florideae grow on them and this would be impossible 

 it the current turned the knolls roughly over. The structure of this peculiar bank near Saleyer 

 \\ 1 bi r explains as follows : 



et ] 'Expi lition du Siboga 1902, p. 38. 



