there was an opportunity her staff would go ashore or land on the numerous reefs that 

 surround the islands to collect animals and plants. Great was my astonishment to find Litho- 

 thamnia on almost every reef; in not less than 55 stations did we gather these organisms in 

 greater or smaller quantities, indeed almost on every occasion, where marine algae could be 

 gathered. This impressed me mnch, as up to the time of the Siboga Expedition little was known 

 about Lithothamnia from the Malay Archipelago. Vox Martens ') in his standard-work "Die 

 Tange von Ost-Asien", attributed our slight knowledge of them to the neglect by botanists 

 to collect them. I was well acquainted with the fact that Darwix 5 ) had mentioned three 

 Nullipores of the Keeling- Atoll, that Heydrich 8 ) had lately described four new species from 

 New-Guinea, and that Martin ') had described Lithothamnium Rosenbergi from the Tertiary 

 of Timor and New-Guinea, still I was not prepared to meet with such masses of these algae 

 nor above all to find them almost everywhere. 



I am sorry to say that two geological papers had escaped my notice, for as early as 

 1891 Walther 3 ) had described subfossil banks of Lithothamnia from the Palk Straits and in 

 1898 — the year we left Europe — W. Stanley Gardiner 6 ) published two papers, one on 

 the coral reefs of Funafuti, the other on the building of Atolls. In these papers he mentions 

 several times the presence of great numbers of Nullipores recent and fossil on the coral reefs 

 of Funafuti, and their presence everywhere in great heaped up masses impressed him so 

 strongly that he writes in the latter paper p. 121: "The chief organisms, so far as I have 

 seen, engaged in building up coral reefs are massive and incrusting Xulliporcs" . 



The results of the Siboga confirming, as they do, all those of previous and of 

 simultaneous investigators 7 ) deserve special notice as throwing some light on the conditions 

 under which Lithothamnia grow. Lithothamnia, as everybody knows, belong to the family of 

 the Corallinaceae. Areschoug 8 ) united them with Hapalidinm, Mclobesia and Mastophora in 

 the group of the Melobesieae in opposition to the Coral lincac (verae) to which he referred 

 Amphiroa, Cheilosporwn, Arthrocardia, Jania and Coralliua. The inarticulated fronds of the 

 Melobesieae and the articulated fronds of the Corallincae are still a good character, whereby 

 to distinguish the two groups, although that of the Melobesieae has undergone many changes 

 since Areschoug's Monograph appeared, as will be seen in the following pages by Foslie. 



The Siboga Expedition found Lithothamnia, as already stated, at 55 stations; their 

 favourite habitats as a rule being where a strong current was running. If a strong tidal or 

 other current swept along the Siboga, while she lay at anchor, this was enough to induce us 



1) G. v. in' Martens. Die Tange von Ost-Asien. 1866. p. 107. 



2) Ch. Dakwin. A naturalist's voyage round the world. 1860, p. 498. 



3) F. Heydrich. Beitr. zur Kenntn. der Algentlora von Kaisev Wilhelm's Land (Deutsch Xeu-Guinea). Ber. d. D. Bot. Gesellsch. 

 1892, p. 483. — Beitr. z. Kenntn. d. Algenflora von Ost-Asien. Hedwigia 1894, p. 299. — Neue Ralkalgen v. D. Xeu-Guinea. Biblioth. 

 botanica 1897. 



4) K. Martin. Samml. d. Geol. Mus. in Leiden 1SS1. Sedimente Timor» p. 1. Tertiar vod Xeu-Guinea p. 65. 



5) P. L Walther. Die Adamsbrücke u. d. Korallenriffe d. Palkstrasse. Erganz. Heft Pet. Mittlr. 1891. — Lithogenesi» d. 

 Gegenwart. Jena 1893. 



6) W. Stanley Gardiner. The coral reefs of Funafuti, Roturaa and Fiji. Proc. Cambridge Phil. Soc. IX, 189S. The building 

 of Atolls Proc. Intern. Congress Zoology 1898. 



7) Agassiz found "Nullipores'" or huge masses of calcareous algae on almost every reef in the Pacific Ocean which he visited 

 during the winter 1S99 — 1900. 



8) L E. ARESCHOUG. Corallineae in Agardh's Genera et Species Floridearum 1S51. p. 506. 



