elongated, with thick walls; fig". 21. Here and there appear short hypothallic rows, which have 



been formed over damaged parts of the plant or foreign 



bodies. A rather indistinct stratification is to be found, now 



and then formed by rows of minute cells. Heterocysts are 



very scarce in the sporangia-bearing specimens in hand ; they 



are seldom overgrown and then appearing in the inner 



layers of tissue. 



As mentioned above, sporangia are the only repro- 

 ductive organs hitherto known in this species. The concep- 

 tacles appear in great number almost all over the plant, and 

 they are often so densely crowded that the roofs become 

 angular. They are at first subconical or subhemispherical, Fig. 21. Goniolithon ReMoidi a. Web. et Fosi. 



•,i 1 1 1 • 1 r 11 Part of a vertical section; X 72. 



with a coarse, but very snort tip which soon falls away, at 



length very low, frequently 350 — 500, or occasionally up to 700 ij., in diameter, when seen 

 from the surface. The conceptacles by and by become overgrown by new-formed tissue and are 

 to be found in great number in a section. The plant is furnished with these organs almost all 

 the year, but particularly old specimens are often sterile. 



This species is easily recognized. In habit it approaches to coarse forms of Lithophyllum 

 Okamurai and L. racemus, sometimes in this respect not easily distinguishable when sterile. 

 Cp. pi. X, fig. 6 and pi. XI, fig. 14 — 16. It cannot be confounded with any other species 

 occurring in the Pacific or Indic. But on the other hand it comes near to Goniolithon Börgesenii 

 from the West Indies. Of the latter, however, only a few specimens are known. They are rather 

 differing from old specimens of G. Reinboldt in habit, but approach to young ones. These two 

 species are hardly distinguishable in structure, but in regard to the conceptacles there is some 

 difference, as the said organs seem frequently to be somewhat larger in the species in question. 



Occurrence; Xext to Archaeolithothamnion erythraeum this species seems to be the 

 most widely distributed one in the Pacific, and apparently in the Indic as well. There have 

 been brought home but a single or a couple ot specimens from most of the stations cpioted, 

 many of which partly young, partly rather stunted. At some places, however, it occurs in great 

 number and vigorously developed, e. g. stat. 91, but it is uncertain whether the plant forms real 

 banks. It is also known from Pulu Kelamala, east of Pulu Adi, on the north coast of Xew Guinea, 

 here anastomosed with Archaeolithothamnion erythraeum, collected by Prof. A. Wichmann *). 



Area: South Pacific: Samoa; Xorth Pacific: The Carolines, Sandwich Islands ; Indic: 

 The Maldives and Laccadives, Zanzibar, the Mauritius. 



5. Goniolithon laccadivicum Fosl. PI. IX, fig. 10 — 13. 



Goniolithon Brassica-florida f. laccadivica Fosl. Lithoth. Mald. and Laccad. p. 469, pi. XXV, fig. 7. 



Stat. 91. Muaras-reef, inner side : East coast of Borneo. 



Stat. 258. Tual, Kei Islands. 8 — 12 m. Lithothamnion, sand and coral. 



1) The Dutch New Guinea expedition 1902 — 1903. 



