38 



indicate that the plant is a Lithothamnion. They are only 200—300 by 75-110-;.. in diameter, 

 but the sections are apparently not median ones. 



[•],,. species on one hand resembles certain forms of the arctic Lithothamnion tophiforme 

 in habit and on the other hand it ma) sometimes be difficull to distinguish it from Archaeo- 

 lithothamnion timorense. Especially young specimens are sometimes almost quite like certain 

 forms of this in habit and are in this respect hardly distinguishable. Cp. pi. IV and 



pi YI11, fio\ 1 —14. The surface is however a little shining and smoother than in the said 



ies. Even in structure they uiten much approach one another. Thus the cells of the medullary 

 hypothallium are of about the same size in both, in L. pulchrum however less regular and 

 frequently a little broader, and the corners are more rounded. Besides, the cup-shaped layers 

 issue are more distinct in the species in question, whereas on the other hand in A. timorense 

 they partly appear indistinct, partly and most frequently are not to be seen in a section. The 

 perithallic layer is more distinctly marked towards the hypothallic one, and the cells of the 

 tormer are generally smaller than in A. timorense. The most certain distinguishing feature is, 

 however, the presence of small oblique intermediate cells in A. timorense, which are quite 

 wanting in L. pulchrum. This character allows of the distinction even of sterile specimens. But 

 the said cells are often not easily descried when the section is not quite thin. In addition, young 



mens are hardly distinguishable from certain forms of Lithothamnion australe. 



Occurrence: There are several specimens from stat. 315, where the species has 

 probably been rather abundant, but from stat. 96 there is only a solitary, though well developed 

 one. A few and likewise sterile specimens from stat. 282 belong perhaps to this species. They 

 have been brought home together with some specimens which partly belong to Archaeolitho- 

 thamnion timorense, partly are somewhat differing and uncertain. 



Archaeolithothamnion (Rothpl.) Fosl. 



1. Archaeolithothamnion erythraeum (Rothpl.) Fosl. 



Rev. Syst. Surv. Melob. p. 8. 



A. ROTHPLETZ. Über einc neue Pflanze (Lithothamnium erythraeum n. sp.) des Rothen 

 Meeres. Bot. Centralbl. 1893, N" 14. 



f. dura (Heydr.) Fosl. PI. V. 



L. c. p. 8. Sporolithon ptychoides f. dura Heydr. in Bei', der Deutsch. Bot. Gesellsch. 1897, p. 6j. 



f. mol/is (Heydr.) Fosl. PI. VI. 



L. c. p. 8. Sporolithon ptychoides f. mollis Heydr. 1. c. p. Gj. 



Syn. Sporolithon ptychoides Heydr. 1. c. p. 415. 



Syn. Sp. molle Heydr. 1. c. p. 416. 



Syn. Sp. crassum Heydr. 1. c. p. 417. 



St.it. 47. Bima. Rei f. 



Stat. 71. Makassar and surroundings. (Tuin Barang, Samolana, Ley-Ley). Up to 32 m. 



Stat. 81. Pulu Sebangkatan, Borneo-bank. 34 m. Coral bottom and Lithothamnion. 



Stat. 86. Dongala. Palos Bay, Celebes. Reef. 



