45 



II. Melobesieae Aresch. (Fosl. emend.). 



Goniolithon Fosl. 



a. Crustacea [Herpolithon Fosl.). 



i. Goniolithon myriocarpon Fosl. PI. IX, fig. 6 — 7. 



Lithoth. Adriat. Meer. 



Lithothamnion myriocarpon Fosl. On some Lithoth. p. 19. 



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



Stat. 169. Atjatuning, West-coast of New-Guinea. Reef. 



Stat. 225. South of Lucipara-group. Reef. 



Stat. 277. Kulewatti (Sollot) Bay, Dammer Island. Reef. 



In 1897 I described the above species represented by a solitary specimen, picked up 

 at Massauah in the Red Sea. I have not afterwards met with it until last year, when I got a 

 specimen for determination, collected at El Tor in the Red Sea by Dr. Plate, which proved 

 to belong to the same species '). In Lithoth. Adriat. Meer. I have shown that the plant is a 

 Goniolithon ; but I ani still uncertain whether this species and G. Fosliei, recorded below, really 

 are specifically distinct. At any rate, they are closely allied to one another. There is no limit 

 to be drawn in regard to habit, except that the crust as a rule will be thinner in G. myrio- 

 carpon than in G. Fosliei ; and the surface is frequently rather smooth, now and then even a 

 little shining in the latter, whereas it is rather dull in the former. The plant attaches itself to 

 similar hard objects as G. Fosliei, viz. corals, shells or other calcareous algae. Sometimes it 

 even forms very thin crusts on Archaeolithothamnion erythraeum, in a sterile stage scarcely 

 distinguishable from the host plant except in a section, as it in habit gives the impression of 

 a new thickening layer of the latter. PI. IX, fig. 6, represents a part of the type specimen 

 attached to a bucky, forming incrustations 100 — 200 u. in thickness, closely and firmly adherent 

 to the substratum. But it also becomes thicker, and it seems at length to attain nearly the 

 same thickness as G. Fosliei (PI. IX, fig. 7). 



As to structure the cells of the perithallic layer are frequently smaller than in G. Fosliei, 

 and often those of the hypothallium too are smaller. The latter layer of tissue sometimes is 

 not marked coaxial, which, as far as hitherto seen, always is the case in the said species. 

 Besides, the heterocysts appear in much smaller number than in G. Fosliei, often not even to 

 be seen in a section. 



There is certainlv, however, no distinct limit to be clrawn in the mentioned respects, the 

 structure being rather varving in these species as in several others. The distinguishing feature 

 apparently most significant is clue to the reproductive organs. In the species in question only 

 sporangia ' 3 ) are known. The conceptacles are subprominent or often almost superficial, 450— 

 650 u.. in diameter, when seen from the surface. Thus they show only about half the size of 



1) Th. REINBOLD. Meeresalgen von Tor (Sinai-Halbinsel, Rotes Meer). — Hedwigia. Bd. LXII, 1903, p. 232. 



2 ) In the description of the species they are recorded as cystocarps, which is, however, wrong (antheridia uncertain). 



