388 



basal part the distance between the furcations is shorter than 

 upwards. At each furcation the thallus is much narrowed being 

 often here only 1 mm broad. 



Besides this normal ramification proliferations are now and 

 then issued from the margin of the thallus especially near the 

 narrowings. The thallus is slightly sinuated. The apex of the 

 thallus is broadly rounded. 



From a transverse section is seen that the thallus consists 

 of cells which are largest in the middle (about 150 // thick) and 



flflfr 



Fig. 372. Rhodymenia occidentalis nov. spec. 



a, transverse section of the thallus (about 125:1); b, part of the cortical 

 layer seen from above (about 350:1). 



decreasing evenly outwards (Fig. 372, a}. All the cells have very 

 thick walls. This parenchymatic tissue is surrounded by a corti- 

 cal layer composed of a single layer of cells; in transverse section 

 these are roundish polygonal, seen from above polygonal (Fig. 

 372 b). 



Neither tetraspores nor other organs of reproduction were 

 found in the material. 



Considering its entire structure it seems to me that the plant 

 agrees very closely with Rhodymenia, but, if its organs of repro- 

 duction should be found, it is, of course, not impossible that it 

 may turn out to be, for instance, a Gracilaria. 



As to species of Rhodymenia with which our plant may be 

 compared, Rh. flabellifolia (Bory) Mont. (== Sphserococcus tenui- 



