F. Børgesen: Rhodophyceæ of the Danish W. Indies. 



303 



branching (Fig. 306). In the 

 fully developed trichoblast all 

 the branches are arranged fan- 

 like in one plane, the trichoblast 

 turning its flat side against the 

 main filament (Fig. 305). The 

 basal cell of the trichoblasts 

 bears no side-branch, is very 

 short and more or less sunk 

 between the pericentral cells; 

 then follows a short cell bearing 

 the first side-branch. This is al- 

 ways found at the right, ano- 

 dic, side of the trichoblast. It 

 begins with a short, basal cell. 

 In the next branch the basal 



Fig. 305. Lophocladia trlchoclados 

 (Mert., C. Ag.) Schmitz. Part of a fila- 

 ment with trichoblasts. (About 45: 1). 



cell is still short, though somewhat longer. The first side-branch 



of the trichoblast is that which is trans- 

 formed into the stichidium (comp. Figs. 

 306 and 307). 



In the fully developed trichoblasts 

 the cells are long and cylindrical, about 

 23 n thick and 250 u long, somewhat 

 shorter and thicker towards the bottom, 

 longer and thinner towards the top. 



Exogenous branches formed in the 

 summit of the plant seem to be entirely 

 wanting. I have looked for them in 

 vain, and Falkenberg did not find 

 them either. The ramification of the 

 plant takes place by means of endoge- 

 nous, adventitious branches, formed la- 

 ter. The segments in the main filaments 

 are about 175 p. broad, being scarcely 

 double this length, about 270 u long. 



In the upper young parts of the 

 filaments no cortical layer is present; 

 the older parts of the filaments on the 

 other hand are more or less covered by 

 cortex. The first beginning of the cort- 

 ical layer is formed by rhizoids growing 



Fig. 306. Lophocladia trlcho- 

 clados {Mer t., C. Ag.) Schmitz. 

 Young trichoblasts near the 

 summit of a filament, show- 

 ing development of stichidia. 

 The uppermost one is still 

 undivided, the following con- 

 sists of four cells, the lower- 

 most of five. (About 260:1V 



