440 



three kinds: short branchlets, hairs and sporangia. They are 

 mostly arranged in a tier-like manner issuing several from the 

 same cell, each tier being separated by a row of bare cells. 



The branchlets are short, often spinelike, undivided or pro- 

 vided with hairs. Two opposite branchlets are mostly given off 

 from each point. In the upper, more richly developed part of 

 the erect shoots the branchlets grow larger, become ramified 

 and bear often several plurilocular sporangia and hairs. 



The hairs are like those issued from the basal filaments; 

 they have a longer cell at their base, then the growing zone follows 

 above which the cells quickly grow long and colourless. In the lower 

 part of the erect shoots they are given off immediately from the 

 main filament, higher up, as mentioned above, mostly from the 

 branchlets. 



The plurilocular sporangia are rarely sessile, mostly pedi- 

 cellate or placed upon the branchlets. They are spindleshaped 

 about 50100 |u long and 122030 |a broad. 



Unilocular sporangia were not found. 



Considering the species of Myriotrichia hitherto described 

 this plant seems to be most closely related to Myriotrichia repens, 

 this species having for the most part monosiphonous filaments, 

 and the dimensions of the cells and the development of the erect 

 filaments being rather like the West Indian plant. But the West 

 Indian plant differs nevertheless essentially from Myriotrichia 

 repens in the very different development of the basal filaments, 

 and in the fact that the filaments, as far as hitherto found, 

 always are monosiphonous, the knot-cells (Knoten of KUCKUCK) 

 being not even divided and in the development of the pluri- 

 locular sporangia, these having two or more rows of loculi 

 in each. 



Our plant seems to show some likeness, too, to the certainly 

 very imperfectly known species Myr. canariensis Kiitz., but 

 this species has rather many longitudinal walls in the main 

 filaments, and the plurilocular sporangia seem, according to 

 KUTZING'S figure and as pointed out by KUCKUCK, to be very 

 like those found in M. clavaeformis. 



The Dictyota indica upon which this species was found was 

 dredged in the month of February in the open sea at a depth of 

 about ten meters. 



St. Croix: of! Frederikssted. 



