F. Børgesen: List of species. 



439 



Of the long main filaments I have found only a few; one 

 of the longest, reaching a length of about 1 mm, is figured in Fig. 

 413. The breadth of the main filaments is about 18 — 24 ji; they 

 are composed of cells of rather variable length from shorter than 

 the length to about their double length. The filaments found by 

 me have all been monosiphonous throughout, longitudinal walls 

 being not present at all. But having seen so few erect filaments 



Fig. 414. Myriotrichia occidentalis nov. spec. 



a and b, parts of the basal filaments seen from above and from the side. 



c, part of a main filament with hairs, branchlets and sporangia. 



[a, about 260:1. b and c, about 150:1.) 



it is of course possible that such may occur in more devel- 

 oped specimens. As pointed out by Kuckuck^) the growth of 

 the main filaments takes place by means of intercalary divi- 

 sion of the cells (comp. Fig. 413 and 414 c), but this division is 

 restricted mostly to the middle and upper end of the filaments. 

 The top of the filaments end in a terminal hair (comp. Fig. 413 h 

 and a the branch to the right). 



The erect main filaments are provided with side-organs of 



^) Kuckuck, P., Die Gattung Myriotrichia Harvey. Beiträge zur Kenntnis 

 der Meeresalgen, 6, 1899, p. 59. 



