F. Borgesen : List of species. 437 



are quite short and filled Nvith chromatophores; higher up the 

 cells gradually grow longer and become nearly destitute of chro- 

 matophores; in the upper parts of the hairs the cells reach a length 

 of about 180 ji. In the basal part the hairs are thin, their diameter 

 reaching a length of about 6 p. only; higher up the hairs grow 

 thicker to about 16 /i. The cells of the hairs are barrel-shaped 

 cyhndrical, being a little narrowed at the cross-walls. 



The plurilocular sporangia are oblong to spindleshaped, 

 about 16 — 26 n broad and 65 p. long. They have a short stalk 

 consisting of a single or a few cells. 



Owing to its partly endophytic way of growing and to the fact 

 that the basal filaments do not form a disc this plant differs 

 from the hitherto described species of this genus and ought 

 perhaps rather to be referred to a new genus. Nevertheless I have 

 preferred to refer it to the genus Ascocycliis^ having not seen 

 much of it. 



The Hypnea upon which this plant was found was gathered 

 in the month of January near the shore in shallow water. 



St. Croix: Lime Tree Bay. 



Fain. Myriotrichiaceæ^ 

 Myriotrichia Harv. 



11. Myriotrichia occidentalis nov. spec. 



Frons ex fihs basahbus repentibus, ramosis et fihs erectis 

 composita. 



Filamenta basalia ex celluhs, 20 p longis et 10 fx latis compo- 

 sita, ramis aut oppositis aut alternis et unilaterahbus instructa. 



Ex celluhs basahbus aut pili, aut fila brevia, aut rarius 

 sporangia plurilocularia aut filamenta principaha oriuntur. 



Pili ca. 12 « lati ex celluhs hyalinis valde elongatis orti. 



Fila brevia, ca. 150 ,« alta et 12 p lata, ex cellulis ca. 6 com- 

 posita, apice obtuso, rarius ramosa. 



Fila principaha monosiphonia, ca. 1 mm longa, 18 — 24 jx 

 lata; hæc ex celluhs sparsis (»nodis«) fila brevia, simplicia aut 

 ramosa, opposite aut subverticillate orta gerunt. 



Sporangia plurilocularia, aut sessiha aut pedicellata, 50 — 

 100 a longa et 12 — 30 fx lata ex seriebus pluribus loculorum com- 

 posita. 



