128 



L. KOLDERUP ROSKNVINGE. 



off. Sometimes, when the filaments are much branched, they are 

 united to pseudoparenchymatous bodies. I am uncertain whether 

 the plant may also be partly epiphytic. Here and there vigorous 

 hairs, slow^ly tapering upwards, occur; they show one or two trans- 

 verse walls, and their cells, in particular the upper, have not much 

 contents. The vegetative cells almost certainly contain one parietal 

 chromatophore, which how^ever could not be distinguished in the 

 dried plants; on the other hand one or two pyrenoids were often 



distinctly visible (fig. 

 9, A, I). Besides the 

 pyrenoid- starch, the 

 chromatophores con- 

 tained abundant stro- 

 ma-starch. The cell- 

 wall gave intense cel- 

 lulose - reaction with 

 chlor-iodide of zinc. 

 The position of the 

 sporangia is different; 

 they may be terminal 

 on the erect filaments 

 and lateral, sessile, on 

 the same and on the 

 creeping filaments. On- 

 ce I have seen a ter- 

 minal and a subter- 

 minal sporangium on 

 the end of a filament. 



Fig. 9. Arthrochœte phœophila. A, creeping filament with 

 lateral hair. B, terminal hair. C, hranched filament 

 with hair. D, creeping filament with erect filament 



bearing a sporangium. E, creeping filament with two (^^о* ^^ ^)- ^ '^^ sporan- 

 sessile sporangia. F, erect filament, given off from a 

 creeping one, bearing four sporangia, seen from above. 

 G, filament with a terminal and a subterminal spor- 

 angium. H, erect filament with a terminal sporangium. 

 I, lateral sporangium. 350:1. 



gia observed were all 

 emptied through a split 

 in the upper part of 

 the cell-wall. They 

 have undoubtedly con- 

 tained swarm-cells, but whether asexual zoospores or gametes, it is 

 impossible to say. 



I was at first inclined to refer this alga to the genus Pilinia 

 which it somewhat resembles in its mode of growth. It is distin- 

 guished however from this genus by the presence of pyrenoids which, 

 as far as known, are wanting in Pilinia. Moreover, it differs by 

 the pluricellular hairs. Such hairs were certainly pointed out in 

 Pilinia maritima, but as this plant has turned out to be a species 

 of Ectocarpus, as shown above (p. 123), hairs are now not to be found 



