262 F. BORGESEN 



same length as found in the thinner part of the filament. In the young yet 

 growing filaments the zone of cell division lies a little above their base, where 

 shorter cells with rich contents are observed. The cells contain a number of 

 roundish, oval, discformed chromatophores. The length of the vegetative fila- 

 ments is about 300 jj-. 



The fructiferous filaments are branched from their base and composed of very 

 irregular thin-walled cells. These cells are more or less pear shaped, thin below 

 and broadly rounded above, where often several branches are given off. The 

 cells are about 8 — 12 \x broad and 20 jjl long. From the uppermost of these 

 cells the plurilocular sporangia arise. The sporangia are almost cylindrical, 

 uniseriate, about 8 ij. thick and up to 200, generally 150 \s. long. The remains 

 of empty sporangia are long preserved. When a sporangium is emptied a new 

 one is formed at the side of the other one, and one cell may often bear 5 — 6 

 or more emptied sporangia besides a sporiferous one. 



Unilocular sporangia were not observed. Hairs occur, but were not common. 



As mentioned above the present plant seems to show some likeness to the 

 Elackista-foxms, described by SKOTTSBERG. 1 Also the Easter Island plant is 

 more or less endophytic and shows no difference between assimilating filaments 

 and paraphyses, contrary to E. fucicola. Particularly it seems to agree with a 

 plant from Station 17 b of SKOTTSBERG (fig. 10 c) but differs by the narrower 

 sporangia and the more cylindrical vegetative cells. Further, the assimilating 

 filaments in the plant from the Easter Island are shorter. 



It cannot be denied that the present plant shows a striking likeness to 

 Myriactis moniliformis (Fosl.) Kylin, and highly favours the supposition of 

 SKOTTSBERG that all these forms, even if they do not belong to one genus, 

 must be regarded as nearly related to each other. 



Fam. Encoeliaceae. 

 Colpomenia Derb. et Sol. 



C. sinuosa (Roth) Derb. et Sol. 



Derbes, A., and A. I. I. Solier, Memoire sur qilelques points de la Physio- 

 logic des Algues, p. 11 (here incorrectly called sinuata)\ Borgesen, Mar. Algae of 

 the D. W. I., vol. I, p. 176. -- Ulva sinuosa Roth. Catalecta Botanica, III, p. 327, 

 tab. XII. 



Some few large specimens were present in the collection. They were 

 fertile with plurilocular sporangia in irregular groups scattered over the surface 

 of the thallus, as in the West Indian specimens. Still, there are some points 

 of difference. For instance, I have not been able to find any club-shaped para- 

 physes so nicely developed in the West Indian form (comp. my fig. 138) and 

 described by MITCHELL in Murray's Phycological Memoirs, p. 53. 



Further, according to MITCHELL and my own observations the plurilocular 

 sporangia are formed round the cryptostomata, while in the material from 



1 Professor Skotisberg kindly sent me some slides of these species so I have been able 

 to compare my plant with the authentic material. 



