126 



L. KoLDERUP Rosenvinge. 



A fragment of an Acrosiphonia which seems to belong to this 

 species has been met with. The filaments are 154 — 175/^ thick and 

 are partly composed of rather short cells, only twice as long as 

 broad. They are much like A. hystrix f. debilis (K. Rosenv.), only a 

 little thinner (comp. Jonsson 1. с. p. 48). 



Lo с. Danmarks Havn. 



А. sp. 



Some of the samples contain fragments of another species of 

 Acrosiphonia in small quantities. They occur together with several 

 loose algæ and have undoubtedly also been loose. Owing to their 

 small quantity and their incomplete and sterile condition they are 

 scarcely determinable. The filaments are 50—90« thick; hooked 

 branches do not occur. A complete specimen, possibly belonging 

 to the same species, was met with on a stone dredged at Cape Bis- 

 marck Peninsula. Its filaments w^ere up to 121« thick. The cells 

 were in this specimen, as well as in the loose ones, several times 

 as long as broad, and rhizoidal branches were abundant. The last- 

 named specimen was also sterile. 



Loc. East Side of Koldewe}' Island; along Cape Bismarck Peninsula; 

 bay off Vesterdalen. 



Chætomorpha Kütz. 

 48. Ch. Melagonium (Web. et Mohr) Kütz. 



к. Rosenvinge (1893) p. 917, (1898 I) p. 104; Jonsson (1904) p. 51. 



Most of the specimens in the collection seem to have been loose. 

 Some of these specimens are very vigorous, about 1 mm. in diameter 



and consist of cells which are one 

 to two diameters long, while others 

 are much thinner, from 100// up to 

 300« in diameter, and composed of 

 cells which are 3 to 4 diameters 

 long. As there is so great a break 

 between these two forms, one might 



Fig.H. Chætomorpha Melagonium t. tenuis, ^^ inclined tO think that they re- 

 Upper end of a cell, showing nuclei, n, present two different specics, but 

 pyrenoids, p, and stroma starch. 200 : 1. the specimens being 0П the whole 



rather scarce in the collection, and 

 the species being very variable in breadth also in other arctic 

 regions (comp. К. Rosenvinge 1898 p. 104), I judge it preferable to 

 consider the thin filaments as an extremely thin form of the same 

 species. It might be named f. tenuis. The thinnest specimens ap- 

 proach in breadth to the thickest filaments of Chætomorpha tortuosa; 

 they differ however in having much more numerous nuclei, viz. 



