130 L. KOLDEUUP RoSENVINGli. 



Fam. Ulothricaceæ. 

 Ulothrix Kütz. 



54. U.flacca (Dillw.) Thur. 



K. Rosenvinge (1893) p. 935; Wille (1901) p. 18; Jonsson (1904) p. 54. 



Al the upper end of a young Alaria some filaments of a Ulothrix 

 were met with which must be referred to this species. The swarm- 

 cell producing parts of the filaments were curved in the manner 

 characteristic of the species and consisted of low cells undoubtedly 

 producing gametes Ч The filaments were comparatively thin, the 

 fertile parts only reaching 33 /^ in diameter. The cells often con- 

 tained only one pyrenoid, probably in connexion with the small 

 thickness of the filaments. 



Loc. Along Cape Bismarck Peninsula. 



55. U. scutata Jonsson. 



Jonsson (1904) p. 57. 



This species seems to be common within the region explored. 

 However, I am only sure of the determination of the specimens from 

 one locality, as I have seen only in these the basal part character- 

 istic of the species. Most of the specimens from the other localities 

 are dried. At the base the filaments were 5 — 7 /л thick, and the 

 ceils in the lower part of the filaments were frequently up to 4 

 times as long as broad. 



Loc. East Side of Koldcwey Island. Further, uncertain as to the deter- 

 mination from dredging along Cape Bismarck Peninsula, Danmarks Havn 

 and Baadskæret. 



56. и. consociata Wille. 



Wille (1901) p. 25; Jonsson (1904) p. 60. 



The North-East Greenland specimens agree with Wille's descrip- 

 tion; only they were rather thin. Young sterile plants were only 

 7 — 7'5/^ thick near the base, older filaments 10'5/^, fertile filaments 

 125 M thick. The filaments are often decumbent at the base and 

 form rhizoids there. Sometimes two filaments were found coalesced 

 near the base. The apical cell is rounded. — It was found growing 

 on Enteromorpha proliféra in the tidal region. 



Loc. Vestre Havnenæs, September. 



1 In stating (1893 p. 935—36) that I have found this species with zoospores in 

 West Greenland, I have not intended to say anything about the question whether 

 the swarm-cells were asexual zoospores or gametes. Probably they were gametes 

 (comp. Wille (1901) p. 21). 



