4^\ 



Introduction. 



1 have been charged with the determination of the latest 

 collections of marine algæ from East Greenland. These collections 

 have been procured by Mr. C.Kruuse, and the material dates 

 from Amdrup's expedition in which Mr. Kruuse as well known 

 took part, and from Kruuse's own expedition to the district of 

 Angmagsalik. After the pubhcation of L. K. Rosenvinge's 

 exhaustive works on the Marine Algæ of Greenland (Grl. Havalg. 

 and Deux. Mém.) several important papers have been written 

 which have greatly altered the view regarding the limitation of 

 species in some genera, such as Acrosiphonia, JJlothrix and 

 Sphacelaria- therefore I have moreover been charged with a 

 second examination of all the Greenlandic material of the genera 

 Acrosiphonia^ Ulothrix and Sphacelaria. In revising this 

 material 1 have met with some new habitats of some intermingled 

 species, as may be seen by the following list. 



According to Rosenvinge's statement^) 83 species were 

 previously known from East Greenland. To this number one 

 species, Actinococcus subcutaneus^ should be added, it is regarded 

 by Rosen vinge (Deux. Mém. i as the n em athecia of P%//o|)Aora 

 Brodicei and thus not included in the number of species. Of 

 the 85 ^) species gathered by Kruuse 29 were not previously 



) L. Kolderup Rosenvinge, Om Algevegetationen ved Grönlands Kyster, 

 Særtryk af «Meddelelser om Grönland» XX, Kjöbenhavn 1898, p. 180. 



) In Kruuse's collection there were moreover found two species, Ectoear- 

 pus tomentosus (Huds.) Lyngb. and Ectocarpibs fasciculatus (Griff.) Harv. 



XXX. 2 



