292 



f. subsalsa nob. 



f. strata valde iatricata, forma indefinita, e viride flavescentia vel fere albida, in fundo libera expansa 

 formans; thalli asi priraario distincto, latiusculo, compresso secundum totam longitudinera ramos longiores et 

 breviores, simplices vel ramulosos, patentes, uncinatos, curvatos, axi primario graciliores emittente; structura 

 formse typicse persimilis. Tab. 31, fig. 1 — 3. 



Exsicc. Enteromorpha clathrata var. uncinata Kjellm. in Witte. et Nordst. Alg. exsicc. N:o 131. 

 Syn. Enteromorpha clathrata J. G. Ag. Spetsb. Alg, Progr. p. 3; Bidr. p. 11 (?)• 



» » f. uncinata Kjellm. Spetsb. Thall. 2, p. 44; Algenv. Murm. Meer. p. 50. 



Ulva micrococca Gobi, Algenfl. Weiss. Meer. p. 81. 



Remark on f. subsalsa. I have already mentioned, in my treatise on the marine 

 vegetation of the Murman Sea, that the alga recorded here under the name of E. 

 clathrata agreed less, with regard to its structure, with the species of that name than 

 with E. micrococca Kutz. My determination of the alga in question was based on the 

 opinion pronounced by Le Jolis, that the morphological characters are of more im- 

 portance than the anatomical ones in determining the species of the genus Enteromor,- 

 pha. I must now relinquish this view, on account of the results acquired by recent in- 

 vestigations. 



The alga in question closely agrees with E. micrococca in structure. It is cer- 

 tainly different from it in habit by the branching of the frond, but the degree of 

 branching varying very much and even typical E. micrococca being occasionally branched, 

 I have thought best to regard the arctic plant here referred to as a form of the last- 

 named species. It is distinguished from its typical form by being always more richly 

 branching and by forming large, irregular, intertwisted masses lying loose on the bottom. 



Habitat. The principal form of this species grows scattered within the litoral 

 zone, in sheltered localities, attached to stones. The form subsalsa is known only from 

 lagoons with brackish water, often occurring in large masses so as to determine the 

 character of the vegetation. It persists through the winter enclosed in ice, resuming 

 its development when the ice has melted. Of the typical form I have observed speci- 

 mens with zoospores in September. 



Geogr. Distrib. Known both from the Atlantic and arctic region of the Polar 

 Sea. It is apparently widely distributed in the latter region and it has here its maxi- 

 mum of frequency. The northernmost point where it is known to occur is Treurenberg 

 Bay on the north coast of Spitzbergen Lat. N. 79° 56'. 



Localities: The Norwegian Polar Sea: (f. typica) scarce and local at Oxfjord and 

 Talvik. 



The Greenland Sea: abundant in lagoons at Musselbay and Treurenberg Bay on 

 the north coast of Spitzbergen. 



The Murman Sea: the coast of Russian Lapland, f. typica; the west coast of No- 

 vaya Zemlya, f. subsalsa, rather plentiful in lagoons at Besimannaja Bay, and Karma- 

 kul Bay. 



The Siberian Sea: f. subsalsa abundant at Pitlekay. 



Baffin Bay: f. subsalsa on the west coast of Greenland at Tessarmiut. 



