KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 20. N:0 5. 1k3 
to Fartow. I conclude from these facts that A. pluwmula is not more commonly distributed 
nor more abundant in the northern Atlantic than A. boreale in the Arctic Sea, and 
that the latter can be at least almost as luxuriantly developed as the former. 
Habitat. The species is sublitoral in the arctic region of the Polar Sea, descen- 
ding to the lower limit of this zone. It is generally sublitoral even in the Norwegian 
Polar Sea, though it has been met with here also in the litoral zone. It is a common 
element in the formation of Corallinacee, although being of little importance for the 
characterization of this division of the vegetation. I have found it most abundant on 
half-dead bottom, attached to Desmarestia aculeata that lay loose on the bottom. It 
was also found once rather abundant among Phyllophora interrupta. Though preferring 
an exposed coast, it enters also into deep bays. Specimens are generally found scattered, 
but in Actinia Bay I found the species in pretty great, in Musselbay even in very 
great masses. On the north coast of Spitzbergen it occurs during all winter, retaining 
even at this season its ordinary appearance and continuing its development, which does 
not however become vigorous before the month of March, During the winter season 
it is always sterile. It has been found with tetrasporangia at Nordlanden in July and 
August, at Finmarken in August and September, at Spitzbergen in July and August, 
in the eastern part of the Murman Sea in June, July, and September. I have not seen 
specimens with sporocarps from the Polar Sea. 
Geogr. Distrib. It belongs to the Atlantic as well as the arctic region of the Polar 
Sea. In the latter region it is widely distributed and it certainly has its maximum of 
frequency there. Part of that Antithamnion which is reported from the American Arctic 
Sea and Baffin Bay is possibly to be referred to the present species. If that should 
be the case, the species is circumpolar. The northernmost place where it has been 
found is Treurenberg Bay on the north coast of Spitzbergen, Lat. N. 79° 56’. 
Localities: The Norwegian Polar Sea: Nordlanden according to specimens in KLren’s 
herbarium; Finmarken at Maasé and Gjesver pretty common, but scarce, at Oxfjord 
and Talvik local and scarce. 
The Greenland Sea: On the west and north coasts of Spitzbergen commonly diffused, 
but in general scanty; in Musselbay abundant. 
The Murman Sea: the coast of Russian Lapland; the west coast of Novaya 
Zemlya and Waygats from Matotshin Shar to Jugor Shar, commonly distributed, but 
scanty. 
The White Sea: rare. 
The Kara Sea: the eastern coast of Novaya Zemlya at Uddebay in rather great 
number; in Actinia Bay pretty plentiful, but local. 
The Siberian Arctic Sea: Koljutshin Isle, Pitlekay and Tjapka, pretty common, 
but scarce. 
Of the forms mentioned above, f. typica is known from the Greenland Sea, 
the eastern Murman Sea, and the Siberian Arctic Sea; f. lapponica from the Greenland 
Sea and the western Murman Sea; f. corallina from N. Gusinnoi Cape on the west coast 
of Novaya Zemlya. The form observed in the Kara Sea, though most nearly allied to 
the last-mentioned, is not identieal with it, but intermediate between it and f. typica. 
