310 KJELLMAN, THE ALG OF THE ARCTIC SEA. 
Geogr. Distrib. It is known in the Polar Sea north of the Atlantic, occurring 
in large numbers luxuriantly developed even at Spitzbergen. Its northernmost point is 
Advent Bay on the west coast of Spitzbergen Lat. N. 78° 15’. 
Localities: The Norwegian Polar Sea: Nordlanden common according to KLEEN; 
Finmarken, the south coast of Mageré abundant. 
The Greenland Sea: in the lagoons at Advent Bay on the west coast of Spitz- 
bergen, abundant. 
The White Sea: Golaja-Koshka Isle. 
Rhizoclonium Pachydermum KJetim. 
Algenv. Murm. Meer. p. 55. 
f. typica. 
Descr. et Fig. Rhizoclonium pachydermum Keni. |. c. et t. 1, fig. 26—28. 
f. tenuis nob. 
f. quam f. typica tenuior et ramosior; ramis cauloideis 30—40 «. crassis, e cellulis nembrana tenuiore 
contextis, rhizoideis crebris. 
Remark on the forms of this species. In the herbarium of the Copenhagen Muse- 
um there is a considerable quantity of Rhizoclintwum from Greenland coinciding so 
closely with the Ah. pachydermum from Novaya Zemlya described by me, that it can 
hardly be regarded as specifically distinct from this. It is much branched, even more 
so than the typical Rh. pachydermum, with two sorts of branches, numerous rhizoid 
branches, usually formed of more than three cells, and pretty scarce cauloid branches 
that give rise to rhizoid branches and even to one or two cauloid branches of a 
higher order. The sympodial main axis is much thicker than the secondary axes 
and ends downwards in an obovate cell with discoid expanded extremity. The cells 
of the main axis have very thick, distinctly stratiform walls. It is chiefly distinguished 
from the typical form by its cauloid branches being more slender, usually only 30— 
40 «. in diameter. Their cell-walls are somewhat thinner than in f. typica, although 
even in f. tenwis, especially in the lower portions of the cauloid branches, they are 
much thicker than in the majority of known Lhizoclonia. 
Habitat. This species belongs to the litoral zone. At Novaya Zemlya I saw it 
forming a thin stratum on rocks at high-water mark. I have afterwards met with it 
on the north coast of Sibiria in lagoons with somewhat brackish water, forming mats 
lying loose on the bottom. 
Only sterile specimens have been observed. 
Geogr. Distrib. It seems to be widely distributed within the Arctic region, and 
is probably circumpolar. The most northern place where it is known to occur is Kar- 
makul Bay on the west coast of Novaya Zemlya, about Lat. N. 72° 30’. 
Localities: The Murman Sea; the west coast of Novaya Zemlya, scarce at Karma- 
kul Bay. 
