K0N6L. SV. VET. AKADEMIENS HANDLINGAE. BAND 20. N:0 5. 9 



With regard also to the distribution of the vegetation on the several bottom-zones 

 different parts of the Arctic Sea differ essentially. In the Norwegian Polar Sea the 

 literal zone is overgrown with a rich, luxuriant vegetation of varying composition. 

 More than half of the species known from this sea occur on this region of the bottom, 

 either exclusively or at least sometimes. Some of them, for instance Rhodomela lyco- 

 podioides, Gigartina mamillosa, Chondrus crispus, do not certainly attain here the same 

 luxuriant development as farther southwards on the coast of Norway, but the great 

 majority are as flourishing here and form as dense masses as on the coasts of the 

 North Atlantic. On the west coast of southern Greenland there is also to be found a 

 litoral vegetation very rich in individuals, although it is more monotonous. I have been 

 informed by Professor Th. Fries that the litoral zone is clothed with Fucacese, and that these 

 constitute the peculiar character of the litoral vegetation. That however several other 

 species occur, beside these, is shown by the collections made here, containing several 

 purely litoral algae. With regard to several of these, J. Vahl has, besides, expressly 

 noted on the labels, that they were found growing within the litoral zone. Of such 

 species I mention here: Rhodomela lycopodioides, Polysiphonia urceolata, Halosaccion 

 ramentaeeum, Ilea fascia, Pylaiella litoralis, Enter amor pha intestinalis, E. compressa and 

 E. micrococca, Monostroma Blyttii, Diplonema percursum, Spongoinorpha arcta, Cladophora 

 rupestris, Rliizoclonium rigidum and Rh, riparium, Chcetomorpha Wormskioldii^ Urospora 

 penicilliformis, Rivularia atra. In the by far greater part of the Arctic Sea the litoral 

 zone possesses no vegetation at all or an exceedingly meagre one. On the coasts of 

 Spitzbergen I have found the following species in the litoral zone: Rhodochorton Rothii 

 and Rh. intermedium, Fucus evanescens f. bursigera and nana, Chcetopteris plumosa, Pylaiella 

 litoralis, Chcetophora maritima, Enteromorpha compressa, Spongomorpha arcta, Rhizoclonium 

 riparium, Ulothrix disci/era, Urospora penicilliformis, Codiolum Nordenskioldianum, Calothrix 

 scopulorum. This number of species is certainly pretty considerable, but it should be 

 observed, that the majority are either generally very rare or at least very rare in the 

 litoral zone. Fucus evanescens, commonly diffused in its larger forms on the coasts of 

 Spitzbergen, seldom ascends into the litoral zone. In the form bursigera it has been 

 found here in two places, in the form nana in one, always in plots of small extent. 

 Chcetopteris plumosa, one of the commonest algae of Spitzbergen, I have found as litoral 

 only once and then only a few specimens. Pylaiella litoralis and Spongomorpha arcta, 

 both of them rather common in the sublitoral zone, are very rare in the litoral. The 

 two Rhodochorta, Ulothrix discifera and Codiolum Nordenskioldianum have been met with, 

 each of them, only in one place within the litoral zone of Spitzbergen. Only Entero- 

 morpha compressa, Rhizoclonium riparium, Urospora penicilliformis and Calothrix scopulo- 

 rum occur more commonly or in somewhat greater numbers on the uppermost part of 

 the bottom at Spitzbergen. In the by far greatest part of this zone there is no vege- 

 tation at all. The same poverty is exhibited by the litoral zone in the eastern part 

 of the Murman Sea; in the western part of it as well as in the White Sea it probably 

 stands in the middle between the richness of the Norwegian Polar Sea and the poverty 

 of the Greenland Sea ^). In my account of the vegetation on the west coast of Novaya 

 ') Cp. CiENKOWSKY, Bericht. 



K. Vet. Akad. Handl. Band. 20. N:o 6. ^ 



