KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 20. N;0 5. 15 



with their companions, might be regarded as a sort of litoral formation in course of 

 development, precursor of the present formation of Fucacece on the coast of Norway. 

 It might be named a prcelitoral formation. 



The formation of Laminariacece is, as mentioned before, the best marked and most 

 widely distributed vegetation in the whole Arctic Sea, covering also the largest area. 

 Its composition varies in different parts both with regard to the species predominating 

 and the species forming the under-vegetation in these arctic woods of algas. But al- 

 though the LaminariacesB comprise a considerable number of species, agreater one, indeed, 

 than has hitherto been supposed, they are all referable to one and the same general 

 type, and on that account the formation constituted by them makes everywhere, on 

 the whole, the same impression. As the variations in the composition of the formation 

 of Laminariaceae afford the best characteristics for distinguishing and defining different 

 narrower regions of the arctic marine Flora, they will be set forth in detail, in the 

 description of the regions alluded to. The formation of Laminariaceaj is most strongly 

 developed on a bottom of solid rock or large stones. In the Norwegian Polar Sea and 

 in Baffin Bay on the west coast of Greenland its upper margin coincides with high-tide 

 mark, and from there it descends in all its richness to the depth of 2 — 5 fathoms. 

 Deeper down it diminishes in number of individuals, but often increases in luxuriancy. 

 Within the rest of the Arctic Sea, it generally keeps to the lower parts of the sublitoral 

 region, in about 3—10 fathoms water. On the coast of Norway, in such places where 

 the bottom is looser, consisting of sand, gravel, and smaller stones, within the upper 

 portion of the sublitoral zone, the formation of Laminariacea; assumes an aspect very 

 different from the typical one. The common species of Laminaria and Alaria draw 

 back, diminishing in number and luxuriancy, and instead of these another Laminariea, 

 Phyllaria dermatodea, increases so as to form the main mass of the vegetation, in con- 

 junction with Chorda filum, Chordaria flageUiformis, Dictyosiphon hippuroides, Monostroma 

 fuscuin, Spongomorpha arcta, Diploderma amplissimum a. o. 



The formation of Corallinacece is poor in species and differently composed in diffe- 

 rent parts of the, Arctic Sea. On the coast of Norway Lithothamnion soriferum pre- 

 dominates. Fastened to this, there are found in small numbers Chantransia efflore- 

 scens, Delesseria sinuosa, Rhodophyllis dichototna, KaUyinenia septemtrionalis, Antitliam- 

 nion Pylaiscei and boreale, Derbesia marina, and some few others. On the coasts of 

 Spitzbergen and the west coast of Novaya Zemlya Lithothamnion glaciate is the prin- 

 cipal species. Together with this, there are found Ptilota pectinata in great numbers 

 and Delesseria sitiuosa, Rhodophyllis dichotoma, Euthora cristata and Antithamnion boreale 

 less abundant. ^) The formation of Corallinacece on the west coast of Greenland in Baffin 

 Bay is probably constituted in the same way. In the western part of the Kara Sea, 

 where it is characterized by Lithophyllwn arcticurn, it was also found to be uncommonly 

 rich in Euthora cristata. One or two Laminarioe and a small number of Antithamnion 

 boreale were met with besides. ^) 



') Cp. Kjellman, Algenv. Murm. Meer., p. 66. 



^) Cp. Kjellman, Kariska liafvets Algv. pp. 10 — 11. 



