KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 20. N:0 5. 8] 
surely not annual. This seems especially improbable in respect of such algw as Rho- 
dochorton Rothii, Rhizoclonium riparium, and Fucus evanescens. For on the coast of 
Novaya Zemlya I have seen all these algw fully developed early in the year, before 
the land-ice broke up or just as it was dispersing. Thus | cannot but assume that 
they had lain frozen and covered with ice during winter, and when delivered at last from 
their cold cover resumed at once their development which had been interrupted by the ice. 
I have in the arctic region seen quite evident instances of algw being frozen and in- 
closed in ice and continuing their development when delivered. In a lagoon at Pitlekay, 
which during the winter froze to the bottom, there was found in abundance an Lntero- 
morpha which I have below named £&. micrococca f. subsalsa. When the ice of the 
lagoon melted at the end of June, this plant remained at the bottom in large seemingly 
lifeless masses. But in a short time it began to develop vigorously by producing new 
shoots from the parts which had persisted through the winter. This being so, it is 
quite possible that all the species which are litoral within the arctic region, persist all 
the year round and do not complete their development in one year, but in two or 
three years, with longer or shorter interruptions. Accordingly there is as yet no sure 
evidence of the existence of annual species among the arctic alge. I believe, however, 
that such species are to be found on the west coast of Greenland, and that, besides, 
the first-mentioned Chlorophyllophycew are probably also annual. But in any case, to 
state it broadly, we may say with regard to the arctic region, that the conditions 
under which the alge live there, are such that annual alew cannot endure or at least 
cannot occur in any larger number either of species or of individuals, and that the 
perennial species, in the very most cases, need the whole year to reach the develop- 
ment designed for each period of growth. 
But though the development of the arctic alge is thus extended throughout the 
whole year, there appears a certain periodicity at least in certain species. For it may 
be regarded as a pretty general fact that the purely vegetative development is livelier 
and more energetic during the favourable season, while the development of propagative 
organs, on the contrary, is stronger and richer in the latter part of the autumn, in 
winter, and in early spring. But nevertheless I cannot but maintain the statement 
I have made once before, that a development of vegetative parts takes place on a very 
large scale on the coast af Spitzbergen during mid-winter, when the sun is at its lowest 
beneath the horizon and consequently the darkness is intense. Spores germinated and 
grew into pretty well developed embryonic plants. Of several species, for instance, 
Delesseria sinuosa, young plants were common towards the end of the dark season. It 
could not well be doubted that these had been developed during the winter-months. 
Older plants of the same species, and also of Halosaccion ramentaceum, Rhodyimenia 
palmata, Phyllophora interrupta, Rhodomela lycopodioides, Sphacelaria arctica, Phlaospora 
tortilis put forth new shoots in winter, which were in course of growth and more or 
less developed at the entrance of the light season. However, it must be admitted that 
the development of such organs did not set in with greater vigour nor produce any 
considerable results before the beginning of May. 
K. Vet. Akad. Handl. Band. 20. N:o 5. | | 
