6 KJELLMAN, 
*Rhodochorton Rothii, 
Porphyra laciniata, 
*Fucus vesiculosus, 
* ~~»  ceranoides, 
» — spiralis? 
» evanescens, 
»  miclonensis? 
*Alaria Pylaii? 
*Agarum Turneri, 
Phyllaria dermatodea, 
Laminaria saccharina? 
‘ » longicruris, 
» digitata? 
» stenophylla, 
*Chorda filum, 
*Ralfsia deusta, 
*Chordaria flagelliformis, 
*EKlachista fucicola, 
*Lithoderma fatiscens, 
*Tlea fascia, 
THE ALGH OF THE ARCTIC SEA. 
*Scytosiphon lomentarius, 
*Desmarestia aculeata, 
*Dichloria viridis, 
*Phloeospora tortilis, 
*Dictyosiphon foeniculaceus, 
*Chetopteris plumosa, 
*Ectocarpus confervoides, 
*Pylaiella litoralis, 
Enteromorpha clathrata, 
» intestinalis, 
; » compressa, 
Ulva lactuca, 
*Monostroma fuscum. 
*Spongomorpha arcta, 
Cladophora glaucescens? 
*Rhizoclonium riparium, 
*Chetomorpha melagonium, 
» tortuosa, 
*Urospora penicilliformis, 
Bryopsis plumosa. 
Of these 70 species, no less than 41, viz. those marked with an asterisk, accordingly 
584 per cent, are at present known with certainty from the arctic parts of the Polar 
Sea, and amongst these 41 species there are several of the most commonly distributed 
and most characteristic forms of that region of the Polar Sea which is rich in ice. As 
moreover many of them, as has been shown above, are chiefly distributed northwards 
at least in the Atlantic — there are no detailed statements to be had for the Pacific — 
we are justified in placing their origin in a glacial sea and in assuming that they have 
passed from there to the northern Atlantic and the northern part of the Pacific. The 
percentage of arctic forms amongst those species which are reported common to the Arctic 
Sea and the northern part of the Atlantic and of the Pacific, is in all probability larger than 
what is indicated by the figures mentioned. For there is some reason to suppose that a 
rather large number of species from the northern part of the Pacific, which have been 
considered identical with forms from the Atlantic, will prove on closer examination to be 
specifically distinct or wrongly determined. This is probably the case with those marked 
with a sign of interrogation in the above list *). Their number amounts to 16. If 
these are deducted, the arctic forms would constitute about 75 % of the whole number 
of species that the Arctic Sea has in common with the northern part of the Atlantic 
and the northern Pacific. Of the 13 species then remaining, Porphyra laciniata, Entero- 
morpha intestinalis auct., EH. clathrata auct. and Ulva lactuca, which are however met 
1) In support of this supposition, I refer to the notices on these species which are given by J. G. AGARDH in 
Spec. Alg., Epicr. and his treatises on the arctic marine Flora, by Ruprecut in Alg. Ochot., by FarLow in 
New Engl. Alg., by Harvey in Ner. Am. and Alg. Vanc., by Poste,s and Ruprecut in Ill. Alg. 
