KONGL. SV. VET. AKADEMIENS HANDLINGAK. BAND. 20. N:0 5. 133 



the plants in question are so strongly differentiated from one another, that they ought 

 to be regarded as separate species which have issued, probably not long ago, from one 

 or two fundamental types. 



Habitat. D. Bcerii is in the Arctic Sea a sublitoral alga occurring within the 

 formation of Laminariacece and apparently preferring exposed coasts to the interior of 

 deep bays and other sheltered places. It is usually fastened to other algaj, especially 

 to the rhizines of the Laminariacece. On the north coast of Spitzbergen I have found it 

 in full development in the middle of February. Specimens with sporocarps were met 

 with on the west coast of Novaya Zemlya in June and July, at Spitzbergen in August; 

 specimens with tetrasporangia at both these places in the month of July. During the 

 development of the spores part of the branches are dissolved, but at the end of that 

 time a vigorous development of new vegetative parts sets in, by which a great number 

 of the new branch-systems are produced in the axils. 



Geogr. Distrib. This species is known only from the arctic region of the Polar 

 Sea, and in this region it has a pretty narrow range. For it has been found only in the 

 eastern part of the Greenland Sea and in the Murman and the White Seas. Its maxi- 

 mum of frequency seems to be in the White Sea and in the eastern part of the Murman 

 Sea. The most northerly place where it has been met with, is Musselbay on the north 

 coast of Spitzbergen, Lat. N. 79° 53'. 



Localities: The Greenland Sea: the north and west coasts of Spitzbergen, pretty 

 common, but not abundant. 



The Murman Sea: at several places on the coast of Russian Lapland and Cisu- 

 ralian Samoyede-land, Kolgujew Isle, the west coast of Novaya Zemlya from Matotshin 

 Shar to N. Gusinnoi Cape, on the latter coast more plentiful and luxuriant than at 

 Spitzbergen. 



The White Sea: pretty common and abundant. 



Delesseria corymbosa J. G. Ag. 



Spec. Alg. 2, p. 684. 



Descr. Delesseria corymbosa J. G. Ag. 1. c. 



Fig. » » tab. nostra 10, fig. 3. 



Sj/h. Delesseria aiigustissima Croall, Fl. Disc. p. 459(?), 



Habitat. It appears to belong to the sublitoral zone and to the formation of 

 Laminariacece. In support of this view I can quote the inscription of a label by J. 

 Vahl »In stipibus Laminaria3 saccharina3». 



Geogr. Distrib. It is known only from Baffin Bay. Only one Locality is quite 

 sure, namely Godthaab on the west coast of Greenland. If however, as seems most 

 probable, Croall's D. angustissima is the present species, it is reported also from Ja- 

 cobshavn, which is, in that case, the most northerly locality where it is at present 

 known to grow, about Lat, N. 69° 15'. 



