KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 20. N:0 5. 187 
Subg. 2. Thamniscus KJuLum. 
Spetsb. Thall 1, p. 29. 
Rhodochorton mesocarpum (Carm.) nob. 
Callithamnion mesocarpum Car. in Hook. Brit. Fl. 2, p. 348 
f. rupicola nob. 
Descr. Thamnidium mesocarpum Kugen, Nordl. Alg. p. 22. 
Fig. Callithamnion » Harv. Phyc. Brit. t. 325. 
f. penicilliformis KonLun. 
Spetsb. Thall. 1, p. 30. 
Descr, Thamnidium mesocarpum f. penicilliformis KyguuM. |. e. 
Fig. » » » » tab. nostra 16, fig. 6—7. 
Syn. Thamnidium mesocarpum KLEEN, Nordl. Alg. p. 22. 
» » f. penicilliformis Ksenum. 1. ¢.; Algenv. Murm. Meer. p. 25; Kariska 
hafvets Algv. p. 23. 
Addition to the description of f. penicilliformis. In general the appearance of this 
plant is that represented by fig. 6. I have always found it such within the Arctic Sea. 
On the coast of Finmarken among such individuals I have, besides, observed others 
whose primary branches bore a greater number of secund or alternate, appressed branches. 
Hatitat. The form rupicola is litoral or sublitoral, attached to stones, Bryozoa, 
muscles a. 0. The form peniciliformis is sublitoral aud epiphytic on several alge, chiefly 
species of Odonthalia, Delesseria, and Ptilota, and Chatomorpha melagonium. It has been 
met with hitherto only on exposed coasts, always few specimens. Both the forms 
have been found with tetrasporangia in July and August, f. penicilliformis, besides, at 
Greenland in March. 
Geogr. Distrib. The typical form is known only from the Atlantic province of 
the Polar Sea, f. penicilliformis also from the arctic region, within which it is widely 
diffused. Its most northern known locality is Fairhaven on the north-west coast of 
Spitzbergen, Lat. N. 79° 41’. 
Localities: The Norwegian Polar Sea: Nordlanden (f. rupicola) local, scarce; Fin- 
marken at Gjesver (f. penicilliformis) local, scarce. 
The Greenland Sea: the north-west coast of Spitzbergen at Fairhaven, local, scarce. 
The Murman Sea: on the west coast of Novaya Zemlya at several places pretty 
plentiful. 
The Kara Sea: Uddebay on the east coast of Novaya Zemlya. 
bajfin Bay: the west coast of Greenland at Julianeshaab. 
Rhodochorton spetsbergense KsrLim. 
Spetsb. Thall. 1, p. 31. 
Descr. Thamnidium spetsbergense KyeLum. |. e. 
Fig. » » » tue oe, Rae: 
