184 KJELLMAN, THE ALG^ OF THE ARCTIC SEA. 



Antithamnion americanutn (Harv.) Farl. 



New Engl. Alg. p. 123; Callithamnion araericanum Harv. Ner. Am. 2, p. 238. 

 Descr. et Fig. Callithamnion americanum Harv. 1. c. et t. 36 A. 



Syn. Callithamnion americanum Dickie, Alg. Walker, p. 86; Alg. Cumbcrl. p. 239. 

 » Ckoall, F1. Disc. p. 460. 



Habitat. According to existing statements it appears to occur both as litoral and 

 as sublitoral at the places where it has been as yet observed in the Arctic Sea. In 

 the former case it is attached to stones, in the latter to algae: Chcetomorpha melagonium. 



Geogr. Distrib. It has been reported from the American Arctic Sea and Baffin Bay. 



Localities: The American Arctic Sea: Port Kennedy. 



Baffin Bay: Cumberland Sound, plentiful; the west coast of Greenland at or 

 about Disco Island. 



Gen. Rhodochorton Nag. 



Ceram. p. 355. 



Subgen. 1. Thamnidium Thur. 



in Le Jol. Liste Alg. Cherb. p. 110. 



Rhodochorton intermedium Kjellm. 



Spetsb. Thall. 1, p. 28. 

 Descr. Thamnidium intermedium Kjellm. 1. c. 

 Fig. » » » .) t. 1, fig. 10. 



Rhodochorton intermedium tab. nostra 15, fig. 8. 



Habitat. Litoral, growing gregarious on rocks exposed to the surge. Specimens 

 gathered in July bear few tetrasporangia. 



Locality: Found as yet only in the Greenland Sea on the west coast of Spitz- 

 bergen in the interior of Icebay. 



Rhodochorton spinulosum (Suhr) nob. 

 Callithamnion spinulosum Suhr, Flora 1840, p. 292. 

 Descr. Callithamnion spinulosum J. G. Ag. Epicr. p. 12. 



Remark on this species. The present species resembles RIl Rothii in habit, differing 

 from it by the structure and arrangement of those branch-systems which bear tetraspo- 

 rangia. With regard to those systems it approaches nearly to Rh. floridulum as deter- 

 mined by Thuret and figured by Le Jolis, Liste Alg, Cherb. tab. 6. It differs from it 

 in size, habit, ramification, etc. 



Habitat. According to Suhr this plant grows epiphytic on other algge. -1. G. 

 Agardh doubts the correctness of this statement, and after having myself examined 

 specimens in the herbarium of the Copenhague Museum I cannot but embrace the 



