184 KJELLMAN, THE ALG^ OF THE ARCTIC SEA. 



Antithamnion araericanum (Harv.) Farl. 



New Eugl. Alg. p. 123; Callitharanion americaiium Harv. Ner. Ani. 2, p. 238. 

 Descr. et Fig. Callithamnioii americanura Haev. 1. c. et t. 36 A. 



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

 » » Ceoall, Fl. Disc. p. 460. 



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

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

 the former case it is attached to stones, in the latter to algas: Chcetoinorpha melagonium. 



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



Localities: The American Arctic Sea: Port Kennedy. 



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

 about Disco Island. 



Gen. Rliodocliorton Näg. 



Ceram. p. 355. 



Snbgen. 1. Tharauidium Thtjr. 



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



Rhodochorton intermediura Kjellm. 



Spetsb. Thall. 1, p. 28. 

 Descr. Thamnidium intermcdiiim Kjellm. 1. c. 

 Fig. » » » » t. 1, fig. 10. 



Rhodochovton intermediura 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 onlj' in the Greenland Sea on the west coast of Spitz- 

 bergen in the interiör of Icebay. 



Rhodochorton s p i n u 1 o s u m (Suhr) nob. 

 Callithamnion spiniilosiim Sdhr, Flora 1840, p. 292. 

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



Remark on tliis species. The present species resembles Rh. Roihii 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. floridulmn 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 cpiphytic on other algas. .1. G. 

 Agardh doubts the correctness of this stateinent, and after having rayself examined 

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



