,48 M. Foslie. 



that species, and this is not seldom the case. In my collec- 

 tions I have specimens which, as far as I am able to judge, 

 may be referred to either of these two species. 



The plant is sublitoral, occurring partly in the upper 

 part of the region, on a depth of 2 — 5 fathoms, partly on a 

 depth of about 15 fathoms. It prefers exposed localities and 

 has not been met with in the deeper bays, usually growing 

 scattered, attached to shells of Balanidse, Lithothamnia, Eho- 

 dophyllis dichotoma, Ptilota plumosa and pectinata. Specimens 

 bearing tetrasporangia, but sparingly, have been collected at 

 Kjollefjord in the middle of June; at Mehavn in the begin- 

 ning of July, also sparingly (f. corallina); at Berlevaag in 

 the middle of July, rather richly; and at Kjelmo in Sydvar- 

 anger in the beginning of August, very sparingly. 



Some specimens collected at Kjelmo are densely over- 

 grown with small cysts with oily contents, probably Chy- 

 tridium plumulce C o h n. 



Distribution: Scattered and in general very scarce along 

 the unsheltered coast; rather common on an iron buoy at 

 Berlevaag (f. typica). A few specimens of f. corallina found 

 at Mehavn, and at Kjelmo a transition between this form 

 and f. typica. 



Gen. Rhodochorton Nag. 

 Ceram. p. 121. 



Subgen. 1. Thamnidium Thur. 

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



Rhodochorton Rothii (Turt.) Nag. 

 Ceram. p. 121; Conferva Rothii Turt. Syst. 6, p. 1806, sec. Dillw. 

 Brit. Conf. t. 73. 



f. typica. 

 Descr. Callithamnion Rothii J. G. Ag. Epicr. p. 13. 

 Fig. Thamnidium Rothii Thur. in Le Jol. Liste Alg. Cheib. t. 5. 

 Exsicc. „ „ Aresch. Alg. Scand. exsicc. No. 259. 



