Gen. Lithothamnion Phil. 



Wiegm. Arch. p. 387; Aresch. in J. Ag. Spec. Alg. 2, p. 519; 

 Rosan. Melob. p. 96. 



Subgen. Eulithothamnion Fosl. mscr. 



Lithothamnion s. s. auct. 



Sectio I. Innatae Fosl. mscr. 



Conceptaculis sporangiferis demum innatis. 



Lithothamnion boreale Fosl. 

 Contrib. II, p. 2. 

 Dcscr. et Fig. Lithothamnion boreale Fosl. 1. c. et t. 1. 



Syn. Apora polymorpha Gunn. in Act. Nidros. p. 70; ex parte? 



Remark on the species and its synonomy. Of this vigorously 

 developed species no other specimen has been found than the 

 solitary and sterile one described 1. c. A fragmentary one from 

 Mehavn in East-Finmarken may perhaps be referrible to the pre- 

 sent species. The latter, however, only forms the uppermost part 

 of the branch-system of a larger specimen, and, therefore, it cannot 

 be determined with certainty. 



In Gunner us' zoological collection in the Museum (Scientific 

 Society) here are four specimens of Lithothamnion 1 ), one or two 

 of which probably being nearly related or referrible to L. boreale. 

 They are, however, fragmentary and sterile, forming a part of a 

 larger specimen like the above mentioned, and, as no locality is 

 known, not even wheter they are collected on the Norwegian coast,. 

 I have not examined them more closeh/. 



Relation to other species. The plant appears to be nearly 

 related to certain forms of L. glaciale. However, it must be 

 considered a separate species, even if the organs of propagation 

 may prove to be identic, characterized especially by its vigorous 



!) Cp. under L. fruticidosum. 



