17 



P. ampUssima (Kjellm.l is stated by Hus to have 16 pol- 

 linoids in each antheridiiim. A specimen from Norway (Norv. 

 arct. Mehavn leg. Fosl.) had 16 as a rule, more rarely 32 pol- 

 linoids in each antheridium. Sometimes there were only 8 cells, 

 but these were evidently imperfectly divided. A specimen from 

 Iceland likewise mostly had 16 and more rarely 32 poUinoids 

 in each antheridium. In connection with this I shall point out 

 that Kjell man (Arct. alg. PI. 18, Fig. H ) shows more than 16 

 pollinoids in two of the antheridia. 



P. tenuissima Strömf. is described by Hus as containing 

 8 pollinoids in each antheridium. A specimen from Iceland, 

 Ström felt's original specimen, belonging to the Herbarium of 

 the Botanical Museum, had mostly 16 and sometimes 32 pol- 

 linoids in each antheridium. A few limes I saw only 8, but 

 they seemed to be imperfectly divided. 



Thus the number of pollinoids cannot be used as a speci- 

 Gcally distinctive character for the above mentioned species, at 

 least not as far as the Arctic and North Atlantic specimens are 

 concerned. 



In GrI. Havalg. Rosenvinge mentions that the inferior por- 

 tion of the thallus of the distromatic forms of Porphyra always 

 is composed of a single layer of cells («Observandum praeterea 

 est, imam partem frondis in distromalicis etiam formis semper 

 monostromaticam esse («cfr. Kjellman I.e.» [o: Arct. alg.j «tab. 18, 

 fig. 2«) (Hosenv. 1. c. p. 829). Hus calls this in question (1. c. 

 p. 185), as he «cannot confirm Rosenvin g e's statement, that 

 in the distromatic forms the inferior portion of the tallus is 

 composed of a single layer of cells», in order to investigate this 

 matter more thoroughly I have examined specimens belonging 

 to P. mbiiata v. typica and v. amplissima both from Iceland, 

 the Færoes and Norway, besides those from East Greenland. 

 In all the specimens examined, the inferior part of the thallus 

 proved to be monostromatic up to a distance of about 0,-5 cm. 

 from the base. Thus Rosenvinge's observation is perfectly 



3 



