

126 



Tromsø Museums Aarshefter 14. 189 \ 



cell-walls of ten a 1 i t ti e contracted at the inter walls, and 

 the chromatophores rather few. 



Thus the only difference between P. varia and P Uto- 

 r alis f. compacta is, that the former generally has a lighter 

 colour ; the short branches consi sting of 1—8 cells most of- 

 ten appear in larger number than the long ones, the cells 

 are commonly a little shorter, not seldom contracted at the 

 interwalls, the cell-walls thinner and the chromatophores fe- 

 wer than in the latter. Moreover the sporangia are more 

 varying as to the development and arrangement, and the 

 number of sporangia in the chains is in general less than 

 in the latter. However, transitions are not seldom to be 

 fonnd. In my opinion P. varia probably is to be regarded 

 as a de ep water form of P. litoralis f. compacta. 



On the other hand, P. litoralis' f. compacta differs so 

 mnch from the typical form of the species that it, as far as 

 I have seen, deserves to be kept distinct. It is separated 

 as to the habit and, above all, by its ramification and soli- 

 tary or short chains of sporangia which are soraetimes di- 

 vided into 2 daughter-cells. I regard P. varia as a form of 



the species. It seems to possess a number of forms al most 

 similar to that of P litoralis. 



The genus Pylaiella has been separated from Ectocar- 

 pus thereby, that in the former the sporangia rise from 



i 



transformed vegetative cells, intercalar or terminate, raost- 

 ly in chains in a number of until 40. The gametangia are 

 also intercalar, more seldom terminate, cylindric or someti- 

 mes elongated conical. Besides the chromatophores are, in 

 the species hitherto known, always small and disk-shaped. 

 In Ectocarpus the sporangia never or very seldom serve as 

 vegetative organs, are morphological well differentiated from 

 the vegetative cells and al most ever solitary, like the ga- 

 metangia occupying the place of a branch. Cp. Kjell" 

 man, Skand, Ect. o. Tilopt. p. 98 and Handbok p. 71. 





