170 



OTTO VERNON DABBISHIRE. 



the thallus, but often appear to be stalked, this appearance being pro 

 duced by the shoots on which they grow (Figs. 1 and 2) being at first 

 rather narrow. 



These red bodies are the nemathecia of Actinococcus subcutaneus 

 (Lyngb.) Kolderup Rosenvinge, the Floridea mentioned above as 

 growing parasitically on Phyll. Brodiaei. The young shoots of the 

 latter Alga are not usually much modified by the presence of the 

 parasite, but are on the contrary as a rule well developed. 



In the Baltic sea small detached portions of the thallus of Phyll. 

 Brodiaei frequently occur lying on the sea-bottom. They are 



Fig. 4. Phyllophora Brodiaei (Turn.) J. Ag. ' I. Two 

 speimophores. x 10 diam. IT. Longitudinal section of 

 spermophore, showing the antheridial cavities in the 

 cortical layer, x 200 diam. 



characterized by being very narrow, elongated and always sterile 

 (Fig. 3, forma, ligulata, elongata, <kc, of various authors). They 

 therefore never develop antheridia or procarpia. Furthermore they 

 are never attacked, at any rate not successfully attacked, by the 



