256 Dar bishire. — On Actinococcus and Phyllophora. 
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. 
Fig. 3. Phyllophora Brodiaei (Turn.) J. Ag. 
Sterile, Baltic forms. Nat. size. 
They are characterized by being very narrow, elongated 
and always sterile (Fig. 3, forma ligulata , elongata , &*c., of 
various authors). They therefore never develop antheridia 
or procarpia. Furthermore they are never attacked, at any 
rate not successfully attacked, by the germinating spores 
of Actinococcus subcutaneus. This parasite can only enter 
the host when the male (or the female ?) organs of the latter 
are present. It has been known to the author for some 
