Phyllophora Brodizi and Actinococcus subcutaneus. 9 
had observed that the antheridial cavities of Phyllophora 
Brodiæi often accompanied the presence of Actinococcus 
subcutaneus, and after a close investigation of this coin- 
cidence he made out that it was possible to explain it 
by supposing that Actinococcus is a parasite that “only can 
enter the host when the male (or the female?) organs of 
the latter are present”. He thought that he had observed 
the entrance of Actinococcus by the small ostioles of the 
antheridial cavities. “The immediate product of germina- 
tion seems to be a small heap of perhaps 4—8 cells, one 
of which always comes to be near an ostiole leading to 
an antheridial cavity. ... A filament is then formed, which 
passes into the host-plant through the antheridial ostiole 
(Plate XV, Fig. 1)”. However, the figure quoted gives no 
evidence of the correctness of the given interpretation. An 
antheridial cavity seems to be faintly seen under a bunch 
of filaments, but it is situated at a lower level than the 
normal antheridial cavities, and it can by no means be taken 
for granted that the filament has entered the host at this 
place; it would be equally probable that the small heap of 
cells on the surface of the Phyllophora had been produced 
by a filament forcing its way outwards through the cortex, 
perhaps through an antheridial cavity, and that it was on the 
way to forming a nemathecium. DARBISHIRE maintains that 
the presumed parasite “is unable to pierce the outer covering 
of the host, when entering the latter. It can only attack 
the latter through the antheridial ostioles”. He _ thinks, 
however, that Actinococcus may also be able to enter the 
host by means of the opening caused by the projecting 
trichogyne, as he has “seen Actinococcus-bearing shoots of 
Phyllophora, in the cortical layers of which could be seen 
what were apparently remains of undeveloped carpogones” 
