246 Scientific Proceedings, Royal Dublin Society. 
well-known parasitic fungus Achyla penetrans, which would appear 
to take an important share in effecting the detachment of the 
corallum. Itseems probable that the degeneration of the tissues 
in the neck of the Anthocyathus gives rise to degenerative changes 
in the substance of the corallum in that region. The corallum in 
this region may be spoken of as “ dead,” and in the course of time 
would be slowly dissolved out by the action of sea-water, thus 
setting free the Anthocyathus; but it appears to be nearly i vari- 
ably the case that this slow process is hastened by the parasite 
Achyla penetrans, which riddles the dead region of the corallum, 
and so weakens it that the slightest force is sufficient to set free 
the Anthocyathus. | 
The structure of the young and adult Fungia, the arrangement 
of the septa and mesenteries, the mode of growth of the Anthoblast, 
and its division into Anthocaulus and Anthocyathus, show conclu- 
sively that the adult free Fungia is an individual, and is not, as 
Ortmann has supposed, a colony consisting of a central nutritive 
person surrounded by irregularly scattered degenerate persons whose 
function is prehension and respiration. 
