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Phyllophora Brodiæi and Actinococcus subcutaneus. 37 
a systematic group which is typically haplobiontic, where 
these organs as a rule do not take part in the normal life- 
cycle. The extraordinary appearance in question within a 
genus which has otherwise normal cystocarps suggests that 
it is due to a mutation, tetrasporangia having appeared 
here instead of carpospores. In the case of Phyllophora 
Brodiæi it seems more probable that the origin of the 
parasitic tetrasporophyte has been occasioned by the 
degeneration of the procarps and the consequent ab- 
sence of fertilization and of carpospores. The tetrasporo- 
phytes — like the gonimoblasts in Ph. membranifolia — 
arise as outgrowths from the bearing or auxiliary cell, but 
these outgrowths have not the character of gonimoblast 
filaments; they appear first as vegetative intramatrical fila- 
ments, and only later do the nemathecia arise. The whole 
tetrasporophyte has the character of a much reduced form 
of the normal tetrasporophyte as it is known in Ph. mem- 
branifolia; the reduction of the vegetative body is due to 
the parasitical life, and the globular form of the nemathe- 
cium is due to the small size of the latter. 
For a full elucidation of the question here treated of, 
a closer cytological research has yet to be made. It ought 
in particular to be ascertained whether or not a fertili- 
zation takes place, and whether the formation of the tetra- 
spores is initiated by a reduction division. 
The other nemathecia occurring within the Gigartinacee 
and regarded by Scumirz as belonging to parasites analo- 
gous to Aclinococcus and referred to the genera Colacolepis 
and Sterrocolax, will not be treated here. As mentioned 
above, CHEMIN has examined the nemathecia occurring 
