Rhabdonia tenera , J . Ag. 421 
Grdcilaria , and other higher Florideae, and it is probable 
that they originate in a similar way. 
According to De Bary (’84, p. 2 ) the germinating spores of 
Nectria Solani unite (in groups of from two to eight) by means 
of short tubes to form a single individual. Woronin (’95) 
describes a similar case in connexion with the germinating 
spores of Sclerotinia Padi and S. Aticupariae . These cases 
are homologous with that of Rhabdonia , if we consider that 
the tetraspores which are contained in the same sporangium 
are morphologically independent. This seems to be the cases 
since they are capable under favourable circumstances of 
separating from each other and germinating independently 
without having in the meantime undergone any modification 
other than that of escaping from the sporangium. When 
they remain enclosed in the mother-plant, they undergo 
a most fundamental modification, in that each spore, instead 
of developing into a separate individual, produces only 
a small portion of one, and so perfect is the correlation 
that the outermost spore produces merely a growing-point, 
whilst the innermost develops rhizoids. Whether the case 
in question belongs to the category of strictly epigenetic 
phenomena or is an inherited character, I do not attempt 
to decide. 
Two views are easily possible as to the physiological 
conditions obtaining previous to germination. It may be 
assumed that physiological and morphological independence 
are acquired at the same time, and that the former is 
gradually lost as the result of the fact that the spores are 
unable to escape from the sporangium and separate. In the 
case of abnormal eggs of Ascaris, described by Strassen (’96), 
two eggs remain in contact by means of a broad proto- 
plasmic connexion, and throw off the first polar body 
independently ; but they unite to make a second polar 
body common to both eggs. Later they develop into 
a single embryo of unusual size. The separate individualities 
are apparently gradually merged into one as the result of 
continued union ; it must, however, be remembered that the 
