533 
in Pinus and Thuja . 
or as an artifact, employed this term to denote it. As the meaning of the 
synaptic phase became clearer it was generally recognized as being concerned 
with the uniting of somatic univalents in pairs to form the heterotype 
bivalents. Accordingly the term came to be used by certain observers, as 
suggested by McClung (’02), to mean ‘ the fusion of single chromosomes 
into multiple ones, usually of a bivalent value ’. It has been suggested there- 
fore that a new term, synizesis, be adopted to signify the stage of mitosis 
first denominated as synapsis, and that the latter term be used to denote 
the conjugation of the maternal and paternal chromosomes. To this there 
seems to be certain well-founded and serious objections, chief among which 
may be mentioned the fact that the exact meaning and significance of this 
stage of mitosis has not been definitely and finally determined. The term 
has been used through all the literature of the past ten years to denote that 
very definite stage of mitosis which has been universally observed and 
which has as yet been only partially explained. The term should be 
retained with its original meaning whatever significance may be attached 
to the stage of mitosis it represents. If the meaning of synapsis should be 
found to be, as is strongly probable, the conjugating of univalent chromo- 
somes, then we would have two terms which signify the same thing and the 
one would be superfluous, a condition recently reported by Miss King (’07) 
for Bufo. 
The tightly contracted stage of synapsis persists frequently for several 
days, depending upon growth conditions, and in any sporangium the cells 
reach this stage quite uniformly. Cardiff (’06) has attempted to explain 
the one-sided position of the chromatin mass as due to gravity, but in 
neither of the two genera investigated does this explanation hold. In cells 
lying adjacent to each other, the contraction has been always toward the 
periphery, but without any apparent relation to the stimulus of gravity. 
From the balled-up mass threads eventually begin to disentangle themselves 
and pass out into the cavity. These threads unless cut by the knife are 
always in the form of loops (Fig. 6). 
The spirem thread is now seen to exhibit a very uniform structure. 
The chromomeres are much more uniform in size than at the beginning 
of the synaptic phase, and they are embedded in the more lightly staining 
linin. The thread at this time is seen to show indications of longitudinal 
fission. This first becomes evident from a careful examination of the 
chromomeres themselves. In sections well differentiated with the iron-alum 
stain the chromomeres are clearly seen to occur quite regularly in pairs, 
although there is an occasional unpaired one (Fig. 6). Allen suggests that 
the appearance of double chromomeres at this time has been confused, 
because the chromomeres are not always differentially stained, and, being 
larger than the linin cord in which they are embedded, the swellings which 
project over the side have been mistaken for the double rows of chromo- 
