Nov., 1914.] 
Stamens of Smilax herbacea. 
363 
order that they may have a definite position in the spirem during 
the synaptic stages when the bivalent chromosomes are formed 
by an end to end pairing and later longitudinal folding of the 
chromatic elements. By many investigators “synapsis” is used 
to designate the period of contraction which very generally 
appears in the earlier stages of reduction. But it is much better 
to use the term synizesis as was suggested by McClung and 
adopted by Schaffner in the more recent of his cytological papers. 
By eliminating this confusion of terms such expressions as “synaptic 
mates,” etc. in relation to the chromosomes, become intelli¬ 
gible without further explanations. 
The protochromosomes do not retain a definite shape, but in 
a short time there is an apparent elongation of each mass and 
a tendency for the delicate connecting linin threads to become 
thicker as the elongation continues. (Figs. 4, 5, 6). Soon no 
traces of the flaky masses are left, but instead there is a very 
delicate continuous spirem which can be traced for long distances 
in many of the sporocytes without finding any free ends. The 
free ends in most cases can all be accounted for by their having 
been cut in sectioning. (Fig. 7). 
There is now a perceptible enlargement of the nucleus, which 
appears very turgid; as a result of this enlargement the very 
delicate spirem becomes loosened from the nuclear membrane 
and does not appear to be so uniformly arranged about the 
periphery as before, but has the appearance as if it had been 
treated with some plasmolizing reagent. (Fig. 8). 
By this time there is usually one large nucleolus present, 
which very seldom appears in a central position and sometimes 
there are also dark staining granules in the nuclear cavity which 
in all probability are minute nucleoli. Miss Elkins noted this 
same fact in her study of Smilax herbacea. 
The spirem and granules in the earlier division stages show no 
evidence of a double character. Soon after the spirem has 
become loosened from the nuclear wall, there is an irregular 
massing of the thread, which either may or may not enclose the 
nucleolus. (Figs. 9, 10, 11). The types of contraction are not 
always the same and there was no evidence that synizesis is an 
actual stage in the reduction division. As previously mentioned 
Lawson considered this condition to be due to a period of growth 
in the nucleus, there would be thus no actual shrinking of the 
chromatin, but there can be no question that in the preparations 
studied there was a considerable actual contraction. Schaffner 
(15) regarded this condition as an artifact on account of experi¬ 
ments tried with living material of Agave virginica and the 
reactions also obtained by the treatment with different reagents 
which caused plasmolysis to take place in the vegetative cells, 
giving the spirem much the same appearance that was found in 
