540 
The Ohio Naturalist. 
[Vol. IX, No. 8, 
recognizable protochromosomes as in Thalictrum, Agave, and 
various other plants. 
Following this stage the complicated spirem is formed, which 
gradually thickens until its continuity can be traced with 
comparative ease, although it is very irregularly looped and 
twisted (fig. 9). At this stage the so-called synizesis probably 
occurs. This varies from slight contraction to a dense massing 
in the center or side of the nuclear cavity. The nucleolus may 
or may not appear free from the mass (fig. 8). Sometimes 
series of sections, apparently of the proper stage, do not show 
synizesis, while in others contractions are present even in well 
developed spirems. 
The spirem continues to thicken and the irregular twisting 
and winding becomes less complicated, with a strong tendency 
to form loops, the crossing threads producing a dense mass in the 
center (figs. 10, 11). This arrangement of the loops with 
crossing in the center has been noted in other members of the 
lily family. 
No trace could be found of double granules or a split in the 
spirem. This, however, may have been due to the staining. 
The linin and chromatin granules appeared quite distinct in the 
earlier stages (figs. 5a, 9a) but with the twisting and winding 
prior to the formation of loops, they stain much darker and more 
uniformly until differentiation finally disappears. The twisting 
of the spirem now becomes gradually simplified until there are 
approximately eight loosely rounded loops, the eight incipient 
chromosomes, corresponding to the reduction number of chromo¬ 
somes (figs. 12,13 ). These loops thicken and condense until 
there are clearly eight loops radiating from the center, with the 
looped ends pointing outward toward the nuclear wall (figs. 14, 
15). The eight chromatin loops were distinctly seen and counted 
a large number of times. 
The arrangement of the spirem into loops, corresponding in 
number to the reduced number of chromosomes and their 
subsequent separation and massing to form the chromosomes 
was mentioned by Schaffner in his paper on Lilium philadel- 
phicum. He found that the “twisted chromatin band arranges 
itself so as to form twelve loops, the heads of the loops being 
close to the nuclear membrane.’’ This arrangement was also 
found by Brown in his study of the embryo-sac of Peperomia. 
In this case he finds that after the looping becomes more pro¬ 
nounced, the spirem segments, each loop giving rise to a chromo¬ 
some. He draws the conclusion that chromosomes are, therefore, 
formed by the coming together, side by -side, of parts of the 
spirem that before were arranged end to end. Gates notes a 
somewhat similar condition in Oenothera rubrinervis, in which 
