4 BOTANICAL GAZETTE [JULY 
the reticulum has completely disappeared, the thread shows a 
longitudinal splitting which is evident between the chromatin 
masses. In the early stages of the longitudinal splitting of the 
thread I have not seen the small chromatin masses divided. 
Each chromatin mass often. appears to be made up of two 
smaller ones lying side by side, which have fused at the points of 
contact. Even in larger chromatin masses, and among the chro- 
mosomes in Arisaema, there is a strong tendency for those lying 
in contact to fuse more or less, so that the individuals of a single 
mass or of the chromosomes are often more or less obscured. 
While the chromatin masses on the spirem are more or less 
fused, they are small and emarginate at opposite ends, and at a 
point coincident with the axis of the band. By this character 
one can distinguish the double nature, or paired condition of the 
masses. It suggests a division of the original masses, or the 
deposition of the chromatin in paired masses along the thread, 
which fuse more or less at the point of contact. These chro- 
matin masses often stain unevenly, two portions separated by 
the axis of the thread or band taking on a deeper stain. The 
darker points lie in pairs along the thread, each separated by a 
paler chromatin area which runs for a short distance on either 
side along the division of the thread. At the point between the 
deeper staining masses the paler zones fuse. 
As the spirem shortens, these paired chromatin masses are 
brought nearer together. Fusion among them takes place, so 
that the masses increase in length and breadth as the spirem 
broadens. The longitudinal division of the spirem is marked 
here and there, sometimes at quite regular intervals, by rounded, 
elliptical, or oblong openings in the chromatin, while in other 
places, for considerable distances, no line of division can be 
ascertained, though often the difference in the intensity of the 
stain marks the separation of the masses into pairs, while the 
paler surrounding zones are fused. As the band shortens, the 
contour becomes more irregular, showing crenations and irreg- 
ularities, to which are often attached delicate strands, perhaps 
portions of the linin reticulum. 
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