1911] LUTMAN—CLOSTERIUM 419 
to attach the broad ends of the spindle, when it is fully formed and 
functioning, as a sort of anchorage forit. Asa result of my observa- 
tions I am of the opinion that the spindle itself is largely of cyto- 
plasmic origin. The actual ingrowth of fibers which take hold of 
the chromosomes and later pull them apart was not observed. 
Strands of a lighter staining substance, probably what has been 
considered linin, connect the chromosomes to each other and to 
the nuclear wall (fig. 24). All that would seem to be necessary 
to form the attachment to the chromosomes would be a strength- 
ening of those fibers extending to the nuclear wall. If this be true, 
there should be no fibers growing into the nucleus from the outside 
to take hold of the chromosomes, but only a thickening of those 
already present. 
Metaphase 
The spindle (fig. 25) is broad and as wide at the poles as at its 
middle. No bodies in the nature of centrosomes occur at the poles, 
which are broad and platelike structures (fig. 25) very similar to 
those described for S pirogyra. There are occasionally spherical 
bodies found in this region (figs. 28, 29), which may be meta- 
plasmic particles, or perhaps the remains of the old nucleolus, 
although this point was not worked out. The spindle is attached 
by fibers extending from it, especially at the two sides. It is not 
Possible to determine just where the spindle ends (figs. 25, 26). 
In the equatorial plate are arranged the rodlike chromosomes 
(fig. 25). Attached to each chromosome are fibers from either 
Pole which pull it into two parts by a longitudinal split (fig. 26). 
These fibers are in the figure attached toward the middle of the 
chromosome, although many were also observed in which the attach- 
Ment was toward their ends. 
Telophase 
After the chromosomes have been pulled back to the poles 
(figs. 27, 28) in the usual manner, they lie there in the form of a 
Plate which is more or less crescent-shaped in cross-section (figs. 
= 39). The broad: central spindle remains connecting the two 
Poles, but gradually disappears, taking no part in the formation 
of the new cell wall (fig. 30). The chromosomes at either pole 
