1906) OLIVE—NUCLEAR AND CELL DIVISION OF EMPUSA 235 
just what events are transpiring in such a nucleus as that figured in 
fig. 49. But from the later condition shown in fig. 50 to near the 
close of the telophases, a great abundance of successive stages affords 
an easy interpretation of most of the events of nuclear division. 
It is highly probable that fig. 49 illustrates the early divergence of the 
two centers of division present in the middle of the nucleus, although 
no clew is given in the preparation toward the solution of the puzzling 
question as to the origin of these centers. In this figure a clearly defined 
strand connects two darker regions, where, presumably, nuclear 
material is being aggregated. A clear space, probably a cavity filled 
with nuclear sap, separates the two centers and encloses the connect- 
ing filament. Between jig. 49 and fig. 50 is plainly a large gap. In 
the latter, the two centers are large, conspicuous, intranuclear bodies, 
from each of which radiate in all directions granular fibers. These 
fibers appear to connect in some instances midway between the 
centers with those from the opposite system of fibers; others appear to 
cross over the equatorial region and to be independent of the other 
system. 
Figs. 51-61 record successively the phenomena attending further 
divergence of the centers and the massing about them of the material 
of the divided daughter-halves of the nucleus. It may be noted in 
these preparations that one of the first evidences of the activity in a 
nucleus leading to division is the change from a globular to an oval 
form. During the progress of the internal mitotic changes, the nucleus 
finally becomes elliptical or oblong and greatly elongated. It may 
readily be noted also that the long axis of the dividing nucleus corres- 
ponds generally with the long axis of the filament. In some instances, 
however, the nucleus lies obliquely across the hypha, presumably 
carried about by cyclosis. 
An increasing abundance of nuclear sap is shown in figs. 49-58. 
In jig. 49, the clear portion is seen to occupy the space between the 
two diverging centers. From the repeated occurrence of similar nuclei 
in which the middle appears to be occupied by a clear space, it seems 
probable that one of the earliest manifestations of mitotic activity in 
the case of Empusa is the accumulation of karyolymph in the imme- 
‘diate vicinity of the intranuclear centrosomes. In fig. 50 the nuclear 
Sap apparently lies both between the two centers and in the interstices 
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