NUCLEAR DIVISION. 3 
together with the kinoplasmic radiations constitutes the cextrosphere. 
The planes of the longitudinal axes of the centrosomes may be parallel 
or form various angles with each other. In Fig. 1, B, the centrosome 
at the upper side of the nucleus is seen from the side, the lower from 
Fic. 1.—First mitosis in tetraspore mother-cell of Dictyota dichotoma. 
A, B, early prophase; the well-developed centrospheres are on diametrically opposite sides of nuclei. 
C, the kinoplasmic fibers have begun to enter the nucleus to form the spindle and the chromosomes are 
being differentiated. 
D, numerous spindle fibers have entered the nucleus, and the chromosomes are collected in the equa- 
torial region. 
the end. Viewed from the pole, the centrosome is always rod-shaped. 
The kinoplasmic fibers radiate in all directions into the cytoplasm 
where they pass over into the framework of the same. On the side 
next the nucleus they may run parallel with its wall for some dis- 
