NUCLEAR DIVISION. 



together with the kinoplasmic radiations constitutes the centrosphere. 

 The planes of the longitudinal axes of the centrosomes may be parallel 

 or form various angles with each other. In Fig. i, B, the centrosome 

 at the upper side of the nucleus is seen from the side, the lower from 



FIG. i. First mitosis in tetraspore mother-cell of Dictyota dickotoma. 

 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- 



