CELLS. 



49 



(g) Each daughter nucleus then passes into the normal resting 

 phase. The spindle disappears, and the centrosomes may 

 also vanish. 



The essential fact is the exact partition of the nuclear material 

 between the two daughter cells 



Fleniming gives the following summary of karyokinesis : 



MOTHER NUCLEUS 

 (progressive changes). 



a Resting stage. 



b Coil. 



c Astroid. 



DAUGHTER NUCLEUS 

 (regressive changes). 

 Resting stage, g 

 Coil. / 



Diastroid. e 



-> d Division of Astroid and its loops 

 (Prophases) (Metakinesis) 



(Anaphases). 



Fid. 25. Karyokjnesis. After Flemming. 



1. Coil stage of nucleus ; c.c., central corpuscle. 



2. Division of chromatin elements into U-shaped loops, and longitudinal 



splitting of these (astroid stage). 



3. 4. Recession of chromatin elements from the equator of the cell 



(diastroid). 



5. Nuclear spindle, with chromatin elements at each pole, and 



achromatin threads between. 



6. Division of the cell completed. 



Besides the ordinary indirect division just/ described, the 

 net result of which is that each of the two daughter cells 

 gets an equal number of chromosomes, a precise half of 

 each of the chromosomes in the original cell, there is 

 another kind of cell division (meiotic or reducing division) 

 which occurs only in the maturation of the ovum and 



