MITOSIS OR INDIRECT NUCLEAR DIVISION 



61 



same characteristics possessed by the original cell. This equal 

 inheritance is made possible by the dividing of every chromatin 



1 2 3 '4- 



AxtccplaasG 



•Telopliase 



Mitosis of an animal cell, Ascaris egg. Follow the stages shown in the diagram with the 



description given in the text. 



granule into two parts, so that each cell will possess the same 

 number. In order to bring about equal splitting, several distinct 

 stages are gone through. This process takes place in all plant 

 and animal cells, from the protozoans and algae to the cells of the 

 largest trees and the most complex animal, man. 



In many animal cells, the first sign of mitotic activity is the 

 separation of the centrosome into two parts connected by delicate 

 fibers. Around each center, groups of fibers radiate, causing the 

 structures to look like stars. Hence, they are called asters and 

 the radiating rays are known as astral rays. 



The centrosomes move further apart around the nuclear mem- 

 brane and the spindle threads become longer. At the same time 

 the chromatin granules become arranged in the form of separate 

 threads or a continuous coiled thread, the spireme. 



