f A 



D 



B 



x E 



H 



FIG. 10. Diagrams illustrating the process of indirect cell division 

 or karyokinesis. 



A, The resting cell : the nucleus shows a nuclear membrane (#./#), 

 chromatin (chr] arranged in loops united into a network (the latter 

 shown on the right side only), and two nucleoli (nu 1 ) : near the nucleus 

 is a directive sphere (s), containing a centrosome (c ) and surrounded by 

 radiating protoplasmic filaments. 



B, The chromatin has resolved itself into distinct loops or chromo- 

 somes (chr] which have divided longitudinally : the nuclear membrane 

 has begun to disappear : there are two directive spheres and between 

 them is seen the commencement of the nuclear spindle (sp). 



C, The nuclear membrane has disappeared : the chromosomes are 



