



II 



FIG. 33. Diagrams illustrating mitotic cell division : A, resting cell ; 

 B, prophase showing spireme and nucleolus within the nucleus and the 

 formation of spindle and asters (a) ; C, later prophase showing dis- 

 integration of nuclear membrane and breaking up of spireme into 

 chromosomes ; D, end of prophases, showing complete spindle and asters 

 with chromosomes in the equatorial plate (ep) ; E, metaphase each 

 chromosome splits in two; F, anaphase the chromosomes move 

 toward the asters ; if, interzonal fibers ; G, telopljase showing recon- 

 struction of nuclei ; H, later telophase, showing division of the cell into 

 two. (From Hegner, after Wilson.) 



ance, is called a spindle. The nuclear membrane 

 having broken down in the meantime, these rays 

 penetrate the nuclear area and appear to fasten 



