



t^^'^;^•lJ^•;.••<"* -^ 



^^^■-cUj 







4 











4 



/ 



7 



fefrS 



6 



Fig. 72. — (1) Protomitosis, a very early stage in which the plate is 

 beginning as a slight excrescence of the edge of the nucleolus. 

 (2) The split of the chromatin plate into two thin plates, which 

 show slight enlargements at their ends. The spindle is visible 

 and the nuclear membrane has become characteristically 

 shaped. (3) " Double anchor stage." The plates have now 

 become drawn apart and the nucleolus has nearly split. The 

 spindle has become more diffuse and the plates are slightly 

 curved. (4) Plate has become divided, spindle fibres are less 

 visible and the nucleolus has become drawn out and dumb-bell 

 shaped. (.5) Akaryote stage. Chromatin extruded into cyto- 

 plasm and nucleolus has vanished. (6) Spore formation. Heter- 

 typic metaphase. The nuclei in the first division of spore 

 formation, showing clearly marked spindle and chromatin 

 differentiated into chromosomes. (After Cook, Anns. Bot.) 



