OTHER MODES OF NUCLEAR DIVISION 



207 



by the nuclei of higher organisms, they show in the division and distribu- 

 tion of their chromatic elements many of the characteristics of true 

 mitosis. In the evolution of the nucleus through such a series of stag 

 we have an illustration of "the conception of cell structure which im- 



* " V 



B 



/ 



%^«fc./' 



Fig. 73. — Nuclear division in Protozoa. 

 .4, one form of mitosis in Amoeba diplomitotica. (From Minchin, after Aro'ja,*. />. 

 Nuclear division in Coccidium schubergi. X 2250. {From Minchin, a v haudii 

 C, mitotic division of micronucleus of Paramecium (horizontal figure on Bmaller scale 



than others.) {From Minchin, after Hertwig.) 



plies differentiated regions of a colloidal system in which special processes 

 have become localized and tend to remain fixed" Harper L919). 



Protozoa. — Such an apparent derivation of mitosis from a simpler, 



more indefinite division of a less sharply delimited mass of special 



