REPRODUCTION 



133 



similar in structure and behavior to typical metazoan chromo- 

 somes. In many other cases, the so-called chromosomes or 

 "pseudochromosomes" are slightly enlarged chromatin granules 

 which differ from the ordinary chromatin granules in their time 

 of appearance and movement only. In these cases it is of course 



Fig. 61. Stages in mitosis in Zelleriella intermedia, X1840 (Chen), 

 a, early prophase; b, metaphase; c, anaphase; d, telophase. 



not possible at present to determine how and when their division 

 occurs before separating to the respective division pole. In the 

 following table are listed the number of the "chromosomes" 

 which have been reported by various investigators in the Proto- 

 zoa that are mentioned in the present work : 



Protozoa 



Number of 

 chromosomes 



Observers 



