Nucleoli during the Oogenesis of the Dragon-fly. 223 



in only small quantities. This is evidently due to the fact that all 

 the chromatin in the resting- nucleus passes into the nucleolus, causing- 

 it to become much larger and to stain deeply. And, furthermore, 

 the diminution or disappearance of the nucleolus at the time of 

 mitosis is explained on the ground that the chromatin, which was 

 contained in the nucleolus in the resting- condition of the cell, passes 

 out and forms the chromosomes. 



Zoological Laboratory, University of Missouri, 

 Juli 1. 1905. 



