9 8 



PAULINE H. DEDERER. 



larity of form and division of all the chromosomes. The nuclear 

 membrane disappears at the metaphase. In telophase, the chro- 

 mosomes are crowded into a dense mass, in which it is difficult 

 to determine the outlines of individual ones (Fig. 6). 



After the daughter cells have formed, and the nuclear mem- 

 brane again encloses the chromosomes, the nucleus increases in 



Fig. 19, f-q. Various views of nucleoli during growth period, showing relation 

 of idiochromosome to plasmosome. 



Figs. 20, 21. Early ring stage — idiochromosome attached to plasmosome. 



Figs. 22-25. Four views of later stage — showing twelve rings and nucleolus. 



Figs. 26-29. Contraction of rings into chromosomes. 



size, and the chromosomes spread out into the cavity. Figs. 7, 

 8 show a transition from the characteristic round or oval chro- 

 mosomes of the spermatogonia into rods of varying length and 



