224 



N. M. STEVENS. 



a b 



34 



30 



36 



33 



35 



FIG. 27. Double spireme stage. 

 FIGS. 28-29. Prophase stages. 



FIG. 300-1. Various prophase (a-g) and metaphase (h, i) forms of the bivalent 

 chromosomes. 



FIGS. 31-32. Chromosomes in metaphase of the first maturation mitosis. 



