Sept., 1921.] YASUI:— ON THE BEHAVIOR OF CHROMOSOMES 167 



Fig. 15. Interkinesis, showing a chromosome left in the cytoplasm. 



Fig. 16. Second division of meiosis. 



Fig. 17. The same, but axes of two division spindles are perpendicular to each 



other. 

 Fig. 18. A tetrad, some chromosomes are left in cytoplasm. 

 Fig. 19. The partition wall formation between four pollen nuclei, one is not shown 



in this figure. 

 Fig. 20. Two chromosome groups connected by the chromosome bridge. 

 Fig. 21. Chromosomes in the beginning of the second division of the fused nucleus. 

 Fig. 22. Metophase of the division of the fused nucleus. 

 Fig. 23. Later stage of the latter, the partition wall being formed. 

 Fig. 24. The fused two nuclei at the telophase of second division. 

 Fig 25. A pollen mother cell containing one large, two normal sized, and one dwarf 



nuclei. 



