AND SPECIES HYBRIDS WITHIN THE GENUS SACCHARUM 121 
CHAP ELR AT 
THE INVESTIGATION OF THE CHROMOSOME-NUMBER 
$ 1. The prophase of the division of the pollen-mothercells 
We have seen in the former chapter already, that a chromosome- 
count in somatic cells is rather unsatisfactory, while the reduction- 
division of the pollenmothercells is very suitable for our purpose. Con- 
sequently we shall give an account of the karyokinesis. in the last men- 
tioned cells only. We shall refer very shortly only to the youngest sta- 
ges of karyokinesis, as a detailed description of these is outside of the 
purpose ofthe investigation. Moreover the karyokinetic-figures are in 
this stage so complicated and of so minute a structure that it is impos- 

Fig. 9. Fig. 10. 
Fig. 9. Part of a longitudinal section of a mikrosporangium of Saccharum offi- 
cinarum var. Green German Guinea, the PMC. proceeding to synapsis x 900. 
Fig. 10. Crosssection of a mikrosporangium of the same kind of cane with the 
PMC. in synapsis. 
