122 A CYTOLOGICAL INVESTIGATION OF SOME SPECIES 
sible to come to a definite opinion. As long as the PMC are still quies- 
cent or are just proceeding to synapsis, one sees them, in longitudinal 
sections of the mikrosporangia, arranged in two long rows, fitting clo- 
sely into one another and surrounded by tapetumcells (fig. 9) ; on cros- 
sections of the anthers one sees 3—5 PMC at the same time, surrounded 
by a ring of tapetum-cells. It is therefore evident that the tapetum sur- 
rounds the PMC in such a way that each of these cells touches the tape- 
tum with one of its sides. This remains so during the highest contrac- 
tion-stage of the synapsis-skein, during which this is adpressed to the 
nucleolus or even surrounds it. 
Subsequent to this stage, a central lacuna arises between the PMC, 
which, on crosssection, are arranged in a ring, surrounded by a layer of 
tapetumcells. This arrangement is pictured in fig. 11, where the PMC 
however are already in a later division-stage. 
Very delicate chromatme-threads now begin to emerge from the Sy- 

Fol: 
Fig. 11. Crosssesction of a mikrosporangium of Saccharum spontaneum with 
PMC in metaphase x 900. 
napsis-skein. The skein itself now gets looser and looser and changes 
