PLATE 4 



EXPLANATION OF FIGURES 



N. shooterii, first division. X 2000 



51 Polar view, first metai)hase, showing 14 cluomosomes, one small central 

 one and one just within the peripheral ring. 



52 Same, second small one further in.side the ring. 



53 Side view of metaphase, two small ones at the same focus. 



54 A, B, C Serial sections of entire spindle in side view, showing all the chro- 

 mosomes. In B, the second small chromosome lies at a lower level than the 

 large ones. 



55 Oblique section, showing the second small chromosome within the periph- 

 eral ring. 



56 Side view of metaphase, showing components of central chromosome on 

 different fibers, and the second small chromosome nearer the center than the 

 large ones. ,. 



57 A. B Serial sections of entire spindle in side view of late anaphase, showing 

 all the chromosomes in each daughter group. In B, the two small chromosomes 

 are shown in proximit}-. 



58 to 60 Side views of late anaphase groups, showing proximity of the two 

 small chromosomes. 



61 Polar view of late anaphase, showing the two small chromosomes in the 

 center. 



154 



