D- H. WENRICH. 



PLATE III. 



FIGS. 17-26. From prepared slides. X 1,100. Figs. 1721, transitions be- 

 tween varieties; Fig. 17, chlorophyll breaking up, nucleus expanding; Fig. 18, 

 chromatic swellings nearly gone from flagella, chlorophyll partly gone; Fig. 19. 

 some chlorophyll present, striae changing position ; Fig. 20, one extra flagellar 

 root, chlorophyll mostly gone and nucleus expanded; Fig. 21, pellucid char- 

 acters except for presence of chlorophyll; Figs. 22-25, stages in mitosis of type 

 variety accompanied by gradual loss of swellings on roots of flagella ; Fig. 26. 

 probably a daughter cell. 



