134 WILLIAM M. GOLDSMITH. 



EXPLANATION OF PLATES. 

 PLATE I. 



FIG. i. Contraction stage with chromatic fibers bearing granular enlarge- 

 ments. The nucleolus is shown in this, and the three succeeding figures as a 

 homogeneous body. 



FIGS. 2 AND 3. Chromatin threads emerging from the contraction stage. 



FIGS. 4 AND 5. Further elongation of the chromatin threads. The enlarge- 

 ments have become smaller but more compact. 



FIGS. 4 TO 17. Successive stages in the formation of the nucleolus. 



FIGS. 6 AND 7. Individualizing the granules found in succeeding stages. Nu- 

 cleolus shows its achromatic nature. 



FIGS. 8 TO 13. Stages in the formation of the nuclear wall. Further differ- 

 entiation of the chromatin and achromatin. 



FIG. 14. Various shapes assumed by the chromatic and achromatic substance 

 of the nucleoli. 



FIGS. 15 AND 16. Nuclei showing further development of the nucleolus. 



