EXPLANATION OF FIGURES. 



AU fin;urcs were drawn at ihc level of the table leith the aid of an Abbe caméra 



lucida imder a Zeiss apochromaiic objective i m. m. N. A. 1.40, icith a Watson ho- 



loscopic condensor and compensating ocular 18, magnification j ^00. They hâve been 

 rediiced to one-half the original size. 



FIG. 1. Resting nucleus from old cell. Chromosomes visible as bands in the 

 reticulum. Several caryosomes présent. Strong Flemming (Page 3og). 



FIG. 2. Prophase. Chromosomes separate from each other and condensing. 

 Str. Flemming (Page 3 11). 



FIG. 3. Prophase. Détails of condensing chromosomes. Str. Flemming 

 (Page 3 12). 



FIG. 4. Prophase. Chromosomes condensing. Spiral aspect in one above 

 larger nucleolus. Str. Flemming (Page 3x2). 



FIG. 5. Prophase. Condensed chromosomes straightening out as simple zigzag 

 threads. Spiral aspect in several. Str. Flemming (Page 3 12). 



FIG. 6. Prophase. Stage in the formation of zigzag threads. Split starting in 

 one at center. Str. Flemming (Page 3i3). 



FIG. 7. Prophase. Simple zigzag threads. Benda (Page 3i3). 



FIG. 8. The same. 



FIG. 9. Tlie same. Split starting in thread near centre and at bottom. 



FIG. 10. Prophase. Two levels of the same section. Split beginning as vacuoles 

 in very thin threads. Benda (Page 314). 



FIG. 11. Prophase. Splitting of tliin threads; vacuoles, open spaces, and com- 

 plète splits. Benda (Page 3i5). 



FIG. 12. Prophase. Split complète in rather thin threads. Benda (Page 3i5). 



FIG. 13. Prophase. Ail stages of splitting in thicker threads. Benda (Page 3i5). 



