Experimental Studies on Germinal Localization. 9 



perhaps to a lighter tint In the deutoplasm In this region. In the 

 following account, accordingly, it will be necessary always to 

 distinguish clearly between the upper white area, or polar area, 

 and the upper protoplasmic disc or area. 



% 



10 



II 



12 13 



Fig. II. 



Vertical Sections of the Normal Egg. 



Fig. 13 directly from section (picro-acetic) ; outlines of Figs. 10-12 (sublimate- 

 acetic) from optical section of total preparations, details from actual sections. 

 The peripheral zone of deeply staining yolk shown in Fig. 13 occurs in all these 

 stages after picro-acetic fixation, but not after sublimate-acetic. 



10, Unfertilized egg, five minutes after release, showing both protoplasmic 

 areas; chromosome-like bodies in the nucleolus; 11, fertilized egg, 30 minutes alter 

 -fertilization , first polar spindle ; 12, fertilized egg, 60 minutes after fertilization , 

 initial stage in formation of polar lobe; 13, first cleavage, 68 minutes after fer- 

 tilization, just before the complete trefoil stage. 



