PLATE 



EXPLANATION OF FIGURES 



13 Parthenogenetic egg with polar spindle. 



14 and 15 Same as the preceding after maturation. 



16 Two-cell stage, dorsal view. 



17 Two-cell stage, upper view, with asters for second cleavage. 



18 Two-cell stage, ventral view, with CD dividing. 



19 Four-cell stage, upper pole. 



20 Four-cell stage, ventral pole. 



21 Four-cell stage, dorsal view, showing the cells contracted. 



22 and 23 Four-cell stage from left and dorsal sides. 



24 Little later than figure 23, with d^ cleavage-spindle forming; note the 

 anterior extension of D in the process. 



25 Five-cell stage, left side, to show lengthening of cells. 



26 to 28 Five-cell stage, left and dorsal sides; note the abnormal flattening 

 of cell di in figure 28. 



29 Five-cell stage, dorsal pole; shows the position and the rounded condition 

 of the cells in preparation for the next cleavage. 



30 Six-cell stage, dorsal view; note the position taken by d' and c^ in the 

 early third clevage. 



31 Seven-cell stage, dorsal view. 



