PLATE 5 



EXPLANATION OF FIGURES 



8 Portion of first cleavage spindle in uterine egg No. 52 (3) (X 790). 



9 2-celled stage showing elimination of yolk; egg No. 50 (6). The cell to the 

 left has separated from the eliminated material and rounded off. The cell to 

 the right has not yet separated, but the line of separation is indicated by the 

 dark granular zone (CM) (X 405). 



10 2-celled egg, No. 46 (3). The yolk has been eliminated; the cell to the 

 left has not yet rounded off. The yolk granules are again assuming a submarginal 

 arrangement in the blastomeres (X 405). 



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