PLATE S 



EXPLANATION OF FIGURES 



69 Two-cell stage, showing 'diminution division' in the soma cell (so.) (X 

 1000) 



70 Two-cell stage, showing anaphase of the 'diminution spindle' in the soma 

 cell (so.). (X 1000) 



71 Two-cell stage, showing first soma cell (so.) dividing by ordinary mitosis. 

 (X 1000) 



72 Three-cell stage, showing late anaphase of the 'diminution division' in the 

 first soma cell (so.). (X 1000) 



73 Formation of the 'T'-embryo. Soma cell (so.) dividingby a 'diminution' 

 process, and the stem cell (strp.) by ordinary mitosis. (X 1000) 



74 'T'-embryo of four cells, in which the first two divisions have both been by 

 ordinary mitosis. Stem cell (slrp.) at the end of the upright of the'T'. (X 1000) 



600 



