Artificial Parthenogenesis in Starfish Eggs 



397 



form so far as regards the stage at which the treatment was appHed; 

 all portions were treated exactly alike. The results indicate the 

 existence of a fairly well defined period of maximum susceptibility, 

 lasting for a certain period preceding the completion of the first 

 maturation division. Thereafter conditions become rapidly less 

 favorable. 



The results of three satisfactory series of experiments are 

 summarized in the following table: 



TABLE IV 



The temperature of exposure was 55° ^^d the time JO seconds in all cases. The condition of the eggs at 

 the time of exposure in each experiment is indicated by the italicized portion enclosed in parentheses. 

 The time itself (interval after removal of eggs from animal) is given in the second column 



