INITIATION OF DEVELOPMENT IN NEREIS. 



distinguished from the normal either while living or in sectioned 

 material. The higher exposures give more abnormal swimming 

 forms. 



For comparisons I have selected the following tables from my 

 notes to show the percentages of cleavage and of "swimmers" 

 obtained with eggs from worms cut in warm sea-water and with 

 dry eggs. It is apparent at once that while there is no appreciable 

 difference in the percentages of swimming forms after warming 

 either the "cut out" or the dry eggs, there is a marked difference 

 in the percentages of cleaving eggs. This is the case in all the 

 experiments. 



July 12. Two females cut up at 9:55 A.M. in separate flasks 

 of sea-water at 35° C. gave the following results: 



Female No. i. 



Female No. 2. 



July 20. Dry eggs in 30 cc. of warm water at 35° C. gave the 

 following results: 



Swimming Forms. 



1% 



15% 



10% 



7% 



