INITIATION OF DEVELOPMENT IN CILETOPTEkl >. 



45 



sent the proportion of segmented and unsegmentecl swimmers. 

 As is evident C represents 76 per cent, swimmers, of which 59 

 per cent., represented by B, were segmented, and 17 per cent., 

 represented by B', were unsegmented. The falling off in per- 

 centage of segmented swimmers with increasing time in potassium 

 chloride is much faster than the decrease in percentage of un- 



FIG. A. The effect of fertilizing eggs previously treated with potassium 

 chloride. Data taken from Table VII. The abscissae represent minutes, the ordi- 

 nates the percentage of eggs developing to swimming larvae. 



segmented. Compare with these curves those showing the effect 

 of a brief exposure to potassium chloride followed by fertilization 

 after varying intervals in sea-water. CE represents the decrease 

 in total number of swimmers. It is much less rapid than when 

 the eggs were subjected to potassium chloride during all of the 



