1 8 4 



C. M. CHILD. 



reduced polarities and hydranth-stem axes can be easily trans- 

 formed into stolons by inhibiting factors. In these planula? 

 stolons instead of hydranth-stem axes develop because in the 

 earlier stages of acclimation or recovery a considerable degree of 

 inhibition is still present. The apical region of the stolon axis is 



sufficiently active in relation to other levels to grow at their 

 expense, but for the development of a hydranth-stem axis a higher 

 metabolic rate is evidently necessary than for a stolon axis. 



Figure 16 represents a larva in which the second gradient at the 

 basal end did not. develop before inhibition occurred, or was 

 obliterated by the inhibition, while the original gradient was not 

 wholly obliterated. In Fig. 17 and probably in Fig. 18 both 

 gradients have persisted through the inhibiting action and both 

 develop independently as stolons. 



The further history of these stolon outgrowths depends on the 

 degree of acclimation or recovery. When a certain degree of 

 inhibition persists, e.g., very commonly in acclimation, in which 

 the material remains exposed to the agent, the stolon tips 



