38 C. M. CHILD. 



followed without the slightest difficulty. The change at any 

 given level is almost instantaneous: the structure seems simply 

 to dissolve, the cytoplasm swells and the halo of blue pigment 

 appears in the water while the disintegrated part loses most of 

 its color. The peristomal cilia continue to beat until the instant 



3 



4 



when the boundary of the spreading areas of disintegration 

 reaches them when they suddenly stop in most cases, although 

 occasionally they may beat for a few seconds more, but in 

 all cases they disintegrate very soon. As soon as the 



