PLATE 1 



EXPLANATION OF FIGURES 



All drawings were made under oil immersions with the aid of a camera lucida, 

 by the laboratory artist, Miss Krause. 



1. Monaster egg showing the first signs of the bending of the rays. 



2. A monaster egg showing that there are two c-enters involved in the twist- 

 ing process. 



3. A later stage of the same 



4. An egg to show the two areas of movement and the faint spindle in the 

 centrosphere. 



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