LIFE HISTORY OF PRORODON GRISEUS. 



13. The pronuclei elongate slightly during their process of 

 fusion. 



14. In cellular reorganization within the permanent cyst, the 

 cilia and pharynx disappear. The micronucleus and contractile 

 vacuole (?) persist. The macronucleus passes through a distinct 

 metamorphosis. 



15. Reorganization during permanent encystment in P. griseus 

 is of the cytoplasmic or passive type. Nuclear reorganization or 

 formation of a new micronucleus and a new macronucleus from 

 the old micronucleus was not found to occur. 



COLUMBIA, Mo., 

 JULY 6, 1925. 



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