STUDIES OF NON-PARASITIC PROTOZOA 



Z0. 



FIG. 3. STAGES IN THE LIFE OF COLPODA CUCULLUS. (After von Rhumbler.) 



i to 4, Encystment and division within a cyst ; 5 and 6, formation of secondary 

 cysts ; 7 to n, formation of duration-cysts ; 12 and 13, Rhumbler's view of the 

 formation of sporocysts and spores ; 14, escape of spores ; and 5 to 20, forms 

 assumed in the production from these of perfect ciliates. 



