Asexual cycle 



xN 

 Binary fission 



Figure 139. Diagram of the life cycle of Paramecium caudatum exhibiting an alterna- 

 tion of asexual reproduction, or binary fission of the two-cell somatella, and sexual re- 

 production with mutual fertilization of conjugants. The first and second divisions of the 

 eight-cell somatella, or exconjugant, are for convenience included in the diagram of the 

 sexual cycle, since they are preparatory to the asexual phase. 



