122 Life and Death, Heredity and Evolution 



and 34). In these cases too the "male" completely unites 

 with the female, the two merging into one (Figure 34), just 

 as happens with the two germ cells of higher organisms; 

 they do not separate and continue their individual lives, as 

 the two mates do in Paramecium. Each of the mates in 





Figure 35. Diagrams of the micronuclear processes in conjugation, 

 in Paramecium (P) and Vorticella (V), up to the formation of the 

 new micronucleus by the union of the migratory and stationary half 

 nuclei. In each case the original micronuclei of the two mates are 

 shown below, and successive stages and divisions are shown in passing 

 upward. The micronuclei that dissolve and disappear are shown as 

 clear circles. In Vorticella (V) the divisions in the small free indi- 

 vidual (microgamete) are shown at the right; those of the large stalked 

 individual (macrogamete) at the left. Based on diagrams by Maupas, 



