51 



with the result that two groups of four are formed, one 

 group being new meganuclei and the other being new 

 micronuclei. But three of the micronuclei disappear ; 

 only one remains, and it divides into two. 



The Paramecium now divides into two daughter- Para- 

 meciums, and each has two meganuglei and one micro- 

 nucleus which divides into two. The two daughter. Para- 

 meciums each divide, and the final result is therefore four 

 Parameciums, each with a meganucleus and a micronucleus 

 derived from the original zygote or combination nucleus. 



This is the process in P. caudatum. In P. aurelia, which 

 has two micronuclei, it is a little more complicated. 



FIG. 10. Vorticella. (A colony magnified-) 



C.V. Contractile Vaouole. 

 _Note~the detached free -swimming individuals. 



