178 



THE PROTOZOA 



* ehr. 



N 



FIG. 80. Combined diagram to show the different methods of reproduction and 



syngamy in the life-cycle of Arcetta. 



A D, The four stages in the ontogeny : A, the amoebula ; B, the Nudearia-iorm ; 

 C, the Pseudochtamys-iorm ; D, the adult Arcella. 



D G, Stages in the vegetative reproduction by fission : E, the protoplasm 

 beginning to stream out of the shell of the parent-individual ; F, division of the 

 nuclei of the parent, and formation of the shell of the daughter ; G, migration 

 of the daughter-nuclei into the daughter-individual and completion of the division. 



[Continued at foot of p. 179. 



