ONE-CELLED ANIMALS— PHYLUM PROTOZOA 



89 



ment, so we may say that amoebae die frequently by accident, but never 

 from old age. An amoeba is thus potentially immortal — those that you 

 see under a microscope have lived for millions of years through count- 

 less fissions. 



Photo by Winchester 



Fig. 7.3. Amoeba at rest and active. When at rest the animal tends to assume a 

 spherical shape, but when moving it becomes considerably elongated. 



Amoebae in the active state which we have been discussing are said 

 to be in the vegetative condition, but, as such, they are very delicate 

 things and easily destroyed. Some species of amoebae are known to 



