38 THE ANIMALS AND MAN 



Within the endosarc note a clear globular spot which con- 

 tracts and expands, or pulsates, more or less regularly. This 

 is the contractile vacuole. Note the small granules which 

 move about within the endosarc. These are food-particles 



FIG. 12. An Amoeba, showing forms assumed by a single individual in 

 four successive changes. (Greatly magnified; from life.) 



which have been taken in through the body-wall. Note how 

 pseudopodia flow about food-particles in the water and how 

 these are digested by the protoplasm. If an Amoeba comes 

 into contact with a particle of sand, note how it at once 

 retreats. Note within the endosarc an oval transparent body 



