PARAMECIUM AND ITS BELATIVES 



171 



C Excretion of liquid waste. 



Look for a clear, roundish spot in the amoeba which at 

 intervals disappears. This is the contractile vacuole. 

 The liquid waste flows into this space and then the 

 protoplasm pushes together and forces the waste out of 

 the body. 



1. Describe in your own words the. appearance and action of 



the contractile vacuole. 



2. Sketch the contractile vacuole in your drawing of the amoeba 

 ' and label. 



126. A comparison of Paramecium and amceba. — Both amoeba 

 and Paramecium are animals so small that they can barely be seen 

 with the naked eye. 

 Both live in water, 

 both are one-ceUed 

 animals, and both 

 carry on the same 

 functions, but in a 

 somewhat different 

 manner. While the 

 Paramecium main- 

 tains a more or less 

 fixed form, the 

 amceba is capable 

 of assuming almost 

 anyshape(Fig.l20). 

 This it does by caus- 

 ing portions of its 

 substance to flow out in niany directions. These projections 

 are known as psevdopods which mean false feet. By pushing 

 out these pseudopods in front and pulling up its protoplasm 

 from behind, the amoeba slowly flows from one part of the slide 

 to another. 



Unlike the Paramecium an amceba has no definite part of the 

 body through which it takes in food. When the animal is feeding. 



pseudopod 

 Fig. 120. — The amoeba. 



