166 



ANIMAL BIOLOGY 



the gullet strike the swifter and with the more 

 force to bring food particles into the gullet ? 



D. Locomotion. (Optional demonstration.) 



Examine with a high power a paramecium that is 

 comparatively quiet. Focus carefully and look for 

 the cilia. 



1. Describe the cilia and their movements. 



2. When the paramecium strikes against the water in one direc- 



tion, in what direction would its body tend to 

 move? 



Must the paramecium 

 strike harder 

 toward the 

 blunt end or 



3. 



toward 

 pointed 

 when 

 swims 



the 



end 



'it 



with 



E. 



the blunt end 

 foremost ? 



Excretion of liquid waste. 



(Optional demonstration.) 



Look at a 



mouth 



contractile 

 vacuole 



gullet with 

 food ball 



large nucleus 

 small nucleus 



'food balls 



paramecium 



or vorticella 



with both the 



low and high 



power and 



search for 



clear circular 



spots. Watch 



to see if any 



of these contract. ' If they do, they are contractile 



vacuoles. There are two in paramecium and one 



B, vorticella 

 FIG. 117. Protozoa with cilia. 



