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? 



3. Must the paramecium 

 strike harder 

 toward the 

 blunt end or 

 toward the 

 pointed end 

 when it 

 swims with 

 the blunt end 

 foremost? 



cilia 



A, stylonychia 

 cilia 



mouth 



arge nucleus 

 small nucleus 



food balls 



- - stalk 



E. Excretion of liquid waste. 

 (Optional demonstration.) 

 Look at a 

 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 



FIG. 117. 



B, vorticella 

 Protozoa with cilia, 



