14 THE BIOLOGY OF THE CELL 



9. The oesopliagus or gullet. — What is its shape? 

 How far does it extend? How do you distin- 

 guish its lower end ? Look for cilia lining the 

 gullet. 



10. The anus (seen during the ejection of waste 



matter). — Where is it ? Is its position perma- 

 nent? 



11. The food-vacuoles. — In what part of the body 



are they seen ? What is their shape ? Of what 

 are they composed ? Are all of the same size ? 

 Compare several animals to find the average 

 number contained. 

 Make drawings showing the relative position, shape, 

 and size of all the parts studied. 



PHYSIOLOGY 



a. Movements. 



1. Of the entwe hody. — What different motions has 



the body? What are the organs of motion? 

 Are all the movements of the body produced 

 by these organs? If not, how are the excep- 

 tional movements produced ? 



2. Of the cilia. — What sort of motion have the 



cilia? Is it the same for all? What causes 

 their motion ? Are all of the cilia used for the 

 same purpose ? Considering use alone, how 

 many kinds of cilia are there ? 



3. Of the trichocysts. — Run a drop of one per cent. 



acetic acid or of dilute iodine under the cover- 

 glass. What happens to the trichocysts ? From 

 their behavior when the animal is thus irritat- 

 ed, what do you judge their function to be ? 



4. Of the contractile vacuoles. — What sort of motion 



have they? Does each go through the same 



