PARAMECIUM AND ITS RELATIVES 167 



in vorticella (Fig. 117). The liquid waste flows 

 from the protoplasm into these spaces, the pro- 

 toplasm then pushes together and forces the 

 waste out of the body. 



1. Describe the position, appearance, and action of the con- 



tractile vacuoles. 



2. State in your own words the use of the contractile vacuoles. 



3. Sketch the contractile vacuoles in your drawing of the para- 



mecium and label. 



F. Reproduction of paramecium. (Optional demonstration.) 



All the time while you are studying the parame- 

 cium be on the lookout for forms that are dividing. 

 If you do not see any, examine mounted slides that 

 show the paramecium dividing. Make a sketch 

 three inches long of a paramecium dividing, to show 

 how it reproduces. 



120. External structure and locomotion. In form a 



paramecium resembles somewhat the shape of a slipper, 

 hence it is sometimes called the " slipper-animal " (Fig. 118). 



food vacuoles ... 



contractile vacuole ^TJsTT contnucti/e vacuole 



cilia S&&m3OmWP nucleus 



gullet 

 FIG. 118. The paramecium. (Dahlgren.) 



Extending from all parts of its outer surface are many tiny 

 projections of protoplasm that look like colorless hairs; 

 these are known as cilia (singular cilium). In locomotion 



