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 pars/- 



meciimi and label. 



F. Beproditction 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 sUdes 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 VKuoles . . , 



amlradik ncoole , ,.V^v eontracti/e vscuole 



oilla-^S^m^m!^^^-- '■ 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 



