PROTOZOA. 9 



2. Are they as thick as they are wide ? (Watch for 



them to roll over.) 



3. How do the two ends of the animal differ ? 



4. Can they change their shape so as to squeeze between 



obstacles ? 



C. Movements. 



1. Can the Paramoecium swim backwards ? (Which 



way is " backwards " ?) 



2. Can they swim sidewise ? 



3. Can they guide themselves and avoid collisions ? 

 Do they really swim as fast as they seem to swim 



under the microscope ? 



D. Feeding. 



1. The Food-balls. 



Food-balls are numerous little masses of food distrib- 

 uted throughout the body. 



a. Are they located in any particular part of the 

 body? 



b. Do they move about inside the animal ? (If they 

 are located exactly alike in all Paramoecia, you 

 may infer that they do not move about.) 



2. The Gullet. 



The gullet is a diagonal groove where the food is 

 taken in. It is on the side of the body and is 

 best seen as the animal rolls over. 



3. The Food Vacuoles. 



The food vacuoles are spaces surrounding some of 

 the food-balls. 



E. The Pulsating- Vacuoles. 



The pulsating vacuoles are spaces that disappear and 

 reappear in pulsations. 



