STRUCTURE AND FUNCTION 47 



7. What is the food of the paramecia ? How do they 

 fiad it ? Find a specimen at rest and watch the oral 

 groove. Suggest a method by which food may be col- 

 lected into it. If possible, note the process of swallowing, 

 and the resulting food ball. 



Note. — If powdered carmine be placed in the water with some para- 

 mecia, it can be seen in the food balls a half hour or so later. 



8. Where are the food balls located.'' Watch them 

 in an individual until you notice their motion. Where 

 are the larger food balls } the smaller ones } Assuming 

 them to have been of approximately equal sizes when 

 they were taken in, how can you account for differences 

 now ? 



9. Where are the contracting vacuoles? How many 

 are there .'' How often does one contract.' 



What is their function ? 



10. As you have been studying paramecia, to what 

 external influences (as contact, heat, light, etc.) have you 

 seen them respond .' How do they show it when they do 

 respond 1 Is such a response an advantage to them or 

 not .' What would be the result if they were not able to 

 detect changes in their surroundings } 



11. Where does respiration occur in paramecia? 

 Where do they obtain their supply of oxygen ? 



12. Among the paramecia you are studying you 

 usually find at least one in the process of fission. Watch 

 it until the halves separate, if you can. Compare the 

 halves. Do they rank as parent and offspring? If so, 

 which is which ? If not, which are they, parent or off- 

 spring ? 



13. If you happen to find a pair conjugating, notice the 

 process, as far as you can, in the living animals. 



