Branch Protozoa 



THE PARAMECIUM, OR SLIPPER ANIMALCULE 



For a successful study of the Paramecium we must ob- 

 serve the animal alive in water. Find it with the low 

 power : it will appear as a slipper-shaped ci-eature swim- 

 ming rapidly about. To prevent its escape from the field 

 of vision so that it may be studied with the high power, it 

 is often desirable to put a few fibres of cotton under the 

 cover glass. The same end may also be accomplished by 

 drawing off much of the water on the slide by means of 

 blotting-paper, but one should remember that the pressure 

 of the cover glass may thus flatten the Paramecium. 



I. — Determine whether the animal moves in a definite 



direction without changing its outline. Does it move 

 both backward and forward.' By focussing carefully, 

 with light from the small opening of the diaphragm, 

 determine the cause of movement. The short delicate 

 hair-like processes around the margin of the body are 

 called cilia. Do they vibrate when the animal moves ? 

 Can you see any difference in the motion of the cilia 

 when the animal is going forward and backward .■' 



II. — Study the animal as it swims: does it revolve on 

 its longitudinal axis ? Can you see a spiral groove on 

 one side of the body ? It is called the buccal-groove. 

 How long is this groove as compared with the body ? 



III. — Watch the Paramecium as it moves in and out 

 among the particles on the slide. How does its flexi- 

 bility compare with that of the Amoeba ? See whether 

 the liquid endosarc flows back and forth within the body 

 in response to the pressure of the ectosarc. 



IV. — Determine whether locomotion is made with either 

 end foremost. Is the blunter or the more pointed end 



