40 



THE ANIMALS AND MAN 



The Slipper Animalcule {Paramecium sp.). — Technical Note. — 

 ParamcBcia can be secured in most pond-water where leaves or other 

 vegetation are decaying. However, if specimens are not readily se- 

 cured place some hay or finely cut dry clover in a glass dish, cover with 

 water and leave in the sun for several days. In this mixture specimens 

 will develop by thousands. Place a drop of water containing Paramcscia 

 on a slide with cover-glass over it. Using a low power, note the many 

 small animals darting hither and thither in the field. Run a thin 

 mixture of cherry gum in water under the cover-glass. In this mixture 

 they can be kept more quiet and be better studied. 



How does Paramecium (fig. 13) 

 differ from Amceba in form and 

 movement? Has the body an 

 anterior and a posterior end? The 

 delicate, short, thread-like pro- 

 cesses, on the surface of the body, 

 which beat about very rapidly in 

 the water are called cilia, and they 

 are simply fine prolongations of the 

 body protoplasm. What is their 

 function? Note a fine cuticle cov- 

 ering the body. Note also many 

 minute oval sacs lying side by side 

 in the ectosarc. These are called 

 trichocysts and from each a fine 

 thread can be thrust out. 



Note on one side, beginning at 

 the anterior end, the buccal groove 

 leading into the interior through 

 the gullet. Observe also that by 

 the action of the cilia in the buc- 

 FiG. 13. Paramoecium sp.; "^^ 8^°°^^ food-particles are swept 

 note the body-wall, cilia, into the gullet. Rejected or waste 

 buccal groove, gullet, con- particles are ejected from the body 

 tractile vacuoles and nu- . n .,117, ., t,t , 



clei. (Greatly magnified; Of^f^S'On^lly- Where? Note about 



from life.) midway of the Paramosciuman ovoid 



