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ONE-CELLED ANIMALS— PHYLUM PROTOZOA 



about 2,500 cilia on its body. There are also tiny bulbs of a gelatinous 

 liquid, the trichocysts, embedded in the pellicle. When irritated the 

 Paramecium may squirt this liquid out into the water where it hardens 

 and forms sticky threads which act in a protective capacity — enemies 

 are likely to get tangled up in these threads and thereby be rendered 

 harmless. 



Food vacuole 



Anal pore 



Contractile 

 vacuole 



Mouth pore 

 Oral groove 

 Micronucleus 

 Macronucleus 



Pellicle 



Cilia 



Photo by Winchester 



Fig. 7.11. Paramecium caudatum. Right : a photomicrograph of a living form. Left: 

 diagram identifying some of the structures which can be seen. 



Many of the life processes of paramecium are similar to those 

 found in amoeba, but there are certain differences which are noteworthy. 

 For one thing, there is a definite opening for ingestion and another for 

 egestion. The entire process of digestion can be demonstrated if we 

 place some yeast cells stained with congo red on a microscope slide 

 with some paramecia. Under the microscope we can see the masses of 



