UNICELLULAR FORMS 



6^ 



(Fig. 17), may be examined in detail to illustrate the specializations 

 that appear as one goes from the simple amoeba to more advanced 

 types. It is found in great numbers in decaying vegetable matter 

 and is easily cultivated in the laboratory. If a handful of dry grass 



ENDOSARC 



CONTRACTILE VACUOLE 



ORAL GROOVE 



CONTRACTILE VACUOLE 



PELLICLE 



CILIA 



ECTOSARC 



MACRONUCLEUS 



MICRONUCLEUS 



GULLET 

 CYTOSTOME 



FOOD VACUOLE 



Fig. 17. — ^Paramoecium. The upper end in the figure is the leading or anterior 



end of the animal. The anterior contractile vacuole is in the process of filling; 



the posterior vacuole is about to discharge its contents. (From a preparation and 

 various authors.) 



is covered with water in a jar and then seeded with a bit of mud 

 from a stagnant pool and allowed to ferment, in a few days great 

 numbers of paramoecia will appear. In general, the shape of the 

 animal is that of an elongated hen's ^g'g^ and unless it is creeping 



