CHAPTER XVIII. 

 BRANCH PROTOZOA. 



THE ONE-CELLED ANIMALS. 



Amoeba. The Proteus Animalcule. One of the sim- 

 plest forms of animal life is the Amoeba. It is found in 

 the slimy coating usually found on submerged leaves and 

 stems in standing water, or in the slimy ooze resting on 

 the mud at the bottom. If this ooze be examined under 

 a high power of a microscope, amoebae may usually be 

 found, though occasionally one has to search for some time 



Endoplasm 



Ectoplasm 



Pseudopods (/.",; 



retracting ' *\' : - 



Contractile vacuole 



EV Water vacuoles 



Food vacuoles 



FIG. 168. AMCEBA, 



before he is successful. And it is difficult for a begin- 

 ner to be certain, at first, whether what he has found is 

 really an amoeba. An amoeba is a speck of clear, color- 

 less, jellylike substance called protoplasm, with a distinct, 

 though delicate, outline. There can usually be discerned a 

 clearer outer layer, the ectoplasm, and a more dotted cen- 

 tral portion, the endoplasm ; but there is no distinct line 

 between the two. Sometimes one can see a more dense 



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