PROTOZOA EHIZOPODA. 



147 



CLASS 2. Rhizopoda. 



214. The Rhizopoda (Gr. rhiza, a root; poda, feet) may 

 be defined as sarcode animals destitute of a- mouth) and 

 having the power of sending out pseudopodia. 



To this class belong the Amoeba, the Foraminifera, the 

 Eadiolaria, and Spongida, each of which will require a 

 separate description. 



215. (1.) The Amoeba (Gr. amoilos, changing), or Proteus 

 animalcule, is a microscopic animal commonly met with 

 in stagnant ponds. It is the simplest of all animals. It 

 consists of a little mass of jelly-like sarcode, resembling 

 the white of an egg, or rather a drop of gum Vater. It 

 is destitute of all those organs which are usually consi- 

 dered to be essential to life. There is no mouth or 

 digestive apparatus, no heart, no circulatory organs, no 

 respiratory organs, no nervous system. The animal is 



FIG. 60. AA , Different forms of Amoeba ; B, Amoeba difflugia, having the 

 pseudopodia protruded from one extremity only; C, Milliola, one of the For- 

 aminifera. in which the pseudopodia are protruded only from the mouth of the 

 shell. 



able to use any part of its body as a hand or a foot, and 

 to extemporize a mouth and alimentary canal anywhere 

 that may best suit its exigencies at the time. 



