' ; 3OME MINUTE ANIMAL PARASITES 



minute speck of clear, jelly-like substance, in which 

 a somewhat denser mass is embedded. The jelly- 

 like mass can move about and does so, sometimes 

 very actively, at other times slowly and with a creep- 

 ing movement. Always the denser part is dragged 

 about with it. 



The fluid, jelly-like mass is known as protoplasm 



(Fig. i), and the 

 denser body con- 

 tained within 

 the nucleus 



-ps. 



ect 



is 



(Fig. i, W.). This 

 nucleus is most 

 important, for it 

 controls all that 

 the general pro- 

 toplasm does, 

 and regulates 

 the life of the 

 tiny animal. 

 When the death 

 of the nucleus 

 occurs, the 

 whole animal 



ect., Ectoplasm (outer layer of protoplasm); j; j f ^u^ 



end., endoplasm (inner layer of proto- Q | e 

 plasm); ., nucleus; ps., pseudopodia ; vital part of the 

 c.v. t contractile vacuole ; /., food particles r . , 



in food vacuoles living unit, and 



the latter is 



usually called a cell. Every cell consists of proto- 

 plasm and nucleus. 



What are the functions of the single, living cell 

 that constitutes the simplest animal ? The minute 



FIG. i .AMCEBA PROTEUS 



