12 



ANIMAL BIOLOGY 



the particle (Fig. 12). The water and the 

 particle are soon absorbed and assimilated 

 by the endoplasm. 



Excretion. If a particle of sand or other 

 indigestible matter is taken in, it is left behind 

 as the ameba moves on. There is a clear 

 space called the contractile vactiole, which 

 slowly contracts and disappears, then reap- 

 pears and expands (Figs. 9 and 10). This 

 possibly aids in excreting oxidized or useless 

 material. 



Circulation in the ameba consists of the 

 movement of its protoplasmic particles. It 

 lacks special organs of circulation. 



Feeling. Jarring the glass slide seems to 

 be felt, for it causes the activity of the ameba 

 to vary. It does not take in for food every 

 particle that it touches. This may be the 

 beginning of taste> based upon mere chemical 

 affinity. The pseudopods aid in feeling. 



Reproduction. Sometimes an ameba is seen 

 dividing into two parts. A narrowing takes 

 place in the middle ; the nucleus also divides, 



a part going to each portion (Fig. 13). The mother ameba 



finally divides into two daughter amebas. Sex is wanting. 

 Source of the Ameba's Energy. We thus see that the 



ameba moves without feet, eats without a mouth, digests 



without a stomach, feels 



without nerves, and, it 



should also be stated, 



breathes without lungs, 



for oxygen is absorbed 



from the water by its whole FIG. 13. AMEBA, dividing. 



FIG. 12. THE 

 AMEBA tak- 

 ing food. 



