14 



BEGINNERS' ZOOLOGY 



-r There is 

 the macro- 



ages on its surface, called cilia (Latin, eyelashes) (Figs.). 

 The cilia, like the pseudopods of the amoeba, are merely 



prolongations of the cell protoplasm, 

 but they are permanent. The sepa- 

 ration between the outer ectoplasm 

 and the interior granular cndoplasm 

 is more marked than in the amoeba 

 (Fig. 14). 



Nucleus and Vacuoles 

 a large nucleus called 

 nucleus, and beside it a 

 smaller one called the 

 micronucleus. They are 

 hard to see. About one 

 third of the way from 

 each end is a clear, pul- 

 sating space (bb. Fig. 

 15) called the pulsat- 

 ing vacuole. These 

 spaces contract until 

 they disappear, and then 

 reappear, gradually ex- 

 panding. Tubes lead from the vacuoles which probably 

 serve to keep the contents of the cell in circulation. 



Feeding. — A depression, or groove, is seen on one side; 

 this serves as a mouth (Figs.). A tube which serves as a 



gullet leads from the 

 mouth-groove to the in- 

 terior of the cell. The 

 mouth-groove is lined 

 with cilia which sweep 

 food particles inward. 



Fig. 16. — Two Par ameci A exchanging 



parts of their nuclei. The particles accumulate 



Fig. 14. — Paramecium, 

 showing cilia, c. 



Two contractile vacuoles, cv; 

 the macronucleus, nig; 

 two micronuclei, mi; the 

 gullet (<2T), a food ball 

 forming and ten food balls 

 in their course from gullet 

 to vent, a. 



FIG. 15. 



