8 



PROTOZOA 



ClLIATA FROM THE RECTUiM OF THE FROG. 



2. Opalina ranarum. A mouthless holotrichous form. 



3. Nyctotherus cordiformis. A heterotrichous form, pharynx, contractile vacuole, nucleus, 

 anus (permanent). 



4. Balantidium entozoon. A heterotrichous form. Four contractile vacuoles, mouth, nucleus. 

 (a) Examine alive in a drop of the rectal fluid, (b} Stain as in Amoeba, (c) Irrigate fresh drop of 

 fluid with methylene blue. 



5. Stentor. A heterotrichous free-living form. 



