VORTICELLA 43 



tween ectoplasm and endoplasm by dotted line. Nuclei seen in 

 stained demonstrations should be shown in this drawing. Indi- 

 cate direction of protoplasmic currents by a series of arrows 

 showing course through the entire cell. 



13. REPRODUCTION by simple transverse fission. If possible 

 watch and sketch the process in living specimens. Time for pro- 

 cess of fission? How many mouths just before fission is com- 

 pleted ? How many contractile vacuoles ? Are the two resulting 

 individuals alike? See stained demonstrations. 



14. Look for pairs of Paramecia undergoing conjugation. 

 See demonstrations. 



REFERENCES 



Doflein, F., 1911. Lehrbuch der Protozoenkunde. Jena. 

 Maier, H. N. 1903. Ueber den feineren Bau der Wimperap- 

 parate der Infusorien. Arch. f. Protist. Bd. 2:72-179. 



Minchin, E. A., 1912. An introduction to the study of the Pro- 

 tozoa. Arnold, London. 



VORTICELLA 



Classification : Phylum Protozoa, Class Ciliata, Order Peri- 

 tricha. 



Make out: (i) Shape. Is it constant? (2) Cilia. Distribu- 

 tion and functions? Does Vorticella ever swim about? (3) 

 Groove, mouth, and gullet. (4) Ectoplasm and endoplasm. (5) 

 Food vacuoles. (6) Protoplasmic granules. (7) Contractile 

 vacuoles. (8) Macronudcus. (9) Structure of stalk. (TO) 

 Reproduction. (TI) Make a large drawing, 50 mm. across, show- 

 ing the parts you have seen. With ocular micrometer determine 

 the diameter of the bell. 



