66 LABORATORY STUDIES IN ZOOLOdY 



specimens should be studied. Conjugation may be looked upon 

 as a simple form of syngamy. 



To the outline drawing already made, add all the details of 

 structure which have been observed. Such structures as ecto- 

 plasm, endoplasm, cilia, contractile vacuoles (showing radiating 

 canals in connection with one), macronucleus, micronucleus, and 

 gastric vacuoles should be indicated. If the trichocyst threads 

 were seen, add only a few to one side of figure to show their 

 relative length. In the lower left- and right-hand corners of 

 the drawing sheet make sketches of binary fission and 

 conjugation. 



