OTHER NON-COLONIAL PROTOZOA 



77 



have divided twice, followed by degeneration of three of the resulting 

 micronuclei in each and the division of the remaining one to form a 

 stationary and a migratory micronucleiis in each conjugant; the 

 macronuclei will be partly disintegrated. (3) An exconjugant in 

 which the fusion nucleus has divided twice to form four nuclei; frag- 

 ments of the old macronucleus may still be visible. Other intermedi- 

 ate stages may also be shown. Understand fully from textbooks all 

 the changes that occur, and relate the process of conjugation in the 

 Paramecium to the syngamy of non-ciliated protozoans and to fertili- 

 zation in the frog. 



OTHER NON-COLONIAL PROTOZOA 



Exercise 1. — Free-living Species. 



(a) Numerous species of Protozoa will have been observed in the 

 cultures used for Amoeba, Euglena, and Paramecium. The accom- 



Euplotes 



Spirostomum Podophrya 



Uonotus 



Fig. 38. — Common Infusoria and other Protozoa from fresh water. 



(Drawn in part by Wiley Crawford.) 



panying Figs. 36 and 38 show common and representative types seen 

 in fresh water. It is instructive to examine a diversified culture and 

 to list, with aid of your instructor, the different forms that are found. 

 Especially favorable types may then be studied briefly for purposes 



