REPRODUCTION OF THE HYPOTRICHOUS INFUSORIA 



61 



Diagram 5 Graph giving the entire life history of the three cultures of S. pus- 

 tulata, viz., Sb,Sbh, and Sbhb. It shows the average daily rate of division again 

 averaged for ihirty-dRy periods. 



B. Prepared material 



A study of the permanent stained preparations of the non-con- 

 jugants of the Sb and the Sbhb cultures gives conclusive evidence 

 of the degeneration that occurred in these animals. There is a 

 decrease in the size of the animals and a great change in the cyto- 

 plasmic and nuclear structure. In all the animals the micro- 

 nuclei are present but in many instances they are found to be 

 considerably enlarged and situated far from their normal posi- 

 tions. In most cases the macronuclei have undergone a marked 

 change and have lost their characteristic shape. Figure 1 shows a 

 normal individual taken from the Sbhb culture. This specimen 

 is quite typical of the animals to be found in the beef cultures 

 before degeneration had set in. In figures 2 to 6 are to be seen 

 non-conjugating individuals which were preserved at various 

 stages of degeneration. 



