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GEORGE ALFRED BAITSELL 



culture, and was carried until January 14, 1912, a period of 80 

 days, during which time it passed through 150 generations. 

 Diagram 3 shows graphically the life history. Although this cul- 

 ture did not live so long as either of the other cultures it main- 

 tained a considerably higher rate of division. However, the de- 

 cline which began about the middle of December continued quite 

 rapidly and steadily and the culture died, as noted above. 



It is observed, then, that, in all three of the daily isolation 

 cultures of Oxytricha fallax, there is a general decline in the 



I . — 



' I 1 I 



oJ \ U 



Oct. -1911 



Nov. 



Dec. 



Jan. -1912 



Diagram 3 Graph giving the life history of Oxytricha fallax, Culture Ove, 

 showing the average daily rate of division of the four lines of the culture, again 

 averaged for five-day periods. 'Varied environment' culture medium. 



division rate almost from the time the cultures were first started. 

 Of the three media used it appears that the 'varied environment' 

 medium was to a slight degree less suitable for this animal than 

 either the beef or the hay media. The animals of the Ove cul- 

 ture died out almost a month previous to those of the other 

 two cultures. The rate of division was lower in the Ob culture 

 than in either of the others but on the other hand this culture 

 lived the longest. The highest number of generations was at- 

 tained by the Oh culture. In brief, while some minor differ- 



