RHYTHMS AND ENDOMIXIS IN PARAM/ECIUM AURELIA. 



53 



have been presented in earlier papers. Fig. I 1 gives a typical 

 graph of a subculture showing the relation of rhythms and 

 endomixis. 



Race II. (Berlin Race.} Isolated by Erdmann in Berlin. 

 For details see Woodruff and Erdmann, 1914. 



Race III. (Oberlin Race.} The initial animals of this pedi- 

 greed culture was supplied by Professor R. A. Budington, of 

 Oberlin, Ohio. The culture was started October 8, 1914, and 

 was discontinued after nearly two years during which time over 

 1,000 generations w'ere obtained. Fig. 2 is a graph of the 

 average division rate of the four lines of this culture again 

 averaged for each of the first 21 five-day periods of its life when 

 it w r as being intensively studied with reference to the occurrence 

 of rhythms and endomixis. ' The graph shows four rhythms and 

 at the low point between each endomixis occurred. It is to be 



FIG. 3. 



noted that the reorganization process appeared during the fifth 

 five-day period after the isolation of the culture, thus showing 

 once more that this phenomenon is not dependent upon long 

 subjection to culture conditions for its genesis. The length of 

 the rhythmic periods for this race is also essentially the same as 

 in Race I (cf. Fig. i). 



Race IV. (Bryn Mawr Race.} The animal which started 



1 Ibid., 1914, Fig. 17. 



