PHYSIOLOGICAL VARIATIONS IN PARAMECIUM 475 



B. The B series 



The pair B B' was isolated on December 13 from a wild culture. 

 The progeny of B' died after three divisions, those of B were 

 not strong but enough of them continued to live through the 

 early division stages to give three pure lines from quadrant A, 

 two from quadrant B, five from quadrant C, and four from quad- 

 rant D, fourteen lines in all representing all four quadrants. The 

 history up to the present is shown in diagram 4 (p. 490). 



C. The E' series 



This series also started on December 13 with a conjugating 

 line from the same wild culture as the B series, gave more satis- 

 factory results. The progeny from individual E soon died, while 

 E' continued to live. The history is shown in diagram 5. Twenty- 

 four lines continued to live, 3 from quadrant A, 7 from quadrant 

 B, 7 from quadrant C, and 7 from quadrant D (p. 492). 



D. The G, H', L, M, Q and T' series 



These series are all from conjugating pairs isolated from the 

 same wild culture December 13. They differ from the other 

 series described above in comprising only four lines each, these 

 lines coming from the first four cells of the ex-conjugant in each 

 case. Each line thus corresponds to an entire progeny from a 

 quadrant of the preceding series. The history of these series is 

 shown in diagram 6 (p. 494). 



E. The and P series 



These series came from conjugating pairs in line 8 of the J 

 series isolated on December 3. Although many attempts were 

 made to get perfect sets, none was successful, the O series and the 

 P series being the nearest approach to success, and in these only 

 11 pure lines were obtained in the O series and only 10 in the P 

 series, representing in both cases only two of the four quadrants. 

 Their particular interest lies in the fact that they represent the 

 Fo generation and have been derived from a pure line whose his- 

 tory is known. 



