PHYSIOLOGICAL VARIATIONS IN PARAMECIUM 495 



and 26 and 192 pairs were obtained from quadrant A, 110 pairs 

 from quadrant B, and 507 pairs from quadrant C, a result that 

 was confirmed in the April test when 15, 90 and 20 pairs were 

 found in quadrants, A, B, and C, respectively. 



G. Conjugations in the Q series (diagrarn 6) 



The four permanent cultures were started as above on Decem- 

 ber 17 and the first rich cultures were made January 12, and con- 

 jugation tests on the 15th, the 20th, and the 27th. Conjugating 

 pairs were found in three quadrants, 5 in quadrant A, 4 in quad- 

 rant B, and 93 in quadrant C, none being found in quadrant D. 

 A second set of rich cultures were made on February 6 and con- 

 jugation tests on February 8, 9th, 14th, and February 20th, con- 

 firmed the findings of the previous month. Quadrant A gave 24 

 pairs; quadrant B, 20 pairs; quadrant C gave 1303 pairs while 

 quadi'ant D gave none at all. 



In this series the power to conjugate is distributed between 

 three of the four original cells, but it is quite apparent that quad- 

 rant C is the chief conjugating line, about 10 per cent of them con- 

 jugating under the conditions of the test (on February 14 this 

 percentage rose to 33). 



A third set of rich cultures was made March 15, from which 

 only one conjugation test was taken on March 19. This single 

 test yielded 1656 pairs in quadrant A, 640 pairs in quadrant B, 

 and 306 pairs in quadrant D. (Quadrant C died between Feb- 

 ruary 15 and 22.) 



This series was abandoned after the March test since all lines 

 possess high conjugating power. 



H. Conjugations in the G series (diagram 6) 



Again the four permanent cultures were started on December 

 17 and the first rich culture tests were made on December 26, 

 the first set of conjugation tests on December 28, and January 4, 

 yielding 16 pairs in quadrant D, none in the three others. The 

 second set of rich cultures was made February 13 and conjuga- 

 tion tests were made on February 17 and 20. In the meantime, 



THE JOURNAL OP EXPERIMENTAL ZOOLOGY, VOL. 15, NO. 4 



