PHYSIOLOGICAL VARIATIONS IN PARAMECIUM 493 



30 two weeks after isolation, and again on January 4, and Jan- 

 uary 8, and 35 pairs were obtained from quadrant B, none from 

 the others. The second rich cultures were made February 6 

 with conjugation tests on the 9th and 14th, giving 343 conjugat- 

 ing pairs from quadrant B again and not one from the three other 

 quadrants (see diagram 6). 



A third set of rich cultures was made March 15 and conjugation 

 tests were made March 19, 22 and 26. 841 pairs were obtained 

 from quadrant A, 2606 pairs from quadrant B, 798 pairs from 

 quadrant C, and none from quadrant D. 



Similarly in April, 1281 pairs were obtained from quadrant A, 

 227 from quadrant C and again none at all from quadrant D. 

 Quadrant B, the most prolific of this series, died out April 12 one 

 week before the tests were made. 



In this series therefore, progeny from one of the four quad- 

 rants appear to lack the power to conjugate while those of another 

 (B) possess it to a high degree. 



E. Conjugations in the H series {diagram 6) 



This series was also started December 13 and the first four sets 

 were isolated in permanent cultures on the 16th. Rich cultures 

 were made on January 7 and conjugation tests were made Jan- 

 uary 9, January 11, and January 16, giving 23 pairs in quadrant 

 A, but none in the three other quadrants. 



A second set of rich cultures was made February 13 and tests 

 started February 17, 20, and 22. These yielded only 2 pairs, 

 again, in quadi^ant A, none in the others. 



A third set of rich cultures was started March 15. Conjuga- 

 tion tests made on March 19, 22, and 26 gave only 2 pairs in 

 quadrant D, none in the others. 



A fourth set started April 19 gave 151 pairs in quadrant D 

 after three tests, and no pairs in any of the other lines. 



Here therefore, the conjugating power is slightly developed in 

 two quadrants, not at all in the other two. 



