220 



SEX IN MICROORGANISMS 



Fig. ad. Variations in conjugation of Parmnecium tricbiuvi. 



1, 2, 4, from Diller (1948); 3 from Diller (1949), redrawn. 1, transfer of a single 

 gamete nucleus into a mate with degenerating nuclei, leaving one conjugant without 

 a micronucleus; 2, a binucleate animal conjugating with uninucleate one; 3, one 

 pronucleus has passed over without reciprocal exchange, producing a "haploid" 

 animal at left and a "triploid" one at right, intermingling of macronuclcar material; 

 4, two functional nuclei in each conjugant, large lobe of macronuclcar material 

 transferring from one to the other. 



