REPRODUCTION 



Table 6. — Continued 



Paramecium hursaria (Jennings) 



159 



Euplotes patella (Kimball) 



than one micronucleus may divide for the third time to produce 

 several pronuclei, for example, two in Euplotes patella, Stylonychia 

 pustulata ; two to three in Oxytricha fallax and two to four in Uro- 

 leptus mobilis. This third division is always characterized by long 

 extended nuclear membrane stretched between the division prod- 

 ucts. 



Ordinarily the individuals which undergo conjugation appear to 

 be morphologically similar to those that are engaged in the trophic 

 activity, but in some species, the organism divides just prior to 

 conjugation. According to Wichterman (1936), conjugation in 



