PLATE 1 



EXPLANATION OF FIGURES 



Same magnification throughout 



1 Normal Blepharisma undulans with macronucleus in typical vegetative 

 condition after division. From total preparation. 



2 Giant specimen with macronucleus in division stage but with no indication 

 of cell division. Three micronuclei shown. From total preparation. 



3 Section showing details of peristomial region and two micronuclei. 



4, 5, 6, 7 Successive stages in cell division. Note beginning and develop- 

 ment of posterior adoral zone. From total preparations. 



8 Normal nuclear relations in a dividing cell. Seven of the eight micro- 

 nuclei shown within the macronuclear membrane. From section. 



9 Involution truncated form after casting off the elongated posterior end. 

 New vacuoles replace those lost. From total preparation. 



10 Typical ex-conjugant. Two nuclei from the first division of the syn- 

 caryon on opposite sides of the old macronucleus. Note the small size of the 

 cell as contrasted with figure 1. Total preparation from the right side. 



11 Degenerating ex-conjugant five days after separation. From total prep- 

 aration. 



12 Conjugating Blepharisma with macronuclei, enigmatical micronucleus, 

 and four micronuclei in the late anaphase of mitosis — evidently the second matu- 

 ration division. From total preparation. 



688 



