THE NUCLEI OF UROLEPTUS MOBILIS 



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Fig. 1 Uroleptus mobilis Engelmann. Normal vegetative individual with 

 characteristic curvature of posteror end; eight macronuclei each with a nuclear 

 cleft ; four micronuclei and central contractile vacuole. X 800. 



Fig. 2 Peristomial details. Adoral zone, undulating membrane and three 

 frontal cirri. X 1500. 



Fig. 3 Cross-section through anterior region near the mouth of a conjugating 

 individual. Two lateral and three ventral cilia are shown in characteristic posi- 

 tion, indicating the five lines of cilia. The asymmetical peristome is indicated 

 by the single membranelle. The section also shows the anterior macronucleus 

 and one of the maturation micronuclei. X 1500. 



