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University of California Publications in Zoology E V L. 20 



post. c. v 



Pig. I. Balantidium ooli. Ventral view showing principal structures. The 

 adoral cilia, with exception of one at either side, are indicated by basal granules 

 only. The adoral membranelles are also represented solely by the basal apparatus. 

 Ectoplasm is shaded, and ciliary rootlets are shown on one side only. X 1250. 

 ad. oil., adoral cilia; ad. cil. /., adoral ciliary fiber; ad. mcmb., adoral membranelles; 

 ant. c. v., anterior contractile vacuole; bg., basal granule; bg. ad. cil., basal granules 

 of adoral cilia ; cil., cilia ; oil. r., ciliary rootlet ; dr. oes. /., circumoesophageal fiber ; 

 cytpg., eytopyge ; ect., ectoplasm ; enl. ad. cil. r., enlargement of adoral ciliary root- 

 let; end., endoplasm; gr. b., granular band of ectoplasm; long. /., longitudinal 

 fibers; moo., macronucleus ; mic., micronucleus ; mot., motorium; nuc.memb., 

 nuclear membrane; oes., oesophagus; or.pl., oral plug; or.pl.f., oral plug fibers; 

 pel., pellicle ; per., margin of peristome ; post. c. v., posterior contractile vacuole ; 

 rad. /., radial fiber ; ret. v^ rectal vacuole. 



