434 



THE PROTOZOA 



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Fia. 183. Campanetta unibettaria. p.g., Peristomial groove in which runs the 

 adoral spiral zone of cilia, which in this species takes 4i turns ; p.r., peri- 

 stomial ridges between the peristomial grooves ; a.sp., the two undulating 

 membranes, each made up of three rows of cilia fused, which compose the 

 adoral spiral, seen in optical section ; the two undulating membranes pass 

 down into the vestibule (K.), and run down inside it spirally as far as its 

 termination at m., which represents the true mouth, leading into the short 

 eytopharynx or oesophagus (ces.) ; n, micronucleus ; N, maoronucleus ; 

 c.pl., cortical ectoplasm, thick at the base of the body, thin at the sides ; 

 st.c., " collar " of the stalk ; St., stalk ; gr., granules in the endoplasm which 

 stain red with neutral red in the living condition ; f.v., food-vacuoles ; c.v., 

 contractile vacuole opening by two canals into the vestibule. After 

 Schroder (864). 



