PROTOZOA AS CELLS 



29 



Text-figure 2. Schematic drawings of the contractile vacuole 

 apparatus in Paramecium showing main vacuole to right and one 

 radial canal, with enlarged circular inset, to left. Upper drawing 

 shows radial canal in systole, main vacuole in diastole; lower 

 drawing shows radial canal in diastole and main vacuole in systole. 

 RS, clusters of membranous tubules ; EPR, endoplasmic reticulum, 

 showing continuity of this system with NT, nephridial tubules 

 forming a sponge around NK, nephridial canal; Amp, ampulla of 

 radial canal; EK, injector canal; KV, main contractile vacuole; 

 FB, bundles of fibrils in vacuole wall; AK, discharge canal. From 

 Schneider, 1960b. 



