28 ELECTRON-MICROSCOPIC STRUCTURE OF PROTOZOA 



Plate III 



Fig. 10. Section through contractile vacuole canal of Tokophrya 

 infusionum. Outer, permanently open, part of canal is obliquely cut 

 above; below, contracted tubule leading through papilla from main 

 vacuole is cut tangentially. Note fibrils radiating from canal to 

 vacuole wall. X 50,000. From Rudzinska, 1958. 



Fig. 11. Oblique section through part of contractile vacuole canal 

 (cavity at upper right) of Metaradiophrya gigas. Cylindrical fibrils 

 are regularly arranged along one side of canal wall; some fibrils 

 radiate to membrane of contractile vacuole, at left. X 47,000. From 

 de Puytorac, 1961a. 



Fig. 12. Oblique section through radial canal of Paramecium 

 caudatum. Canal is collapsed in systole, as in upper circle in Text- 

 fig. 2. Nephridial tubules form sponge around canal; clusters of 

 tubular elements and canaliculi of endoplasmic reticulum visible in 

 surrounding cytoplasm, x 34,000. From Schneider, 1960b. 



