538 



PROTOZOOLOGY 



Fig. 245. Semi-diagrammatic drawings of nine species of Parame- 

 cium in oral surface view, showing distinguishing characteristics taken 

 from fresh and stained specimens, X230 (several authors), a, P. 

 caudatum; b, P. aurelia; c, P. muUimicronudeata; d, P. bursaria; 

 e, P. putrinum; f, P. calkinsi; g, P. irichium; h, P. polycaryum; i, P. 

 woodruffi.. 



150-210^1 long; 2 contractile vacuoles; 3-4 vesicular micronuclei; 

 brackish water. 



Although Paramecium occurs widely in various freshwater 

 bodies throughout the world and has been studied extensively by 

 numerous investigators by mass or pedigree culture method, there 

 are only a few observations concerning the process of encystment. 

 Biitschli considered that Paramecium was one of the Protozoa 



