B 



FIG. XXII. A, Entamoeba tetragena. Living vegetative form showing 

 character of the nucleus and the well-defined ectoplasm. (After Hartmann.) 

 B, Entamoeba tetragena, stained, showing nuclear membrane, karyosome, 

 and centriole. X 1400. (After Hartmann.) C and D, two nuclei of Ent- 

 amoeba tetragena greatly enlarged, showing the centriole and karyosome 

 and the reticulative appearance due to cyclical changes in the latter. 

 (After Hartmann.) 



^ \ 



,**' 



,V-i* 



FIG. XXIII. Various stages in the development of Entamoeba tctra- 

 gena. (After Hartmann.) A, a parasite showing chromidia and beginning 

 division of the nucleus, the centriole having disappeared; B, organism show- 

 ing division of the nucleus; C, a cystic form in the uninuclear stage; D, 

 encysted form containing two nuclei; E, encysted form containing four 

 nuclei. 



