Fig. 2. a-f, vesicular nuclei; g-j, compact nuclei, X980. a, b, nuclei of 

 Entamoeba invadens (a, in life; b, in stained organism); c, d, nuclei of 

 Amoeba spumosa (c, in life, showing a large endosome; d, stained); e, f, 

 nuclei of A. proteus (e, in life; f, a nucleus subjected to Feulgen's nucleal 

 reaction) ; g, h, nuclei of Paramecium aurelia (g, in life under phase micro- 

 scope, snowing two vesicular micronuclei and compact macronucleus; h, 

 Feulgen-stained nuclei); i, j, nuclei of Frontonia leucas, showing a micro- 

 nucleus and macronucleus, both of which are compact ($ in life, showing 

 many endosomes imbedded among the granules; j, nuclei stained with 

 acidified methyl green), 



