MORPHOLOGY 



35 



caudatum, P. aiirelia, Chilodonella, Nydotherus ovalis, etc., the 

 macronuclear chromatin is colored more deeply than the micro- 

 nuclear chromatin, while in Colpoda, Urostyla, Euplotes, Sty- 

 lonychia, and others, the reverse seems to be the case, which 

 may support the validity of assumption that the two types of the 



Fig. 3. Four macronuclei of Nydotherus ovalis, s^liuwing chromatin 

 spherules of different sizes, X650 (Kudo). 



nuclei of Euciliata and Suctoria are made up of different chroma- 

 tin substances — idiochromatin in the micronucleus and tropho- 

 chromatin in the macronucleus — and in other classes of Protozoa, 

 the two kinds of chromatin are present together in a single 

 nucleus. 



Chromidia. Since the detection of chromatin had solely de- 

 pended on its affinity to nuclear stains, several investigators 



