22 



GENERAL CONSIDERATIONS 



Jakimowitch (1929), occurs in C. steenstvupii, where it is in the form 

 of a finely granular substance which comes from the macronucleus and 

 remains for a time between the nuclear halves after division, but ulti- 

 mately disappears in the cytoplasm. 



There is reason to believe that this phenomenon has something 



Figure 5. Conchophthirus (K'ldderia) mytili. Extrusion of chromatin during division. 

 (From a preparation made by Dr. G. W. Kidder.) 



to do with restoring full metabolic powers of the macronuclear chroma- 

 tin, possibly by the elimination of waste products of chromatin activity. 

 Another process of macronuclear reorganization during division which 

 does not involve the visible elimination of nuclear substance, occurs in 

 species of the families Aspidiscidae and Euplotidae of the Hypotrichida. 

 At the approach of division in Aspidisca (Fig. 6), according to Sum- 

 mers (1935), the area of reorganization first appears as a wedge-shaped 

 cleft at the approximate center of the convex side of the C-shaped 



