122 



PROTOZOOLOGY 



phrys appendtculata and Styloyiychia pustulata; but in Aspidisca 

 lynceus (P'ig. 52) a reorganization band ai)peared first near the 

 middle region of the macronucleus (b), divided into two and each 

 moved toward an end, leaving between them a greater chroma- 

 tinic contents of the reticula (c-i). Summers suggested that "the 



Fig. 52. Macronuclear reorganization prior to division in Aspidisca 

 lynceus, X1400 (Summers), a, resting nucleus; b-i, successive stages in 

 reorganization process; j, a daughter macronucleus shortly after 

 division. 



reorganization bands are local regions of karyolysis and re- 

 synthesis of macronuclear materials with the possibility of an 

 elimination of physically or possibly chemically modified non- 

 staining substances into the cytoplasm." 



The discarding of a certain portion of the macronuclear 

 material during division has been observed in a number of species. 



