XV. 4 



De Leon: Balantidium Hough wouti 



403 



ical and that the elongation and the consequent increase in size 

 are early evidence of beginning nuclear division. 



This nucleus is invested with a delicate nuclear membrane 

 very difficult to demonstrate. There appears to be a cortical 

 layer of homogenous transparent material that stains very 

 lightly with the nuclear stains. In the gross, it appears to be 

 practically a structureless body. Carefully differentiated spec- 



FiG. 5. a, A small meganucleus is present ; the micronucleus seems to have fragmented ; b, 

 the meganucleus and its membrane have disappeared ; the cytoplasm contains chromatinic 

 bodies of unknown nature ; c, the meganucleus has disappeared leaving a body that appears 

 to be its membrane ; the micronucleus appears in a distinct capsule ; d and e, early and 

 late stages showing the incurvation of the meganucleus about the micronucleus. 



imens show, however, that within this achromatinic cortical 

 layer there lies a minute chromatinic granule, or a collection of 

 granules irregularly distributed on a reticulum. This heavy 

 achromatinic cortex is not present in the micronucleus of either 

 Balantidium coli or B. falcifarum. 



" It is a little difficult to determine how much of this "cortex'" 

 is plastinoid substance or how much of it represents nuclear 



