400 



Philippine Journal of Science 



In stained preparations the meganucleus is the most con- 

 spicuous intracellular object. It takes the stain deeply and it 

 is only by good differentiation that its true structure is seen. 

 The shape of this nucleus is quite characteristic. In the vege- 

 tative state of the cell its normal form might be said to be 

 sausage-shaped to reniform, but it shows an orderly and pro- 

 gressive series of form changes that develop until it has finally 

 completely curved upon itself to form a circle with the two ends 

 of the nucleus in apposition. The micronucleus is usually lodged 

 in the concavity of the meganucleus and tends to become en- 

 closed by it. The possible significance of these form changes 

 will be discussed later. 



Fig. 2. Cytoplasmic structure and meganuciear and micronuclear relations in Balantidium 



haugkwouti. 



In stained preparations the meganucleus measures on the 

 average 19.83 p in length by 7.5 p. in width. In general shape 

 it closely resembles the meganucleus of Balantidium coli, and 

 that of B. entozoon as figured and described by Stein, who ap- 

 pears to have noticed the same variation in form. 



In deeply stained specimens the meganucleus appears to be 

 formed of a solid mass of chromatin. Careful differentiation 

 shows the chromatin to be distributed in the form of fine gran- 

 ules more or less closely packed together. The appearance 

 varies, however, so that the finer structure frequently appears 

 as a reticulum of varying texture. Many nuclei show areas that 

 appear more or less alveolar — that is to say, give the appearance 

 of a network of chromatinic material surrounding clear spaces 



