402 
Philippine Journal of Science 
1919 
Many cells have been encountered in which the meganuclei 
have undergone marked changes in shape and appearance. In 
these cases the nuclei have become spherical or globular and the 
chromatin is condensed into deeply staining bands or clumps, in 
the meshes of which is seen clear, achromatinic material. The 
micronucleus in these cases seems to be sunk deeply into the 
substance of the meganucleus. 
Fig. 4. a and b, Early stages in inclosure of micronueleus in meganucleus ; c, later stage. 
Other individuals have been seen lacking even a trace of either 
nucleus, and there are those in which either one or the other 
nucleus is absent. In such animals there can be seen in the 
endoplasm fragments of stained substance, possibly of the nature 
of chromatin, and in one case there was observed (see fig. 5, c) 
a structure which, to all appearances, was the membrane of the 
meganucleus lacking its chromatin contents. It is impossible 
at present to arrive at any definite conclusion regarding the real 
nature of these chromatinic bodies. Walker(l2) has described 
a process of sporulation in Balantidium falcifarum, and Stein (10) 
hints at something of the same nature as occurring in B. ento- 
zodn. The possibility of endomixis as described by Woodruff 
and Erdmann must also be borne in mind, but the evidence here 
is too slight to admit of a discussion of any of these points. The 
possibility of these bodies being ingested organic matter must 
likewise be considered. The disappearance of the micronucleus 
may yet be explained by its incorporation into the meganucleus. 
Apparent total absence of both nuclei in an uninjured individual 
is mysterious unless explained on the basis of the fragmentation 
of both nuclei, or as a result of abnormal division following 
conjugation. 
The micronucleus is a small rounded or elongate body. It is 
strikingly different in size and structure from that of either 
Balantidium coli or B. falcifarum, but most closely resembles 
Stein’s figure of the nuclei of B. entozoon. When round it has 
an average diameter of 3.3 p, but when elongated it measures 
6.88 fx by 4.22 /x. It seems likely that the normal shape is spher- 
