Opalina. 269 
of the previous telophase united to form the ribbon. Fundamentally 
the same assumption is involved in the belief in the individuality 
of the chromosomes in any animal. In the binucleated Opalinae the 
chromatin is less diffuse in the “resting nuclei” than it is in most 
animals, so that it is easier to conceive of the chromatin masses 
which appear before the new mitosis as being merely the old chro- 
mosomes of the previous telophase which have again become distinct. 
Each chromosome itself soon constricts into two, this being appa- 
rently the true division of the chromosomes. Division of some of 
the chromosomes may occur at the time when the chromatin ribbon 
is constricting to reform the chromosomes, so that the number of 
masses coming out of the chromatin ribbon may be more than eight, 
but this, of course, does not affect the interpretation of the phenomena. 
Nuclear condition and cytoplasmic movements, 
Attention has been called to the fact that the two nuclei in 
the binucleated Opalinae are often in slightly different condition. 
This divergence is never great. In the multinucleated species the 
conditions of the numerous nuclei are very different. No disturbance 
of the movements of the cell arises from this diversity in condition 
of the different nuclei, which tends to confirm the general belief 
that the chromatin of the nucleus is not directly concerned in the 
control of protoplasmic movements. Mrves (1899) showed that 
secretion in the cells of the kidney in salamander larvae is inter- 
rupted during mitosis, the chemical activities of the cytoplasm being 
influenced by the condition of the chromatin in the nucleus. 
Analogies of the chromatin spherules. 
Some light may be thrown upon the problem of the nature of 
the chromatin spherules and cytoplasmic spherules by comparison 
with the conditions in other ciliate Infusoria. The macronucleus of 
most Ciliata consists of granules aggregated into a more or less 
compact group. This group breaks up under certain conditions, the 
granules scattering through the whole endoplasm and soon disap- 
pearing by solution. When a new macronucleus is formed, it arises 
from one (or more?) of the micronuclei. The macronucleus of the 
Ciliata is generally regarded as especially connected with nutrition. 
The chromatin spherules in Opalina are derived from the chro- 
matin of the chromosomes and by their origin from chromatin and 
their solution and disappearance remind one of the macronuclear 
