244 M. M. Mercarr 
observe the chromatin spherules in the early part of my study of: 
Opalina in the fall and early winter.') They were abundant in the 
late winter and early spring. I have since found them in material 
preserved in the fall. As I have not yet studied material from tad- 
poles preserved in the summer, [ cannot say for how long a period 
their formation is interrupted, though it seems probable that they 
are absent from the nuclei which have cast off their vegetative 
chromatin (a process to be described later) and in which. the ordinary 
proportions of vegetative and reproductive chromatin, characteristic 
of the vegetative phase of the life cycle, have not been restored 
by subsequent growth. 
Their fate is a little doubtful. They seem to go into solution. 
It is apparently these chromatin spherules which Contr & VANryY 
(1902) have described as passing through the nuclear membrane into’ 
the cell-body and there giving rise by division to the refractive 
spherules in the cytoplasm. Jt seems as if they do occasionally 
pass undissolved through the ends of the nucleus at the place where 
the nuclear membrane broke in a former division. In several dozen 
instances I have found the end of a nucleus drawn out into an 
irregular protrusion and one (rarely more) body resembling a chro- 
matin spherule lying in this protrusion, apparently ready to pass 
out into the cell-body (Figs. 78—80, Pl. XX). In some instances 
the membrane bounding the protrusion is noticeably more delicate 
than that of the rest of the nucleus. The chromatin spherules in 
these protrusions generally stain but faintly, having already some- 
what changed their character. On the other hand there were 
several times seen, in these protrusions from the nucleus, spherules 
which with iron-haematoxylin were deeply stained. Fig. 5, Pl. XIV, 
shows one such nucleus. The slide was well decolorized and the 
endoplasmic spherules are quite light colored, only their granules 
being dark. Even the chromosomes are lighter than usual, but the 
chromatin spherule in the nuclear protrusion, and two other sphe- 
rules at the base of the protrusion, are heavily stained. Apparently 
they stain almost as strongly as if newly formed, though this nucleus 
is in a late anaphase. Their persistence in this condition to so late 
a stage in very exceptional. 
There are from twenty to one hundred or more, of the chromatin 
spherules in one nucleus (cf. Pl XV: Figs. 21 and 22 show one 
nucleus, Figs. 28—31 another). If they all passed undissolved through 
1) Because my attention was not then directed to them. 
