56 
At the anterior end is a very large nucleus (7) which almost: com- 
pletely fills that portion of the egg; it contains a few scattered rods 
of chromatin. Near the posterior end is a smaller but even more 
conspicuous body (Fig. 1, k) which stains very deeply with iron- 
haemotoxylin. This may be vacuolated and irregular showing signs 
of disintegration as shown in Fig. 1, or may possess a smooth outline 
and be entirely homogeneous. It is undoubtedly of a very tough 
nature since it not infrequently tears outh of the egg substance 
when struck by the sectioning knife. This obviously represents the 
‘nucleolo’ of Strvestri, the body whose origin it was the object of this 
investigation to ascertain. SILvESTRI claims that this ‘nucleolo’ is a 
plasmosome which was cast out of the oöcyte nucleus at an early 
stage in the growth period, but an examination of my material proves 
that it really contains all of the chromatin of the oöcyte nucleus. 
Since it is not a nucleolus, at least in the species I have studied, it 
can no longer be called a ‘nucleolo’, and therefore the term ‘ keimbahn- 
chromatin’ will be applied to it in the following account of its origin. 
Fig. 2 was drawn from a longitudinal section through an oöcyte 
(0) in an early stage of growth. It is surrounded by follicle cells 
(f.e) and accompanied by a group of nurse cells (n.c) at the anterior 
end. A large part of the oöcyte is occupied by the nucleus (n) within 
which are a comparatively few irregular rods of chromatin, forming 
a group in the center. This nucleus thus differs quite strikingly from 
those of the follicle and nurse cells. A slightly later stage in the 
growth of the oöcyte is represented in Fig. 3, the nurse cells being 
omitted. The nucleus has already assumed an eccentric position, 
lying nearer the anterior than the posterior end. When compared 
with the nucleus of the younger oöcyte (Fig. 2) it will by noticed 
that a considerable increase in size has taken place and that the 
chromatin rods are longer and scattered about throughout the nuclear 
sap instead of lying in a group at the center. Some of the chromatin 
rods seem to cross at their extremities as at a, or exhibit near the 
center a knob-like swelling as at 6. In Fig. 4 is shown a still older 
oöcyte (o) and two of the accompanying nurse cells (n.c). A distinet 
nutritive strand (n.s) extends from the anterior end to the nurse cells. 
The nucleus contains many long slender rods of chromatin which 
often cross each other at their extremities. 
Soon after this stage is reached the nuclear membrane disappears 
and a sort of spindle is formed as illustrated in Fig. 5. No asters 
