396 GEORGE T. HARGITT 
matter left in the nucleus (figs. 10, 12, 13, 15, 17, ete.). This last 
condition is strong evidence that the suggested interpretation is 
correct; certainly the fact that breaking up of the nucleolus and 
streaming currents from the nucleus into the cytoplasm co-incide; 
the fact that when the nucleolus has disappeared there is no 
longer such an arrangement of the cytoplasmic granules near the 
nucleus (i.e., no strong currents going from the nucleus into the 
cytoplasm) can not indicate other than a causal relation. 
The nucleolus entirely disappears in the process just described. 
First of all, there is a very great increase in size of the nucleolus 
during the early growth of the egg, as a comparison of figures 3, 4 
(x 1900) with figures 5, 8, 9, 10 (x 1228) shows, an increase which 
is much greater in amount than the increase in volume of the nu- 
cleus itself. Very soon, however, the nucleolus begins to undergo 
the modifications figured. It is certainly significant that a rapid 
increase in the body of the egg should be evident at the time when 
the nucleolus becomes vacuolated and breaks up, and streams of 
matter are going from the nucleus into the cytoplasm (figs. 8 to 
10, 16). These are evidences that changes are occurring within 
the nucleolus, apparently quite rapid and considerable. In figures 
6 to 11 there appears to be a change in shape of the nucleolus only, 
with little breaking into fragments, but a great vacuolization 
(these fragments, vacuoles, etc., are visible in the living egg). 
In later stages (figs. 12 to 17) the entire nucleolus breaks into 
many pieces, usually quite small, which, by the time the stage 
shown in figure 17 is reached, have almost entirely disappeared 
and a little later nothing of the nucleolus is left. 
Another phase of these same activities is indicated in the char- 
acter and appearance of the material which is leaving the nucleus 
and getting into the cytoplasm. In figure 6, as already noted, 
there are a few small deeply staining granules in the cytoplasm, 
close against the nuclear membrane; in figure 7 this is more evi- 
dent. In the stages which follow this the same thing is seen, 
sometimes very plainly, at other times not so clearly (figs. 7 to 
15). What becomes of the material when it gets into the cyto- 
plasm? Let it be noted, as figures 3 to 7 show, that the cytoplasm 
is at first finely granular, in very early stages very closely packed 
