HARGITT: PENNARIA TIARELLA AND TUBULARIA CROCEA. 183 
which may extend for a considerable distance among the odcytes (Plate 
7, Fig. 55). The boundaries of the odcytes break down, and their 
cytoplasm fuses with that of the growing egg, as described by Allen 
(:00), the nuclei of the absorbed odcytes remaining as the “‘pseudo- 
cells.” Some of these remain undigested even in the actinula at the 
time of its liberation, as Allen showed. ‘The egg as it approaches 
maturity gradually withdraws its pseudopodia (Fig. 56) and becomes 
spheroidal. Until this condition is reached the final stages in matu- 
ration do not occur. The nucleus, which in the odcytes is central 
(Figs. 29-38), remains so for a short time after growth begins, but 
as soon as pseudopodia are formed, or even before that time, it takes 
a position at the periphery (Figs. 55, 56). 
a. Nucleolus.— After the last o6gonial division is completed, and 
while the nucleus is re-forming in the young oécyte, the chromatin 
is so closely massed and so intensely stained that nothing can be de- 
termined as to the origin of the nucleolus; for when the details of 
the nuclear structure become visible, the nucleolus is already present. 
In the oégonia and young oécytes the nucleoli and nuclear reticulum 
stain as follows: with either Ehrlich’s or Delafield’s hematoxylin 
and eosin nucleolus red, reticulum blue or purple; with Conklin’s 
picro-hematoxylin the nucleolus yellow or brownish, reticulum blue; 
with Delafield’s hematoxylin and cochineal the nucleolus brownish, 
reticulum bluish; with Heidenhain’s iron hematoxylin both nucleolus 
and reticulum intensely black or deep blue. In destaining, following 
the last mentioned method, the nucleolus holds the color as tenaciously 
as the reticulum. Often fine linin fibres, which stain with the plasma 
or acid dyes, can be seen extending from the nucleolus to the reticulum. 
With the formation of the nuclear reticulum in the odcyte the 
nucleolus increases in size, as is to be seen by comparing o6gonia with 
oocytes (Plate 4, Fig. 29). Figure 34 (Plate 5) shows two odcytes in 
different stages of development, the older and larger one containing the 
larger nucleolus. Apparently the increase in the size of the nucleolus 
is not due to the acquisition of chromatin, since the nucleolus retains 
its original affinity for acid dyes. Moreover, the spireme itself is at 
the same time growing in length and volume, and shows an increasing 
affinity for plasma or acid dyes. Even at the time of synapsis the 
spireme stains purplish with hematoxylin and eosin, thus selecting 
some of the acid stain. Hence it seems probable that the increase in 
the size of both nucleolus and spireme is due to the same cause, per- 
haps to the absorption of nuclear sap. 
The degenerative changes of the nucleolus first become evident in 
