182 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
ent eggs of the same size, the reticulum retaining the deeply staining 
capacity in some for a long time. Just before the time of polar-cell 
formation, however, the germinative vesicle shows a minimal affinity 
for basic stains. 
During the changes last described there occurs a great increase in 
the size of the nucleus. Figures 29-46, all drawn to the same scale, 
make evident this growth. In the full grown egg the germinative 
vesicle is, however, very small in proportion to the size of the egg, as 
may be learned from Plate 7, Figures 55 (a nearly full grown egg) 
and 56 (one that has completed its growth). ‘The failure of certain 
observers to find the germinative vesicle is partly due, without doubt, 
to its relatively small size and its lack of affinity, at this time, for 
nuclear stains. 
Almost as soon as growth begins, though sometimes much later, 
the cytoplasm, which at first is compact and finely granular, becomes 
vacuolated or alveolar, and this condition continues throughout its 
subsequent development. In the early stages of growth, even when 
the egg has increased to one-quarter of its final size, no “‘pseudo-cells”’ 
are present. Grodnberg (’98) described the same condition in young 
ova of Tubularia coronata, and thought it was an indication that the 
increase in the size of the ovum was due to the formation of vacuoles 
in the cytoplasm, no oécytes, in his opinion, being absorbed until later. 
But in Tubularia crocea, at least, another explanation is more satis- 
factory. ‘The odcytes which are situated near the spadix and often 
retain their original position till a late stage, are usually the ones which 
first show signs of growth, and they probably secure nourishment 
from the spadix. Moreover, in Tubularia crocea, odcytes are absorbed 
by the egg during its early growing period, as well as at later stages. 
The absence of ‘“‘pseudo-cells”’ is a sign of complete digestion of 
absorbed odcytes, rather than of an increase of the ovum by simple 
vacuolization of the cytoplasm. Evidence of this is found in the fact 
that there are odcytes of many times their original size in which the 
cytoplasm is still granular or only slightly vacuolated. ‘The presence 
of ‘‘pseudo-cells”’ is, in part, an indication of the storing of food matter 
for future use. The absence of ‘“‘pseudo-cells”’ is characteristic of 
the eggs of Pennaria through their entire growth period, as Hargitt 
(:00, :04°) has shown; yet during this period the surrounding odécytes 
are being absorbed, and they furnish the food for the growing ovum, 
precisely as in Tubularia. 
The odcyte, though at first nearly spherical or ellipsoidal and having 
regular outlines (Plate 5, Fig. 38), later sends out blunt pseudopodia, 
