590 SYDNEY J. HICKSON. 
with a little experience, to distinguish at a glance sections 
of the oosperm nucleus and of the germinal vesicle at the 
stage represented in Pl. XXXVIII, fig. 12; but the determi- 
nation can in all cases be confirmed by the presence or absence 
of the remnants of the polar bodies. 
When the membrana limitans disappears it is impossible to 
distinguish the outline of the oosperm nucleus. The ovum 
then bears, in the middle of the distal side near the periphery, 
a protoplasmic portion, surrounded by numerous very small 
yolk-spheres irregularly distributed, that stains rather more 
deeply than the rest of the protoplasm of the egg. This 
portion contains, so far as I can observe with high powers, no 
other histological elements than a few scattered fragments of 
chromatin fibres. 
In the next stage observed I found one or two irregular 
lumps of nuclear substance close to the distal side of the 
young embryo, and seven or eight oval or spherical deeply 
stained nuclear bodies (‘005 to ‘01 mm. in diameter) scattered 
about in the protoplasm of the distal pole. In the next stage 
the irregular lumps have disappeared, and the nuclear bodies 
increased in number (Pl. XX XVIII, figs. 14, 16. 
I have paid particular attention to these stages in the 
development of Allopora, and I can find no trace whatsoever 
of any division of the protoplasm in the neighbourhood of the 
nucleus, and no evidence that would lead me to suppose that 
I have missed any stages of regular segmentation either of the 
nucleus or the egg protoplasm. 
The evidence before me, so far as it goes, seems to show 
that in Allopora the oosperm nucleus, after losing its mem- 
brana limitans, simply breaks up into fragments, and that 
from the fragments a number of embryonic nuclei are formed 
that wander into the region of the embryo that might be 
called the blastoderm, where they rapidly multiply by a process 
of growth and simple division. The larger irregular lumps of 
nuclear substance found only in the earliest stages I take to 
be portions of the oosperm nucleus that have not so frag- 
mented, 
