OVUM IN THE CAPE AND NEW ZEALAND PERIPATUS. 2] 
presence points to its possessing any special function, since I 
am not able to trace any such, and it appears to be completely 
absorbed before the disappearance of the nucleus, and does not, 
as Blochmann (5) describes in Neritina fluviatilis, break 
up and given rise to the chromatin particles of the nuclear plate. 
Disappearance of the Germinal Vesicle. 
The existence of a stage in the ripening of the ovum in 
which no nucleus is visible has now been described in almost 
all eggs whose maturation has been at all completely investi- 
gated. In many of these cases the mode of disappearance has 
not been observed, but in most of those in which the process 
has been seen it is similar to that which I have described in 
Peripatus capensis and P. Balfouri, namely, that the 
nucleus loses its round shape, its outline becomes irregular, 
and by the loss of its membrane its contents mingle with and 
finally become indistinguishable from the protoplasm of the 
egg. Between this stage and that at which the nucleus is 
again visible, when it is small and in the spindle stage about 
to bud off the second polar body, there is no trace of the ger- 
minal vesicle in the ovum. I wish here to draw attention to 
the fact that my observations were made on complete series of 
sections of well-preserved ova, so that the probability of my 
having overlooked it is not great. ‘This mode of disappearance 
has been described by Henking (10) in Phalangeden, and by 
Stuhlmann (17) in a considerable number of insects. The 
loss of the nuclear membrane is also described by Scharff (13) 
as occurring in some osseous fishes, although he does not state 
that all trace of the nucleus disappears. Lankester (12) also 
describes a stage in the ovum of Sepia in which no germinal 
vesicle is present. 
Blochmann (5) describes in Neritina fluviatilis the loss 
of the nuclear membrane, and consequent mingling of the 
nucleo- and egg-plasma, but states that the germinal spot 
remains, and, breaking up, gives rise to the chromatin of the 
nuclear plate. This certainly cannot be the case in the Cape 
