IG.
1.
A
3PN
embryo
fixed
at
the
pronuclear
stage.
(a)
Centriolar
complex
and
sperm
midpiece
are
closely
associated
with
the
nuclear
envelope
of
one
pronucleus
(arrowhead).
Two
dense
compact
nucleoli
are
seen
within
the
pronucleus.
G,
Golgi
complex.
(x7000.)
(b)
Centriolar
complex
at
higher
magnification.
The
proximal
centriole
(C)
is
sectioned
longitudinally
and
is
obscured
by
osmiophilic
centrosomal
material.
Outer
dense
fibers
are
evident
in
the
axonemal
region
of
the
midpiece
(M).
0,
ooplasm;
P,
pronucleus.
(x70,000.)