//. The Ovule of Stangeria paradoxa . 285 
possible to demonstrate any connexion between them and 
the nuclear division. 
None of the cones collected supplied the first stages of 
division within the megaspore, but from the study of the 
ovules next in age to the one last described (Fig. 7) it was 
clear that keeping pace with the increase in size of the ovule 
the embryo-sac enlarges. Its fairly thick wall is lined by 
a cytoplasmic layer in which numerous nuclei are distributed. 
Fig. 8 shows the longitudinal, and Fig. 9 the transverse, section 
of the nucellus of an ovule at this stage. The increase in size 
of the embryo-sac up to this stage does not appear to in¬ 
volve any considerable destruction of the sporogenous tissue, 
but to stand in relation to the growth of the ovule as 
a whole. As this takes place, the histological regions of the 
integument become more clearly marked out, and the differ¬ 
entiation of the xylem-elements takes place in the vascular 
bundles. 
But the only point which calls for more special description 
has regard to the changes in form and mutual relations which 
take place in the nucellus and integument-margin in the 
region of the micropyle. In the youngest ovules examined 
the sides of the free apex of the nucellus are vertical, while its 
flat broad top stands on a level with the margin of the 
integument or even projects slightly above the latter (Figs. 2, 
3, 10). In the general growth of the ovule the projecting 
portion of the nucellus keeps pace for some time with the 
free portion of the integument. It becomes more conical, 
however, but the flat top is retained. In the ovule repre¬ 
sented in Fig. 11 this top is just below the level of the 
micropylar margin which is formed by the edge of the integu¬ 
ment. As the latter comes to project further beyond the 
nucellus-apex, the micropyle is greatly narrowed, though the 
margin of the canal is still thin. In a slightly more advanced 
stage the integument becomes greatly thickened so that the 
micropyle forms a long passage, the external opening of 
which is narrow, while it widens out in passing inwards. 
Into this wider portion the conical tip of the nucellus-apex 
