4 66 Oliver . — Z&? Ovules of the older Gy mno sperms. 
bundles could take place, and in an instance like Cycas 
Rumphii it is readily comprehensible that a certain number 
of the nucellar strands in the neighbourhood of the principal 
plane might have joined up with the integumental bundles 
as shown in Fig. 3. In other cases, as in Stangeria where 
nucellar and integumental bundles appear to arise in common, 
the whole of the nucellar bundles may have undergone this 
change of insertion ; whilst even in the complex Zamia it 
is possible to understand that the growing basal zone gave 
opportunity for the production of the anastomoses outlined 
above. But of course no attempt is made to offer a special 
explanation for each several case— that is out of the question. 
The suggestion made is a general inference from the facts, and 
its validity must depend on the degree in which it renders 
the structure of the Cycad ovules more intelligible than it 
was before. The main significance of this intercalation is 
probably nutritive — the provision of a suitable brood-chamber 
for the nursing of the embryo. 
The other point that calls for notice here is the retreat 
of the nucellar bundles from the pollen-chamber (of. Figs. 1, 
2, and 3). In the Cycadean ovule they are no longer needed 
so urgently as in the palaeozoic seeds (especially the Radio- 
sperms), mainly because the pollen effects haustorial attach- 
ments in the nucellar tissues, obtaining thus the water required 
in further development, and even for the swimming of the 
spermatozoids in their brief journey to the archegonium. 
In part, perhaps, the broader surface of continuity of the 
tissues of nucellus and integument (a result of the basal 
extension) would be a contributing factor in the decline of the 
water-excreting tracheal contrivance which was so conspicuous 
in palaeozoic times. 
4. Torreya. 
The facts of the vascular anatomy in the seeds of this genus 
of Taxaceae are peculiar and isolated among recent plants, 
and in the light of palaeozoic seeds would mark it as an 
archaic type even were Torreya not recognized as far back as 
