462 Oliver . — The Ovules of the older Gymnosperms. 
not yet fully studied, seem to have been filled with a tissue 
as in the well-known case of Stephanospermum 1 . They would 
in that case belong to the old type, and it may reasonably be 
suspected that they liberated spermatozoids. A consideration 
of the relations of this pollen-chamber at one time suggested 
that perhaps the pollen-grains formed haustorial attachments 
in the central cone of parenchyma and behaved somewhat as 
in Cycads, but the best specimens give no support to such an 
hypothesis, which must accordingly be rejected. Another 
view is based on the peculiar relations of the micropyle. As 
shown in Fig. 9, the micropyle is plugged by the summit 
of the nucellus, so much so that if this condition obtained at 
pollination the intervention of a micropyle would be dispensed 
with. If, now, there were any reason for believing that the 
apices of the chambers of the canopy were porous, if the 
tracheal strands could be supposed to end in hydathodes, all 
the essentials of a contrivance for supplying the pollen- 
chamber with water would be present. For whatever may 
have been the natural position of the seed (pendent or erect), 
a drop of water at the summit would inevitably be drawn into 
the narrow crevice of the pollen-chamber. The specimens 
convey the impression that the wall of the pollen-chamber was 
so tightly jammed in the micropyle as to exclude the siphoning 
of water into the spacer*. (Fig. 9) which lies between the canopy 
and the true pollen-chamber. As yet no sections are available 
which fully elucidate the mode in which the strands end at 
the micropyle ; but the preservation of this seed occasionally 
reaches such a high standard of excellence as to encourage the 
hope that such sections may eventually be forthcoming. 
Sufficient has been said regarding Lageno stoma to show 
that whilst it resembled Cycads in the considerable area 
of ‘ fusion ’ that obtains between the nucellus and testa, as 
well as in the presence of vascular strands in the plane of 
‘ fusion,’ it is yet marked by peculiarities all its own. The 
confined form of the pollen-chamber marks an advance in 
precision on the open type of the ordinary palaeozoic seed, 
1 Cf. Renault, Cours de bot. fossile, IV, PI. XXI, p. 99. 
