THE PALJEOZOIC SEED LAGENOSTOMA OVOIDES. 483 
evidence forthcoming in its support, we are still faced with the difficulty as 
to the source of the water which must have been required for fertilization. 
Is it not just possible that this was obtained from the exterior by means of 
the apical grooves? Any atmospheric water, rain, dew, ete. would be held 
by surface tension, and the tiny rivulets would tend to form a drop where 
they converge. 
It is unfortunate in this connection that we have no indication as to how 
our seed was borne, but, to quote Oliver (p. 462), “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," and any pollen-grains on the apex of the seed would thus be 
swept along the grooves into the lagenostome. As already recorded (p. 478), 
one certain and several suggestive cases of pollen in the grooves have been 
found, all that could be expected to occur among the few sections passing 
through this region. 
A very tempting hypothesis as to the method of pollination is that the 
dark, upper part of the nucellar cone was glandular and excreted a sugary 
substance to which the grains would stick, whether brought by wind or 
insects. But though there seems nothing directly to negative this possi- 
bility, there is, on the other hand, no evidence in its favour. The tissue is 
difficult to examine, but gives the impression of being thick-walled and 
without contents, which is not what one would expect to be the appearance 
of secretory tissue. A more probable function subserved by this organ is 
that of protection, against cold, desiccation, etc., of the delicate organs 
which lie beneath—particularly the growing embryo. We have physio- 
logically analogous cases in the closing of the cone-scale after pollination in 
recent Gymnosperms, and in the obliteration of the micropyle at the same 
period in Gnetum Gnemon, recently described by Berridge (3) *. Ап even 
closer parallel is afforded by the approximation and hardening of the walls 
forming the “beak” in Cycadean tseeds (6, p. 128). Of course it is not 
beyond the bounds of possibility that the apex of the central cone was at 
first glandular, and subsequently became modified to form, as it were, a 
stopper for the flask-shaped, pollen-containing organ. But while facts are 
lacking in support of the former hypothetical function, some evidence can 
be adduced in favour of the latter. In the first place, the very peculiar 
organization of Lagenostoma whereby the pollen-chamber projects beyond 
the integument in a seed that almost certainly, when mature, had no 
envelope of any sort extending over the micropyle, would suggest the 
necessity for some protective organ for the important structures which 
would otherwise be exposed to the outer air, invasion by fungus, ete. But 
* The author suggests that the micropyle of Bennettites M. orierei was blocked in a similar 
way, but this is denied by Lignier (9). 
