170 Benson . — Telangium Scotti , a Species of 
evolved, a period probably anterior to the Carboniferous epoch, it may 
be conjectured that the arrangement of the sporangia in the sorus was 
irregular, and that the more centrally placed sporange with its better 
vascular supply may have gradually attained the megasporangial condition. 
In Gleichenia and Oligocarpia some sori have, and others have not, a central 
sporange. As respects the vascular supply in the centre of each compartment 
of the integument, it is well known that in many of the Permo-Carboniferous 
seeds a vascular bundle entered the base of the nucellus, even passing 
from the chalaza to the pollen-chamber \ and it is hence easy to conceive 
of a vascular strand having early entered its sister sporangia. Again, if we 
take an example from a seed of very remote affinity, we find that in Castanea 
a vascular strand may be demonstrated running up the whole length of the 
nucellus, and is especially well developed in nucelli whose embryo-sacs have 
long remained unfertilized. 
I will now proceed to show that this interpretation of the integument 
of Lagenostoma is helpful in clearing away many of the difficulties that 
have beset the general problem of the integument hitherto. The more 
generally accepted interpretation of the inner integument is that it 
is due to a special development of the indusium. We are compelled 
to regard the integument of Lagenostoma as a single integument, firstly 
because of the primitive character of the seed, and secondly because of 
the existence in Z. Lomaxi of an exterior envelope. Hence it is probably 
safe to regard it as homologous with the inner integument, and conse- 
quently as hitherto accounted for merely by Celakovsky’s theory of the 
indusium, or by another theory to which I will allude later. But the 
cohesion of integument and nucellus which we know to be characteristic 
of the Cycadean seed receives no explanation on the indusial theory, 
whereas on the synangial theory the cohesion is seen to be due to the 
origin of the seed from structures already coherent. 
Moreover, as it is generally agreed that the heterosporous habit arose 
from the homosporous, it is a priori probable that there should be a cor- 
respondence between the microsporangial sorus and the primitive seed, 
and this correspondence seems best obtained by harmonizing the seed 
and the synangium. 
If it should be shown conclusively that T. Scotti is the micro- 
sporangial organ of Lyginodendron the homologizing of Lagenostoma with 
its £ synangium would simplify the problem of the integument in that 
we should then have but one envelope to account for in the seed over 
and above what was present in the male sorus. 
I will now refer shortly to another widely accepted view, which has 
been adopted by Strasburger, Treub, and Dr. Lang. Though their views 
Oliver, loc. cit., p. 454. 
