Review . 
Evidence of pollination lias not been found. No organ is present 
that can be termed a pollen-chamber, nor have microspores been 
found within the slit-like micropyle ; assuming for the moment that 
we have here a true seed, where would one search for a pollen- 
chamber ? In the Cycads and in the fossil Gymnosperm seeds the 
nucellus has a definite apex in which the chamber is excavated. It is 
a reasonable conjecture that the development of a pollen-chamber 
is only an adaption from an ancestral sporangial dehiscence. But 
we know nothing about the dehiscence of the bulky sporangia of 
Lepidostrobus , which in all probability was irregular and undefined. 
Ex niJuIo etc. On this view the absence of a pollen-chamber in the 
present case is intelligible. 
Turning to the alternative hypothesis that the “seeds” were 
not real seeds, but that all the specimens observed, whether with or 
without-prothallia, were still unfertilized or even unpollinated, Dr. 
Scott remarks—“ If this were so, the organs in question were 
certainly not true seeds, though it is possible that the evolution of true 
seeds may have started in the same way.” Lepidocarpon may be 
regarded as representing the lowest member of a series (not of course 
a phylogenetic series) in which the macrosporangium became integu- 
mented, and, unpollinated and unfertilized, fell to the ground. The 
next stage may be represented by the fossil Gymnosperm seeds in 
which the evidence points to a shedding of an integumented macro¬ 
sporangium, already pollinated but not yet fertilized. 
A further advance is perhaps represented by Cycas and Ginkgo 
where the seed is already fertilized at the time of its detachment, 
but as yet no embryo has been developed. Finally we come to Finns , 
which is not only fertilized but embryonated as w r ell, giving us the 
structure upon which we base our definition of a seed. 
In such a series we note amongst other things (1) a prolongation 
of the period of retention on the parent plant in relation to the time 
of occurrence of the act of fertilization; (2) a gradual retarding of 
the maturing and hardening of the integument; (3) an increase of 
the intimacy between sporangium and integument; at the outset 
{Lepidocarpon) the integument grows up freely from the sporophyll 
as a mere sporangial envelope and is in nature a sporangial envelope 
rather than a seed coat (the microsporangium is similarly provided). 
In the second stage the coat has become a definite portion of a seed, 
still probably free from it, though subordinated to the special seed 
requirements. Finally in the late stages, in the typical seeds on 
