the seed-like organs of certain Lycopods out of consideration) were always,
so far as we know, highly complex structures, with an elaborate vascular
system, a pollen-chamber, and often a much-differentiated testa. In the
present day such seeds exist only in a few Gymnosperms which retain their
ancient characters--in all the higher Spermophytes the structure is very
much simplified, and this holds good even in the Coniferae, where there is
no countervailing complication of ovary and stigma.

Reduction, in fact, is not always, or even generally, the same thing as
degeneration. Simplification of parts is one of the most usual means of
advance for the organism as a whole. A large proportion of the higher
plants are microphyllous in comparison with the highly megaphyllous fern-
like forms from which they appear to have been derived.

Darwin treated the general question of advance in organisation with much
caution, saying: "The geological record...does not extend far enough back,
to show with unmistakeable clearness that within the known history of the
world organisation has largely advanced." ("Origin of Species", page 308.)
Further on (Ibid. page 309.) he gives two standards by which advance may be
measured: "We ought not solely to compare the highest members of a class
at any two periods...but we ought to compare all the members, high and low,
at the two periods." Judged by either standard the Horsetails and Club
Mosses of the Carboniferous were higher than those of our own day, and the
same is true of the Mesozoic Cycads. There is a general advance in the
succession of classes, but not within each class.

Darwin's argument that "the inhabitants of the world at each successive
period in its history have beaten their predecessors in the race for life,
and are, in so far, higher in the scale" ("Origin of Species", page 315.)
is unanswerable, but we must remember that "higher in the scale" only means