nks." But considered from the point of view of
Paedogenesis, they all assume quite a different aspect, and seem rather to
represent very highly evolved species, and to be, not primitive forms, but
conservative and regressive forms. Paedogenesis is the phenomenon exhibited
by a number of species, which may stop short at one of the stages of their
embryonic or larval development, become sexually mature, and produce
offspring without having attained their own fully developed form.

Another argument is the old, suggestive, and really important one urged by
Koelliker, that "inorganic nature shows a natural system among minerals
(crystals) just as much as animals and plants do, yet in the former there
can be no question of any genetic connection in the production of forms."

Yet another argument is found in the occurrence of "inversions" and
anomalies in the palaeontological succession of forms, which to some extent
upsets the Darwinian-Haeckelian genealogical trees. (Thus there are forms
in the Cambrian whose alleged ancestors do not appear till the Silurian.
Foraminifera and other Protozoa do not appear till the Silurian.)

From embryology in particular, as elsewhere in general, we read the
"fundamental biogenetic law," that evolution is from the general to the
special, from the imperfect to the more perfect, from what is still
indefinite and exuberant to the well-defined and precise, but never from
the special to the special. According to Hamann's hypothesis we must think
of evolution as going on, so to speak, not about the top but about the
bottom. The phyla or groups of forms are great trunks bearing many
branches and twigs, but not giving rise to one another. Still less do the
little side branches of one trunk bear the whole great trunk of another
animal or plant phylum. But they all grow from the same roots among the
primitive forms of life. Unicellulars these must have been, but not like
our "Protists." They should be thought of as primitive forms having within
themselves the potentialities of the most diverse and widely separate
evolution-series to which they gave rise, as it were, along diverging
fan-like rays.

It would be instructive to follow some naturalist into his own particular
domain, for instance a palaeontologist into the detailed facts of
palaeontology, or an embryologist into those of embryology, in order to
learn whether these corroborate the assumptions of the Theory of Descent
or not. It is just in