y Articulates as
Insects or Crabs. Thus, by misplacing certain animals, he arrived at a
series which, like that of Lamarck, made a strong impression on the
scientific world, till a more careful investigation of facts exposed its
fallacy.

Oken, the great German naturalist, also attempted to establish a
connected chain throughout the Animal Kingdom, but on an entirely
different principle; and I cannot allude to this most original
investigator, so condemned by some, so praised by others, so powerful in
his influence on science in Germany, without attempting to give some
analysis of his peculiar philosophy. For twenty years his classification
was accepted by his countrymen without question; and though I believe it
to be wrong, yet, by the ingenuity with which he maintained it, he has
shed a flood of light upon science, and has stimulated other naturalists
to most important and interesting investigations. This famous
classification was founded upon the idea that the system of man, the
most perfect created being, is the measure for the whole Animal Kingdom,
and that in analyzing his organization we have the clue to all organized
beings. The structure of man includes two systems of organs: those which
maintain the body in its integrity, and which he shares in some sort
with the lower animals,--the organs of digestion, circulation,
respiration, and reproduction; and that higher system of organs, the
brain, spinal marrow, and nerves, with the organs of sense, on which all
the manifestations of the intelligent faculties depend, and by which his
relations to the external world are established and controlled: the
whole being surrounded by flesh, muscles, and skin. On account of this
fleshy envelope of the hard parts in all the higher animals, Oken
divided the Animal Kingdom into two groups, the Vertebrates and
Invertebrates, or, as he called them, the "_Eingeweide und Fleisch
Thiere_"--which we may translate as the _Intestinal Animals_, or
those that represent the intestinal systems of organs, and the _Flesh
Animals_, or those that combine all the systems of organs under one
envelope of flesh. Let us examine a little more closely this singular
theory, by which each branch of the Invertebrates becomes, as it were,
the exponent of a special system of organs, while the Vertebrates, with
man at their head, include all these systems.

According to Oken, the Radiates, the lowest type of the Animal Kingdom,
embody digestion. They all r