ed by curved lines, the crystalline by
straight; the intermediate partly by curved and partly by straight
lines. They are the dicone (the shape of a diabolo) and the cylinder.
These forms must necessarily be of importance for the skeleton, which is
intermediate between the organic and the inorganic. "The dicone embodies
the real significance of the bone," writes Carus. Each dicone and
cylinder composing the skeleton is called by Carus a vertebra.

We may expect then all skeletons to be composed of spheres, cylinders
and dicones in diverse arrangements. Nature being infinite, all the
possible types of arrangement of these elements must exist in the test
or skeleton of some animal, living, fossil, or to come (p. 127). One
conceives easily what the main types of skeleton must be. In some
animals, _e.g._, sea-urchins, the skeleton is a simple sphere; in
others, _e.g._, starfish, secondary rows of spheres radiate out from a
central sphere or ring; in annulate animals the skeleton consists of a
row of partially fused spheres.

In Vertebrates the arrangement is more complex. There are first the
protovertebral rings of the dermatoskeleton, these being principally the
ribs, limb-girdles, and jaws. Round the central nervous system are
developed the deutovertebral rings of the neuroskeleton (vertebrae in the
ordinary sense). The apophyses and bodies of the vertebrae, and the bones
of the members[160] are composed of columns of tritovertebrae, or vertebrae
of the third order. Thus the whole vertebrate skeleton is a particular
arrangement of vertebrae, which in their turn are modifications of the
primary hollow sphere.

The German transcendentalists were more or less contemporary with E.
Geoffroy, and no doubt influenced him, especially in his later years, as
they certainly did his follower Serres. Oken indeed wrote, in a note[161]
appended to Geoffroy's paper on the vertebral column of insects, that
"Mr Geoffroy [_sic_] is without a doubt the first to introduce in France
_Naturphilosophie_ into comparative anatomy, that is to say, that
philosophy one of whose doctrines it is to seek after the
_signification_ of organs in the scale of organised beings." This is,
however, an exaggeration, for Geoffroy was primarily a morphologist,
whereas the morphology of the German transcendentalists was only a
side-issue of their _Naturphilosophie_.

Geoffroy, on his part, exercised some influence on the
transcendentalists. He asserts[162] ind