of Hosts."

But, you will object, the grandest kings have had, as a rule, the
fewest loyal subjects. The prophets and seers are stoned. Elijah
stands alone on Carmel and opposed to him are more than a thousand
prophets of Baal, with court and king at their head. Heroism does
not pay, and heroes are few. Right is always in a hopeless minority.
Let us look into this matter carefully, for the objection, even if
overstated, certainly contains a large amount of truth.

Let us go back to two forms having much the same grade of
organization: both worms. One of them sets out to become a
vertebrate, building an internal skeleton. The other forms an
external skeleton and becomes a crab. To form its skeleton the crab
had only to thicken the cuticle already present in the annelid. It
had to modify the already existing parapodia and their muscles,
changing them to legs. The external skeleton gave from the start a
double advantage--protection and better locomotion. Every grain of
thickening aided the animal in the struggle for existence in both
these ways. The very fact that the skeleton was external may have
rendered it more liable to variation, because it was thus exposed to
continual stimuli. And the best were rapidly sifted out by Natural
Selection. The change and development went on with comparative
rapidity. In the mollusk the change was apparently still more easy
and the development still more rapid.

But the development of an internal skeleton was more difficult and
slower. It was of no use for the protection of the animal, and only
gradually did it become of much service in locomotion. Being
deep-seated it very possibly changed all the more slowly.
Furthermore, a cartilaginous rod, like the notochord, even fully
developed, hardly enabled the animal to fight directly with the
mail-clad crab. The internal skeleton had to become far more highly
developed before its great advantages, and freedom from
disadvantages, became apparent. The mollusk and crab were working a
mine rich in surface deposits although soon exhausted. The
vertebrate lead was poor at the surface, and only later showed its
inexhaustible richness. It looked as if the vertebrate were making a
very poor speculation.

Whether this explanation be true or not, a glance at a chart,
showing the geological succession of occurrence of the different
kingdoms, proves that in the oldest palaeozoic periods there were
well-developed cuttlefish and crabs before there we