C h a p t e r XVII.
Proofs o f Design in the Structure of Fossil
Radiated Animals, or Zoophytes.
The same difficulties which we have felt in selecting
from other grand Divisions of the animal
kingdom, subjects of comparison between the extinct
and living forms of their respective Classes,
Orders, and Families, embarrass our choice also
from the last Division that remains for consideration.
Volumes might be filled with descriptions
of fossil species of those beautiful genera
of Radiated Animals, whose living representatives
crowd the waters of our present seas.
The result of all comparisons between the living
and fossil species of these families would be,
that the latter differ almost always in species,
and often in genus, from those which actually
exist ; but that all are so similarly constructed on
one and the same general Type, and show such
perfect Unity of Design throughout the infinitely
varied modifications, under which they now perform,
and ever have performed the functions
allotted to them, that we can find no explanation
of such otherwise mysterious Uniformity, than
by referring it to the agency of one and the same
Creative Intelligence.
FOSSIL ECH1NODERMS. 415
SECTION I.
FOSSIL ECHINODERMS.
The animals that compose this highest Class in
the grand division of Radiated animals, viz.
Echinidans, Stelleridans, and Crino'ideans, have,
till lately, been considered as made up of many
similar parts disposed like Rays around a common
centre.
Mr. Agassiz has recently shewn, (London and
Edin. Phil. Mag. Nov. 1834, p. 369), that they
do not partake of this character, from which the
division of radiated animals is named; but that
their rays are dissimilar, and not always connected
with an uniform centre; and that a bilateral
symmetry, analogous to that of the more
perfect classes of animals, exists throughout the
families of Echini, Asteriae, and Crinoidea.
ECH IN ID A NS AND ST E LL ERIDANS.
The History of the fossil species of Echinidans
and Stelleridans has been most beautifully illustrated,
in the plates of the Petrefacten of Prof.
Goldfuss. Though derived from Strata of various
degrees of high antiquity, they are for the most
part referred by him to existing Genera.
The family of Echinidans appears to have ex