ny of the later groups, for
they recall the past, as the former anticipate the future. And it is not
only among the Fishes and the Reptiles that we find these combinations.
The most numerous of the ancient Radiates are the Acalephlan Corals,
combining, in the Hydroid form, the Polyp-like mode of life, habits, and
general appearance with the structure of Acalephs. The Crinoids, with
the closed cups in some, and the open, star-like crowns in others, unite
features of the present Star-Fishes and Sea-Urchins, and, by their stem
attaching them to the ground, include also a Polyp-like character; while
the Trilobites, with their uniform rings and their prominent anterior
shield, unite characters of Worms and Crustacea.

These early types seem to sketch in broad, general characters the
Creative purpose, and to include in the first average expression of the
plan all its structural possibilities. The Crinoid forms include the
thought of the modern Star-Fishes and Sea-Urchins; the simple chambered
shells of the Silurian anticipate the more complicated structure of the
later ones; the Trilobites give the most comprehensive expression of the
Articulate type; while the early Fishes not only prophesy the Reptiles
which are to come, but also hint at Birds and even at Mammalia by their
embryonic development and their mode of reproduction.

Looked at from this point of view, the animal world is an intellectual
Creation, complete in all its parts, and coherent throughout; and when
we find, that, although these ancient types have become obsolete and
been replaced by modern ones, yet there are always a few old-fashioned
individuals, left behind, as it were, to give the key to the history
of their race, as the Gar-Pike, for instance, to explain the ancient
Fishes, the Millepore to explain the old Acalephian Corals, the Nautilus
to be the modern exponent of the Ammonites and Orthoceratites of past
times, we cannot avoid the impression that this Creative work has been
intended also to be educational for Man, and to teach him his own
relation to the organic world. The embryology of the modern types
confirms this idea, for here we find an epitome of their geological
history. The embryo of the present Star-Fishes recalls the Crinoids;
the embryo of the Crab recalls the Trilobites; the embryo of the
Vertebrates, including even that of the higher Mammalia, recalls the
ancient Fishes. Does not this fact, that the individual animal in its
growth rec