sive tail,
enabling it to strike the water powerfully and dart forward with great
rapidity. There were also a host of small Fishes, comparing with those
above mentioned as our Perch, Herring, Smelts, etc., compare with our
larger Fishes; but, whatever their size or form, all the Fishes of those
days had the same hard scales fitting to each other by hooks, instead of
the thin membranous scales overlapping each other at the edge, like the
common Fishes of more modern times. The smaller Fishes, no doubt,
afforded food to the larger ones, and to the aquatic Reptiles. Indeed,
in parts of the intestines of the Ichthyosauri, and in their petrified
excrements, have been found the scales and teeth of these smaller Fishes
perfectly preserved. It is amazing that we can learn so much of the
habits of life of these past creatures, and know even what was the food
of animals existing countless ages before man was created.

There are traces of Mammalia in the Jurassic deposits, but they were of
those inferior kinds known now as Marsupials, and no complete specimens
have yet been found.

The Articulates were largely represented in this epoch. There were
already in the vegetation a number of Gymnosperms, affording more
favorable nourishment for Insects than the forests of earlier times; and
we accordingly find that class in larger numbers than ever before,
though still meagre in comparison with its present representation.
Crustacea were numerous,--those of the Shrimp and Lobster kinds
prevailing, though in some of the Lobsters we have the first advance
towards the highest class of Crustacea in the expansion of the
transverse diameter now so characteristic of the Crabs. Among Mollusks
we have a host of gigantic Ammonites; and the naked Cephalopods, which
were in later times to become the prominent representatives of that
class, already begin to make their appearance. Among Radiates, some of
the higher kinds of Echinoderms, the Ophiurans and Echinolds, take the
place of the Crinoids, and the Acalephian Corals give way to the Astraean
and Meandrina-like types, resembling the Reef-Builders of the present
time.

* * * * *

I have spoken especially of the inhabitants of the Jurassic sea lying
between England and France, because it was there that were first found
the remains of some of the most remarkable and largest Jurassic animals.
But wherever these deposits have been investigated, the remains
contained i