eological remains.

The very earliest existing fossils would lead us to believe what is
otherwise quite probable, that life on our planet began with very small
forms--that it passed at first through a baby stage. The animals of the
Cambrian period are almost all small mollusks, star-fishes, sponges, and
other simple, primitive types of life. There were as yet no vertebrates
of any sort, not even fishes, far less amphibians, reptiles, birds, or
mammals. The veritable giants of the Cambrian world were the
crustaceans, and especially the trilobites, which, nevertheless, hardly
exceeded in size a good big modern lobster. The biggest trilobite is
some two feet long; and though we cannot by any means say that this was
really the largest form of animal life then existing, owing to the
extremely broken nature of the geological record, we have at least no
evidence that anything bigger as yet moved upon the face of the waters.
The trilobites, which were a sort of triple-tailed crabs (to speak very
popularly), began in the Cambrian Epoch, attained their culminating
point in the Silurian, waned in the Devonian, and died out utterly in
the Carboniferous seas.

It is in the second great epoch, the Silurian, that the cuttle-fish
tribe, still fairly represented by the nautilus, the argonaut, the
squid, and the octopus, first began to make their appearance upon this
or any other stage. The cuttle-fishes are among the most developed of
invertebrate animals; they are rapid swimmers; they have large and
powerful eyes; and they can easily enfold their prey (_teste_ Victor
Hugo) in their long and slimy sucker-clad arms. With these natural
advantages to back them up, it is not surprising that the cuttle family
rapidly made their mark in the world. They were by far the most advanced
thinkers and actors of their own age, and they rose almost at once to be
the dominant creatures of the primaeval ocean in which they swam. There
were as yet no saurians or whales to dispute the dominion with these
rapacious cephalopods, and so the cuttle family had things for the time
all their own way. Before the end of the Silurian Epoch, according to
that accurate census-taker, M. Barrande, they had blossomed forth into
no less than 1,622 distinct species. For a single family to develop so
enormous a variety of separate forms, all presumably derived from a
single common ancestor, argues, of course, an immense success in life;
and it also argues a vast lapse of