ughout all past
ages to have found a niche for themselves where strenuous and active
competition is absent. Year after year, century upon century, age upon
age, they have lived and died, almost unchanged down to the present day.
When you look at the tiny animal, troubling the water and drawing its
inconceivably small bits of food toward it upon the current made by its
tentacles, think of the earth changes which it has survived.

To the best of our knowledge the Age of Man is but a paltry fifty thousand
years. Behind this the Age of Mammals may have numbered three millions;
then back of these came the Age of Reptiles with more than seven millions
of years, during all of which time the tentacles of unnumbered generations
of Bryozoans waved in the sea. Back, back farther still we add another
seven million years, or thereabouts, of the Age of the Amphibians, when
the coal plants grew, and the Age of the Fishes. And finally, beyond all
exact human calculation, but estimated at some five million, we reach the
Age of Invertebrates in the Silurian, and in the lowest of these rocks we
find beautifully preserved fossils of Bryozoans, to all appearances as
perfect in detail of structure as these which we have before us to-day in
this twentieth century of man's brief reckoning.

These tiny bits of jelly are transfigured as well by the grandeur of their
unchanged lineage as by the appearance of the little animals from within.
What heraldry can commemorate the beginning of their race over twenty
millions of years in the past!

The student of mythology will feel at home when identifying some of the
commonest objects of the pond. And most are well named, too, as for
instance the Hydra, a small tube-shaped creature with a row of active
tentacles at one end. Death seems far from this organism, which is closely
related to the sea-anemones and corals, for though a very brief drying
will serve to kill it, yet it can be sliced and cut as finely as possible
and each bit, true to its name, will at once proceed to grow a new head
and tentacles complete, becoming a perfect animal.

Then we shall often come across a queer creature with two oar-like feelers
near the head and a double tail tipped with long hairs, while in the
centre of the head is a large, shining eye,--Cyclops he is rightly called.
Although so small that we can make out little of his structure without the
aid of the lens, yet Cyclops is far from being related to the other still