The Log of the Sun: A Chronicle of Nature's Year

by William Beebe

Any primer of Natural History will tell us that our bath sponges are the fibrous skeletons of aquatic animals which inhabit tropical seas, but few people know that in the nearest pond there are real sponges, growing sometimes as large as one’s head and which are not very dissimilar to those taken from among the corals of the Bahamas. We may bring home a twig covered with a thick growth of this sponge; and by dropping a few grains of carmine into the water, the currents which the little sponge animals set up are plainly visible. In winter these all die, and leave within their meshes numbers of tiny winter buds, which survive the cold weather and in the spring begin to found new colonies. If we examine the sponges in the late fall we may find innumerable of these statoblasts, as they are called.

Scattered among them will sometimes be crowds of little wheels, surrounded with double-ended hooks. These have no motion and we shall probably pass them by as minute burrs or seeds of some water plant. But they, too, are winter buds of a strange group of tiny animals. These are known as Polyzoans or Bryozoans; and though to the eye a large colony of them appears only as a mass of thick jelly, yet when placed in water and left quiet, a wonderful transformation comes over the bit of gelatine.... “Perhaps while you gaze at the reddish jelly a pink little projection appears within the field of your lens, and slowly lengthens and broadens, retreating and reappearing, it may be, many times, but finally, after much hesitation, it suddenly seems to burst into bloom. A narrow body, so deeply red that it is often almost crimson, lifts above the jelly a crescentic disc ornamented with two rows of long tentacles that seem as fine as hairs, and they glisten and sparkle like lines of crystal as they wave and float and twist the delicate threads beneath your wondering gaze. Then, while you scarcely breathe, for fear the lovely vision will fade, another and another spreads its disc and waves its silvery tentacles, until the whole surface of that ugly jelly mass blooms like a garden in Paradise—blooms not with motionless perianths, but with living animals, the most exquisite that God has allowed to develop in our sweet waters.” At the slightest jar every animal-flower vanishes instantly.

A wonderful history is behind these little creatures and very different from that of most members of the animal kingdom. While crabs, butterflies, and birds have evolved through many and varied ancestral forms, the tiny Bryozoans, or, being interpreted, moss-animals, seem throughout 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 smaller beings which swim about him, many of which consist of but one cell and are popularly known as animalculæ, more correctly as Protozoans. Cyclops has a jointed body and in many other ways shows his relationship to crabs and lobsters, even though they are many times larger and live in salt water.

Another member of this group is Daphnia, although the appropriateness of this name yet remains to be discovered; Daphnia being a chunky-bodied little being, with a double-branched pair of oar-like appendages, with which he darts swiftly through the water. Although covered with a hard crust like a crab, this is so transparent that we can see right through his body. The dark mass of food in the stomach and the beating heart are perfectly distinct. Often, near the upper part of the body, several large eggs are seen in a sort of pouch, where they are kept until hatched.

So if the sea is far away and time hangs heavy, invite your friends to go sponging and crabbing in the nearest pond, and you may be certain of quieting their fears as to your sanity as well as drawing exclamations of delight from them when they see these beautiful creatures for the first time.