If the ocean which contains these wondrous forms should suddenly become dry, we should find that its contour is very similar to that of the land. There would be hills, valleys, plains, mountains, and seeming river-beds where currents have flowed; and so sharply are these defined, where growing atolls and reefs abound, one may stand--as I have often done upon those of the Florida reef--and drop a leaded line almost directly to the bottom in the clear blue waters. This submarine scenery would not show the rough and jagged outlines which are a characteristic of terrestrial mountain ranges. Nearly all prominences in water at a considerable depth are well rounded off by a coating of fine ooze, formed of the minute and delicate shells of the _globerigina_, one of the lowest organized of animal life. These little creatures live upon the bottom, or in the watery space above, and the ooze which makes the sea-bottom, in great thickness, is almost entirely made up of the dead and cast-off shells of these microscopical creatures. The chalk cliff of Dover, England,--that white headland which has given the ancient name of Albion to the mother country,--is an upheaved mass of the same material, once found in the ocean bottom, now elevated by some geological change, and hardened into chalk, which it really is. What a surprising monument, erected by Nature’s processes from the myriads of bodies of her most minute and most simply organized animals! The familiar modern term “protoplasm” represents what is know to be the simplest form of life; scarcely more, seemingly, than a bit of jelly, without form, and we might say void of organization, for it is alive, and yet has no nerves, no organized vessels which we can perceive, but exists in our pools as the least organized animal known. There is a species which belongs to one of the numerous kinds or groups of this the first and least perfect of the animal kingdom, which has also the great distinction of being the best known and most brilliant of marine light-bearers. This is the _Noctiluca_, or, as its name implies, the night-light. This little creature, but little more than visible to the naked eye, is the largest of the so-called infusorians; others of this group of animals requiring the aid of a microscope to determine the form. It is but little more in structure than the bit of protoplasm, or simplest organism or animal known. It looks when magnified--its natural size being about that of a pin’s head--much more highly organized than the others, by being almost a complete globe, and provided with a whip-like process or member. It is also veined somewhat, and reminds one of a currant or gooseberry. Now, it is often noticed that the smaller the animal, the more numerous; indeed, also, the more numerous its progeny. We may well be prepared, then, to hear that these minute creatures often swarm on the ocean surface in myriad masses.