A good idea of the celebrated red and pink Coral of commerce, so much admired for its brilliant color, and the high polish of which it is susceptible, may be gathered from our next illustration. As in the other species to which we have referred, the calcareous skeleton is enveloped in a living gelatinous substance, from which the Zoophytes seem to shoot out like buds from the bark of a tree. Several of these animalcules are exhibited in our figure, in the active enjoyment of life; gathering in, with their expanded tentacles, the elements of their stony edifice from the surrounding waters. After death the fleshy integument is wasted away by the action of the sea; and the framework that remains behind, washed ashore by the waves, or hooked up by the coral fisherman, is wrought into brooches, bracelets, necklaces, and other ornaments of various kinds. Not a few varieties of the Coral-producing Zoophytes are to be found in actual living reality on our own coasts, where the curious student may examine for himself their habits and general structure. But it is in the warmer regions of the Earth that they are developed in the greatest numbers, and decked in the brightest hues. Those who have seen them through the crystal waters of tropical seas, swarming in countless multitudes on the clear white sand below, speak with enthusiasm of their luxuriant profusion and of their striking beauty. Combining to a picturesque elegance of form a rich variety and pleasing harmony of colors, they present to the eye a scene which has been compared to a magnificent garden, laid out in diverse beds of rare and splendid flowers. So far we have spoken only of the Polypidom, that is to say, the community of Polyps living together on a common stem of their own construction. Now this Polypidom is the first element of the Coral Reef. In some species of Zoophytes, the Red Coral for instance, the calcareous stem never attains a size greater than that of a diminutive shrub. But in others, and they are very numerous, especially in tropical seas, there seems to be no limit to the growth of the solid stony framework. As the existing generation of Zoophytes is dying out, new individuals are ever budding forth, which continue unceasingly to secrete carbonate of lime, as their predecessors had done before them, from the waters of the ocean; and thus the tree-like form spreads its branching arms on every side, growing upward and outward day by day. The soft gelatinous parts of those generations that have passed away are, in a short time, dissolved, and the stony skeleton alone remains behind. Ages roll on: the calcareous framework, ever increasing in size, becomes at length a formidable rock; and this rock is the Coral Reef.