In the sixteenth century some stones were found bearing the impression of a star on their surface. They received the name of Trochites, and gave rise to much discussion. Naturalists puzzled their brains about them, called them star-shaped crystals, aquatic plants, corals; and to these last Linnaeus himself, the great authority of the time on all such questions, referred them. Beside these stony stars, which were found in great quantities when attention was once called to them, impressions of a peculiar kind had been observed in the rocks, resembling flowers on long stems, and called "stone lilies" naturally enough, for their long, graceful stems, terminating either in a branching crown or a closer cup, recall the lily tribe among flowers. The long stems of these seeming lilies are divided transversely at regular intervals;--the stem is easily broken at any of these natural divisions, and on each such fragment is stamped a star-like impression resembling those found upon the loose stones or Trochites. About a century ago, Guettard the naturalist described a curious specimen from Porto Rico, so similar to these fossil lilies of the rocks that he believed they must have some relation to each other. He did not detect its animal nature, but from its long stem and branching crown he called it a marine palm. Thus far neither the true nature of the living specimen, nor of the Trochites, nor of the fossil lilies was understood, but it was nevertheless an important step to have found that there was a relation between them. A century passed away, and Guettard's specimen, preserved at the Jardin des Plantes, waited with Sphinx-like patience for the man who should solve its riddle. Cuvier, who held the key to so many of the secrets of Nature, detected at last its true structure; he pronounced it to be a Star-Fish with a stem, and at once the three series of facts respecting the Trochites, the fossil lilies, and Guettard's marine palm assumed their true relation to each other. The Troehites were recognized as simply the broken portions of the stem of some of these old fossil Crinoids, and the Crinoids themselves were seen to be the ancient representatives of the present Comatulae and Star-Fishes with stems. So is it often with the study of Nature; many scattered links are collected before the man comes who sees the connection between them and speaks the word that reconstructs the broken chain.