CHAPTER III. FIXED LUMINARIES OF THE SEA. We have examined and admired the movable and the moving luminaries of the ocean world, in the firmament of the deep, we may call it,--slowly moving stars of extreme minuteness, but great brilliancy, in one group, and the large orbs, more or less moving in erratic spheres, trailing in long lines of coruscating light, representing the lowest grand branches of the animal kingdom, the protozoans, and the vast colony of the sea-jellies, or _medusæ_. We now come to the third chapter, which embraces those animals forming the grand branch of the animal kingdom which included in Cuvier’s time the radiated animals. All who have visited the New-England shores, or those beyond, farther north, or the warmer waters of our semi-tropical regions, have probably become acquainted with the soft and leathery forms, which, when seen undisturbed in the water, appear like flowers. For example, should we visit the delightful beaches and coves of Lynn, or Nahant, or Swampscott, the loved hunting-grounds of Agassiz and his disciples, we would see, on well-advised instruction from some one informed, what at first would suggest a moss pink in full bloom, nestled perhaps in groups, in crevice or open pool, among the crags or broken boulders. These are the common, and well nigh the only, representative of its family on our coast, within reach. Others there are, living in deeper water, within reach of a hand dredge, as work with such, in former years, well informed us. These are beautiful and very showy, like large asters and zinnias. But we dwell upon the in-shore one because it is always at hand and easily obtained, if you know where to look; and it well represents the characters of the group. Time was, when, forty years since, if some medical doctor of the town, or some of that ilk, did not have a sort of half knowledge of the creature, no one about did. But a few years before that, scientists in Europe were quarrelling over the question, Is it a vegetable, or an animal? Dr. Marsigli, a nobleman, asserted that such were vegetable, with further seeming good argument that the creatures looked like flowers and nothing else, therefore they must be flowers of the sea, notwithstanding that a poor, but educated Londoner, by the name of Ellis, demonstrated in good round science that they were animals. The striking case of mistaken identity, with the force of nobility, carried it. But Ellis lived to see his theory prevail. Scarcely any in the whole range of Nature’s objects are more surprising and more beautiful. The _Urticena nodosa_ is a form found off our shores, which is luminous; the light being confined to its tentacles, and to the soft portion near the summit.