Page 69, fig. 1. Oculina varicosa, extremity of a branch. Author's Report on Zoöphytes, page 67, corrected from specimen. fig. 2, 3. Stylaster erubescens; 2. corallum, natural size; 3. extremity of a branch enlarged. Pourtales, Deep-Sea Corals. fig. 4, 5. Stylophora Dana; 4. extremity of a branch; 5. one of the fig. 10. Vertical section of corallum of P. plicata, showing the tabular 72, Polyp of Madrepora cribripora, enlarged. Author's Atlas, Plate 31. 75, Polyp of Dendrophyllia nigrescens, enlarged. Ibid., Plate 30. 76, Dendrophyllia nigrescens, natural size. Ibid., Plate 30. 77, Alveopora Verrilliana, natural size; the corallum covered below with a peritheca. Alveopora dedalea in part of Author's Atlas, Plate 48. The species is here named after Prof. A. E. Verrill, as it is not the true A. dedalea. Alveopora spongiosa, vertical section of corallum, and upper view of calicle, much enlarged; the diameter of the cell being about a fifteenth of an inch. Author's Atlas, Plate 48. 78, Polyp of Porites levis, enlarged. Author's Atlas, Plate 54. 79, Porites levis, with the polyps of one of the branches expanded, natural size. Author's Atlas, Plate 54. 82, Xenia elongata. Author's Atlas, Plate 57. 83, Anthelia lineata. Verrill, Proceedings of the Essex Institute, vol. iv., Plate 5. From a drawing by Dr. Stimpson. 84, Telesto ramiculosa. Verrill, Proc. Essex Inst., vol. iv., Plate 6; the second figure, an enlarged view of expanded polyp. From drawings by Dr. Stimpson. Tubipora syringa; fig. 1. part of a clump, natural size; 2. one of the polyps expanded. Author's Atlas, Plate 59. Tubipora fimbriata (3d figure), polyp, expanded. Plate 59. 85, Gorgonia flexuosa, part of zoophyte, natural size. Plate 60. Author's Atlas, Author's Atlas, 86, Spicules of Gorgoniæ, much enlarged. Verrill, Transactions of the Connecticut Academy of Sciences, vol. i., Plates 4 and 5. 88, Isis Hippuris. La Vie et les Mœurs des Animaux. 89, Corallium rubrum, the coral, natural size. L. Sanford, from specimen. Extremity of branch of C. rubrum, enlarged, with some of the animals expanded. Lacaze-Duthiers, from La Vie et les Mœurs des Animaux. 91. Cophobelemnon clavatum: the small figure, enlarged view of one of the polyps. Verrill, Proc. Essex Institute, vol. iv., Plate 5. From a drawing by Dr. Stimpson. Page 91, Veretillum Stimpsoni, enlarged three diameters. Verrill, Proc. Essex Institute, vol. iv., Plate 5. From a drawing by Dr. Stimpson. 95, Caulastræa furcata. Author's Atlas, Plate 9. 101, Hydra. Le Monde du Mer. 103, Hydrallmania falcata. Le Monde du Mer. 104, Animals of M. alcicornis, enlarged. L. Agassiz, Contributions to the Natural History of the United States, vol. iii. Plate 15. 105, Millepora alcicornis. La Vie et les Moeurs des Animaux. 106, Hornera lichenoides: 1. natural size; 2. part of branch enlarged. Smitt's Mém. des Bryozoaires. Discosoma Skenei, part of a group much enlarged. Ibid. 130, High Island, with Barrier and Fringing Reefs. Author's Exp. Geol. Report. 140, The Lixo Coral Reef, Abrolhos. Hartt's Brazil, p. 202. 149, Coral Reefs off the North Shore of Tahiti. Author's Exp. Geological Report, from the Wilkes Expl. Exp. Maps. 162, Coral Island or Atoll. Wilkes's Narr. Expl. Exped. 168, Maps of Taiara, IIenuake, Swain's Island, Jarvis Island, and Fakaafo. Author's Geol. Rep.; from Expl. Exp. Maps. 170, Map of Menchicoff Atoll. Darwin on Coral Reefs; from Kotzebue's Atlas. 176, Section of the rim of an Atoll. Author's Exp. Geol. Report. 179, Blocks of Coral on the shore platform of Atolls. Author's Exp. Geol. Report. 189, Map of Mahlos Mahdoo Atoll, one of the Maldives. Darwin on Coral Reefs. 191, Map of Great Chagos Bank. Darwin on Coral Reefs. 192, East and West Section across the Great Chagos Bank. Ibid. 193, Metia, an elevated Coral Island. Wilkes's Narrative of Expl. Exp., vol. i. 219, Map of the Bermuda Islands; reduced from an English Chart. 235, The "Old Hat." 243, Harbor of Apia. Expl. Exped. Author's Exp. Geol. Report. Author's Exp. Geol. Rep.; from Charts of the Wilkes 247, Part of North Shore of Tahiti. Ibid. 248, Harbor of Falifa. Ibid. 250, Whippey Harbor. Ibid. 263, Section illustrating the Origin of Barrier Reefs. Ibid. 264, Map and Ideal Section of Aiva Island. Ibid. 266, Map of Gambier Islands. Darwin on Coral Reefs. 267, Section illustrating the Origin of Atolls. Author's Exp. Geol. Rep. 268, Menchicoff Atoll. Darwin on Coral Reefs. 311, Fakaafo. Author's Exp. Geol. Rep.; from Charts of Expl. Exped. 413, Map of part of Oahu; reduced from chart of Hawaiian Government Survey. CORALS AND CORAL ISLANDS. CHAPTER I. CORALS AND CORAL MAKERS. A SINGULAR degree of obscurity has possessed the popu lar mind with regard to the growth of corals and coral reefs, in consequence of the readiness with which speculations have been supplied and accepted in place of facts; and to the present day the subject is seldom mentioned without the qualifying adjective mysterious expressed or understood. Some writers, rejecting the idea which science had reached, that reefs of rocks could be due in any way to "animalcules," have talked of electrical forces, the first and last appeal of ignorance. One author, not many years since, made the fishes of the sea the masons, and in his natural wisdom supposed that they worked with their teeth in building up the great reef. Many of those who have discoursed most poetically on zoöphytes have imagined that the polyps were mechanical workers, heaping up the piles of coral rock by their united labors; and science is hardly yet rid of such terins as polypary, polypidom, which imply that each coral is the constructed hive or house of a swarm of polyps, like the honey-comb of the bee, or the hillock of a colony of ants. Science, while it penetrates deeply the system of things 2 about us, sees everywhere, in the dim limits of vision, the word mystery. Surely there is no reason why the simplest of organisms should bear the impress most strongly. If we are astonished that so great deeds should proceed from the little and low, it is because we fail to appreciate that little things, even the least of living or physical existences in nature, are, under God, expressions throughout of comprehensive laws, laws that govern alike the small and the great. It is not more surprising, nor a matter of more difficult comprehension, that a polyp should form structures of stone (carbonate of lime) called coral, than that the quadruped should form its bones, or the mollusk its shell. The The processes are similar, and so the result. In each case it is a simple animal secretion; a secretion of stony matter from the aliment which the animal receives, produced by the parts of the animal fitted for this secreting process; and in each, carbonate of lime is a constituent, or one of the constituents, of the secretion. This power of secretion is then one of the first and most common of those that belong to living tissues; and though differing in different organs according to their end or function, it is all one process, both in its nature and cause, whether in the Animalcule or Man. It belongs eminently to the lowest kinds of life. These are the best stone-makers; for in their simplicity of structure they may be almost all stone and still carry on the processes of nutrition and growth. Throughout geological time they were the agents appointed to produce the material of limestones, and also to make even the flint and many of the siliceous deposits of the earth's formations. Coral is never, therefore, the handiwork of the manyarmed polyps; for it is no more a result of labor than bonemaking in ourselves. And again, it is not a collection of cells into which the coral animals may withdraw for concealment any more than the skeleton of a dog is its house or cell; for every part of the coral-or corallum as it is now called in science of a polyp, in most reef-making species, is enclosed more or less completely within the polyp, where it was formed by the secreting process. It is not, perhaps, within the sphere of science to criticise the poet. Yet we may say in this place, in view of the frequent use of the lines even by scientific men, that more error in the same compass could scarcely be found than in the part of Montgomery's "Pelican Island" relating to coral formations. The poetry of this excellent author is good, but the facts nearly all errors-if literature allows of such an incongruity. There is no "toil," no "skill," no "dwelling," no "sepulchre" in the coral plantation any more than in a flower-garden; and as little are the coral polyps shapeless worms that "writhe and shrink their tortuous bodies to grotesque dimensions." The poet oversteps his license, and besides degrades his subject, when downright false to nature. Coral is made by organisms of four very different kinds. These are: First, POLYPS, the most important of coral-making animals, the principal source of the coral reefs of the world. Second, Animals related to the little Hydra of fresh waters, and called HYDROIDS (a division under the Acalephs), which, as Agassiz has shown, form the very common and often large corals called Millepores. Third, The lowest tribe of Mollusks, called BRYOZOANS, which produce delicate corals, sometimes branching and mosslike (whence the name from the Greek for moss animal), and at other times in broad plates, thick masses, and thin incrustations. Although of small importance as reef-makers at the |