- [Footnote: up islands from fathomless depths of the ocean. They
excite the liveliest interest, whether considered as subjects of physiology and of the study of the gradation of animal forms, or whether they are regarded in reference to their influence on the geography of plants and on the geological relations of the crust of the Earth. According to the great views of Leopold von Buch, the whole formation of the Jura consists of "large raised coral-banks of the ancient world surrounding the ancient mountain chains at a certain distance."
In Ehrenberg's Classification, (Abhandlungen der Akad. der Wiss. zu Berlin aus dem, J. 1882, S. 393-432) Coral-animals, (often improperly called, in English works, Coral-insects) are divided into two great classes: the single-mouthed Anthozoa, which are either free or capable of detaching themselves, being the animal-corals, Zoocorallia; and those in which the attachment is permanent and plant-like, being the Phyto-corals. To the first order, the Zoocorallia, belong the Hydras or Arm-polypi of Trembley, the Actiniæ decked with beautiful colours, and the mushroom-corals; to the second order or Phyto-corals belong the Madrepores, the Astræids, and the Ocellinæ. The Polypi of the second order are those which, by the cellular wave-defying ramparts which they construct, are the principal subject of the present note. These ramparts consist of an aggregate of coral trunks, which, however, do not instantly lose their common vitality as does a forest tree when cut down.
Every coral-trunk is a whole which has arisen by a formation of buds taking place according to certain laws, the]*
