XXIII.—The Expedition to the South Pacific of the S.Y. “St. George.” Marine Ecology and Coral Formations in the Panama Region, the Galapagos and Marquesas Islands, and the Atoll of Napuka

Abstract

Two contrasted oceanographical regions are dealt with in this paper, the fauna of the eastern Pacific being distinct from that of the Marquesas, which are the farthest outliers of the western ocean. In each of these two regions again are two divisions of markedly different ecology, physical conditions in the Galapagos being as great a contrast as could well be to those of the coast of Panama, while the Marquesas Islands differ from their neighbours farther west, which are either atolls, or high islands surrounded by broad reefs, in being without coral deposits of any considerable size, and certainly no true reefs. The corals afford a striking example of the contrast between the two main regions; in Panama the only abundant coral is Pocillopora, in the Marquesas the only “reef” is of Porites, and the other deposits depend upon this genus for their existence. Several species of Pocillopora are abundant in the Marquesas, but are all distinct from those of Panama.