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Show 274 PHYSIOGNOMY OF PLANTS. same artifices and modes of capture among nations who are entirely unconnected with each other. Although, as we have already remarked, the zone included between 22 or 24 degrees of latitude on either side of the equator, appears to be the true region of the calcareous saxigenous lithophytes which raise wall-like structures, yet coral reefs are also found, favored it is supposed by the warm current of the Gulf Stream, in lat. 32° 23', at the Bermudas, where they have been extremely well described by Lieutenant Nelson. (Transactions of the Geological Society, 2d Series, 1837, vol. v. pt. i. p. 103.) In the southern hemisphere, corals (Millepores and Cellepores) are found singly as far south as Chiloe, the Archipelago of Chonos, and Tierra del Fuego, in 53° lat.; and Retepores are even found in lat. 72~0 • Since the second voyage of Captain Cook there have been many defenders of the hypothesis put forward by him as well as by Reinhold and George Forster, according to which the low coral islands of the Pacific have been built up by living creatures from the depths of the bottom of the sea. The distinguished investigators of nature, Quoy and Gaimard, who accompanied Captain Freycinet in his voyage round the world in the frigate Uranie, were the first who ventured, in 1823, to expre&s themselves with great boldness and freedom in opposition to the views of the two Forsters (father and son), of Flinders and of Peron. (Annales des Sciences Naturelles, t. vi. 1825, p. 273.) ((En appelant !'attention des naturalistes sru· les animalcules des coraux, nous esperons demontrer que tout ce qu'on a dit ou cru observer jusqu'a ce jour relativement aux immenses travaux qu'il sont susceptibles d'executer, est le plus souvent inexact et toujours excessivement exagere. Nous pensons que les coraux, loin d' elever des profondeurs de 1' ocean des m urs perpendiculaires, ne forment que des couches ou des encroutemens de quelques toises d'epaisseur." Quoy and Gaimard also propounded (p. 289) the conjecture, that the Atolls (coral walls enclosing a lagoon) probably owed their origin to submarine volcanic craters. Their estimate of the depth below the surface of the sea at which the animals which form the coral reefs (the species of Astrrea, for example) could live, was doubtless too small, being at the utmost from 25 to 30 feet (26! to 32 E). An investigator and lover of |