POLYPUS. 



489 



timially supplied with aliment, and the principal 

 materials for the construction of their submarine 

 habitations. 



The fearless navigator, confidently sailing in a sea 

 that former adventurers had indicated as free from 

 rocks, dashes his prow on an unexpected ridge, 

 whose sides are so perpendicular that no sounding 

 can be found at the ship's stern ; but, while com- 

 bating with the fury of the tempest, he happily meets 

 one of these openings which chance, or rather the 

 animal's instinct> has left unclosed ; by this he is 

 saved. He enters a harbour of slightly undulating 

 waters, sheltered from the contending storms which, 

 outside the barrier, seem bent on its annihilation, 

 but cannot shake it, and spend their force in air. 



The Polypidoms do not always rise to the surface 

 of the waters ; some extend themselves horizontally 

 on the base of the sea, or pursue its curvatures, 

 spreading ocean's floor with an enamelled carpet of 

 varied brilliant hues ; at other times this carpet has 

 only one shade, nearly equalling the Tyrian purple of 

 antiquity. Many of these beings resemble a shrub 

 that winter has despoiled of its verdure, but which 

 spring has renovated with fresh flowers, their branches 

 covered from its base to the extremities with petaled 

 animals, whose beauty vies with the most delicate 

 and richly-coloured blossoms. 



The Polypulomg are found near the surface of the 

 water as well as at the greatest depths of the ocean. 

 Some exist in parts where the light of the sun cannot 

 penetrate, and there multiply to infinity, notwith- 

 standing the enormous pressure and extreme cold 

 which they must experience at a depth of two or 

 three thousand fathoms. There are strong grounds 

 to presume that their growth is slow in proportion as 

 they are immersed in the water, and that, at five 

 hundred fathoms from the surface of the sea, it would 

 require a century before coral attained the same 

 growth as when only a few yards of fluid covered it. 



Polypidoms, like plants, vary with the climate they 

 inhabit. In the colder latitudes the Cellularia and 

 Sertularia only are to be found, with a few closely- 

 woven Sponges and a small number of Alci/onia. In 

 the neighbourhood of the volcanic isles of the polar 

 regions, or on those shores exposed to the marine 

 flow and ebb, which, after having been warmed by a 

 tropical sun, has bathed the eastern coast of America, 

 and then directed its course to the western shores of 

 Europe, Coral Una, Gorgonia, and Isidia, are met 

 with. The two first multiply a little from sixty to 

 fifty degrees of northern latitude ; their numbers then 

 increase to the forty-fourth or forty-filth degree ; and 

 Gorgonias, with rampant stems : Spongias, with loose 

 tissue, brittle or clastic j and Milleporcs, with foliated 

 and fragile expansions, are found. A little farther 

 the coral reddens the depths of the ocean with its 

 brilliant branches ; and this is soon followed by the 

 PolypoEan madrepores. 



It is not, however, before the thirty-fourth degree 

 of northern latitude that these animals commence 

 the development of that grandeur and immensity that 

 presents itself at every step to the extent of a parallel 

 southern latitude. Here they disappear, after having 

 exhibited the same series of phenomena observed in 

 the northern hemisphere. 



It is then within the tropics, or in a zone of more 

 than sixty degrees' expansion, that these beings, 

 these animalculse, scarcely visible to the naked eye, 

 and whose operations uninterruptedly proceed, eter- 



nally exercise their empire in a medium of never- 

 changing temperature. 



From the depths of the ocean they elevate those 

 immense reefs that may ultimately ensure a com- 

 munication between the inhabitants of the tem- 

 perate zones. The naturalist visiting these madre- 

 porous islands, once covered with the ocean, is 

 astonished at their extent and perfect preservation, 

 so perfect, indeed, that the sea appears to have 

 abandoned them recently ; and the same species of 

 Poli/pidom that crowns the greatest heights, and forms 

 the whole island, frequently extends from its shores 

 to an endless distance ; so that, when the tide 

 recedes, perhaps an interminable league presents 

 the same Polypidom to observation that composes 

 the heads of their mountains. The air, light, and 

 rains, have contributed to destroy the animals of 

 these madrepores. Their skeletons alone remain 

 to attest the ancient sojourn of the ocean in these 

 elevated sites, and the slow but incessant diminution 

 of the waters on the planet we inhabit. The greater 

 number of Polypidoms are found to originate in the 

 heart of the ocean, and in its numerous divisions, 

 with the exception of the Xaissce and the Ephydatias, 

 which inhabit fresh water, whether current or stag- 

 nant. 



Some of the Polypidoms appear to prefer the 

 immediate influence of the atmospheric changes. 

 They are seen on rocks, and on the plants which the 

 tide leaves uncovered, sometimes in such profusion 

 that they all appear concealed under a membrano- 

 calcareous covering. These species, however, at 

 least on our own shores, are neither numerous, nor 

 attain to any considerable size. 



They almost all surfer from the action of the air. 

 At the period of the great equinoctial tides the sea 

 retires from those rocks it covered many preceding- 

 months. When the water first leaves them the 

 Polypi are full of life, but suffer and languish as they 

 lose their moisture, nor fail to perish altogether, 

 should the sea remain too long without again cover- 

 ing them. Those whose structure enables them to 

 retire within the recesses of their cells are better 

 enabled to hold out for a longer period, being sus- 

 tained by the moisture they preserve ; but the un- 

 covered Polypi, and those whose whole mass is ani- 

 mated like the Alcyonia, experience a more rapid 

 alteration, proportioned to the higher temperature and 

 the dryness of the air. Taken in this state of 

 sufferance, and replaced in sea-water, these little 

 animals slowly resume their activity. There are 

 some which do not expand their tentaculas till the 

 seconder third day; whilst those which, immediately 

 after their exposure to the air, have been carefully 

 restored to their natural element in a tranquil spot 

 where the water was not agitated, have soon ex- 

 panded from their cells, or the mass to which they 

 were attached. It may here be necessary to remark, 

 that naturalists have frequently erred in describing 

 the contracted polypus for one expanded ; and so 

 extremely different is their appearance, that such 

 errors may well be excused in those who have fallen 

 into them. 



Of the duration of life in these creatures, like all 

 other organised beings, both in the animal and vege- 

 table kingdoms, they have three epochs of existence, 

 their growth, their maturity, and their decline. Some 

 commence and terminate their existence in the short 

 space of a day, perhaps an hour only, while others 



