These words have more than fulfilled themselves since they were written. Those Deep-Sea dredgings, of which a detailed account will be found in Dr. Wyville Thomson's new and most beautiful book, "The Depths of the Sea," have disclosed, of late years, wonders of the deep even more strange and more multitudinous than the wonders of the shore. The time is past when we thought ourselves bound to believe, with Professor Edward Forbes, that only some hundred fathoms down, the inhabitants of the sea-bottom "become more and more modified, and fewer and fewer, indicating our approach towards an abyss where life is either extinguished, or exhibits but a few sparks to mark it's lingering presence."Neither now need we indulge in another theory which had a certain grandeur in it, and was not so absurd as it looks at first sight, -namely, that, as Dr. Wyville Thomson puts it, picturesquely enough, "in going down the sea water became, under the pressure, gradually heavier and heavier, and that all the loose things floated at different levels, according to their specific weight, - skeletons of men, anchors and shot and cannon, and last of all the broad gold pieces lost in the wreck of many a galleon off the Spanish Main;the whole forming a kind of 'false bottom' to the ocean, beneath which there lay all the depth of clear still water, which was heavier than molten gold."The facts are; first that water, being all but incompressible, is hardly any heavier, and just as liquid, at the greatest depth, than at the surface; and that therefore animals can move as freely in it in deep as in shallow water; and next, that as the fluids inside the body of a sea animal must be at the same pressure as that of the water outside it, the two pressures must balance each other;and the body, instead of being crushed in, may be unconscious that it is living under a weight of two or three miles of water. But so it is; as we gather our curiosities at low-tide mark, or haul the dredge a mile or two out at sea, we may allow our fancy to range freely out to the westward, and down over the subaqueous cliffs of the hundred-fathom line, which mark the old shore of the British Isles, or rather of a time when Britain and Ireland were part of the continent, through water a mile, and two, and three miles deep, into total darkness, and icy cold, and a pressure which, in the open air, would crush any known living creature to a jelly; and be certain that we shall find the ocean-floor teeming everywhere with multitudinous life, some of it strangely like, some strangely unlike, the creatures which we see along the shore.
Some strangely like. You may find, for instance, among the sea-weed, here and there, a little black sea-spider, a Nymphon, who has this peculiarity, that possessing no body at all to speak of, he carries his needful stomach in long branches, packed inside his legs. The specimens which you will find will probably be half an inch across the legs. An almost exactly similar Nymphon has been dredged from the depths of the Arctic and Antarctic oceans, nearly two feet across.
You may find also a quaint little shrimp, CAPRELLA, clinging by its hind claws to sea-weed, and waving its gaunt grotesque body to and fro, while it makes mesmeric passes with its large fore claws, -one of the most ridiculous of Nature's many ridiculous forms.
Those which you will find will be some quarter of an inch in length; but in the cold area of the North Atlantic, their cousins, it is now found, are nearly three inches long, and perch in like manner, not on sea-weeds, for there are none so deep, but on branching sponges.
These are but two instances out of many of forms which were supposed to be peculiar to shallow shores repeating themselves at vast depths: thus forcing on us strange questions about changes in the distribution and depth of the ancient seas; and forcing us, also, to reconsider the old rules by which rocks were distinguished as deep-sea or shallow-sea deposits according to the fossils found in them.
As for the new forms, and even more important than them, the ancient forms, supposed to have been long extinct, and only known as fossils, till they were lately rediscovered alive in the nether darkness, - for them you must consult Dr. Wyville Thomson's book, and the notices of the "Challenger's" dredgings which appear from time to time in the columns of "Nature;" for want of space forbids my speaking of them here.
But if you have no time to read "The Depths of the Sea," go at least to the British Museum, or if you be a northern man, to the admirable public museum at Liverpool; ask to be shown the deep-sea forms; and there feast your curiosity and your sense of beauty for an hour. Look at the Crinoids, or stalked star-fishes, the "Lilies of living stone," which swarmed in the ancient seas, in vast variety, and in such numbers that whole beds of limestone are composed of their disjointed fragments; but which have vanished out of our modern seas, we know not why, till, a few years since, almost the only known living species was the exquisite and rare Pentacrinus asteria, from deep water off the Windward Isles of the West Indies.
