Part 21

The neck of a popular error is hard to break; but it is time that one so palpable as that concerning the "spouting" of whales should cease to be promulgated and disseminated by fanciful illustrations of instructive books.

THE "SAILING" OF THE NAUTILUS.

One of the prettiest fables of the sea is that relating to the Paper Nautilus, the constructor and inhabitant of the delicate and beautiful shell which looks as if it were made of ivory no thicker than a sheet of writing paper.

It is an old belief that in calm weather it rises from the bottom of the sea, and, elevating its two broadly-expanded arms, spreads to the gentle air, as a sail, the membrane, light as a spider's web, by which they are united; and that, seated in its boat-like shell, it thus floats over the smooth surface of the ocean, steering and paddling with its other arms. Should storm arise or danger threaten, its masts and sail are lowered, its oars laid in, and the frail craft, filling with water, sinks gently beneath the waves.

When and where this picturesque idea originated I am unable to discover. It dates far back beyond the range of history; for Aristotle mentions it, and, unfortunately, sanctioned it. With the weight of his honoured name in its favour, this fallacy has maintained its place in popular belief, even to our own times; for the mantle of the great father of natural history, who was generally so marvellously correct, fell on none of his successors; Pliny, and AElian, and the tribe of compilers who succeeded them, having been more concerned to make their histories sensational than to verify their statements.

Naturally, the Paper Nautilus has been the subject of many a poet's verses. Oppian wrote of it in his 'Halieutics':--

"Sail-fish in secret, silent deeps reside, In shape and nature to the preke allied; Close in their concave shells their bodies wrap, Avoid the waves and every storm escape. But not to mirksome depths alone confined; When pleasing calms have stilled the sighing wind, Curious to know what seas above contain, They leave the dark recesses of the main; Now, wanton, to the changing surface haste, View clearer skies, and the pure welkin taste. But slow they, cautious, rise, and, prudent, fear The upper region of the watery sphere; Backward they mount, and as the stream o'erflows, Their convex shells to pressing floods oppose. Conscious, they know that, should they forward move, O'erwhelming waves would sink them from above, Fill the void space, and with the rushing weight, Force down th' inconstants to their former seat. When, first arrived, they feel the stronger blast, They lie supine and skim the liquid waste. The natural barks out-do all human art When skilful floaters play the sailor's part. Two feet they upward raise, and steady keep; These are the masts and rigging of the ship: A membrane stretch'd between supplies the sail, Bends from the masts, and swells before the gale. Two other feet hang paddling on each side, And serve for oars to row and helm to guide. 'Tis thus they sail, pleased with the wanton game, The fish, the sailor, and the ship, the same. But when the swimmers dread some dangers near The sportive pleasure yields to stronger fear. No more they, wanton, drive before the blasts, But strike the sails, and bring down all the masts; The rolling waves their sinking shells o'erflow, And dash them down again to sands below."

The octopus.

Montgomery also thus exquisitely paraphrases the same idea in his 'Pelican Island':--

"Light as a flake of foam upon the wind, Keel upwards, from the deep emerged a shell, Shaped like the moon ere half her orb is filled. Fraught with young life, it righted as it rose, And moved at will along the yielding water. The native pilot of this little bark Put out a tier of oars on either side, Spread to the wafting breeze a twofold sail, And mounted up, and glided down, the billows In happy freedom, pleased to feel the air, And wander in the luxury of light."

Byron mentions the Nautilus in his 'Mutiny of the Bounty' as follows:--

"The tender Nautilus, who steers his prow, The sea-born sailor of his shell canoe, The ocean Mab--the fairy of the sea, Seems far less fragile, and alas! more free. He, when the lightning-winged tornadoes sweep The surge, is safe: his port is in the deep; And triumphs o'er the armadas of mankind Which shake the world, yet crumble in the wind."

The very names by which this animal is known to the science which some persons erroneously think must be so hard and dry are poetic. In Aristotle's day it was called the Nautilus or Nauticus, "the mariner," and though two thousand two hundred years have passed since the great master wrote, the name still clings to it. As the Pearly Nautilus, a very different animal, also bears that name, Gualtieri perceived the necessity of distinguishing the Paper Nautilus from it, and was followed by Linnaeus, who therefore entitled the genus to which the latter belongs, Argonauta, after the ship Argo, in which Jason and his companions sailed to Colchis to carry off the "Golden Fleece" suspended there in the temple of Mars, and guarded by brazen-hoofed bulls, whose nostrils breathed out fire and death, and by a watchful dragon that never slept. According to the Greek legend, the Argo was named after its builder Argus, the son of Danaus, and was the first ship that ever was built. Oppian ('Halieutics,' book I.) expresses his opinion that the Nautilus served as a model for the man who first conceived the idea of constructing a ship, and embarking on the waters:--

"Ye Powers! when man first felled the stately trees, And passed to distant shores on wafting seas, Whether some god inspired the wondrous thought, Or chance found out, or careful study sought; If humble guess may probably divine, And trace th' improvement to the first design, Some wight of prying search, who wond'ring stood When softer gales had smoothed the dimpled flood, Observed these careless swimmers floating move, And how each blast the easy sailor drove; Hence took the hint, hence formed th' imperfect draught, And ship-like fish the future seaman taught. Then mortals tried the shelving hull to slope, To raise the mast, and twist the stronger rope, To fix the yards, let fly the crowded sails, Sweep through the curling waves, and court auspicious gales."

Pope, too, in his 'Essay on Man' (Ep. 3), adopted the idea in his exhortation--

"Learn of the little Nautilus to sail, Spread the thin oar, and catch the driving gale."

Poetry, like the wizard's spell, can make

"A nutshell seem a gilded barge, A sheeling seem a palace large,"

but the equally enchanting wand of science is able by a touch to dispel the illusion, and cause the object to appear in its true proportions. So with the fiction of the "Paper Sailor."

I have elsewhere described the affinities of the Nautili and their place in nature, therefore it will only be necessary for me here to allude to these very briefly, to explain the great and essential difference that exists between the two kinds of Nautilus which are popularly regarded as being one and the same animal.

The Pearly Nautilus (Nautilus pompilius) and the Argonaut, which from having a fragile shell of somewhat similar external form is called the Paper Nautilus, both belong to that great primary group of animals known as the Mollusca, and to the class of it called the Cephalopoda, from their having their head in the middle of that which is the foot in other mollusks. In the Cephalopoda the foot is split or divided into eight segments in some families, and in others into ten segments, which radiate from the central head, like so many rays. These rays are not only used as feet, but, being highly flexible, are adapted for employment also as prehensile arms, with which their owner captures its prey, and they are rendered more perfect for this purpose by being furnished with suckers which hold firmly to any surface to which they are applied. The Cephalopods which have the foot divided into ten of these segments or arms are called the Decapoda, those which have only eight of them are called the Octopoda. All of these have two plume-like gills--one on each side--and so are called Dibranchiata; and in the eight-armed section of these is the argonaut or Paper Nautilus. Of the Pearly Nautilus and the four-gilled order I shall have more to say by-and-by: at present we will follow the history of the argonaut.

Notwithstanding all that has been written of it, it is only within the last fifty years that this has been correctly understood. An eight-armed cuttle was recognised and named Ocythoe, which, instead of having, like the common octopus, all of its eight arms thong-like and tapering to a point, had the two dorsal limbs flattened into a broad thin membrane. Although this animal was sometimes seen dead without any covering, it was generally found contained in a thin and slightly elastic univalve shell of graceful form, and bearing some resemblance to an elegantly shaped boat. It did not penetrate to the bottom of this shell; it was not attached to it by any muscular ligament, nor was the shell moulded on its body, nor apparently made to fit it. Hence it was long regarded as doubtful, and even by naturalists so recent and eminent as Dumeril and De Blainville, whether the octopod really secreted the shell, or whether, like the hermit-crab, it borrowed for its protection the shell of some other mollusk. Aristotle left the subject with the faithful acknowledgment: "As to the origin and growth of this shell nothing is yet exactly determined. It appears to be produced like other shells; but even this is not evident, any more than it is whether the animal can live without it." Pliny, as usual, instead of throwing light on the matter, obscured it. He regarded the shell as the property of a gasteropod like the snail, and the octopod as an amateur yachtsman who occasionally went on board and took a trip in the frail craft, and assisted its owner to navigate it for the fun of the thing. This is what he says about it: "Mutianus reports that he saw in the Propontis a shell formed like a little ship, having the poop turned up and the prow pointed. An animal called the Nauplius, resembling an octopus, was enclosed in the shell with its owner, for its amusement in the following manner. When the sea is calm the guest lowers his arms, and uses them as oars and a helm, whilst the owner of the shell expands himself to catch the wind; so that one has the pleasure of carrying and sailing, and the other of steering. Thus, these two otherwise senseless animals take their pleasure together; but the meeting them sailing in their shell is a bad omen for mariners, and foretells some great calamity."

Naturalis Historia, lib. ix. cap. 30.

Although the animal was never found in any other shell, and the shell was never known to contain any other animal, and though, when the shell and the animal were found together they were always of proportionate size, this octopod, as I have said, was looked upon by some conchologists as a pirate who had taken possession of a ship which did not belong to him, until Madame Jeannette Power, a French lady then residing in Messina, having succeeded in keeping alive for a time an argonaut the shell of which had been broken in its capture, discovered that the animal quickly repaired the fracture, and reproduced the portions that had been broken off. Induced by this to make further experiments, she kept a number of living argonauts in cages sunk in the sea near the citadel of Messina, and in 1836 laid before the "Academy" at Catania the following results of her observations of them:--

1st. That the argonaut constructs the shell which it inhabits.

2nd. That it quits the egg entirely naked, and forms the shell after its birth.

3rd. That it can repair its shell, if necessary, by a fresh deposit of material having the same chemical composition as its original shell.

4th. That this material is secreted by the palmate, or sail, arms, and is laid on the outside of the shell, to the exterior of which these membranous arms are closely applied.