Near Van Diemen's Land, Péron saw a sepia about as big as a tun rolling about in the waters. Its enormous arms had the appearance of frightful snakes. Each of these organs was at least seven feet long, and measured seven or eight inches round the base. These well authenticated proportions are truly formidable, and fully justify the dread and abhorrence which the Polynesian divers entertain of those snake-armed monsters of the deep; but not satisfied with reality, some writers have magnified the size of the cephalopods to fabulous dimensions. Thus Pernetti mentions a colossal cuttle-fish, which, climbing up the rigging, overturned a three-masted ship; and Pliny notices a similar giant, with arms thirty feet long and a corresponding girth. But all this is nothing to the Norwegian kraken, a mass of a quarter of a mile in diameter, and a back covered with a thicket of sea-weeds. When it comes to the surface, which seems to be but rarely the case, it raises its arms mast-high into the air, and, having enjoyed for a time the lovely daylight, sinks slowly back again into abysmal darkness. Fishermen are said to have landed on a kraken, and to have kindled a fire upon the supposed island for the purpose of cooking their dinner. But even a kraken, thick-skinned as he may be, does not like his back to be converted into a hearth, and thus it happened that the treacherous ground gave way under the mistaken mariners, and overwhelmed them in the waters. Strange that the oriental tale of Sinbad the sailor should thus be re-echoed in the wild legends of the north. All the dibranchiate cephalopods are destitute of an outward shell, with the sole exception of the Spirula, a small species chiefly found in the South Sea, and of the far more renowned Argonaut, which poets, ancient and modern, have celebrated as the model from which man took the first idea of navigation. Its two sail-like arms expanding in the air, and the six others rowing in the water, the keel of its elegant shell is pictured as dividing the surface of the tranquil sea. But as soon as the wind rises, or the least danger appears, the cautious argonaut takes in his sails, draws back his oars, creeps into his shell, and sinks instantly into a securer depth. Unfortunately there is not a word of truth in this pleasing tale. Like the common octopus, the argonaut generally creeps about at the bottom of the sea, or when he swims, he places his sails close to his shell, stretches his oars right out before him, and shoots backwards like most of his class by expelling the water from his respiratory tube. [Illustration: Argonaut.] As he sits loosely in his shell, he was supposed by some naturalists to be a parasite enjoying the house of the unknown murdered owner; but this is perfectly erroneous, as the young in the egg already show the rudiments of the future shell, and the full-grown animal repairs by reproduction any injury that may have happened to it. [Illustration: Pearly Nautilus.]