156 



NATURAL HISTORY. 



more perfect organs of vision, and they are able to secrete an inky fluid with which to cloud the water, 

 and so conceal their retreat. 



The Dibranchiate order of Cephalopoda also had its representatives in the seas of the ancient 

 world, as the shells called jBelemnites, or " thunder-bolts," the fossil shells of Sepia discovered by 

 Cuvier, and the horny rings of the acetabula or suckers, found by Biickland in the fossil exuvise of 

 Ichthyosaurus, sufficiently testify ; but our knowledge of this order is chiefly founded on observation 

 of existing species. These are extremely numerous ; they frequent the seas of every clime, from the 

 ice-bound shores of Boothia Felix to the open main, and floating " gulf- weed," or Sargasso Sea, of the 

 equator Atlantic ; they seem, however, to be most abundant in temperate latitudes. Many species 

 frequent the coasts, creeping among the rocks and stones at the bottom ; others are pelagic, swimming 

 well, and are found in the open ocean at a great distance from any land. 



OEDER I. DIBRANCHIATA. SECTION A. OCTOPODA. 

 FAMILY I.-ARGONAUTIDJE. 



The first section of the Dibranchiate order are called Octopoda, from the fact of their possessing 

 only eight arms furnished with suckers. In it are placed two apparently very dissimilar families, 

 the Argonaut, or Paper Nautilus, and the Octopus, or Devil-fish. 



The Argonaut is perhaps the most interesting of this group, from the legends connected with its 

 sailing propensities. It is the only member of the Dibranchiate order which secretes an external 

 shell. But the shell is developed only by the female, the male being destitute of any calcareous 

 covering. It was the Nautilus (primus) of Aristotle, who described it as floating on the surface of the 

 sea, in fine weather, and holding out its sail-shaped arms to the breeze, a pretty fable, which poets 

 have repeated ever since. Thus the Argonaut, or Paper Nautilus, has been regarded as giving to 

 man the first lesson in the art of navigation. It has been usually represented with six arms 

 extended over the sides of its little vessel to act as oars, and two others upraised as sails. Such 

 having been the universal belief among the earlier naturalists, it is to be expected that poets would 

 not fail to celebrate its nautical powers : 



He, when the lightning- wing' d 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."- 



BTROK. 

 Again, Pope bids us : 



" Learn of the little Nautilus to sail, 



Spread the thin oar, and catch the driving gale." 



And James Montgomery, in his "Pelican Island," 

 gives a picture so exquisitely finished that even the 

 naturalist can scarcely bring himself to wish that it 

 were different : 



" Light as a flake of foam upon the wind, 

 Keel upward from the deep emerged a shell, 

 Shaped like the moon ere half her horn is fill'd ; 

 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 billow 

 In happy freedom, pleased to feel the air, 

 And wander in the luxury of light." 



It is now ascertained that the Nautilus never moves 

 in the manner here described. The account, though so 



universally accredited, is altogether fabulous. It swims backwards by ejecting water from its funnel, 

 like other Cuttle-fishes. It can creep along the bottom, carrying its shell over its back like a snail, 



" 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. 



FABLED POSITION OF THE PAPER NAUTILUS. 



