THE PAPIER NAUTILUS.

New Zealand Illustrated Magazine, Volume VIII, Issue 1, 1 April 1903, Page 38

THE PAPIER NAUTILUS.

By E. HODGKINSON, M.A,

This is the ship of pearl, which, poets feign Sails the unshadowed main — The venturous bark that flings On the sweet summer air its purpled wings In gulfs enchanted, where the Siren sings, And cord reefs lie bare, Where the cold sea-maids rise to sun their streaming hair.

fHE beautiful poem of Oliver Wendel Holmes, from whi;;h ; the opening verse is quoted, will be familiar to many "f?" readers. The spiral shell of the nautilus that forms the subject of his poem is formed of a series of chambers gradually increasing in size. As each in turn is outgrown a new one is formed, and then the old one is shut off by a partition-wall from the new one with its livingtenant. Tt is this peculiarity that inspired Holmes' poem with its lofty moral : " Build thee more stately mansions, 0 my soul, As the swift seasons roll ! Leave thy low- vaulted past ! Let each new temple, nobler than the last, Shut thee from Heaven with a dome more vast, Till thou at length art free, Leaving thine outgrown shell by life's unresting sea." The paper nautilus, which is here described, is quite a different creature to that of Holmes' poem, though in some measure allied to it. The verse quoted as a heading, however, applies to the paper nautilus quite as well as to the chambered one. The shell — which, although as we shall see directly, is a mere appendage of the

animal, and the sole thing about it known to most people — is of most delicate texture, so thin as to be translucent, and of exquisite pearly whiteness. It is spiral in shape, marked with transverse fhitings, and variegated in colour by a dark shading on the ridge of the spiral, this being darkest at the head of the curve, and gradually lightening towards the open end. From its colour, thinness of texture and transparency, the shell is somewhat suggestive of crinkled tissue paper, so that its popular name is very appropriate.

It is, perhaps,, the rarest as the finest of all New Zealand shells. Jn fact, it is not truly a New Zealand shell, the living animal being a denizen of tropical or semi-tropical seas. The comparatively few specimens that reach our shores are apparently stray arrivals, borne southward away from their true homes by force of gale or current. I have not heard of the shells being found south of Cook Strait, and it is only here and there along the North Island coasts that it is at all frequent. I never heard of its being found in Taranaki. But about Wairoa and Mahia Peninsula, and I believe many parts of the eastern coast of Auckland province, it is;

pretty often met with. Two specimens are to be seen in the Auckland Museum, but they are not remarkable in size. The late keeper of Portland Island lighthouse, Mr Robson, has a fine collection of all sizes, the largest measuring nine inches in length and twenty- two along the spiral. Small ones may be less than an inch across, and fragile in proportion.

Portland Tsland is a small rocky islet just off the southern extremity of Mahia Peninsula, and the shells of Mr Robson's collection were

preservation, and I should think they were fully worth it. Some people have the shells mounted or set for various purposes of use or ornament ; I have heard of two small ones being set in silver so as to form a pair of salt-cellars. Unfortunately from the extreme fragility of the shell, perfect specimens, especially of the larger sizes, are the exception. Often the outer cover is damaged ; usually there are some holes or chips in the shell. Considering the rocky nature of the beach about Mahia and Portland

chiefly found on the island, a few specimens being brought from the neighbouring mainland by the Maoris. From their rarity and beauty the shells are much sought after, and the Maoris, who usually have the best chance of procuring them, can sell them at a good price. I was told by the lighthousekeepers at Portland Island that the late Captain Fairchild had offered £5 for a pair of fine ones in good

Island, it is a wonder that so many are found perfect, or with but little injury. Even supposing the shell is washed ashore free from damage, a strong wind may blow it against stones or drift-wood, and break it to pieces, or an inquisitive seagull may take a bite out of it, though he is not likely to find anything edible inside. The shells found on the sands are usually empty ; but sometimes they are taken in the

water with the living animal inside ; sometimes this is found in the

water near the shell. It is evident to the most cursory observer that the shell of the paper nautilus and the animal that frames it are not related to one another as are the ordinary mollusc, such as the periwinkle and its shell. Tliere does not appear to be any mode of attachment of the nautilus to its shell ; nor is the shape of the latter with its large opening favourable to its use as a home like that of the snail or periwinkle. Then the living creature is found apart from the shell, and shells washed ashore are empty and clean, as though builder and shell had parted company before the latter came to land. From the fact of the nautilus being found without a shell, it has been thought by some observers that (he shell did not truly belong to the animal at all, but was merely borrowed by it, as the hermit crab takes possession of some empty shell for his home.

For a, Jong while the nature and growth of animal and shell were a mystery. Even now they are not well understood, for these deep-sea creatures are not easy of observation.

It has, however, been pretty well established that the shell belongs to the female nautilus only, and that its main use is to form a nest for the eggs, of which large masses are often found in the shell. The nautilus belongs to the octopus family, and like the cuttle-fish, has a central head with two well-de-fined eyes and light limbs or feelers. It is from the broadest pair of these that the material of the shell is secreted.

The nautilus sits in her shell and floats along; the surface of the water. It used to be thought in olden times that the broad mantle of the tentacles was expanded as a sail, and the other limbs used as oars. Pictures of the animal in this position have actually been drawn, and poets and moralists

even went so far as to say that from watching it primeval man took his first lessons in boat-build-ing and navigation ! Thus Pope says : " Learn of the little nautilus to sail, Spread the thin oar and catch the driving gale." The name, as, every one knows, signifies " little sailor." Science has demolished this pretty fable, like so many more* ; but the, reality left to us is just as wonderful as the fable. Why should a creature so lowly in organization, and to us so repulsive in appearance, possess a shell of such exceeding beauty. Of what advantage can grace of form and delicacy of colouring be in a thing destined to serve as cradle for the eggs of a creature certainly without any aesthetic faculty ? Beauty is distributed with apparent capriciousness throughout nature. Scientists, however, tell us. that both general form and each small peculiarity of structure and colour must be of advantage to the possessor. Thus every one knows that the colours of different species of wild animals are protective, either directly by serving to conceal them from their enemies, or indirectly by enabling them to capture their prey ; some special peculiarities have been judged useful as marks of recognition. The colours of the shells of various molluscs have been shown to be protective, and diversities of form to be connected with the habits of the creature and its mode of progression through water, and the grooves of some species are shown to be favourable to their mode of motion. The shape and lightness of the shell of our nautilus render it eminently fitted for floating, and presumably the timings are of some advantage. But the labours of some ardent investigator are needed to lead to a comprehension of the nautilus, and how form is allied to function. A spiral shell, external or internal, seems characteristic of the cephalopods to

which the nautilus belongs. Many will be familiar with the small, coiled, white shells often found in abundance on northern beaches. If one is broken, it is seen to be formed of separate chambers with dividing walls, something after the style of the chambered nautilus. These small shells are said to be found in the octopus. Two well-marked varieties of the paper nautilus shell are found

about Mahia Peninsula. One much the rarer, is more narrow and compressed in form than those here described ; the grooves are also more regular, and the tinting a little different. The shells are found chiefly in the summer months, during calm, warm weather, when the sea may be smooth enough for the little sailor, in its fairy craft, to venture on the surface of the ocean.