Beautiful Shells of New Zealand Part 1

Beautiful Sh.e.l.ls of New Zealand.

by E. G. B. Moss.

PREFACE

Often have I heard my young friends regret the great difficulty experienced in identifying the things of beauty found on our coast; and some time back it occurred to me that the time had arrived when an attempt should be made to remedy this. New Zealand is a maritime country, most of its inhabitants living near the sea, and there are few indeed who do not enjoy occasionally the pleasure of wandering along the seash.o.r.e, gathering sh.e.l.ls, seaweed, echini, and the numerous other relics of the deep. This pleasant hobby is robbed of a great deal of its interest by a lack of knowledge as regards the names, habits, and mode of preserving the various finds, and especially the finds of sh.e.l.ls.

When properly preserved and carefully cla.s.sified they are much more attractive than otherwise they would be. In almost every home sh.e.l.ls are seen; some highly prized as ornaments, others as mementoes of pleasant hours in foreign lands; but seldom are our really beautiful sh.e.l.ls represented in a collection.

In this work marine sh.e.l.ls alone are dealt with, our numerous land and fresh water sh.e.l.ls being, with six or seven exceptions, small and insignificant. Of land and fresh water sh.e.l.ls about two hundred varieties, and of marine sh.e.l.ls about four hundred and fifty varieties, have up to the present been discovered in New Zealand. For some inscrutable reason, however, the New Zealand authorities are continually changing the cla.s.sical names of our sh.e.l.ls. The names I have used are taken from the late Professor F. W. Hutton's last list, published in 1904. It is really time some attempt was made to stop this foolish proceeding. Most of the sh.e.l.ls, since I began collecting 20 odd years ago, have had their names changed once, many of them twice, and some even three times. It is more than probable some of the names will be altered while this volume is in the press. These frequent changes in the names cause great confusion, and but for the kindly help and encouragement given me by Mr. T. F. Cheeseman, F.L.S., of Auckland, I should have hesitated to undertake its publication. What most enn.o.bles science is the willingness to give a.s.sistance to beginners shown by really scientific men, and doubly pleasing is that help to the recipient when given spontaneously and without stint.

This is the first attempt to publish a popular work on New Zealand sh.e.l.ls, and is written by an amateur for amateurs. Nearly every sh.e.l.l likely to be met with by an ordinary collector (except the minute sh.e.l.ls) will be found in the ten plates at the end of this work. I have endeavoured to describe the sh.e.l.ls in simple language, as the scientific words may puzzle some of my readers. For instance, Professor Hutton describes a certain sh.e.l.l as "thick, irregular, sharp ribbed, with the margin dentated or lobed, very inequivalve; upper valve opercular, compressed, wrinkled, with thick concentric laminae; lower valve cucullated, purple, white within, edged with purple or black; lateral margins denticulated; hinge generally attenuated, produced, pointed."

When a sh.e.l.l is found that fully answers this description you will know it is an Auckland rock oyster. Errors and omissions will, I trust, be charitably dealt with, as the inevitable mistakes of a man who is blazing a track. I have endeavoured to give the Maori names also, but, unfortunately, in different parts of New Zealand the same name is frequently used for different sh.e.l.ls.

My own collection of New Zealand marine sh.e.l.ls, made during my residence in Tauranga, Bay of Plenty, is, I believe, the best and largest yet made, and among the specimens I can number no less than a dozen new sh.e.l.ls which I had the pleasure of adding to the recognised list. Over 90 per cent. of the known species of New Zealand marine sh.e.l.ls were found there by my friends or myself during the 15 happy years I spent in that delightful, though not very progressive, part of New Zealand.

My thanks are especially due to Mr. Charles Spencer, of Auckland, an ardent conchologist, and for many years my colleague in collecting sh.e.l.ls, for the care taken with the photographs, and for valuable suggestions and help.

CHAPTER I.

Sh.e.l.lS AND THEIR INMATES.

Before the study of sh.e.l.lfish, or molluscs, was conducted on the scientific principles of the present day, sh.e.l.ls were cla.s.sified as univalves, bivalves, and multivalves. The univalves were sh.e.l.ls in one piece, such as the whelk; the bivalves those in two pieces, such as the mussel or oyster; and the multivalves those in more than two pieces, such as barnacles or chitons, barnacles, however, being no longer cla.s.sed with sh.e.l.ls.

The highest of the five types, or natural divisions, of animals are the Vertebrata, the Mollusca, and the Annulosa. The vertebrates usually have vertebrae, or jointed backbones, and from this the highest division takes its name; but the real test is the colour of the blood, which in the vertebrates is always red.

The molluscs have soft bodies and no internal skeleton, but in lieu of this the animal is usually protected by an external sh.e.l.l, harder than the bones of vertebrates. The annulosa, like the molluscs, have soft bodies and no internal skeletons; but the external sh.e.l.l is divided into joints or segments, and is usually softer than the bones of vertebrates.

Fishes belong to the vertebrate division, oysters to the mollusc, and crabs and starfish to the annulosa.

The remaining two of the five divisions are the Caelenterata, in which the general cavity of the body communicates freely with that of the digestive apparatus, and the Protozoa, which includes all animals, such as sponges, etc., not included in the above four divisions.

The sh.e.l.l of an oyster takes the place of the bones of a dog; and although it may seem strange for an animal to have its bones on the outside of its body, it is really no more strange than for a fruit, such as the strawberry or raspberry, to have its seeds on the outside. Lime is the princ.i.p.al ingredient of all bones; and the bones of vertebrate animals contain a large proportion of phosphate of lime, while the sh.e.l.ls of molluscs, or sh.e.l.lfish (as they are popularly called), consist almost entirely of carbonate of lime.

When scientists began more carefully to examine the structure of sh.e.l.lfish, they found that those similarly constructed had sh.e.l.ls with certain marked peculiarities. The days of conchology were then doomed; and the study of the mollusc, or malacology, took its place.

Besides those necessary for digesting food, most sh.e.l.lfish have organs equivalent to those of vertebrate animals, such as feet, arms, eyes, head, heart, and tongue. Although bearing the same names, these organs rarely have a similar shape to those of the vertebrates, being necessarily adapted to the different mode of living. The foot of a c.o.c.kle, shaped like an animal's tongue, enables it to move slowly from place to place, as well as to burrow in a sandy beach with the comical jerks so well known to observers. The tongues are beautifully designed for their work. The long, narrow tongue of the vegetarian mollusc works like a scythe, and mows down the delicate marine gra.s.ses on which the animal feeds. The powerful tongues of those that prefer an animal diet are able to bore through the strongest sh.e.l.ls; and woe betide the unfortunate sh.e.l.lfish which, having shown signs of weakness, or disease, is surrounded by its active, carnivorous brethren. The tongue, sometimes longer even than the sh.e.l.l itself, is covered with rows of very hard spikes, or teeth, arranged similarly to the burrs on a file. As these teeth break, or are worn out, they are replaced by others that push themselves forward when wanted. Under a microscope of moderate power, the radula, or tongue, of a sh.e.l.lfish, especially a limpet, is a most interesting sight, and many molluscs can be identified merely by examining the tongue under a microscope. The shape of the teeth, the number, and the arrangement of them will settle the question.

The appet.i.tes of molluscs verge on the voracious. Break up a few c.o.c.kles, or other sh.e.l.lfish, and place them in shallow water on a calm day, and watch the result. If in the vicinity of rocks, and during a rising tide, all the better. First come the wary little shrimps to the feast. Some are creeping cautiously, and some are jumping and racing, as if afraid of not being in time. Then the carnivorous sh.e.l.lfish approach from all directions, foremost amongst them being the different species of Cominella. While they are lumbering along, sh.e.l.ls appear to be actually running; but a close inspection shows that these contain active little hermit crabs, whose tender tails, having no hard covering of their own, are snugly stowed in the empty sh.e.l.ls of defunct molluscs.

Then the sand or gravel moves, and crabs appear. The shrimps, crabs, and hermit crabs run off with the smaller morsels; but the molluscs gather round the remnants and pull and haul and roll over one another until the feast is ended, when some, being satiated, contentedly burrow into the sand; while others, with their appet.i.tes only sharpened, will wander away in search of fresh prey.

In many sh.e.l.ls, such as the Triton, or Lotorium as it is now called (Plate III.), every increase in growth can be traced in the thick lip formed by the animal when it has increased the size of its sh.e.l.l. Others again, such as the Struthiolaria (Plate IV., Fig. 4), only form a lip when their full size has been attained, and by this the difference between an old and young Struthiolaria can at a glance be seen. Others form a lip at each growth, and then dissolve the lip before starting again. Vertebrate fish are supposed to grow, and increase in size, till the day of their death, but sh.e.l.lfish do not do this. The sh.e.l.l becomes stronger and thicker with age, the animal having the ability to add layer after layer of nacreous, or pearly deposit, on the inside of the sh.e.l.l; and as the animal shrivels and lessens in size the thickness of the sh.e.l.l increases. And some, when they become too large, have power to dissolve the part.i.tions in the sh.e.l.l, and deposit the material on the outside of the sh.e.l.l.

The time it takes a sh.e.l.lfish to grow to its full size varies a great deal. Oysters take about five years; but the giant Tridacna, the largest bivalve in the world, has been found so enclosed in the slow-growing coral that it could hardly open its valves.

The young of most sh.e.l.lfish are active little things, and are usually so different from their parents as to be unrecognisable. Some swim, or frisk about, and travel even long distances in search of suitable quarters to settle in. Others float on the surface, and are driven where the winds and currents list. Some, like mussels, are distributed all over the world, others again are found, perhaps, on one rock, or on one small sandbank in a large district. Many sh.e.l.ls are rare, because we do not know where to look for them; but if we know and can find their food, we will find the sh.e.l.lfish not far away. Some change their shape so much that, as they age, they have to dissolve all the part.i.tions made in their youth in the sh.e.l.l. The eggs of some are scattered on the surface of the water, while the eggs of others are hatched by the mother before being turned adrift.

Marine sh.e.l.lfish live in all kinds of places below high water mark; and some of the semi-amphibious ones thrive even above ordinary high water mark, where for days at a time nothing but the tops of the waves could reach them. They are found on seaweed and on rocks, and on sand or mud-banks; but especially in places near rocks on marine gra.s.s banks bare at low spring tides. Some live on the surface of the water, some burrow in sand or mud, and some bore holes for themselves in the softer rocks. Some live in deep water; but the better coloured sh.e.l.ls are found near low water mark, or in shallow water; for light is as necessary to the perfecting of colour in sh.e.l.ls as in flowers. Sh.e.l.ls that have grown in a harbour are more fragile than those grown in the ocean, and are usually less brilliant in colour, as harbour water is not as clean as ocean water. The colour of sh.e.l.ls (as of insects) depends largely on environment, and is only one, and by no means the most reliable, method of deciding the species. An expert can at a glance tell whether a given sh.e.l.l has come from shallow or deep water, and whether from an exposed or sheltered spot. Most sh.e.l.lfish move about a great deal, and migrate into deeper water in summer; and on bright clear days retire into dark corners amongst, and even under, stones. On a dull day a collector is frequently more successful than on a bright, sunny day; and in spring or early summer the best hauls of live sh.e.l.ls can be made. Nearly all sh.e.l.ls have an epidermis, or outer skin. In some this is very apparent, as in the Lotorium olearium (Plate V., Fig. 1), or the Solenomya parkinsoni (Plate IX, Fig. 18), while in others it is nearly transparent, and hardly perceptible. To enable the true colours of a sh.e.l.l to be seen the epidermis must be removed.

The supposed original form of a sh.e.l.l was that of a volute univalve, such as the Triton (now Lotorium), or Struthiolaria. To properly enclose the animal, and make it safe from enemies, an operculum, or lid, was so formed that when the animal retired into the sh.e.l.l this filled up the opening. The operculum is usually like a piece of thin, rough brown horn, and where no reference is made to an operculum in this work, it must be understood that the operculum is h.o.r.n.y. Some sh.e.l.ls, such as the Astralium sulcatum (Plate VI., Fig. 18), and the Turbo helicinus (Plate VI., Fig. 17), have a sh.e.l.ly operculum; that of the latter being the well-known cat's eye.

In some sh.e.l.ls the operculum is small, in others large, and progressing step by step we find some, such as the scallop and oyster, with one side round, and the other (really an operculum) flat and as large as the sh.e.l.l; until we come to the perfect type with each valve the same shape and size. Then the operculum disappears, as in the limpet, and the covering sh.e.l.l becomes smaller and smaller, till in the Scutum ambiguum (Plate IX., Fig. 23) the sh.e.l.l bears about the same proportion to the animal that the little bonnet, fas.h.i.+onable a few years ago, bore to the lady that wore it. The sh.e.l.l is built up of very thin layers of nacre, or mother of pearl, and calcareous or chalky matter, the thinner being the layers of nacre the more l.u.s.trous and iridescent is the sh.e.l.l.

As would be expected from its isolated position, many of the genera of New Zealand sh.e.l.ls are not found elsewhere. The late Professor Hutton mentions nine genera in this position.

The dispersal of sh.e.l.ls is an interesting natural phenomenon. The eggs of molluscs are so small that they can easily be carried by currents, attached to floating seaweed or floating timber, on the hulls of s.h.i.+ps, or in the feathers or feet of our migratory birds, such as the G.o.dwit, which every year travels from New Zealand to Siberia and back. A great many of our sh.e.l.ls are found on the Australian coasts; and a surprising number are common to both New Zealand and Queensland.

In describing the ill.u.s.trations, length means extreme length, and by measuring the sh.e.l.l on the plate the proportionate width can be ascertained. The ill.u.s.trations are, generally speaking, half the natural length of the sh.e.l.l depicted; and the sh.e.l.l photographed, although in most cases an average full-sized specimen, in some instances was smaller than the average.

[Ill.u.s.tration]

CHAPTER II

COLLECTING AND CLEANING Sh.e.l.lS.

Sh.e.l.ls are described as live and dead sh.e.l.ls. Live sh.e.l.ls are those found with the animal enclosed, and are more likely to be perfect in form and colour than dead sh.e.l.ls. Dead sh.e.l.ls found amongst rocks are nearly always battered and worn, and useless from the collector's point of view. Live sh.e.l.ls are found below high water mark, among rocks, or in the sand, or amongst seaweed and marine gra.s.ses.

Wait till a storm from the sea is ended, and then, if the wind is blowing from the land, a rich harvest of live and dead sh.e.l.ls will be found on the sandy beaches and amongst the seaweed and wrack that comes ash.o.r.e. Many of the smaller sh.e.l.ls will be found amongst the leaves and roots of kelp. Start early in the morning, or pigs, rats, and seabirds will have destroyed the choicest specimens. Even such solid bivalves as the Dosinia will be carried skywards by the gulls and dropped on to a hard part of the beach, so that the sh.e.l.ls may be cracked and the gulls get the contents. Most birds have this habit; even thrushes can be seen carrying snails up in the air and dropping them on to paths. Soak the dead sh.e.l.ls in hot water for a few hours to get rid of the salt, and then scrub with a hard brush, or, if encrusted or very dirty, rub with sand, using a brush or cloth. No need to fear hurting them, unless very fragile, in which case the best thing is a soft toothbrush, with fine sand. If patches of dirt, or encrustations, still remain, sc.r.a.pe with a piece of hard wood or a knife. As a last resource use muriatic acid, diluted with an equal volume of water; but be careful to put it only on the spots to be cleaned, using a penholder, or small stick, with a small piece of rag tied to the point. The inside of the sh.e.l.l, if discoloured, can be cleaned in the same way. When cleaned, wash again carefully, and dry thoroughly. Then rub the sh.e.l.l with a mixture of sewing machine oil and chloroform in equal parts. The machine oil, being fish oil, will replace the oil the sh.e.l.l has lost, and chloroform is the best restorer of colour we have. For very delicate sh.e.l.ls poppy oil is sometimes used; but it is expensive and difficult to obtain.

The greatest trouble is getting the animal out of live sh.e.l.ls. Anthills are few and small in New Zealand, so the lazy man's method of putting sh.e.l.ls on an anthill, and letting the insects do the work, is impracticable. Boiling for a minute will not hurt the stronger and heavier sh.e.l.ls; but even pouring boiling water on the more delicate sh.e.l.ls will cause them in time to fade. After taking the sh.e.l.ls out of the boiling water, let them cool, and then place them in cold, fresh water for a couple of days in summer or for a week in winter, changing the water every day. The animal can then usually be removed with a bradawl, or, better still, a sail needle stuck into a cork. Although soaking in fresh water for a few days makes the animal slip out more easily, still a large proportion will break during extraction. The piece left behind must also be extracted, or the sh.e.l.l will be offensive. The coa.r.s.er sh.e.l.ls can be buried for a few months in sandy soil, or for a few weeks on a sandy beach below high water mark, or put in baskets or bags made of twine or netting, and placed in tidal pools, or fastened to stakes at low water mark, where the marine insects will quickly do their share of the work. Or they may be buried in a boxful of clean sand or sandy soil, and the sand kept moist by watering it every few days. The box is all the better for being put away in a damp place under a tree, or on the shady side of a building or fence. This, however, is a slow process, and if the specimens are required at once, the best way is to extract all you can of the animal by the hot water and soaking process, and then keep the sh.e.l.l half-full of water in a shady place, every morning holding it under a water tap and shaking it carefully. After each shaking a very little pure muriatic acid may be put into the sh.e.l.l, and when all the effervescing from the acid is over, wash and shake it again. Two or three mornings of this treatment should clean the sh.e.l.l.

The more delicate sh.e.l.ls will lose their colour if put into boiling water, so first put the boiling water in a basin and then place the sh.e.l.ls in it. Nearly all salt water sh.e.l.lfish, if soaked for a few hours in fresh water, will die. The only exceptions I know of are the Nerita and Littorina, families which are semi-amphibious. The best way to remove coral or vegetable growths from sh.e.l.ls is to leave them for a few weeks, or if very hard, for a few months, in a shady place, where the wind and rain can get at them, but not the sun. The growths will then be sufficiently soft to be sc.r.a.ped off with a piece of hard wood or a knife, or rubbed off with sand. It is a good plan to oil or paste calico over portions not covered with growths, so as to reduce the risk of the colour fading. When the animal is removed and the growth cleaned away, wash, scrub, and dry, as with dead sh.e.l.ls.

Sh.e.l.lfish are sometimes obtained by dredging with a naturalist's dredge, or by diving for them, or lifting them out of the water with instruments such as hay forks and hooks. Sandy beaches and banks yield many of the most beautiful specimens, but only with experience will the collector be able to identify the marks of the syphons of the various sh.e.l.lfish.

Nearly all sh.e.l.lfish that burrow have two syphons, or tubes, which they push through the sand. The water is drawn down one syphon and up the other; and as it pa.s.ses through its stomach the mollusc absorbs the animal and vegetable particles in the water. Some of these sh.e.l.lfish live feet below the surface of the sand; some, such as the common c.o.c.kle, only a fraction of an inch. Apparently even c.o.c.kles do not come to the surface, except to die. Some instinct seems to urge a sh.e.l.lfish, when sick unto death, to save its fellows from infection by leaving the common shelter. c.o.c.kles found on the surface are to be avoided as unhealthy, and, unless they die naturally, are soon killed by the carnivorous sh.e.l.lfish. It does not take one of the whelk family long to bore a hole in the centre of the c.o.c.kle sh.e.l.l. It knows too much to risk having its radula, or tongue, nipped off by putting it between the partly-open valves of the dying c.o.c.kle. The end of the syphon, which projects from the sand, is like a miniature sea anemone. Each sand-burrowing sh.e.l.lfish has a different shaped end to its syphon, and the skilled collector can tell at a glance what sh.e.l.lfish is down below.

If he can grip the syphon with his hand he will have no difficulty in digging up the sh.e.l.lfish, even such a deep-living one as the Panopaea (Plate VIII., Fig. 3), one of which was captured by Mr. C. Spencer on Cheltenham Beach, near Takapuna Head, in Auckland Harbour. I believe this was the only Panopaea captured in New Zealand in situ, and was about eighteen inches below the surface of the sand at half-tide mark.

If he miss gripping the syphon he will probably lose the sh.e.l.lfish; as it can burrow nearly as fast as a man can dig with his hand. A beginner cannot do better than take a small spade, and walk along a sandy beach at low water. As the tide begins to rise, and the buried sh.e.l.lfish feel the water, he will see the sand moving, or showing signs of life; and if he digs quickly enough he may unearth rare and beautiful specimens for his cabinet.

Wherever animals or vegetables are crowded, disease appears. This is true of molluscs, and it is seldom worth while looking for a specimen fit for a collection where any particular kind of sh.e.l.lfish lives in great numbers. Animal and vegetable parasites will be found wherever sh.e.l.lfish are crowded together. For instance, a perfect c.o.c.kle, or one good enough for a collection, will not be found on a c.o.c.kle bank, but solitary ones must be looked for elsewhere.

[Ill.u.s.tration]

CHAPTER III.

DESCRIPTION OF PLATES.