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"There are curious things of which men know

As yet but little.

—————————— Shells

Which ocean flingeth forth from off her billows

On the low sand.

Unfortunately for our knowledge of Conchology, collectors content themselves too frequently with gathering the dead and empty shells washed up by the 'tide, as if they, fractured, waterworn, and colourless, could give any idea of the glorious creatures which had inhabited them;—as well might they judge of a man's habits and character by walking through his house;—and it is the mere formation of cabinets for the beauty of the shells which has led to this being considered a frivolous study, and so, without knowing the habits of the animal, and its conformation, affecting the form of the shell so very materially, it is. Still collectors often hunt up objects which had escaped the eye of those more educated in scientific pursuits, so instead of criticising the past, we will rather give a brief digest of the peculiarities which characterise this division of the Natural Kingdom, as well as some few hints for the guidance of the Amateur Naturalist in his researches for the future.

Shell-fish then, be it known, belong to that division of the Natural World called "Mollusca" from the Latin word mollis (soft), their bodies consisting universally of a soft consistence and generally ​protected by a hard shell, Univalve or Bivalve. Taking first now the Univalves, which have a distinct head, eyes, and tentacles, the mouth being armed with jaws, we find that Cuvier has arranged them into three classes, the animals belonging to the first of which are termed Cephalopoda (from Cephale the head, and poda feet), because their feet, or rather arms, which are attached to the head form a circle around the mouth; the Cuttle fish is a familiar example, and its shell, which is internal, as in almost all comprised in this class, is constantly thrown upon our shores;—the beautiful little discoidal chambered shell of the Spirula, is not uncommon on the Warrnambool and other of our coasts, the animal itself would indeed be a prize, for although an inhabitant of all the warm seas, it is not often met with.

The animals of the second class, or Gasteropoda, of which the common garden snail is a good type, creep by the successive expansion and contraction of their broad muscular foot, which is formed by the under side of the body, and thus the name of the class is obtained from gaster, the belly, and as before poda, feet. Some breathe air, (pulmonifera), others water (branchifera.) Many of the individuals of the latter division close their habitations with a horny or calcareous covering called an operculum, and it presents strange modifications of structure; we find it in some spiral, in others concentric, and occasionally claw-shaped; that of a Natica found on the Western Coast, is commonly used as card counters, and we have seen them polished and tastefully mounted as wrist studs and shawl pins. ​Our shores give us many Carnivorous Gasteropods, for example, Murex; Fusus, or Spindle shell; Nassa, or Dog-whelk; Purpura, or Purple shell, (some species of which afford a dye); Conus or Cone shell; Voluta; Mitra or Mitre shell; Cypræa, (Cowrie), &c., &c. Livnigstone, in his entertaining travels tells us that the chief Shinte, as a last proof of his friendship came into his tent, which he closed to prevent the possibility of there being any witnesses to his extravagance, and then presented him with the conical end of a Cone shell, adding as he did so, "There now you have a proof of my friendship." So high a price was set on these shells, that five of them would be a handsome sum for an Elephant's tusk worth £10.

In brackish water we may find many of the Seasnails, the pretty little mottled Natica, the long spiral Cerithium, and on the rocks at Lady Bay we have seen specimens of the Siliquaria or Pod shell, which is longitudinally slit all along its twisted spire; the Litorina or Periwinkle, is always found within the action of the tide, as it feeds on sea-weed, and the brackish lagoons afford us the pretty minute Looping snail (Truncatella) in abundance, and it has one recommendation that it can survive for a considerable time in the mud, when the water has been dried up by the Summer's sun.

The richly-colored Pheasant shell (Phasianella) should be sought after eagerly on the Warrnambool and other shores, since it forms so lovely an object for the Cabinet; its generic name has its origin in the resemblance of the markings of the shell to the plumage of the Pheasant (Phasianus): the hoop shells ​Trochi, are found attached to rocks on all our coasts; of the Ear shells (Halotis), and Boat shells (Chiton), we shall have much to say hereafter when we meet with them.

Of the Pulmonifera or air-breathing Mollusca, some are terrestrial, others fresh-water, and many inhabit damp places near the sea; their respiratory organ is so simple a form of lung, that this order is called by Gray, "concealed lunged," as the orifice is small and valve—like to guard against the entry of water in the aquatic tribes, and to prevent the rapid desiccation in the land snails.

The latter do not abound in Australia, but we find abundant interest in the beautiful shells which exist in the Yarra, the Moorabool, the Merri, and other of our rivers, lurking on the large, ovate, floating leaves of the Nymphæa-like Damasonium, or the broad paler Potamogiton (Pond-weed), which is always so gay and refreshing an object, but these we must needs put into an Aquarium to watch with the aid of a pocket lens their structure and habits. We place along with them some of the green scum which covers the surface of the water (we say scum, but it is in reality a beautiful freshwater Alga,) a Zygnema in conjugation, and a few plants, such as Chara, the velvety Azolla rubra or pinnata, one or the other of which is to be met with on the Merri, at Warrnambool; the Moorabool, at Geelong; on the lagoon in the Botanical Gardens, Melbourne, and such like situations. The flat many-whorled shell, so brittle—is a Planorbis, this other, ovate-shaped and also very thin with a large aperture, is a Physa, so called from its resemblance to a pouch; ​and the one, with the aperture on the right, which distinguishes it from the former is an allied genus, Limnæa, or Pond-snail. All these are widely distributed throughout the world. Now then let us watch how industriously they are cleaning off the dark coating of Conferva, which has already commenced growing on the sides of our Aquarium, and with this lens see how they use their tongue; the upper lip with its mandible is raised, the lower lip which is horse-shoe shaped, expands, the tongue is protruded and applied to the surface for an instant, and then withdrawn; its teeth glitter like glass paper, and in Limnæa it is so flexible that frequently it will catch against projecting points, and be drawn out of shape slightly as it vibrates over the surface.^[1]

Both these last species crawl beneath the surface of the water with their shells downwards, the Limnæa depositing its eggs, some fifty or sixty in number, in small sacs, and Mr. Hogg, in his valuable work on the Microscope, (Edition 4, p. 423,) gives us some interesting information on their subsequent development, " When examined soon after they are deposited, the vesicles appear to be filled with a perfectly clear fluid; at the end of twenty-four hours a very minute yellow spot, the nucleus or germ, may be seen near the side of the cell-wall. In about forty-eight hours afterwards, this small germ has a smaller central spot, rather deeper in color, which is the nucleolus. On the fourth day the nucleus has changed its position, and is enlarged to double the size upon viewing it more closely a depression or fissure is seen—this on the ​eight day most distinctly divides the small mass into the shell and soft part of the future animal. It is then detached from the side of the cell, and moves with a rotatory motion around the cell interior; the direction of this motion is from the right to the left, and is always increased when the sunlight falls on it. The increase is gradual up to the sixteenth day, when the spiral axis can he made out, and it presents a striking difference to the soft parts in appearance. On the eighteenth day these changes are more distinctly visible, and the ova crowd down to the mouth of the ova-sac; by using a higher magnifying power, a minute black speck, the future eye, is seen protruded with the tentacles. Upon closely observing it, a fringe of cilia is noticed in motion near the edge of the shell. It is now apparent that the rotatory motion first observed must have been in a great measure due to this, and the current kept up in the fluid contents of the cell by the ciliary fringes. For days after the young animal has escaped from the egg, this ciliary motion is carried on, not alone by the fringe surrounding the mouth, but by cilia entirely surrounding the tentacles themselves, which whips up the supply of nourishment, and at the same time the proper aeration of the blood is effected. Whilst in the ova it probably is by this motion that the cell contents are converted into tissues and shell. From the twenty-sixth to the twenty-eight day, it appears actively engaged near the side of the cell, using all its force to break through the cell wall, which at length it succeeds in doing, leaving the shell in the ova sac, and immediately attaching itself to the side of the glass vase to ​recommence its ciliary play, and appear in a still more advanced stage. It is still some months before it grows to its perfect form. One of these snails may deposit from two to three of these ova-sacs a week, producing in the course of six weeks or two months from 900 to 1,000 young,"

It is to the Microscope then we owe this pithy description of the progress ab ovo, of a species allied to the common IAmnaa of our rivers.

We now turn to the Sea-slugs, whose shell, where it exists, is small and thin, slightly rolled and pearly white, and partially concealed by the animal; in Bullæa (Bubble shell,) we find an organ resembling the gizzard of a fowl, paved with calcareous plates capable of crushing the shell-fish on which it feeds. Many specimens of this shell we have obtained on the shore at Geelong. The Pteropoda our readers are seldom likely to meet with;—the Lamp-shell (Waldheimia) is not uncommon, attached by its pedicel to the oysters from Western Port, and its structure is worthy of examination; it belongs to Cuvier's 4th class, Brachiopoda, commencing the bivalve section, the animals comprised in which take their name from the ciliated arms on the side of the mouth, wherewith their food is obtained.

The well known bivalve shells of the Oyster and the Cockle are good types of the Conchifera, the animals of which are, with few exceptions, aquatic, and range at all depths on almost every coast and every clime. There are amongst them some burrowing shells, as the large white oblong Anatina (Lantern shell?) such splendid specimens of which are found in Corio Bay, a species of Solen, or Razor shell, and the ​borers are well represented by a Teredo which abounds on the piles at Williamstown.

The ability of many molluscs, especially the freshwater, to sustain life for a considerable time, is recorded in some remarkable instances; indeed it is probable that they become torpid in warm climates during the hottest and driest part of the year.^[2] Mr. Gray, of the British Museum, received from this country a Pond mussel which had been more than a year out of water, and it still lived; some pond snails have been found alive after five years, although in the warm climate of Jamaica, and an individual of the Desert snail which had been affixed to a tablet in the British Museum in 1846, was found, on some suspicion having arisen as to his having made determined efforts to escape from confinement, still flourishing after being immersed in tepid water.^[3]

A Cabinet of Shells is necessary for those who desire to study Conchology, and we may therefore hint, that to obtain specimens, perfect in shape and colour, dredging is the only good plan; but this may not be feasible, if so, the collector should wade amidst the rocks, examining the heaps of seaweed thrown on the sand after a storm, or carefully grope about all dark fissures, where many good species congregate, or are driven, nolens volens. Chitons and Limpets are only detached from the rocks by the aid of a strong bladed knife, as the former especially repel the air and water on all sides to produce a vacuum and so obtain a firmer hold, and they will sooner part with a portion of their shells than leave their places of attachment. Bivalves, and all live shells should be boiled ​and the soft parts removed when the valves separate or gape, but in doing this care should be taken not to injure the hinge, as it is often of material importance in the determination of genera; to preserve it therefore it is well to tie the shell round with some light thread. The operculum of Univalves must also be preserved, and should the contents of the shell at any time emit an unpleasant smell, a small quantity of chloride of lime will quickly and effectually remove it.

The arrangement of a collection of Shells is a mere matter of taste, much depending on the space that can be afforded to it. We who lead a somewhat nomadic life, prefer keeping the smaller species in small pill boxes, which can be purchased in nests at a trifling cost, the name of each species being carefully recorded on the lid; but a pair of each shell arranged on a cardboard, with the operculum glued down alongside, facilitates easy classification and subsequent examination.

We have not deemed it necessary to enter into a technical description of the columella, the hinge, and other portions of the shell, as this may be found in any elementary Work on the subject; to the amateur, Miss Catlow's little Manual will be of interest, but to the working Conchologist, we recommend Woodward's "Manual of the Mollusca," of which we need only say, that it is one of Weale's series, a sufficient testimony to its excellence.

1 ↑ Woodward's "Manual of the Mollusca.', p. 161.

2 ↑ Woodward's "Manual of the Mollusca."

3 ↑ Ann. Nat. History, 1860.