Part 3

which may be either large or small, plain or handsome, in accordance with the means of the collector. Perhaps for a beginner just a nest of shallow drawers in a deal or other case, may be quite sufficient; these drawers should be divided into compartments, on the front side of each of which should be pasted a neatly written label, with the common and scientific name of the species of shell contained in it, together with brief mention of the date when, and the place where, it was taken; and any observations relating to it which can be comprised in a few words, and may seem to the collector of sufficient interest to warrant their insertion. This would be a good beginning; by and by, when the collection is large, the knowledge more ample, and the outlay can be spared, it will be time to think of something ornamental—mahogany and glass, and carved or inlaid work, such a Cabinet as would properly display and enhance the beauties of your testaceous treasures, which are too often stowed away, with other natural curiosities, in a very disorderly, higgledy-piggledy sort of manner, like the collection described by Dryden.

“He furnishes his closet first, and fills The crowded shelves with rarities of shells; Adds orient pearls, which from the wave he drew, And all the sparkling stones of various hue.”

When live shells, as they are called, that is having the living fish in them, are obtained, the best plan is to place them in spirits of wine, this at once deprives the inhabitant of life, without injuring the shell, which should then be placed in hot water for a time, the body of the mollusk is thus rendered firm, and may be removed by means of some pointed instrument; care should be taken to leave no portion of animal matter within, or after a while it will become putrid and give out a stain, which will show through and injure the delicate markings of the shell; the surest, most expeditious, and least troublesome mode of cleansing a shell, is to place it in an ant heap for a day or two; the busy little insects will penetrate into its inmost cavities, and remove hence all offending matter. There will be no difficulty in this respect with the multivalve and bivalve kinds, which are only kept closed by means of a set of muscles, which can be tightened or relaxed at the pleasure of the animal within, and become powerless to keep the shell closed as soon as that is dead. Great care must be taken to preserve unbroken the smaller parts of these shells, such as the hinges or teeth, as on the structure of these the scientific arrangement into genera chiefly depends; the beard also, as it is called, and silky threads, must not be removed, as these have much to do in determining the particular species.

River and land shells are generally very thin and brittle, and must be carefully handled; their colours are not usually so brilliant as those of the marine species, but they form links in the testaceous chain, which are necessary to a proper study and elucidation of conchology.

The most glowing and gorgeous of all shells are those brought from the Tropical seas, and, excepting in a few rare instances, specimens of most of these can be obtained at little cost from any dealer, or from sailors returning from a voyage. If it is necessary to send either those, or British shells, any distance, or to pack them away in a small compass, the best plan is to wrap them separately in soft paper, place them in a box, and then pour in sawdust, bran, or fine sand, very dry, until all the open spaces are completely filled up.

ON CLEANING AND POLISHING SHELLS.

All shells, whether inhabited or not, when taken should be soaked for a while in hot water, to remove the dirt which may adhere to them, and dissolve the saline, that is salt, particles contained in the sea water; they should then be thoroughly dried, and if, as is the case with many, they naturally possess a good polish, they are at once fit for the cabinet. Generally, however, it happens that when shells are dry, they lose much of the peculiar brilliancy of hue, which they possess when seen through the medium of the glistening water; to restore this, wash them over with a thin solution of gum arabic, or white of egg; some collectors use a varnish made of gum mastic, dissolved in spirits of wine; this is perhaps preferable, as it is not affected by moisture. Many shells have a very plain, dull, appearance, in consequence of being covered over with a kind of skin called an epidermis, a word derived from the Greek, and signifying the outer skin, sometimes called the cuticle. To remove this, soak the shell in warm water for some time, and then rub it over with a stiff brush until the covering is removed; should this be very thick, it will be necessary to mix a little nitric acid with the water, but this must be done very cautiously, for if too strong it will remove all the lustre from the surface of the shell subjected to its influence. Sometimes the file, and a substance called pumice stone has to be used, but these are dangerous agents in inexperienced hands. The best polish for the shell after the skin is removed, is a red earth called tripoli, applied on a piece of soft leather.

FOSSIL SHELLS.

An eminent Geologist, named Dr. Mantell, has very beautifully and poetically termed rocks “The Medals of Creation.” As on coins and medals we see stamped enduring records of great historical events, so upon the rocks are written by the finger of God, a history of some of the mighty changes which the earth has undergone, and fossil shells are among the plainest and most easily read of the characters or letters, in which these truths are written. As Dr. Harvey, in his “Sea-side Book,” observes, “Shelly-coated mollusca have existed in the waters of the sea and in rivers, from a very early period of the world’s history, and have left in its most stratified rocks and gravels abundance of their shells preserved in a more perfect manner than the remains of most other animals. Now as the species in the early rocks differ from those found in later formations, quite as much as the latter from the mollusca of our modern seas, the gradual change in the character of the embedded shells marks a certain interval of time in the world’s history.” So we see that these rocks are the leaves of a great book, written all over with wonderful truths, and those who study such sciences as Geology and Conchology, are enabled to read much that is there written.

Every fossil shell that such a student picks out of the chalk, or limestone, is like a letter in the Alphabet of Creation; it has a significance, or meaning, and a number of such put together, form as it were, words and sentences, that can be made up into chapters, full of instruction, aye, and of amusement too. The study may seem a little dry at first, but never mind, go on, and you will soon be rewarded for your diligence, by the wonders that will unfold themselves to your understanding—the fresh and delightful views which you will obtain into the wide universe, the new and enlarged ideas of the wisdom and goodness of the Creator, and of the formation, habits, and connexion each with each of his various creatures.

Properly to treat of fossil shells, would require a book of itself, and a large book too; we can here but allude to the subject, as a part, and a very important and interesting part of the study of Conchology; more will be said about it in a volume which we purpose writing for this series, on Rocks, and the petrified organic remains found in and about them.

“Those relics of an older world, which tell Of changes slow or sudden, that have past Over the face of nature; fossil shell, Shark’s tooth, and bone of megatheran vast, Turned into stone, and so preserved to show Man of those things whereof he ought to know.”

BEAUTIFUL SHELLS.

UNIVALVES.

Gasteropoda is a name given by some naturalists to a very extensive group of molluscous animals; the term is derived from two Greek words, signifying stomach and foot;—it has reference to the kind of fleshy foot which generally occupies the whole under side of the body, and by the contraction and extension of the muscles of which, the creature is enabled to glide, with a slow but steady motion, from place to place. The Slug and the Snail are the commonest examples which can be adduced of gasteropods; and one may tell by their slimy tracks, shining like silver in the morning sunshine, that during the night, which is their principal feeding time, they manage to get over a considerable extent of ground, although “a snail’s gallop” is a proverbial expression for slow motion; but it is astonishing how much work of any kind may be done if one “keeps at it;” by doing this the Tortoise beat the Hare, illustrating the truth of the proverb, that “slow and sure wins the race.” If you watch a Snail travelling with its house upon its back, it does not seem to make much way, and you are inclined to think that it will be long ere it reaches the new settlement to which it appears journeying with bag and baggage; but leave the spot for a while, and the chances are that on your return, the “slow coach” will have got somewhere out of sight. Here is a lesson for boys and girls; whatever you take in hand, don’t be in a hurry, and if people say you are “slow,” think of the snail, and keep on!

This, then, is a shelled mollusk of the third class, called Gasteropoda, according to the system of the French naturalist Cuvier. It has a distinct head, which, like the hinder part of the body, which we may call a tail if we like, projects, when the creature is in motion, considerably from the shell; it is also furnished with what we commonly call horns, naturalists say tentacles, from the Latin tento—trying, or essaying; with these the creature, as it were, feels its way; being extremely sensitive; they answer the purpose of organs both of sight and touch; put your finger slowly towards one of them, and you will observe that, even before contact, it begins to retract, or draw in, as though sensible of the approach of some opposing body, as it no doubt is. These horns of the snail, then, are its feelers—eyes to the blind, fingers to the fingerless; so God provides for his creatures all that may be necessary for their existence, and compensates for the deprivation of one sense or organ, by some admirable contrivance which meets the necessities of the case.

It appears likely that the little knobs at the end of the snail’s feelers, are, as some naturalists assert, in reality eyes; if so, we were wrong in calling the creature blind. Yet is their position and construction so different from organs of sight generally, that they serve rather to strengthen than invalidate the above observations. The number of the horns varies in different kinds of snails from two to six, and some have none at all. These tentacles, when present, are always situated above the mouth; some of them have the knobs at the base, others at the sides; and it has been conjectured that they may be organs of smell, as well as of sight and touch.

THE COMMON SNAIL

Is called by naturalists Helix aspersa, the generic name being derived from a Greek word signifying spiral, and having reference to the shape of the shell; the plural is Helices, a term applied to all convoluted or twisted shells, which terminate in a point like a church spire: a spiral-shelled fossil is called a helicate. The specific name comes from the Latin asper—rough, whence also our English word asperity—roughness, and several others. The Helicidæ, or Helix family, is that which includes the land shell Snails and the naked Slugs, and in this family there are several genera; they are distinguished from the shelled water Snails, both sea and river, by having a different breathing apparatus, and some other points of internal construction which it is not necessary to describe here.

The Common Snail has a mouth, of which it makes good use, as market gardeners well know, and yet this mouth is not furnished with teeth; instead of these, the upper lip, which is of a horny texture, is what is called dentated, from the Latin dentus—a tooth, that is, divided or separated, so as to present somewhat the appearance of a row of teeth in the jaw; this lip is of an arched form, and appears to be a very serviceable kind of instrument to Mr. Helix aspersa, who, if his character be not aspersed, is very destructive to all sorts of greenery. The lower lip is divided only in the middle, where there is an opening of some width: it is not horny, like the upper one.

Snails lay eggs, which are about the size of very small peas; they are soft, and of a whitish colour. Being semi, that is, half, transparent, or clear, their contents can be partly seen; and in those of a water Snail, deposited against the side of a glass bottle, the young were detected with partially formed shells upon their backs.

To shew how tenacious they are of life, it has been mentioned that Mr. S. Simon, a Dublin merchant, had a collection of fossils and other curiosities left him by his father; among these were some shells of Snails, and fifteen years after the collection came into his possession, his son had the shells to play with, and placed them in a basin of water, when lo! out came the slimy bodies and knobbed horns of several of the Gasteropods, no doubt hungry enough after their long sleep.

We all know that our Common Snails hybernate, or sleep through the winter. As soon as the chills of autumn are felt, they seek out some snug crevice in an old wall, or burrow in the earth, or congregate beneath garden pots, roots of trees, thatched roofs, or in any hole or corner that may be convenient, and then throwing a kind of temporary skin, like a drum head, which naturalists call operculum, over the opening of their shells, and sticking themselves fast to the sides of their refuge, or to each other, they sleep away, careless of frosts and tempests.

A moist and rather warm state of the atmosphere seems most congenial to the land Snails, some species of which are found in all countries, except those where the most intense cold prevails. Generally speaking, they do not like dry heat, and to escape from it will get under stones, and into other cool places, from whence a shower brings them forth in such numbers, the smaller species especially, as to lead to the popular belief that it sometimes rains Snails.

These Gasteropods, although extremely injurious to vegetation, must not be regarded as worse than useless, as they commonly are; besides furnishing food for several wild, as well as domesticated, birds, they are no doubt a nourishing article of diet for man. The Romans had their cochlearia, where Snails were regularly fed and fattened for the table; and the French at the present day their escargotoires, or Snailery, for the same purpose; some of the Snails so kept, attain an immense size, as well they may if fed, as by the Romans, on new wine and meal. Many poor persons, especially those who are consumptive, might no doubt derive much cheap sustenance and benefit from using the larger species of Helicidæ, which might be collected from hedges and gardens as food. Why should they not eat those as well as the marine mollusks, such as Oysters, Cockles, Whelks, etc.

Snails have an extraordinary power of re-producing any part which may be injured or cut off, even to the extent of the whole head, as has been observed to be the case; the reparation of injury done to the shell they can effect easily, as can all testaceous mollusks. Respecting the construction of the shell it may be observed that it is produced in the thickness of the mantle, or cloak-like covering which envelopes the body of the animal; the formation commences at the small end or spire, and gradually goes on, whorl upon whorl, as the still widening circles which give the ridgy appearance to most univalves, are called. Columella, or pillar, is the name given to the spire on which the cones are rolled; this is sometimes solid, and sometimes hollow; when the latter, the open end is called the Umbilicus, meaning the navel or centre. The opening at the bottom, from which the animal issues, is the last portion finished, and this is called the aperture, a Latin word adopted into the English dictionary. Some of these Helices are wide and flat, even hollow and cup-like, with the whorls rising above the pillar—these are called discoid shells; others which are long and narrow, with projecting spires, are termed turbinated shells; the former being more or less flat or disk-like, the latter twisted, whirling, like a spinning-top, from the Latin turbo—a whirling, a turning round.

If we take a Common Snail, and plunge it into boiling water, which will instantly kill it, so that it can be removed from the shell, we shall find the whole of that part of the body which was lodged in the upper whorls, or spiral part of the shell, is covered with a thin membrane or skin; this is called the mantle, and that portion of it which corresponds with what we may consider as the back of the mollusk, and which is considerably thickened, is termed the collar; here are situated the glands, which secrete the colouring and other matter of which the shell is mainly composed; although the substance called nacre, or mother-of-pearl, is secreted in the thinner part of the mantle; it is however from the collar that the growth or increase of the shell proceeds. It is in accordance with certain variations in the shape and disposition of this mantle and collar, that shells assume such very different shapes. Sometimes the whorls or spiral ridges, are projected or thrown far out, and this produces the turbinated shell. Sometimes they scarcely rise above each other, but rather spread towards the sides, and then we have the discoid shape. Generally speaking, the whorls of a shell take a direction from left to right, but occasionally an opposite one; they are then called sinistral, or left-handed shells: such are not common. If one of the twisted shells be divided length-ways, it will be seen that the inside of the whorls wind in an ascending direction, round the Columella, or central column, as the spiral staircases in the Crystal Palace.

But let us return to our Garden Snail, who has many near relatives in Britain, several of which have beautifully-marked and convoluted shells, as will be seen by a reference to our coloured illustrations, Plate I. We will introduce them in due order. Fig. 1, the Banded Snail, (Helix nemoralis,) from the Latin nemus—a wood or grove; the prettily-striped shells of this species may be found in great plenty among the roots and in the crevices of the rugged boles of old forest trees, as well as in hedge-rows and in mossy banks, and other situations near woods. Fig. 2, the Heath Snail, (H. ericetorum,) from erica, the Latin for heath; a small species with brown bands, remarkable for its large umbilicus, perforating the centre of the shell nearly through. Fig. 3, the Silky Snail, (H. sericea,) from the Latin sericus—silk-like; the shell of this species is covered with short slimy hairs, which give it a glistening appearance. Fig. 4, the Stone Snail, (H. lapicida,) from the Latin lapis—a stone: Linnæus called the species the Stone Cutter, probably on account of its habit of frequenting stony places, and the peculiar construction of the shell, which has a sharp edge running round each whorl; it is commonly found lodged in the cavities of loose-lying stones, but which it can scarcely be suspected of having hollowed out for its own accommodation.