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a remarkable fact, that in many spots where the Romans-great connoisseurs in Snailshad fixed their establishments, the Edible Snail is still to be found. I have seen many of these great Snails caught near Oxford. Regular houses were built for the purpose of fattening the Snails, which were bred to an enormous size by constant feeding with a mixture of meal and new wine. There are even now on the Continent several snaileries, where the inmates are abundantly supplied with food, though they are not fattened with the elaborate precaution of the Roman times.

Even the common Snail is thought a delicacy by those who are sufficiently strongminded to eat it; and it is quite common to see, even in Paris, the poorer orders dressing their dinner of Snails on an iron plate, heated over burning charcoal. I once knew an old woman, one of the few surviving wearers of scarlet cloaks, who used daily to search the hedges for Snails, for the purpose of converting her milk into cream. This cheap luxury was obtained by crushing the Snails in a piece of linen, and squeezing their juice into the milk. She showed me the whole process, which I afterwards imitated as far as the mixture with the milk, but could not bring myself to test the result by taste.

Towards the end of autumn, the Edible Snail ceases to feed, withdraws itself to some sheltered spot, mostly under grass, moss, or dried leaves, and then sets about making its winter habitation. This process is very curious, and is thus described by Mr. Bell:

"A large quantity of very viscid mucus is secreted on the under surface of the foot, to which a layer of earth or dead leaves adheres; this is turned on one side, and, a fresh secretion being thrown out, the layer of earth mixed with mucus is left. The animal then takes another layer of earth on the bottom of the foot, turns it also to the part where he intends to form the wall of his habitation, and leaves it in the same manner, repeating the process until the cavity is sufficiently large, and thus making the sides smooth, even, and compact. In forming the dome or arch of the chamber, a similar method is used, the foot collecting on its under surface a quantity of earth, and the animal, turning it upwards, leaves it by throwing out fresh mucus; and this is repeated until a perfect roof is formed.

As I have very often watched this curious process, I am certain of the facts. On removing very carefully a portion of the roof soon after its completion, I was enabled to see the formation of the operculum. In about an hour, or even less, the whole surface of the collar of the mantle instantaneously pours out the calcareous secretion in considerable quantity. This is at first a fluid or thick cream, but very soon acquires exactly the consistence of bird-lime, being excessively adhesive and tenacious; and in about an hour after it is poured out, it is perfectly solid."

ON the same engraving may be seen a shell, represented as climbing up a daffodil. This is the LEMON BULIMUS, an example of another large genus, containing more than six hundred species. These shells can be distinguished from those of the snails, to which they are closely allied, by the greater comparative length, the oval shape of the aperture, and the thickness of the outer lip. The last whorl is always very large. Some of the exotic species, such as Bulimus ovatus, attain a large size, and lay eggs even larger than those of the chaffinch, the young animal having a shell measuring an inch in length when hatched. Several species are very beautifully coloured. Many species of Bulimi are excellent food, and are sold in the markets.

THE largest of all the land snails are the great AGATE-SHELLS (Achatina) of Africa, which attain a length of eight inches, and lay eggs larger than those of the bulimus, and with hard calcareous shells.

WE now come to the CHRYSALIS-SHELL, shown as creeping up a sapling.

This shell belongs to a large genus, containing about one hundred and sixty species, and has received its popular name from its shape, which bears some resemblance to that of a chrysalis. This animal has always a short foot, pointed behind, and very short lower tentacles.

We now arrive at the great family of Limacidæ, or Slugs, a race of beings which many a gardener doubtlessly wishes extinct.

THE COMMON RED SLUG, OR LAND SOLE.

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In these creatures the foot and body are indistinguishable from each other; the head is retractile; and the whole creature can be gathered into a short rounded mass, looking so like a pebble that it would escape a casual glance. At the first view, the Slugs appear to be destitute of shell, but, on a closer examination, the shell is found upon the fore part of the body, and either entirely or partially buried beneath the integuments. When removed, it is not unlike the operculum of many molluscs, being small, flattish, and with an evident nucleus. They have four tentacles, like those of the snails, the eye-dots appearing, as in those molluscs, on the tips of the upper and longer pair. The respiratory orifice is placed on the right side of the body.

The GREAT GREY SLUG is the largest of the British species, and when furnished with abundant food, on which it can fatten itself during the night, and a secure hiding-place, whither it can retreat during the day, often attains an enormous size. The careless gardener, who has suffered heaps of old rubbish to collect in his dominions, is often horrified, when he at last removes the stones or sticks, to find under them a number of huge Grey Slugs, that have been silently consuming his flowers and vegetables, and lie slimy and obese at his mercy, bewildered with the unaccustomed light, and unable to escape their impending and deserved fate. It is true that Slugs, snails, and all similar creatures, must have been created for some useful purpose, and in their proper place discharge the duty for which their forms were designed and their instincts implanted; but it is clear that a garden is not the proper place for Slugs, and that if they make their appearance within its precincts, they must be extirpated; just as rats, which are useful in a sewer, are noxious in a house, and must pay with their lives the penalty of their intrusion.

In the fields, this Slug is very common, though not often seen, as it hides itself by day, and only comes out to feed at night. While engaged in "sugaring" trees for moths in the summer evenings, I have often been surprised at the number of Great Grey Slugs which came crawling down the trunks of the trees, attracted apparently by the scent of the sweet mixture, and induced by its odour to leave the hiding-place in which they had been cunningly ensconced during the daytime. Hollow trees, especially those where the entrance is very small, are great haunts of this Slug, and the crevices found at the junction of branches are also in favour with these destructive molluscs. Pollard willows are generally very populous with these Slugs.

Just below the figure of this animal may be seen its little shell, represented as it appears when removed from the body.

THE well-known BLACK SLUG (Limax ater) belongs to the same genus as the preceding species, and is very common during the summer, coming out of its hiding-place during the evening, and making its appearance along the sides of roads, in hedgerows, and similar situations. It is nearly, but not quite so large as the grey species.

THE common RED SLUG, or LAND SOLE (Arion rufus), is another member of this family. It may be known by the deep red-brown of its body, which sometimes approaches to black. It is very plentiful in gardens, and as, on account of its colour, it is not readily seen in the dark, it escapes observation, and does much damage without being discovered. Those who desire to rid their gardens of these pests will find that a very effectual plan is to search the grounds after dark, by the aid of a "bull's-eye" lantern.

The greater number of the Slugs can thus be discovered, and the remainder can. mostly be destroyed by watering the ground with a very weak solution of ammonia. This substance is fatal to slugs as well as to worms; causes them to pour out a white frothy mucus, so as to betray their presence; and, if employed in sufficient quantity, will kill the mollusc without injuring the vegetables. The Slugs and worms that are thus captured should be thrown into a vessel containing a strong solution of the same fatal substance, when they will perish almost immediately, and after they have been left in the vessel for twelve hours, so as to make their death absolutely certain, may be used as a valuable manure.

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Another useful plan is to make an attractive shelter from boards or tiles, and place cabbage-leaves within. The Slugs will crowd to the bait during the night, and, finding themselves sheltered, will remain there during the daytime, when they may be captured and destroyed.

On the left of the illustration on page 405 may be seen a little Slug with a semi-spiral shell, represented as crawling up a short stump.

This is the TESTACELLA, one of the very few carnivorous land molluscs. The Testacella, although plentiful, is seldom seen, on account of its peculiar habits. It feeds almost wholly on earth-worms, which it pursues through all the windings of their retreats, its long lithesome body enabling it to insinuate itself wherever the worm can burrow, and its hard little shell securing it froin danger by stopping up the tunnel behind its progress. This curious slug can be obtained in gardens by digging up the loose soil, but, on account of its services to the gardener, should be released, and permitted to resume its destructive avocations.

The tooth-ribbon of this creature is most formidably armed, having about two thousand teeth arranged in fifty rows. The teeth are needle-shaped, barbed, sharply pointed, slightly curved, and converge towards the centre of the ribbon, thus forming a weapon which no worm is capable of resisting. Only three species of Testacella are known; our British species is supposed to have been introduced from Southern Europe. IN the following illustration is shown a group of Water-snails, several of which can be found in every large pond or stream.

The two central figures represent two species of APPLE-SNAILS, belonging to a genus remarkable for several peculiarities of formation. Although placed with the pond-snail and planorbis for the convenience of bringing the various water-snails into a single illustration, the Apple-snails belong more properly to the gill-bearing molluscs, and in the systematic arrangement follow the phorus, described on page 394.

The Apple-snails are found throughout the warmer parts of the world, inhabiting the lakes and rivers, and, in case of drought, burrowing deeply into the mud and remaining buried for a lengthened period, sometimes for a term of years, until a fresh supply of water arouses them from their strange torpor and urges them again to seek the upper regions.

In his "Natural History of Ceylon," Sir J. Emerson Tennent mentions this curious habit. "The Ampullaria glauca is found in still water in all parts of the island, not alone in tanks, but in rice-fields and the water-courses by which they are irrigated. When, during the dry season, the water is about to evaporate, it burrows and conceals itself till the returning rains restore it to activity and reproduce its accustomed food. There, at a considerable depth in the soft mud, it deposits bundle of eggs with a white calcareous shell, to the number of one hundred or more in each group.

The Melania paludina, in the same way, retires during the droughts into the muddy soil of the rice-lands, and it can only be by such an instinct that this and other molluscs are preserved when the tanks evaporate, to reappear in full growth and vigour immediately on the return of the rains.

A knowledge of this fact was turned to prompt account by Mr. Edgar S. Layard, when holding a judicial office at Point Pedro in 1849.

A native who had been defrauded of his land complained before him of his neighbour, who, during his absence, had removed their common landmark, diverting the original watercourse and obliterating its traces by filling it up to a level with the rest of the field. Mr. Layard directed a trench to be sunk at the contested spot, and discovering numbers of the Ampullaria, the remains of the eggs, and the living animal which had been buried for months, the evidence was so resistless as to confound the wrong-doer and terminate the suit." After a few hours of rain, the Apple-snails may be observed emerging from their muddy retreat as if to welcome the newly found moisture.

As may be seen from the illustration, the animal of the Apple-snail is very curiously formed. The long siphon, formed by a development of the neck-lappet, is seen on the left. Projecting just without the shell are seen the eyes, set at the extremities of short

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RAM'S-HORN APPLE-SNAIL.-Ampullária cornu-arletis. WATER-SNAIL-Limnæa stagnális.

POUCH-SHELL.-Physa hypnórum. COMMON PLANORBIS. - Planorbis córneus. STAIRCASE APPLE-SHELL-Ampullária scaláris. RIVER LIMPET.-Ancylus lacustris.

and stout footstalks, and the enormously long tentacles are placed just in front of the eyes. At the first glance the creature appears to have four tentacles, but; on a closer examination, the front pair are seen to be merely developments of the muzzle. In one respect, the Ampullaria seems to be a connecting link between the gill-bearing and lungbearing molluscs, being said by high authorities to possess a pulmonic or lung sac, in addition to its gills.

ON the left hand of the illustration the common POND-SNAIL, or LIMNEA, is shown in the act of climbing up the stem of a water-plant. In all the members of this family the shell is thin, and sufficiently capacious to contain the entire animal when it desires to withdraw itself into its home. The aperture is simply rounded, without notches or ridges, and the lip is sharp.

The Pond-snail may be found in almost any fresh water, and, if carefully watched, proves to be quite an interesting creature. It can creep with tolerable rapidity after the usual manner of snails, and has besides a curious method of progression without making any exertion of its own. In streams, when the animal has a mind to change its locality without needing to exert itself, it achieves the task of converting the journey into a voyage, and its foot into a boat. This transformation is soon effected, the animal first crawling up some plant that projects out of the water, reversing its position, so that the shell lies undermost, and then hollowing the foot so as to form it into a shallow boat-like

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shape. It then looses its hold of the supporting plant, and boldly launches itself on the surface.

Hundreds of these creatures may often be seen floating in successive squadrons along the surface of a stream, knocking against all kinds of obstacles without fear, and travelling farther in one hour than they could otherwise have achieved in a week. If, however, the spectator throw a stone into the water all is changed in a moment, the expanded foot is suddenly contracted as the circling ripples reach the voyagers, and the mimic fleet sinks to the bottom as if by magic.

The tentacles of this animal are rather short, broad, compressed, and triangular. The eggs of the Pond-snail are laid in ribbons of transparent gelatinous substance, and the process of their gradual development can easily be watched by means of the microscope. Most of the Pond-snails feed on vegetable substances, more especially decaying leaves, but the present species is carnivorous in its habits.

ON the right-hand of the engraving, and exactly opposite the pond-snail, is an equally common British shell, called from its flattened whorls the PLANORBIS. In this animal, the foot is short and round; the tentacles are long, slender, and leave the edges at their inner bases. Both this and the preceding species are in the habit of burying themselves in the mud during a drought, and there passing a semi-torpid existence.

BELOW the planorbis is a very remarkable species, called, from its peculiar shape, the FRESH-WATER or RIVER LIMPET. This appears not to be a British shell, but is found in various parts of America, Madeira, and some portions of Europe. It inhabits swiftly running streams, and is mostly seen attached to stony and aquatic plants. Although the shell is so limpet-like, the animal does not partake of the resemblance, being very like that of the pond-snail, and having triangular tentacles with the eyes at their bases. The generic term, Ancylus, is of Greek origin, and signifies a small round shield or target. An empty shell is represented lying on the ground near the animal.

THE little elongated shell shown crawling over the body at the right-hand top corner of the engraving is the POUCH-SHELL, a British species of a rather small genus, extending over the greater part of the globe. In the greater number of species, the mantle is fringed with long filamentary appendages, but in the present example the edges are quite plain. It is, however, always flat and much expanded. The tentacles are long and slender, and the eyes placed at their bases. The shell is thin, spiral, polished, and the aperture is rounded in front.

IN the accompanying illustration are represented some of the strange and almost grotesque forms which are assumed by many of the molluscs. These belong to a fresh order, in which the shell is sometimes altogether wanting, and even when present is of very small dimensions, and is almost, if not wholly, concealed by the soft parts. In fact, they may be considered as the marine analogues of the common land slugs. The gills of these animals are rather curiously formed, not being placed in a definite cavity as is the case with the previous species, but projecting boldly from the surface of the animal, and set towards the rear of the body. On account of this position of the gills, the animals are termed Opistho-branchiæ, or Rearward-gilled molluscs. The whole internal structure of these creatures is fully as curious as their external form, and well repays dissection, the organs of digestion especially being rather complicated, and possessing many points of interest.

IN the centre of the engraving is seen an empty and rounded shell, with the exterior spotted and the interior of the lip shown. This is the BUBBLE-SHELL, one of a moderately large genus of molluscs, that are found in almost all tropical and temperate seas, and may generally be captured where the bed of the ocean is of a sandy nature. Another species is drawn on the upper left-hand corner, for the purpose of showing the manner in which the shell is enveloped in the tissues of the animal. In all the family to which the Bubble-shells belong, the shell is very thin, globular, and cylindrical, and the aperture is long and rounded. The large side lobes are said to be often used as fins for swimming.

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