Sea snail

“ Occasionally, too, very minute land-snails would arrive alive on the island after their long sea-voyage on bits of broken forest-trees—a circumstance which I would perhaps hesitate to mention in mere human society were it not that I have been credibly informed your own great naturalist, Darwin, tried the experiment himself with one of the biggest European land-molluscs, the great edible Roman snail, and found that it still lived on in vigorous style after immersion in sea-water for twenty days. ”

“ Death by this process is instantaneous, and consequently painless; but to leave snails in cold salt water is to inflict on them the tortures of a lingering death; while for the brutality of gardeners and other thoughtless persons who seek to destroy the poor snail they find eating their plants by crushing it under foot on the gravel path, no words of condemnation are too strong, since it must always be borne in mind that snails have not, like [Pg 41] us, one nervous centre, but three, and are far more tenacious of life ”

“ Where the ground is made of chalk or limestone, they will be found most abundant; for as the snail's shell is composed of layers of animal tissue, strengthened by depositions of calcareous earthy-matter which the creature gets from the plants on which it feeds, and these in their turn obtain from the soil—it naturally follows that the snail prefers to dwell where that article is most abundant, as an hour's hunt on any chalk-down will soon show. ”

“ Others live permanently attached to sea weeds. Most abundant of the sea snails probably are the pterepods, or sea butterflies, which live several feet below the surface in daylight but come to the top in countless hordes at night. ”

“ Other functions are sometimes attributed to them; the anterior tentacles are sometimes considered to be the organs of smell. This, at all events, is certain, that the snail is very sensible of strong odours, and is easily attracted by many plants the odour of which pleases it.
The black points which terminate the first pair of tentacles have been considered as eyes: but the existence of a visual organ in the snail is not quite certain. They are quite insensible to sudden changes of light; they always travel in the dark, and never recognize obstacles placed before them. ”

“ Like snails, we were fixed to our shells, and I declare it is easy to lead a snail's life. ”

“ The truest and most snail-like snails are found in greatest abundance upon high chalk-downs, heathy limestone hills, and other comparatively dry places; while the truest and most slug-like slugs are found in greatest abundance among low water-logged meadows, or under the damp fallen leaves of moist copses. The intermediate kinds inhabit the intermediate places. Yet to the last even the most thorough-going snails retain a final trace of their original water-haunting life, in their universal habit of seeking out the coolest and moistest spots of their respective habitats. ”

“ No more interesting object can be placed in a library or study than a snailery with several species of snails. They are far superior in interest to goldfish or canaries.
The most interesting snails are by no means the largest. Frequently the small snail shells with their animals have habits or shell structures of absorbing interest. ”

“ The chief facts of interest in regard to the habits of snails as shown by these observations, are these: 1, The snails of both species are to be found commonly in uncontaminated water which is running at a fairly rapid rate, and the most common orientation is with the heads pointing up stream; 2, The snail population in any stream is subject to wide fluctations depending upon flood conditions; 3, Physa because of its shape is less affected by floods than Planorbis ”

“ Many instances, nevertheless, are on record, especially in the case of molluscs, where snails thus transported have not only survived but are apparently in a flourishing condition and spreading. Helix aspersa, for example, our large garden snail, has been naturalised in many foreign countries by French and Portuguese sailors, who had taken them on board their ships as food.
It certainly cannot be denied that a number of species among almost all groups of invertebrates have been unintentionally conveyed by man from Europe into foreign countries. ”

“ They are content to straddle the crawling, leather-jointed circumspection that they call knowledge. The bird flutters to his mate, sings, soars, and is taken before night by the fowler. The snail creeps his rheumy round covered with the slime and slobber of prudence, to rot in the end under a tree-stump, unless some good throstle cracks him prematurely on a stone. ”

“ Our Cincinnati observer mentions three kinds of snails which move along at the rate of a mile in forty-four hours; they inhabit the most dense forests, and it is regarded as a sure indication of rain to observe them moving towards an exposed situation. Others indicate the weather not only by exuding fluids, but by the colour of the animal. After rain the snail has a very dark appearance, but it grows of a bright colour as the water is expended; whilst just before rain it is of yellowish white colour, also just before rain streaks appear from the point of the head to the jointure of the shell. ”

“ If the pupil has any of these operculated snails alive, he will observe that they do not come to the surface to breathe air. Instead of a lung, they have a cavity containing an organ, or part, called the gill, by means of which the snail is capable of getting from the water what the air-breathing snail gets from the air, namely, oxygen. It will be seen that the head of the snail is shaped differently in the snails having an operculum, the mouth being at the end of a sort of proboscis or rostrum. ”

“ More complex is the obstructing mechanism in many of the snails of the Southern States and of South America. In some species—the Caracolus labyrinthus of Panama, for example—one wonders how the snail himself can get in or out of his own shell, so tortuous is the passage. ”

“ Every conchologist takes it for granted, of course, that the shells which he receives from foreign parts have had their inhabitants properly boiled and extracted before being exported; for it is only the mere outer shell or skeleton of the animal that we preserve in our cabinets, leaving the actual flesh and muscles of the creature himself to wither unobserved upon its native shores. At the British Museum the desert snail might have snoozed away his inglorious existence unsuspected, but for a happy accident which attracted public attention to his remarkable case in a most extraordinary manner. ”

“ Two species of shelled snail take harbour in the wall—one of them the beautiful Helix nemoralis. There are insects innumerable, bronze and gilded flies, and spiders that hang out their golden webs to the dews of morning. These are festooned from stone to stone, and are productions of the night. Weasels love the old wall, mice hide beneath it, and from it in spring the hedgehog rolls, its spines covered with dead oak leaves. ”

“ Yet even then he carried a house on his back, a tiny, perfect shell, into which he could creep when danger threatened.
“Some people say I am very slow,” said the snail, “but they forget I have only one foot and carry my house on my back. Yet I am not complaining, for I have a head in which [268] are my eyes, mouth, feelers, and organs of smell, while my relative, the oyster, having no head, has to wear his eyes, ears, and feelers on his mantle and his mouth near his hinge, poor fellow! Even my own cousin, the land-snail, has her eyes on long feelers, and has to draw them in if danger is near. ”

“ It contains specimens of all the British land shells with the exception of the slugs, which (with the exception of one of which I shall speak in its place) have no external or covering shell, although a small sort of shell, or at any rate some chalky grains, is found inside most of them. You would see that some are as small as a pin’s head although full grown, and they would require a magnifying glass to distinguish one from the other. The largest is Helix pomatia (figured on pp. 11 and 12) , which often goes by the name of “the edible snail.” All snails are edible and nutritious ”

“ They are vegetable feeders and unless there is some green slime in the water, cabbage or lettuce leaves may be put where the snails can get them. The eggs of the snail are excellent food for fishes, and if a few could be secured for special study, their form, habits and development may be made delightful observation and drawing lessons. Snails can be kept out of the water for some time on moist earth. Land snails and slugs should be kept on wet sand and fed with lettuce and cabbage leaves. The common slug of the garden is often injurious to vegetation. ”

“ Motion, slow at the outset, became more difficult, and the protection of the shell therefore all the more necessary. The shell increased in size and weight and motion became almost impossible. The snail represents the average result of the experiment. It can crawl, but that is about all; it is neither swift nor energetic. Even the earthworm can outcrawl it. It has feelers and eyes, and is thus better provided with sense-organs than almost any worm. It has a supra-œsophageal ganglion of fair size. ”

“ Thus in some species of our common snails there are seventy-one teeth in a single row, and the whole radula is made up of a hundred rows of teeth, making a grand total of seventy-one hundred teeth in the mouth of a single snail!
Land snails are found almost everywhere, in valleys, high up on mountains, and even in deserts. They may be found in the cold climate of Alaska or in the tropical zone under the equator. As a rule, they prefer moist localities, where there is an abundance of vegetation and where the ground is strewn with rotting logs, beds of decaying leaves or moss-covered rocks. ”

“ They come suddenly upon us—two species at once, and these representing two distinct forms of the snail tribe, the elongated and the rounded. They were very numerous. In the beds where they occur, probably thousands of specimens, more or less perfect, could be collected. Were they the first-born of land snails? It would be rash to affirm this, more especially since in all the coal-fields of the world no specimens have been found except at one locality in Nova Scotia; [N] and in all the succeeding beds we meet with no more till we have reached a comparatively modern time. ”

“ Bivalves generally at the bottom, among stones, or buried in the sand, or among the roots of aquatic plants.
3. Land Shells.—These resemble, more or less, in their habits the garden snail, though varying greatly in character, size, and colour. They mostly abound in a chalk or limestone district, and in moist and wooded situations. Some species inhabit low and damp spots, roots of trees, hollows and crevices of rocks and walls; [Pg 67] some lie under stones or pieces of wood, or in the earth; others climb shrubs, and in tropical climates even lofty trees. ”

“ THE SPIRAL SNAIL “WHEN the snail crawls, it bears aloft, as you know, four horns.”
“Horns that come out and go in at will,” added Jules.
“Horns that the animal turns every way,” said Emile, “when you put the shell on the live coals. Then the snail sings be-be-be-eou-eou.”
“Stop that cruel play, my child. The snail does not sing; it is complaining, in its own way, of the fiery tortures. Its slime, coagulated by the heat, first swells and then shrinks, and the air that escapes by little puffs produces that dying wail. ”

“ There are more than 80,000 kinds of snails in the world. They swim, jump, crawl, burrow, live at the bottom of the sea and in the tops of trees. They range in size from the horse conch of Florida, two feet long, to animals hardly the size of a grain of sugar. About half of all species live in the seas.
Most are bottom dwellers, unable to swim, but several spend their lives on the surface. ”

“ They are to be found floating on the top of the water by means of a small cluster of bubbles filled with air, composed of a tenacious slimy substance, not easily parting with its contents; these keep them suspended on the surface of the water, and serve as a nidus for their eggs: it is probable that they never go down to the bottom, or willingly come near any shore, as the shell is of so brittle a construction that few sea-water snails are so thin. ”

“ No transmutationist can have the hardihood to assert the convertibility, by any direct method, of a snail into a millipede or an insect, or of either into a reptile. The plan of structure in these creatures is not only different, but contrasted in its most essential features. It would be far more natural to suppose that these animals sprang from aquatic species of their respective types. We should then seek for the ancestors of the snail in aquatic Gasteropods, for those of the millipede in worms or Crustaceans, and for those of the reptiles in the fishes of the period. ”

“ While the majority of species live either between tides or near low water, there are not a few which live in the abysses of the ocean, and have been dredged from the bottom of the sea at a depth of two thousand, seven hundred and forty fathoms, or, to put it more plainly, over three miles. The average depth at which mollusks are found in any number is about one thousand fathoms. The variability of marine snails is so great that we shall be able to call attention to but a limited number of typical forms. ”

“ In summer, when walking out in country places, we often find pretty little snail-shells. Some of these are empty, and some have a live snail within.
2. The shell is the snail's house. It is a queer house, as it grows on him, as hair grows on a cat; and he carries it about on his back when he walks.
3. The snail lives upon plants. In the day he finds some safe place under a stone, or in a hole, draws himself into his house, and goes to sleep. In the night he comes out and feeds. ”