Land 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. ”

“ Their vast and far-reaching tails lost their length, and their bones spread out laterally into flexible fans of toughest gristle, with which they could propel themselves through the waves at speeds to which their swiftest progress upon land had been but a snail’s crawl. ”

“ 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. ”

“ When the snail encounters an obstacle in its path, it lays its eggs, sensible beast. Ten thousand snails can be raised on a plot of land one hundred by two hundred feet. The ground is plowed deeply in the spring, the snails are placed on it and covered with from two to four inches of moss or straw which is kept damp. They must be fed daily with lettuce, cabbage, vine leaves, or grass; as they eat at night, they are fed shortly before sunset. Aromatic herbs, like mint, parsley, etc., are planted in the inclosure to improve the flavor of the snails. ”

“ Now, some snails with such houses took to living in very damp and marshy places, which they were naturally apt to do—as indeed the land-snails in a body are merely pond-snails which have taken to crawling up the leaves of marsh-plants, and have thus gradually acclimatised themselves to a terrestrial existence. We can trace a perfectly regular series from the most aquatic to the most land-loving species, just as I have tried to trace a regular series from the shell-bearing snails to the shell-less slugs. ”

“ One can readily understand, at all events, how snail-shells might be swept down the slopes of the land at the time of the spring thaws, and how large numbers might find their way eventually into the swollen glacial rivers. I have often observed, during the melting of snow and the thawing of soils, quantities of snail-shells in the very act of being swept into our brooks and rills. And we are all familiar with the fact that, after a spring-flood has subsided, snail-shells, along with vegetable débris, are often plentifully stranded upon the valley-slopes and flood-plains of our rivers. ”

“ 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. ”

“ Some species are to be looked for on trees and bushes; others on rocks and stone walls; others again on the ground, and others again on the blades or in the roots of grass. In the tropics it is particularly desirable to watch for the beautiful land snails, which are almost strictly arboreal in their habits. ”

“ 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 ”

“ The true land-shells offer a still more difficult case, for they are exceedingly sensitive to the influence of salt water; they are not likely to be carried by aquatic birds, and yet they are more or less abundant all over the globe, inhabiting the most remote oceanic islands. It has been found, however, that land-shells have the power of lying dormant a long time. Some have lived two years and a half shut up in pill boxes; and one Egyptian desert snail came to life after having been glued down to a tablet in the British Museum for four years! ”

“ Among the land snails, if anywhere, we should find evidence either of autochthonous evolution or of specific change. These animals have existed on the earth since the Carboniferous period, and, notwithstanding their proverbial slowness and sedentary habits, they have contrived to colonize every habitable spot of land on the globe—that is, unless in some of these places they have originated de novo. In the Azores there are sixty-nine species of land snails, of which no less than thirty-two, or nearly one-half, are peculiar, though nearly all are closely allied to European types. ”

“ Since, however, in the Carboniferous age, Batrachians, Arachnidans, Insects and Millipedes occur on both continents, it is not unlikely that ere long European species of land snails will be announced The species hitherto found in Eastern America are in every way strangely isolated. In the plant beds of St. John, about 9,000 feet in thickness, and in the coal formation of the South Joggins, more than 7,000 feet in thickness, no other Gasteropods occur, nor, I believe, do any occur in the beds holding land snails in Illinois. ”

“ If these are really the oldest land snails, it is curious that they are so small,—so much inferior to many of their modern successors even in the same latitudes. The climate of the coal period must have suited them, and there was plenty of vegetable food, though perhaps not the richest or most tender. There is no excuse for them in their outward circumstances. Why, then, unlike so many other creatures, do they enter on existence in this poor and sneaking way. ”

“ American land snails have been a favorite study with me since boyhood; during most of that time chiefly as an occupation of evenings and in the intervals of other work. A field acquaintance with them, begun as a student in Iowa, has been continued in vacations and collecting trips in the southern Appalachians, the Ozark region of Missouri and Arkansas ”

“ 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 ”

“ 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. ”

“ 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 ”

“ One of the most humorous sights in nature, less common in America than Europe, is a snail wandering about with a shell on its back. The progenitors of snails once lived in the sea, and when they evolved themselves ashore they carried this relic of the water with them,—an anomaly which, seen to-day, seems as ridiculous as if one were to meet an Indian in Paris with his canoe on his back. But there are more animals besides snails that once lived in the water. If embryology is any guide to the past, nothing is more certain than that the ancient progenitors of Man once lived an aquatic life. ”

“ Among the commonest of fresh-water snails are various species of Limnaea (Fig. 234, A) . They may be found abundantly in ponds, [Pg 383] and are often kept in aquaria, where they perform a useful service by devouring the minute plants which are apt to accumulate to an undesirable extent and form green scum on the sides. These snails, like the garden snail, breathe air, and often come to the surface to take a fresh supply into their lung chambers. Some other water snails, however, breathe dissolved oxygen by means of gills beneath the shell. ”

“ The African snail looks like an enormous whelk, he haunts the Ashanti forest, and is at his best just at the commencement of the rains, when he begins to grow fat and succulent, but is not yet too gross and slimy. He is hunted for assiduously, and all along the forest paths may be seen men, laden with sticks on which are impaled snails drawn from their shells, dried, and smoked. ”

“ The louse probably discovered the hydra the first time by accident; but when it swam back to the source of its food-supply the second time and then returned again to its sheltering bit of mud, it clearly evinced conscious memory of route and a sense of direction.
The common garden-snail is a homing animal, and it will always return to a particular spot after it has made an excursion in search of food. In front of my dwelling there is a brick wall capped by a stone coping; the overhanging edge of this coping forms a moist, cool home in summer for hundreds of snails. ”

“ The “run” is fixed up on a sunny stretch of lawn, hemmed in with boards upon which is smeared clay mixed with vinegar and salt and water—so as to prevent any crawling out of bounds.
In the United States edible snails are frequently to be seen exposed for sale; but they are not raised in that country, and those on sale have been shipped to America alive from Europe.
In Vienna, again, during Lent there is a snail market, the snails coming in barrels [Pg 216] from Swabia. The great centre for the consumption of snails, however, is Paris and some of the French provinces. ”

“ 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. ”

“ 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. ”

“ 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. ”

“ 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. ”

“ 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. ”