240 



THE POPULAR EDUCATOR. 



then subjected to a carefully-conducted and thorough drying 

 process, on trays or shelves arranged in sheds erected for the 

 purpose. Very large quantities of dry wood are consumed 

 before the drying process is complete, as the slugs require very 

 perfect and careful preparation before they are in a condition 

 to be shipped. Some idea of the importance of the trepang 

 trade may be gathered when we inform the reader that one 

 trader obtained amongst the Feejee group of islands, by barter 

 with the natives, 25,000 dollars' worth, during a seven months' 

 round of trade. The influence brought to bear on the shipping 

 interests of the southern seas by the slug trade is immense, as 

 will be believed when we give the returns of one voyage in 

 pursuit of trepang : Pecals of Eiche, de mer collected, 1,200 ; 

 cost of outfit of ship, etc., 3,500 dollars ; returns of cash on 

 sales effected, 27,000 dollars. The value of dry Beche de mer, 

 as brought to the markets of China, ranges between ten and 

 sixty dollars per pecal* according to class and quality. 



Snails of both land and sea are of very considerable com- 

 mercial importance and value. The common periwinkle (Turbo 

 littoreus) of our coasts is without doubt the most familiar 

 and best-known type of the sea-snail. 

 A visit to Billingsgate at high-market 

 tide will serve at once to show how 

 vast the consumption of these little mol- 

 lusks must be. Shovelled up, measured 

 by the peck and bushel, like piles of 

 black grain, and then carted away 

 throughout the length and breadth of 

 mighty London, the periwinkle 

 becomes a noteworthy element 

 in British industry, and, al- 

 though eaten from a pin's 

 point, affords in the gathering 

 and vending honest employ- 

 ment to thousands. A com- 

 bination of prejudice and 

 custom renders the land-snail 

 of England a production of 

 comparatively small import- 

 ance. On the Continent, how- 

 ever, especially in France, the 

 snail may be fairly regarded as 

 ranking next to the oyster in 

 the list of shell-food. The 

 true edible snail (Helix poma- 

 tia), the apple snail, or Grand 

 escargot of the French, is by 

 no means common in this 

 country. Specimens are oc- 

 casionally found in the neigh- 

 bourhood of Ashford, in Kent, near Dorking, and in some 

 other localities. It has long been a popular belief that this 

 particular kind of snail was first introduced by the Romans, as 

 it has been found in the neighbourhood of the sites of ancient 

 Roman encampments. In England, the existence or non-exist- 

 ence of H. pomatia is a question interesting to the scientific 

 only. In France, considerable pains are taken, and much atten- 

 tion paid to its culture and well-doing. Snail-gardens, or escar- 

 gatoires, as the French call them, are established for feeding the 

 snails in. These are formed either by making a sort of pound, 

 or enclosure, with boards and upright posts, or a number of shal- 

 low square or oblong pits are dug in the earth for their recep- 

 tion. Vegetables and herbs are scattered on the floors of the 

 snail-pens, in order to afford the shell-bearing flock an agreeable 

 feeding-ground. Whilst summer lasts, the snail's food consists 

 of potatoes, green leaves, and bran. As winter approaches, and 

 the cold wind warns H. pomatia that hard times are coming, 

 he proceeds to some corner, or quiet nook, and commences to 

 form and secrete the operculum, or trap-door, with which its 

 castle-gate is soon closed and defended. It is whilst the snails 

 are in this sealed-up and torpid condition, that they are gathered 

 for the market. When a sufficient number have been collected, 

 they are packed in suitable casks or barrels, and dispatched 

 to their purchasers. Over four millions of snails have been 

 gathered annually by the proprietor of one set of snail-gardens, 



* The pecal, consisting of 133J Ibs., is a weight in general use amongst 

 the Japanese and Malay traders, and is equal to the " tan " of China. 



1. PALUDINA VIVIPARA. 2. TKOCHUS MAGUS. 3. CYCLOSIOMA SUBAS- 

 PEEA. 4. Amon Erose. 5. TEEGIPES DESPECTUS. 



and snail-culture is on the increase. Our common brown 

 garden snail (Helix aspersa), although inferior in size (and, it is 

 said, in flavour) to the great apple snail, is capable of furnishing 

 good and wholesome food, which might ward off the pangs of 

 hunger in many poor families, did not the stern and un- 

 yielding bar of custom and prejudice stand obstructively in 

 the way. Whilst on the subject of snails, it may not be out 

 of place to refer to the belief which exists amongst certain of 

 our sheep-farmers, that the flavour of the celebrated Portland 

 mutton is in great measure owing to the vast number of minute 

 snails which the sheep, in feeding on the close, short pasture 

 of that locality, are necessarily obliged to masticate with it, 

 Two descriptions of land shells are found in countless thou- 

 sands on the sheep pastures of the Portland dunes : one is 

 Helix virgata, a banded, yellow snail; and the other Bulimus 

 acutus. That these little creatures contribute largely in 

 building up the tissues of the sheep which feed on them, 

 there can be no doubt, as the mutton from sheep which 

 have been reared in this snail-land has been found to lose its 

 piquant flavour on being removed to other localities, even when 

 fed on a liberal allowance of the most 

 approved artificial food. We shall have 

 occasion, as we proceed, to refer to certain 

 marine creatures, whose habit it is to bore 

 holes in the solid rock. Here, again, we 

 may trace the curious similarity which 

 exists in the habits of both sea and land 

 shells, for we find a particular species of 

 snail (Helix saxicava) indulg- 

 ing in regular and systematic 

 rock-boring habits. During 

 the summer months, this de- 

 scription of snail, which is 

 found abundantly in Picardy, 

 feeds in the thickets and 

 about the hedge-rows, but as 

 winter approaches it makes 

 its way to the hills of cal- 

 careous rocks (marbre napo- 

 I6ori) found in the commune 

 of Retz, and betakes itself to 

 the deep excavations formed 

 by a legion of former stone- 

 borers, and there hybernates 

 until warm weather shall come 

 again ; but instead of sealing 

 himself up, as we found H. 

 pomatia to do, the living snail 

 finds the bottom of his gallery 

 which is not unfrequently 

 over six inches in depth by one inch and a-half in diameter a 

 sufficient protection, without the aid of an operculum. These 

 curious galleries, or rock-tubes, contract gradually from the ex- 

 ternal orifice to the bottom of the cell, where they terminate in a 

 sort of cup-shaped indentation to which the snail firmly attaches 

 itself by suction. It is most curious, that these snail-burrows 

 are almost invariably made on the rocks which face the east and 

 north-east. It has been computed that the result of the winter's 

 hybernation of each snail deepens the hole in which it shelters 

 at the rate of half an inch per season. The manner in which 

 the boring and perforating process is achieved, has been a 

 subject for much debate and investigation. The labours of the 

 sea-borers have also led to a great deal of scienti-fi'o contro- 

 versy, some investigators maintaining that an acid secretion 

 thrown out by the borer softened the rock and so led to its 

 being easily entered by the shell, whilst others have positively 

 asserted that secretion had nothing to do with the process, and 

 that the shell alone, acting by the aid and agency of intensely 

 hard and spine-like cutting teeth, filed or cut away the stone 

 much as an artesian well-boring tool, when moved forward and 

 back, aided by water, cuts its way far into the solid rock. Tee 

 limits of this paper will not admit of our fully discussing this 

 knotty subject. There are many curious and deeply interesting 

 matters of evidence which have been by experienced naturalists 

 brought to bear on the question of friction versus chemistry in 

 the matter of rock-perforation by shells. We must, therefore, 

 defer this question until the publication of another paper enables 

 us to resume it. 



