TURBINATED SHELL-FISH. 



,361 



the one is seen to shoot its weapon, which is 

 received by the other, though it sometimes 

 falls to the ground; some minutes after, the 

 snail which received the weapon, darts one of 

 its own at its antagonist, which is received in 

 like manner. They then softly approach still 

 nearer, and apply their bodies one to the 

 other, as closely as the palms and fingers of 

 hands when grasped together. At that time 

 the horns are seen variously moving in all di- 

 rections ; and this sometimes for three days to- 

 gether. The coupling of these animals is ge- 

 nerally thrice repeated, at intervals of fifteen 

 days each; and, at every time, a new dart is 

 mutually emitted. 



At the expiration of eighteen days, the 

 snails produce their eggs, at the opening of 

 the neck, and hide them in the earth with the 

 greatest solicitude and industry. These eggs 

 are in great numbers, round, white, and co- 

 vered with a soft shell : they are also stuck to 

 each other by an imperceptible slime, like a 

 bunch of grapes, of about the size of a small 

 pea. 



When the animal leaves the egg, it is seen 

 with a very small shell on its back, which has 

 but one convolution ; but in proportion as it 

 grows, the shell increases in the number of its 

 circles. The shell always receives its addi- 

 tions at the mouth, the first centre still re- 

 maining ; the animal sending forth from its 

 body that slime which hardens into a stony 

 substance, and still is fashioned into similar 

 volutions. The garden-snail seldom exceeds 

 four rounds and a half; but some of the sea- 

 snails arrive even at ten. 



The snail, thus fitted with its box, which is 

 light and firm, finds itself defended, in a very 

 ample manner, from all external injury. 

 Whenever it is invaded, it is but retiring into 

 this fortress, and "waiting patiently till the 

 danger is over. Nor is it possessed only of a 

 power of retreating into its shell, but of mend- 

 ing it when broken. Sometimes these ani- 

 mals are crushed seemingly to pieces, and, to 

 all appearance, utterly destroyed ; yet still 

 they set themselves to work, and, in a few 

 days, mend all their numerous breaches. The 

 same substance by which the shell is original- 

 ly made goes to the re-establishment of the 

 ruined habitation. But all the junctures are 

 very easily seen, for they have a fresher col- 

 our than the rest; and the whole shell, in some 

 measure, resembles an old coat patched with 

 new pieces. They are sometimes seen with 

 eight or ten of these patches ; so that the da- 

 mage must have been apparently irreparable. 

 Still, however, though the animal is possessed 

 of the power of mending its shell, it cannot, 

 when come to its full growth, make a new 

 one. Swammerdam tried the experiment; he 

 stripped a snail of its shell, without hurting 



VOL. n. 



any of the blood-vessels, retaining that part of 

 the shell where the muscles were inserted; 

 but it died in three days after it was stripped 

 of its covering : not, however, without making 

 efforts to build up a new shell T for, before its 

 death it pressed out a certain membrane round 

 the whole surface of its body. This mem- 

 brane was entirely of the shelly nature, and 

 was intended, by the animal, as a supply to- 

 wards a new one. 



As the snail is furnished with all the or- 

 gans of life and sensation, it is not wonderful 

 to see it very voracious. It chiefly subsists 

 upon leaves of plants and trees ; but is very 

 delicate in its choice. When the animal 

 moves to seek its food, it goes forward by 

 means of that broad muscular skin which 

 sometimes is seen projecting round the mouth 

 of the shell ; this is expanded before, and then 

 contracted with a kind of undulating motion, 

 like a man attempting to move himself for- 

 ward by one arm while lying on his belly. 

 But the snail has another advantage, by which 

 it not only smooths and planes its way, but also 

 can ascend in the most perpendicular direc- 

 tion. This is by that slimy substance with 

 which it is so copiously furnished, and which 

 it emits wherever it moves. Upon this slime, 

 as upon a kind of carpet, it proceeds slowly 

 along, without any danger of wounding its 

 tender body against the asperities of the pave- 

 ment; by means of this it moves upwards to its 

 food upon the trees*; and by this descends 

 without danger of falling, and breaking its 

 shell by the shock. 



The appetite of these animals is very great; 

 and the damage gardeners in particular sus- 

 tain from them, makes them employ every 

 method for their destruction. Salt will destroy 

 them, as well as soot ; but a tortoise in a garden 

 is said to banish them much more effectually. 



At the approach of winter, the snail buries 

 itself in the earth ; or retires to some hole, to 

 continue in a torpid state, during the severity 

 of the season. It is sometimes seen alone, but 

 more frequently in company in its retreat ; se- 

 veral being usually found together, apparently 

 deprived of life and sensation. For the pur- 

 poses of contitming in greater warmth and se- 

 curity, the snail forms a cover or lid to the 

 mouth of its shell with its slime, which stops 

 it up entirely, and thus protects it from every 

 external danger. The matter of which the 

 cover is composed, is whitish, somewhat like 

 plaster, pretty hard and solid, yet, at the same 

 time, porous and thin, to admit air, which the 

 animal cannot live without. When the cover 

 is formed too thick, the snail then breaks a 

 little hole in it, which corrects the defect of 

 that closeness, which proceeded from too much 

 caution. In this mariner, sheltered in its hole 

 from the weather, defended in its shell by a 

 2 z 



