SNA 
by the help of one arm when lying on his belly. 
But the Snail has another advantage, by which it 
not only fnioothes it's way, but alfo afcends in the 
moft perpendicular direftion. This is efFedled by 
means of that flimy fubftance with which it is fo 
copioufly furnifhed, and which it emits whenever 
it moves. On this flime> as on a kind of carpet, 
it proceeds Oowly along, without any danger of 
lacerating it's tender body on the afperities which 
lie in it's way: by the afTiftance of diis glutinous 
matter it afcends trees for the purpofe of feeding; 
and alfo defcends by the fime aid, without danger 
of falling, and breaking it's fhcll by the fliock. 
Thcfe animals are extremely injurious to gar- 
deners; and therefore every method of deftruftion 
is pradtifed for their extirpation. Salt or foot will 
prove their bane; but a tortoife, turned loofe in a 
garden, is faid to banifli them moft efFeftually. 
At the approach of winter, the Snail buries it- 
felf in the earth, or retires to fome hole, where 
it continues in a torpid (late during the fevericy 
of the feafon. It is fometimes found fingly in it's 
retreat, but more frequently in company. For 
the purpofcs of greater warmth and fecurity, it 
forms a kind of cover for the mouth of it's (hell; 
•which flopping it up entirely, protefts it from 
every external injury: it is compofed of a whitirti 
fubftance fomewhat refembling plaifter, pretty 
hard and folid, but at the fame time porous and 
thin, for the admifTion of air, without which the 
creature cannot exift. When this cover happens 
to be too thick, the Snail makes a fmall hole in it, 
■which correfts the defeft of that clofenefs origi- 
nally proceeding from extreme caution. In this 
manner, fheltered in it's hole from the weather, 
and defended in it's fhell by a cover, it fometimes 
lies torpid for fix or feven months, till the genial 
warmth of the returning fpring awakens it to a ftate 
of adlivity. 
The Snail generally recovers it's dormant facul- 
ties the firft fine days in April ; breaks open it's 
cell, and comes forth in queft of nouriftiment. It 
is not at all furprifing that fo long a faft fhould 
have much reduced this animal, and rendered it 
very voracious. At firft, therefore, it is not very 
nice in the choice of it's food ; almoft every vege- 
table that is green feems to be acceptable : but the 
fucculent plants of the garden arc peculiarly grate- 
ful; and the various kinds of pulfe are, at fome 
feafons, almoft wholly deftroyed by thefe crea- 
tures. So great is the multiplication of Snails at 
times, that fome gardeners have entertained the 
weak idea of their having burft from the earth. 
A rainy feafon generally contributes much to 
their increafe; for they fcem incapable of exifting 
either in very dry fituations or feafons, as their 
flime, without which they Cannot live, is then 
confumed in too great abundance. 
Such are the moft ftriking particulars in the 
general hiftory of the Snail; and may ferve as the 
outlines of the whole tribe, which is pretty nume- 
rous. Naturalifts, indeed, have enumerated fif- 
teen fpecies of the Sea-Snail; eight of" ih; Frefii- 
water Snail ; and five of the Land-Snail : thefe all 
bear a ftrong refemblance to the Garden-Snail in 
the formation of their fliells, in their hermaphro- 
dite nature, in the flimy fubftance with which 
they are covered, in the formation of their in- 
teftines, and the difpofition and ufe of the aperture 
on the right fide of the neck, v/hich ferves at once 
for the dilcharge of the fseces, for lodging the in- 
ftruments of generation^ and for refpiration, when 
Vol. II. 
SNA 
the animal Is under the neceffity of admitting 
frefli fupply. 
Neverthelefs, no two kinds of animals in na- 
ture, however much they may refemble each other 
in figure and conformation, are the fame both as to 
manners and difpofitions. Though the commori 
Garden-Snail bears a ftrong fimilitude to that of 
frefli-ivater, as well as that of the fea, yet there 
are diftinftions to be found, and fuch too as are 
pretty confidcrable. 
If we compare Land-Snails with thofe of frefh- 
waters, one or two remaikable variations will be 
obvious. Firft, the Frelb-water Snail, like moft 
other animals deftined for an aquatic life, is pe- 
culiarly endued by Nature with the faculty of ei- 
ther rifing to the furface, or finking to the bot- 
tom; and the manner in which this is performed, 
is by opening and (hutting the orifice on the right 
fide of the neck, which is provided with mufcles 
for that purpofe. The Snail fometimes collefts 
this aperture into an oblong tube, and ftretches it 
above the furface of the water, in order to draw 
in or expel the air, as occafion requires. This 
is not only perceptible to the eye, but may be 
judged by the ear, from the noife which the crea- 
ture makes in moving the water: by the dilatation 
of this, it rifes to the furface; and, by it's com- 
prefllon, it finks to the bottom. 
But there is a circumftance which renders Snails 
far more worthy of notice, namely, their vivipa^ 
rous nature; their young being not only produced 
alive, but alfo with their (hells on their backs. 
However incredible this may appear, it is never- 
thelefs inconteftably true: the young arrive at 
fome degree of perfeftion in the womb of the pa- 
rent ; there they receive their ftony coat; and from 
thence are excluded with all the neceflTary appara- 
tus for their fubfiftence. 
' On the twelfth of March,' fays Swammer- 
dam, ' I began my obfervations on this Snail;, 
and colIecSted a great number of the kind, which 
I put into a large bafon filled with rain-water, and 
fed for a confiderable time with potter's earth dif- 
folved in the furrounding water. On the thir- 
teenth of the fame month, I opened one of thefe 
Snails, when I found nine living young in it's 
belly, the largeft of which were placed foremoft, 
as the firft candidates for exclufion. I put them 
into frefli-water, and they lived to the eighteenth 
of the fame month, moving and fwimming like 
Snails full grown : nay, their manner of fwimming 
was much more beautiful.' Thus, at whatever 
feafon of the year thefe Snails are opened, they 
are found pregnant with eggs, or with living 
Snails, or with both together. 
This ftriking difference between Frefh-water 
and Garden-Snails obtains alfo in fome of the fea 
kind; among which fome are found to be vivi- 
parous, and others oviparous. In general, how- 
ever, the Sea-Snails bringforth eggs; from whence 
the animal burfts, at a proper ftate of maturity, 
compleatly equipped with a houfe, which the 
fluidity of the element where it refides does not 
prevent it from enlarging. How the foft flime 
of the Snail hardens, at the bottom of the fea, 
into tiie ftony fubftance of a (hell, is not eafily 
conceived: the only reafonable conjefture feemj 
to be, that this flime muft poifefs fome unknown 
petrifying quality. 
All animals of the Snail kind, asprevioufly re- 
marked, are hermaphrodites, each containing the 
inftruments of generation double. But fome of 
4 E the 
