SMYRUS. a name by which Pliny has ex- 
prejTed the Mursena Myrus of Linnaeus. Ar- 
tedi makes this fifh a fpccies of mursena; and 
diftinguifhes it from the refi: of that genus by the 
appellation of the mursna v.'ith a fharp fnout, va- 
riegated with white fpots, and with the edge of 
the dorfal fin black. 
SNAIL. A genus of the teftacea order of 
Worms: the charafters of which are; that the ani- 
mal is a fliig ; the fhell univalve, fpiral, fub-pellu- 
cid, and brittle; and that it has a femilunar aper- 
ture. 
The firft frriking peculiarity of the Snail tribe 
that prefents itfelf to a fpeftator, is, that it's eyes 
are fituated on the points of it's longeft horns. 
When the Snail is in motion, four horns are di- 
ilinftly feen : but the two uppermoft and longeft 
deferve peculiar confideration, both on account of 
the various motions with which they are endued, 
and their having eyes fixed at their extremities. 
Thefe appear like two blackifh points : when taken 
out of the body, they exhibit a bulbous figure; 
they have only one coat; and the three humours 
which are common in the eyes of other animals, 
the vitreous, the aqueous, and the chryfcalline, are 
in thefe very diftinftly feen. The animal can di- 
rect thefe eyes to diff^erent obje6ls at pleafure, by 
a regular motion of the body ; and fometimes 
it hides them, by a very fwift contraftion into the 
belly. Tlie animal's mouth is placed under the 
fmall horns ; and though it may appear too foft a 
fubttance to be furniihed with teeth, yet it has no 
lefs than eight of them, with which it devours 
leaves, and other fubftances feemingly harder than 
itftlf ; and fometimes bites off pieces of it's own 
fnell. 
But tfie moft fingular circumftances in the con- 
formation of this animal, are the parts that ferve 
for generation. Every Snail is at once male and 
female ; and while it impregnates another, is itfelf 
impregnated in it's turn. ThevelTels which fup- 
piy the fluid for this purpofe, are chiefly fituated 
in the fore-part of the neck, and extend them- 
felves over the body ; but the male and female 
organs of generation are always found united, and 
growing together. There is a large opening on 
the right fide of the neck, which ferves for very 
different purpofcs : as an anus, it gives a paffage 
to the excrements ; as a mouth, it ferves for an ex- 
piratory du£l; and alfo, as an organ of- genera- 
tion, it dilates v/hen the defire of propagation 
comm.ences. Within this opening each animal 
has thofe parts, or fomething fimilar to them,, 
v/hich continue the kind. 
Some days before coition, the Snails affemble 
together; and lying quiet near each other, eat very 
]itcle; but they fettle the body in fuch a pofture, 
that tiie neck and head are placed ere6t. In the 
mean time, the apertures on the fide of the neck 
being greatly dilated, two organs, refembling in- 
teftines, iffue from them, which fome have appre- 
hended to be the inftruments of propagation. Be- 
fides the protrufion of thefe, each animal is pof- 
feffed of another peculiarity; for, from the fame 
aperture, they protrude a kind of dart, which is 
pretty hard, barbed, and terminates in a very 
lharp point: this they apply to each other Vv^hen 
the apertures approach, each weapon being re- 
ceived by the other, though it fometimes falls 
to the ground. Some minutes afterv/ards, the 
Snail wliich received the weapon darts one of it's 
ov7n at it's antagonifl:, which is received in a fim,i- 
SNA 
kr manner. They then foftly approach ftilt 
nearer, and apply their bodies to each other, as 
clofely as the palms and fingers of the hands when 
grafped together: at that time the horns are feerv 
moving in all direftions; and this fometimes for 
three days together. The coupling of thefe ani- 
mals is generally thrice repeated, at intervals of 
fifteen days each; and at every time a nev/ dart is 
mutually ejefted. 
Eighteen days being expired, the Snails pro;- 
duce their eggs by the apertures of their necks, 
and bury them in the ground with the greattfi: 
care and induftry. Theie eggs are very nume- 
rous, round, white, and covered with foft Ihells: 
they are alfo united to each other by an impercep- 
tible flime, like a bunch of grapes, of about the 
fize of a fmall pea. 
When the Snail leaves the egg, it is obferved 
with a very fmall fhell on it's b'ack, having only 
one convolution: but, in proportion as it grows, 
the fliell increafes in the number of it's fpiral 
turns. The addition is always at the mouth, the 
firft centre ftill remaining; the animal fending 
forth from it's body that (lime which hardens into 
a ftony fubftance, and is ftill fafliioned into fimi- 
lar convolutions. The Garden- Snail has feldom 
more than four rounds and a half; bur fome of the 
Sea-Snails acquire ten. 
Thus fitted with it's covering, which is light 
and firm, the Snail finds itfelf defended in a very 
ample manner from all external injury; and, 
whenever invaded, it is only retiring into this for- 
trefs, and waiting patiently till the danger is over. 
Nor does it only poffefs a power of retreating into 
it's llicll, but alio of mending it when broken. 
Som.etimes the fhclls of thefe animals are 
crufhed to pieces, and, to all external appearance, 
utterly deftroyedj ftill, however, they fet them- 
felves to work, and in a few days repair their 
numerous breaches. The fame fubftance of which 
the ftiell is originally fabricated, ferves for the re- 
eftablilhment of the ruined habitation : but all the 
jundlures are eafily feen, having a freftier colour 
than the reft; fo that, after this operation, the 
whole fiiell refcmbles a patched coat. Some- 
times they are feen with eight or ten of thefe 
patches; fo that the damage muPc have been ap- 
parently irreparable: ftill, however, thougli the 
animal is poffeffed of the power of mending it's 
ftiell, it cannot, when arrived at it's full grov/th, 
make a new one. Swammerdam tried tlie expe- 
riment. He divefted a Snail of it's Ihell, with- 
out injuring any of the blood-veiTels, retaining 
that part of the fliell where the m.ulcles were in- 
ferted; but the creature died in three days after 
being ftripped of it's covering: not, however, 
without making fome efforts to build a new fneii; 
for, before it's death, it prcffedout a certain mem- 
brane round the whole furface of it's body: this 
memibrane was entirely of the fhelly nature ; and 
feemed intended by the animal as a fapply to- 
wards a new one. 
The Snail being furniftied with all the organs 
of life and fenfation, it is no wonder that we find 
it extremely voracious. It chiefly fubfifts on the 
leaves of plants and trees, but is extremely delicate 
in it's choice. V/hen in queft of food, it m.oves 
forward by means of that broad mufcular flcin 
which is fom.etimes feen projecling round the 
mouth of the Ihell : this is expanded before, and 
then contracted with a kind of undulating motion, 
like a pcrfon attempting to move him.felf forward 
by 
