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slugs are Limax agrestis, of a greyish colour, 
without any spots, and from one inch to two inch- 
es long,—Limaxz cinereus, of a greyish or dusky 
colour, with spots or stripes of a darker hue, and 
from 8 to 5 inches long,—and Limaz ater, of a jet 
black colour, and wrinkled on the back, and very 
commonly crawling about in wet weather; and 
the most common snails are Hilex aspersa, which 
has a dull coloured shell, marked with three 
faint mottled brownish bands, and a white 
rim round the aperture,—and Milex hortensis, 
which is much smaller than the preceding, and 
has a glossy shell with distinct bands of vivid 
colours, and a brown rim round the aperture, 
and which, in spite of its name of hortensis, fre- 
quents the field much more than the garden. 
Slugs and snails differ from each other in the 
latter having shells and the former not; and 
they agree in shape, in general conformation, 
and even in most of their minute characteristics. 
They have four tentacula placed in front of the 
head, and which, by a singular process of inver- 
sion, can be drawn entirely within it. The su- 
perior pair are always the longest ; and they 
carry near the tips, but a little on one side, each 
a small eye, by which the animals distinguish ob- 
jects nigh at hand. With the inferior pair, they 
feel and try the road which they have to travel. 
Between and under this pair is situated the 
mouth, guarded by two swollen lips, in which, 
perhaps, the sense of taste may reside. The 
mouth is armed above with a semilunar horny 
jaw, placed transversely, and having its outer or 
cutting edge furnished with one or several ser- 
ratures. Within the mouth, stretched upon a 
protuberant, fleshy, buccal mass, the tongue is 
laid, shaped somewhat like the bowl of a spoon, 
and consisting of a thin membrane reticulated in 
a manner so exquisitely regular and minute, that 
no one can examine it without admiration. On 
the right side, or neck, of the slug and snail 
there are three apertures. “The largest, which 
is the respiratory orifice, is situated at the edge 
of the shield: the second is at the posterior and 
upper margin of this first orifice; it is the anus: 
the third is either placed directly under the pul- 
monary opening, or immediately behind the up- 
per tentaculum ; it is the exit for the organs of 
generation.” The skin is soft, and lubricated 
with a viscid mucus, which is secreted most co- 
piously when the animals are in motion ; and 
running down on the ground, it serves to smooth 
the way, and leaves a glistening tract behind, 
which may lead to the discovery of their retreats. 
They are strictly gasteropodous, crawling at a 
slow pace on the flat sole which constitutes their 
foot and belly. This foot is very muscular, and 
all its fibres aid in the act of locomotion ; but 
progression is principally performed by a pair of 
muscles which extend from the tail to the fore 
part, running along the middle of the foot. On 
opening the cloaks, they are seen projecting on 
the interior surface of the foot as two raised lines, 
SLUG. 
larger before than behind. By putting a slug 
into a bottle partly filled with water, the regular 
contractions of these longitudinal muscles may 
be distinctly seen, recalling to recollection the 
apt comparison of Swammerdam, — “following 
each other like the waves and billows of the sea.” 
These animals are hermaphrodite and oviparous. 
They deposit their eggs under clods of earth, 
loose stones, or in the ground, in which the pa- 
rent digs with its foot a circular hole, about one 
inch deep. The eggs vary from twelve to thirty 
in number ; they are white, oval or round, about 
the size of a common shot, with a smooth soft 
skin, which is entirely membranous in the slugs, 
but in the snails contains innumerable minute 
calcareous grains always in a crystalline state, 
and usually of a rhomboidal figure. They are, 
in ordinary seasons, hatched in about three 
weeks after being laid, but the time is regulated 
much by temperature, so that in cold seasons it 
is greatly retarded. The young issue from the 
egg in the likeness of their parents, active, and 
furnished with every organ; and the young 
snails have even then a shell fitting their size 
and strength. To what length of years the life 
of a snail or slug is prolonged has not been de- 
termined. It is a gross error to suppose that the 
marks on the shell, which indicate the succes- 
sive stages of its growth, indicate also the tenant’s 
age ; every space between two such marks being 
said to be formed in one season. This is not the 
case. These creatures are very patient of injury, 
recovering after the cruellest wounds ; and they 
are capable of repairing their broken shells, and 
of reproducing such parts of their body as may 
have been cut away in the perils to which they 
are exposed. In winter, they retire under stones 
and clods, or into crevices of walls. The slugs 
become merely less active and more hebetous 
than usual ; but the snails properly hybernate ; 
and to protect them from annoyance during this 
dead sleep, of a winter’s continuance, they seal 
up the apertures of their shells with a horny mem- 
brane. 
The natural uses of the slug and the snail ap- 
pear to be, to serve as food for reptiles, birds, 
and the smaller quadrupeds, such as foxes, 
badgers, weasels, hedgehogs, &c. The blackbird 
and the thrush are remarkably fond of them ; 
and may be seen flying off with snails in their 
bills, and breaking the shells against stones or 
the branches of trees. There is some apparent 
reason for supposing that the worm is more use- 
ful than injurious to plants, but none that we 
know of as far as respects the slug or the snail. 
These animals retire under the cover of foliage 
or some other protection from the sun and dry 
air during the day, and come abroad to feed dur- 
ing the night, after rain, or when the weather is 
cloudy. They select, in preference, tender seed- 
ling plants, or the leaves of maturer plants which 
have become tender and somewhat sweet by 
incipient decay. They are very fond of greasy 
