3rd Year Special Annual Double Issue Vol 4 Issue 1 & 2 Jan - Apr 2 3rd Year Special Annual Double Issue Vol 4 Issue | Page 115

ADVENTURE & WILDLIFE
slugs). However, it is not always easy to say which
species are terrestrial, because some are
more or less amphibious between land and
fresh water, and others are relatively amphibious
between land and salt water.
The majority of land snails are pulmonates.
That is, they have a lung and breathe air. A minority,
however, belong to much more ancient lineages
whose anatomy includes a gill and an
operculum. Many of these operculate land
snails live in habitats or microhabitats that are
sometimes (or often) damp or wet, such as in
moss.
Several species of the genus Achatina and
related genera are known as giant African land
snails; some grow to 15 in (38 cm) from snout
to tail, and weigh 1 kg (2 lb). The largest living
species of sea snail is
Syrinx aruanus; its shell
can measure up to 90
cm (35 in) in length, and
the whole animal with the
shell can weigh up to 18
kg (40 lb).
The
snail
Lymnaea
makes decisions by
using only two types of
neuron: one deciding
whether the snail is
hungry, and the other
deciding whether there is
food in the vicinity.
The largest known land
gastropod is the African giant snail Achatina
achatina, the largest recorded specimen of which
measured 39.3 centimetres (15.5 in) from snout
to tail when fully extended, with a shell length of
27.3 cm (10.7 in) in December 1978. It weighed
exactly 900 g (2 lb). Named Gee Geronimo,
this snail was owned by Christopher Hudson
(1955–79)
of
Hove,
East
Sussex,
UK, and was collected in Sierra Leone in June
1976.
Land snails have a strong muscular foot; they
use mucus to enable them to crawl over rough
surfaces and to keep their soft bodies from
drying out. Like other mollusks, land snails have a
mantle, and they have one or two pairs of
tentacles on their head.
Their internal anatomy
includes a radula and a
primitive brain. In terms
of
reproduction,
all
known species of land
snails are hermaphro-
dites (they have a full set
of organs of both sexes)
and most lay clutches
of eggs in the soil. Tiny
snails hatch out of the
egg with a small shell
in place, and the shell
grows spirally as the
soft parts gradually
increase in size. Most
land snails have shells
that are right-handed in their coiling.
A wide range of different vertebrate and
invertebrate animals prey on land snails.
Types Of Snails By Habitat
Land Snail
A land snail is any of the numerous species of
snail that live on land, as opposed to sea snails
and freshwater snails. Land snail is the common
name for terrestrial gastropod mollusks that
have shells (those without shells are known as
Vol 4 | Issue 2 |Mar - Apr 2019
115