A Guide for Terrestrial Gastropod Identification - University of ...

the head, , forming a slight s hump (in Arionidaae,
Argiolimaacidae
and LLimacidae
sllugs),
or covvers
the lengthh
of the body y (in Philommycidae
slugs).
Microscuulpture
– des scribes any textural
featuures
of the shhell’s
surface
usually as seen with thhe
aid of a mmicroscope.
Operculuum
– a chitin nous (proteinnaceous)
or ccalcified
platte,
attached to the dorsall
tail area of f
operculatte
snails, tha at, when the snail is withhdrawn
into iits
shell, covvers
some or all of the
aperture.
Palatal –
lip.
refers to the e area of the outer portioon
(greatest ddistance
fromm
columella) ) of the aperttural
Parietal ddenticle
or to ooth – the caalcified
projeection
on thee
body whorl
within the aperture, preesent
in certainn
species.
Periostraacum
– the th hin outer covvering
of thee
shell, compposed
of chittinous
(proteeinaceous)
material. In certain species s it beaars
hairs or ttriangular
sccale-like
projjections,
whiile
in others it is
smooth.
Pneumosstome
– the opening o in thhe
mantle thhat
allows airr
to pass throough
and leaads
to the maantle
cavity wiithin,
where gas exchangge
occurs thrrough
a vasccularized
reggion
of the tissue.
The
pneumosstome
can be e seen openinng
and closinng
in a land snail when iit
is active.
Posteriorr
– directiona al term meanning
towardss
the tail.
Protoconnch
– the sma allest, earliest-formed
wwhorl
or whorrls
(developeed
in embryoonic
stages) at
the centeer
of the shel ll’s coil.
Ribs – raaised
ridges on o the shell’ s surface thaat
run in an aaxial
or transsverse
directtion.
Slug – a snail with a shell that is much reducced
or absentt.
Its mantlee
may be possitioned
anteriorlyy
or may cov ver the entiree
length of thhe
body, deppending
on tthe
taxa (maiinly
for easteern
N. Ameriican
slugs).
Anterio orly-positionedd
mantle
Manttle
covering lenngth
of body
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