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

Spire – thhe
top whorl ls of the shelll
above the last full (boddy)
whorl
Spiral – rrefers
to the direction of f the coil of tthe
whorls; oopposite
of aaxial.
Striae – iindented
line es on the sheell’s
surface; ; can be in eiither
a spirall
or an axial direction.
Subcylinndrical
– refe ers to a shell shape that iss
higher thann
wide, as illlustrated
bellow.
Striae – iimpressed
lin nes on the shhell’s
surface
that run axxially.
Succinifoorm
– the sh hell shape of the Succineidae,
which is higher thaan
wide and with a very large
aperture. Typically the t spire is relatively
muuch
shorter aand
smaller tthan
the bodyy
whorl.
Suture – the seam wh here the shelll’s
whorls jooin.
Suturess
are describeed
as being iimpressed
too
varying ddegrees,
for example, shallowly
or ddeeply
impreessed,
dependding
upon thhe
species.
Tentacless
–the sensor ry appendagges
on the heead
of a landd
snail. Therre
is an uppeer
pair (also
called poosterior)
and a lower pairr
(also calledd
anterior; thhese
are usuaally
much smmaller),
bothh
of
which aree
used for ch hemical senssory
functionn.
The uppeer
pair also contains
the eeyes,
for moost
land snaiils
(some sna ails are blindd,
for example,
Helicodisscus
parallelus).
In the genus Vertiggo
only the uupper
tentac cles bearing tthe
eyes are present, the lower tentacles
are abseent.
Basommmatophoran
sn nail species such as Caryychium,
as wwell
as opercculate
land snnails,
have oonly
one pair of tentacles with the eyees
at their baases.
Umbilicuus
– Opening g in the center
of the basse
of the shelll.
It may bee
open, with the inside oof
the
columella
visible, or partially cloosed
by part of the lowerr
insertion off
the aperture,
or compleetely
closed annd
appearing g as a depression.
Its widdth
is measuured
at its greeatest
diameeter,
with thee
lower inssertion
as an n outer point on the diammeter.
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