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

Anterior – directiona al term meanning
towards the head.
Aperturee
– the openin ng of the snaail
shell, fromm
which thee
animal exteends
its headd
and foot.
Apex – thhe
top or mo ost central wwhorls
of the snail shell, wwhere
the eaarliest
growthh
occurred.
Apical – on the top side
of the shhell,
oppositee
the base.
Axial – rreferring
to direction d thatt
is parallel tto
the colummella;
opposite
of spiral.
Base – thhe
underside or ventral suurface
of thee
shell, oppoosite
the apiccal
side.
Basal – rrefers
to lower
or ventrall
area of the shell or aperrtural
lip.
Beehive – a shell sha ape that lookks
somethingg
like a tradittional
beehivve.
Body whhorl
– the out termost and largest shelll
whorl, formmed
most reccently
in the snail’s growwth;
from the aperture to 1.0 whorl baack.
Bulimoidd
– a higher-than-wide
shhell
shape, ee.g.
of Bulimmulidae
Callus – a thickened area of the sshell.
Columellla
– the cent tral axis of thhe
whorls off
the shell.
Conical – a type of sh hell shape thhat
is relativeely
broad at its basal porrtion,
with ann
elongated spire
that taperrs
to a point. .
Depresseed
heliciform m – a commoon,
wider-thaan-high
shell
shape.
5