Physical Characteristics
The shell of this snail is ovately globose (rounded
egg shape), is thin, dark, and sometimes tinged purple, and has
five whorls (Baker). Within its own species, the specimens from Lake
Michigan, on average, have longer spires than those from
Bayfield County in Lake Superior
(Baker).
The part of the snail which secretes the shell is called the
mantle (Hickman). The shell supports the snail's soft tissues and protects
it from predators.
A gastropod, S. walkeriana exhibits torsion, a 180° twisting of the visceral mass
which brings the anus of the snail near its head
(Hickman). It has an open
circulatory system, which means that the blood-like fluid of the
snail is not restricted to the heart or blood vessels
(Hickman). The snail has
a muscular ventral foot which it uses to move
(Hickman). It also possesses
a trait characteristic to mollusks, a
radula that it uses to obtain food
(Hickman).
As a member of the family Lymnaeidae its tentacles are flat,
wide, and triangular and their heads have two flat lateral lobes
(EOL).
How does the snail get
energy to keep its body running?