Adaptation
For environment and habitat in which they live?
The St. Lawrence pondsnail has
developed lungs for breathing in the air rather than having
gills for filtering water for oxygen (Walter 1960). Instead of gills their mantle cavity has
become their lungs. They are able to fill their lungs with
air by concentration of the mantle floor
(Hickman et al. 2009).
Locomotion?
Like its mollusca family, Stagnicola emarginata move by means
of a large, ventral muscular foot. They are able to move and
creep by the wave-like movement of their foot
(Hickman et al. 2009).
Like their family lymnaeidae, Stagnicola emarginata can also crawl on the surface of the water
upside down.
They fill their pallial cavity with air to make
themselves buoyant in the water. The pallial cavity is where
the gills are housed and where water is filtered through for some
gastropods feeding (University of
California museum of paleontology 2001). The water's surface tension
along with the snail's slime tract are able to support the weight of
the snail to enable it to feed on algae
(Nordsieck 2011).
Sense
organs?
Like all snails Stagnicola
emarginata
have specialized sense organs for smell, taste, humidity,
temperature, and touch. These organs are usually concentrated
in the head, the tentacles and the lips of the snail. Their
lips and their tentacles are used for smell and taste. Besides
having eyes, snails also have light sensitive cells called a shadow
reflex. These cells enable the snail to identify when a shadow
falls on them so it can react. The shadow often means that a
predator is near. The statocyst or equilibrium organ are
capsules filled with liquid. When the snail is moving, it uses
little hairs to detect the movement of the liquid inside of the
capsule
(Nordsieck 2011).
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