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).

    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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