Euchemotrema leai is a terrestrial land snail that has gone through many evolutionary changes differentiating it from its ancient ancestors.  Being a part of the class Gastropoda it has evolved a muscular foot on the underside of the body that serves a dual purpose: attachment and locomotion (Martin 2000).  For attachment, the snail secretes a sticky mucus and uses its “belly-foot” as a sucker (Martin 2000).  As for movement, this secretion of mucus from the glands in the muscular foot not only helps for attachment but also facilitates movement over rough surfaces (Martin 2000).  Over this secretion, this snail travels through consecutive contractions and expansions of the ventral, muscular foot (Martin 2000).  Unfortunately, with mucus secretion comes a high metabolic cost.  Therefore, they limit movement over long distances and only travel for reasons such as food, mates, predators, and environmental changes (Martin 2000). 

 Since the Lowland Pillsnail possesses bilateral symmetry, it is a cephalized organism with a developed sensory and nervous system (Hickman et al. 2009).  Two of its main sensory organs are its two pairs of retractile, sensory tentacles which is characteristic of the order Stylommatophora.  As seen in the displayed image, the taller pair holds the eyes at the tips while the other, lateral pair are chemosensory receptors used to sense and feel its environment (Martin 2000).


Along with sensory tentacles, terrestrial air-breathing snails possess a mantle with a modified lung which is also a sheath of skin that secretes the coiled shell and holds the mantle cavity (Hickman et al. 2009).  This secreted shell forms the exoskeleton of the snail species providing it with support and protection (Hickman et al. 2009).  In Euchemotrema leai their shell is a dull brown color which is characteristic of secretive species or those that live in shady habitats (Martin 2000).  This helps them avoid predators by blending into their surroundings.  


 For feeding, most mollusks including this individual possess a chitinous radula used for scraping and tearing of food.  It also uses its many rows of individual teeth to move the food particles into the mouth using a conveyor belt like motion (Hickman et al. 2009).  This structure can be seen from multiple angles in the image displayed.







Finally, a characteristic of terrestrial gastropods is the process of torsion during early development.  This procedure rotates the visceral body mass 180 degrees bringing the anus and mantle cavity towards the head (Hickman et al. 2009).  With this adaptation, only one hole in the shell is needed. 

The Lowland Pillsnail has greatly evolved from its ancient ancestors.  Only a few of the evolutionary changes have been listed above but all are in response to the environment in which they live and to promote their survival.  Because of its adaptation, Euchemotrema leai is still living today and has been around since the Yarmouthian period on the geologic timescale (Brown and Bruder 1968).   

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