Nutrition        

            The diet of Allogona townsendiana is unknown, however it is believed that their diet is similar to that of other snails. Feeding occurs at night when the air is more humid in order to prevent moisture loss. For example many polygyrids are believed to be mainly mycophagous (Pilsbry, 1939), and are believed to eat algae as well. They obtain the algae by using their radula, which is a small chitinous structure covered with tiny teeth, that is used in a rasping manner (Hickman et al. 2009). Furthermore, a majority of Pulmonates or air-breathing snails are herbivores, but some are  found to prey on earthworms and other snails (Hickman et al. 2009). Lastly, calcium is an important component of their diet in order to maintain their calcareous shell (Hutchins, 2003).
         Snails are prone to water loss through their skin and use water to produce their trail of mucus. The pallial cavity, oesophageal crop, haemolymph, and tissue cells hold water within the snail's body (Barker, 2001). Snails obtain water through osmosis also known as 'contact rehydration.' The snail absorbs water through the skin of their foot sole while it is flattened on the wet substrate (Barker, 2001).
         To locate food snails use chemoreceptors, that can be found on their tentacles, and once they find it they proceed to use both their mouth and foot to touch it before using their radula (Hotopp et al. 2006). The food then passes down their esophagus after being partially broken down by saliva and proceeds to be further broken down by digestive juices upon moving into the gastric pouch (Hotopp et al. 2006). A large digestive gland connected to the gastric pouch aids in food absorption and the excretion of wastes, which is found in the mantle cavity (Dimitriadis, 2001).
         In terms of a circulatory system a snail’s is very well developed. Snails have an open circulatory system with the heart located in the pericardial cavity that has one atrium and one ventricle (The Living World of Molluscs). In the pulmonate Helix pomatia, a terrestrial snail, blood flows back to the lung to be oxygenated and is nearly colorless until is re-oxygenated and turns back to its former blue color due to the blood pigment haemocyanin (The Living World of Molluscs). The circulatory system is open therefore the blood flows from the heart through the artery, then the aorta, and into the body cavity and around the organs.
         Snails are known to be intermediate hosts of trematode parasites. Microphallus is one example of a trematode parasite that snails contract by ingesting the parasites eggs (King et al. 2010). The eggs then hatch in the snail’s gut and penetrate the snail’s tissues to reach the gonads where they then begin to develop (King et al. 2010). Nutrition is key for A. townsendiana and without proper nutrients the snail would not be able to carry out reproduction.

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