page_title: Epiphragm
section_title: Calcareous epiphragm
hierarchical_section_title: Epiphragm / Calcareous epiphragm
caption_attribution_description: Helix pomatia with epiphragma in spring
context_page_description: An epiphragm is a temporary structure which can be created by many species of shelled, air-breathing land snails, terrestrial pulmonate gastropod mollusks. It can also be created by freshwater snails when temporary pools dry up.
  In most species the epiphragm is made of dried mucus, and although it is elastic, it is fairly easily torn when forcibly removing a snail from its substrate. In a few species the epiphragm is thick and quite rigid, being reinforced with calcium carbonate. This kind of epiphragm is very strong and may be difficult to break.
context_section_description: A few species, including Helix pomatia create a normal mucus epiphragm for short periods of rest, but can also create a different, specialized solid hard epiphragm, prior to annual hibernation. This kind of epiphragm is a solid structure composed mainly of calcium carbonate. This specialized epiphragm is much more efficient at conserving water loss than a thin mucus epiphragm would be. 
  This very sturdy flat calcareous structure has a small perforation to allow for oxygen exchange.  Helix pomatia snails hibernate for many months buried in the soil, and a strong solid epiphragm protects them not only from desiccation, but also against attacks by soil-dwelling predators such as carnivorous beetle larvae.
caption: A hibernating Helix pomatia with a calcareous epiphragm in place
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