from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A dry layer of mucus used by a snail or mollusk to seal itself inside its shell during hibernation.
from the GNU version of the Collaborative International Dictionary of English
- n. A membranaceous or calcareous septum with which some mollusks close the aperture of the shell during the time of hibernation, or estivation.
from The Century Dictionary and Cyclopedia
- n. In botany: The disk-like apex of the columella of Polytricheæ, which extends over the mouth of the capsule below the operculum.
- n. A delicate membrane closing the cup-like receptacle of the Nidulariacei.
- n. In conchology, the plate of hardened mucus secreted by a gastropod, as a snail, to plug up or seal the opening of the shell during hibernation; a sort of temporary or false operculum, sometimes hardened by calcareous deposit. See clausilium.
Sorry, no etymologies found.
When I examined them again yeaterday, the smaller one had sealed its aperture with an epiphragm.
SNAIL'S TALES: Cepaea nemoralis and its epiphragm skip to main
There is only a very narrow, short gap, visible at the top corner of the epiphragm, that the snail may have left open for air exchange, although I am not sure if it goes all the way thru the epiphragm to the other side.
Its aperture is almost perfectly sealed by its calcerous epiphragm.
After all, the shell is a hard solid structure that in most cases envelopes the entire snail and the aperture could be blocked by an epiphragm or by various folds and lamellae here is an example.
I wouldn't have expected a snail that is supposed to have originated in southeast Asia to build a similar epiphragm.
What struck me as odd was that they had their apertures sealed with a hard calcareous epiphragm as opposed to a membranous one observed in eastern U.S. snails that normally don't experience long dry periods.
In an another post, I remarked about the differences between the epiphragm of snails from California and Maryland.
The snail pictured below still had its epiphragm intact, which was actually transparent, but in the picture reflected light makes it look shiny.
In _Polytrichum_ a membranous epiphragm stretches across the wide mouth of the capsule between the tips of the short peristome teeth, and closes the opening except for the interspaces of the peristome.