Carychium tridentatum

Carychium tridentatum is a species of small air-breathing land snail, a terrestrial pulmonate gastropod mollusk in the family Ellobiidae.

If the last whorl above the aperture is opened this shows the parietalis (a spiral ridge on the parietal region projecting into the interior of the shell) descending in a characteristic double curve (see figure below).

This species occurs in European countries and islands the Mediterranean, the Caucasus region and North Africa.

It is recorded from Siberia as Carychium striolatum J.R. Bourguignat, 1857 (synonym)[2] The European countries include: Albania, Andorra, Austria, Azores, Belarus, Bulgaria, Channel Islands , Croatia, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Italy, Kaliningrad, Latvia, Liechtenstein, Lithuania, Luxembourg, Madeira, Moldova, Montenegro, Norway, Romania, Serbia, Slovenia, Spain, Sweden, Switzerland.

[4] It has been introduced to North America, including to:

Drawing of shells of Carychium tridentatum that have been broken open to show the internal structure.