Carychium tridentatum
Carychium tridentatum is a species of minute air-breathing land snail, a terrestrial pulmonate gastropod mollusk in the family Ellobiidae. Description. The shell is 1.8-2.3 mm high x 0.8-0.9mm. wide. The shell is more slender than that of "Carychium minimum". 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). Distribution. 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) 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. It has been introduced to North America, including to: