Wisconsin Land Snails: Snails of Wisconsin by Prof. Karthryn Perez:
snails of North America are a diverse and imperiled group but conservation
status of the majority of species is uncertain. Previous research has
estimated ~100 species of terrestrial snails occur in Wisconsin. Only 52 of
these species have some information about their conservation status".
http://www.northamericanlandsnails.com: North American Land Snail Links.