Main Key

This key is based on major shell characters and will first take you to major groups of snails based on major differences in shell morphology. Then, it will follow through to smaller groups of species and , when possible, to an individual species.

The main characters used are primarily those described in the “Snail Structure” section, plus others as needed. Familiarize yourself with those.

​The first "cut" is into 8 major groups - 7 with shells and the eighth is the slugs. Remember that images are NOT to scale.

Group A

Shell taller than wide; lip simple or slightly reflected, no teeth; bulimoid, columnar, conical, fusiform, or succiniform, ~2 to >20 mm (Go to Group A key)

includes: Cochlicopa, Columella, Pomatiopsis, Rabdotus, Succineidae 

Group B

Shell taller than wide; reflected lip; lip reflected to thick, one or more tooth, columnar to pupilliform (Go to Group B key) 

includes: Carychium, Gastrocopta, Pupillidae, Vertigo 

Group C

Group C. Beehive to domed to roundish shape (Go to Group C key)

includes: Euconulus, Helicinidae, Strobilops, Ventridens

Group D

Group D. Pill-shaped (Go to Group D key) 

includes: Euchemotrema, Stenotrema, Inflectarius

Group E

Wider than tall; reflected lip, umbilicate or rimate (Go to Group E key)

lip is reflected, spire more globose to depressed, teeth vary, umbilicus varies from rimate to open to widely open umbilicus

includes: Mesodon (in part), Allogona, Triodopsis, Daedalochila, Vallonia

Note: Some of the non-native species may fall into this group of characters, yet they differ. Note the images provided to see if what you have is one if the unusual ones. 

Group F

Wider than tall; reflected lip, imperforate (Go to Group F key)

 spire subglobose to subglobose/depressed; umbilicus imperforate 

includes: Mesodon (in part), Neohelix, Patera (in part), Webbhelix, Xolotrema

Note: Some of the non-native species may fall into this group of characters, yet they differ. Note the images provided to see f what you have is one if the unusual ones.

Group G

Wider than tall; simple lip (Go to Group G key) 

includes: Anguispira, Haplotrema, Mesomphix, Oxychilus, Helicodiscus, Glyphyalinia, Discus, Nesovitrea, Zonitoides, Guppya, Hawaiia, Lucilla, Punctum, Striatura, Gastrodonta, Paravitrea

Group H

No external shell – slugs (Go to Group Slug key)

​includes: Arion, Deroceras, Limacus, Limax, Megapallifera, Pallifera, Philomycus