Ambigolimax is a genus of air-breathing land slugs in the family Limacidae, the keelback slugs. There is still ongoing disagreement whether it is more appropriate to consider Ambigolimax as merely a subgenus of Lehmannia; the evidence for splitting them is phylogenetic trees constructed on the basis of DNA sequences.
Ambigolimax
A. valentianus, drawn by Pollonera; from his original subgenus description
Slug, or land slug, is a common name for any apparently shell-less terrestrial gastropod mollusc. The word slug is also often used as part of the common name of any gastropod mollusc that has no shell, a very reduced shell, or only a small internal shell, particularly sea slugs and semi-slugs.
Slug
An active Ambigolimax slug in Fremont, California
Deroceras juvenile with eggs of another (larger) slug species, most likely Arionidae
Pair of mating slugs, suspended by mucous thread and pad on wall