A Pacific Coast slug in the genus Ariolimax of Family Arionidae.

The genus includes three species. This one is probably A. californicus, the California Banana Slug.

A. columbianus, the Pacific Banana Slug, occurs in this region, but is spotted. Ariolimax
dolichophallus, the Slender Banana Slug, may also occur in our region (description TBD).

"Limax" is Latin for slug. Limax is also the main genus of European
slugs which have been placed in a different family, Limacidae.