Tenellia adspersa
Tenellia adspersa, common name the miniature aeolis, is a species of very small sea slug, an aeolid nudibranch, a marine gastropod mollusk in the family Fionidae. It is the type species of the genus Tenellia.
In Britain this solitary species is... Wikipedia
Scientific name: Tenellia adspersa
Higher classification: Tenellia