Last Monday I was at the University of Maryland, visiting my friend Megan's lab. Megan is studying slugs for her Ph.D. One of the many specimens she had was this Arion rufus. It was actually a rather large individual, but it refused to stretch itself out and preferred to remain contracted in the shape of a hump that is characteristic of many Arion species.
Arion rufus, a native of Europe, has been introduced into the U.S. This particular specimen came from the Seattle area. There are many other color varieties of this species, including red, black and lighter shades of brown.
Incidentally, the species was described by Linnaeus in 1758.