Prophysaon foliolatum, or the yellow-bordered taildropper, is a slug in the genus Prophysaon, native to North America, ranging from Alaska to Oregon.
Appearance This species is an overall dull brown colored slug, with a yellow line bordering its mantle. The similar species P. andersonii does not have this yellow border.
Forms
There is a Canadian color form that is almost black, but it can still be distinguished by the bright yellow border the mantle.
Albino individuals have been spotted on the Olympic coast.
References
Gould, A.A. (1851). The terrestrial air-breathing mollusks of the United States, and the adjacent territories of North America. Vol. 2. Little, Brown and Company, Boston. 1-366.