- You may also be looking for the similarly-named Arcadian star system.
Arcadians were distinguished from most humanoids by their broad, enlarged heads with two parallel lines of hair running front to back on the top outer edges of the cranium. In contrast, the bodies of Arcadians were slim and delicate. Their noses protruded very little from the face and their ears were large and pointed. They had wide-set eyes that were particularly brightly colored, and did not have eyebrows. (Star Trek IV: The Voyage Home)
The name for this species comes from the non-canon FASA book Star Trek IV Sourcebook Update. It is unclear if the species' intended home system is the above-mentioned "Arcadian star system," which is featured in TAS: "Mudd's Passion". The novelization of TAS: "Once Upon a Planet", which immediately precedes "Mudd's Passion" in Star Trek Log 3, refers to the inhabitants of the Arcadian system (e.g. those on the planet Motherlode) as Arcadians.