tur·bel·lar·i·an 
(tûr′bə-lârē-ən)
(tûr′bə-lârē-ən)n.
Any of various free-living chiefly aquatic ciliate flatworms, including the planarians.
[From New Latin Turbellāria, class name, from Latin turbella, bustle, diminutive of turba, turmoil (from the motion of their cilia in the water); see TURBID.]
tur′bel·lari·an adj.