[pluh-nair-ee-uh
n] 
| any of various free-swimming, mostly freshwater flatworms of the class Turbellaria, having an undulating or sluglike motion: popular in laboratory studies for the ability to regenerate lost parts. |
| pla·nar·i·an (plə-nâr'ē-ən) n. Any of various small, chiefly freshwater turbellarian flatworms of the order Tricladida, having soft, broad, ciliated bodies, a three-branched digestive cavity, and the ability to regenerate body parts. [From New Latin Plānāria, genus name, from feminine of Late Latin plānārius, on level ground, from plānus, flat; see pelə-2 in Indo-European roots.] |
| planarian (plə-nâr'ē-ən) Pronunciation Key
Any of various small, chiefly freshwater flatworms of the class Turbellaria, having soft, broad, ciliated bodies shaped like a leaf. Planarians have a mouth on their lower side that is often closer to the tail than the head, and a three-branched digestive cavity. If a planarian is cut into several pieces, each piece can grow into a whole new organism. |