flat worm-like animal, 1819, from Modern Latin (1776) noun use of fem. of Latin planarius, literally "on level ground" (here used to mean "flat"), from planum, planus "flat, level, even, plain" (see plane (n.1)). Related: Planarian.
Examples from the Web for planaria
We mentioned that when a piece is cut from a Planaria between pharynx and head a new mouth is formed in the middle.
Planaria is displaced by Canaria, which term first applied to the great central island, now gives the name to the whole group.The Pre-Columbian Discovery of America by the Northmen|B. F. De Costa
It seems also possible that Morgans well-known experiment on regeneration in Planaria can be explained by a flow of substances.
This planaria may be cut into several pieces, and each will reproduce what is requisite to complete the mangled organism.