Planaria \Pla*na"ri*a\, n.; pl. L. {Planari[ae]}, E. {-rias}.
[NL. See {Planary}.] (Zool.)
Any species of turbellarian worms belonging to {Planaria},
and many allied genera. The body is usually flat, thin, and
smooth. Some species, in warm countries, are terrestrial.
[1913 Webster]