rias

Planaria \Pla*na"ri*a\, n.; pl. L. {Planari[ae]}, E. {-rias}. [NL. See {Planary}.] (Zo["o]l.) 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]