Source : Webster's Revised Unabridged Dictionary (1913)

Planorbis \Pla*nor"bis\, n. [NL., fr. L. planus flat + orbis a
   circle.] (Zo["o]l.)
   Any fresh-water air-breathing mollusk belonging to
   {Planorbis} and other allied genera, having shells of a
   discoidal form.

Planorbis \Pla*nor"bis\, n. [NL., fr. L. planus flat + orbis a
   circle.] (Zo["o]l.)
   Any fresh-water air-breathing mollusk belonging to
   {Planorbis} and other allied genera, having shells of a
   discoidal form.