the world > animals > invertebrates > subkingdom Metazoa > grade Triploblastica or Coelomata > class Gastropoda > [adjective] > belonging to order Pulmonifera > of or belonging to Inoperculata > of shells of genus Planorbis (3)
= planispiral, adj. Also occasionally as n.
Forming a flat coil; of or relating to a flat spiral form, as the shell of certain molluscs (including many fossil species), the proboscis of a…