'Rhizostomata' definitions:

Definition of 'Rhizostomata'

From: GCIDE

Rhizostomata \Rhi`zo*stom"a*ta\, n. pl. [NL., fr. Gr. ??? a root + ???, ????, a mouth.] (Zool.) A suborder of Medusae which includes very large species without marginal tentacles, but having large mouth lobes closely united at the edges. See Illust. in Appendix. [1913 Webster]