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]