rhizostomata

Century Dictionary and Cyclopedia

1. An order of discomedusans, or suborder of Discomedusæ, having the parts arranged in fours or multiples of four, and the single primitive mouth closed up and replaced by several secondary oral apertures, whence several long root-like processes or so-called polypites depend (whence the name), and provided with four subgenital pouches, distinct (Tetragameliæ) or fused in one (Monogameliæ). Rhizostoma, Cassiopeia, Cephea, and Crambessa are leading genera. See cuts under acaleph and Discophora.

GNU Webster's 1913

1. n. (Zoöl.) A suborder of Medusæ which includes very large species without marginal tentacles, but having large mouth lobes closely united at the edges. See Illust. in Appendix.