Source : Webster's Revised Unabridged Dictionary (1913)

Semaeostomata \Se*m[ae]`o*stom"a*ta\, n. pl. [NL., fr. Gr. ????
   a military standard + ???, ???, mouth.] (Zo["o]l.)
   A division of Discophora having large free mouth lobes. It
   includes {Aurelia}, and {Pelagia}. Called also {Semeostoma}.
   See Illustr. under {Discophora}, and {Medusa}.