The Collaborative International Dictionary of English v.0.48:
Semaeostomata \Se*mae`o*stom"a*ta\, n. pl. [NL., fr. Gr. ???? a military standard + ???, ???, mouth.] (Zool.) A division of Discophora having large free mouth lobes. It includes Aurelia, and Pelagia. Called also Semeostoma. See Illustr. under Discophora, and Medusa. [1913 Webster] Semantic