acraspeda

Century Dictionary and Cyclopedia

1. The name given by Gegenbaur to the acalephs proper; that is, to those jelly-fishes and sea-nettles the lobate border of whose disk is not provided (with few exceptions, as in Aurelia) with a contractile marginal fold or velum: nearly synonymous with Discophora (which see): opposed to Craspedota. See cut under acaleph.

Wiktionary

1. n. zoology A group of acalephs that includes most of the larger jellyfish

GNU Webster's 1913

1. n. (Zoöl.) A group of acalephs, including most of the larger jellyfishes; the Discophora.