ephyra

from The Century Dictionary.

• noun Pl. ephyræ (-rē). One of the so-called Medusæ bifidæ; an attached or free-swimming lobate discoidal medusoid, resulting from transverse fission, by agamogenetic multiplication, in the scyphistoma stage, of the actinula of a discophorous hydrozoan.
• noun [capitalized] plural Same as Ephyromedusæ.
• noun [capitalized] A genus of geometrid moths.
• noun [capitalized] A genus of crustaceans.
• noun [capitalized] A genus of dipterous insects.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Zoöl.) A stage in the development of discophorous medusæ, when they first begin to swim about after being detached from the strobila. See strobila.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun An immature medusoid stage of a scyphozoan jellyfish once it breaks off from its segmenting polyp.