Gymnophthalmata

Gym`noph`thal´ma`ta

    (jĭm`nǒf`thăl´må`tå)
n. pl.1.(Zool.) A group of acalephs, including the naked-eyed medusæ; the hydromedusæ. Most of them are known to be the free-swimming progeny (gonophores) of hydroids.
Webster's Revised Unabridged Dictionary, published 1913 by G. & C. Merriam Co.