Gymnophthalmata
Gymnophthalmata (jim`nof*thal"mȧ*tȧ) , noun, plural
[New Latin, from Greek gymno`s naked + 'ofqalmo`s the eye.]
(Zoology) A group of acalephs, including the naked-eyed medusa; the hydromedusa. Most of them are known to be the free-swimming progeny (gonophores) of hydroids.