from
The Collaborative International Dictionary of English v.0.48
Hydromedusa \Hy`dro*me*du"sa\, n.; pl. {Hydromedus[ae]}. [NL.
See {Hydra}, and {Medusa}.] (Zool.)
Any medusa or jellyfish which is produced by budding from a
hydroid. They are called also {Craspedota}, and {naked-eyed
medus[ae]}.
[1913 Webster]
Note: Such medus[ae] are the reproductive zooids or
gonophores, either male or female, of the hydroid from
which they arise, whether they become free or remain
attached to the hydroid colony. They in turn produce
the eggs from which the hydroids are developed. The
name is also applied to other similar medus[ae] which
are not known to bud from a hydroid colony, and even to
some which are known to develop directly from the eggs,
but which in structure agree essentially with those
produced from hydroids. See {Hydroidea}, and
{Gymnoblastea}.
[1913 Webster]