Gonophore

A gonophore is a reproductive organ in Hydrozoa that produces gametes. It is a sporosac, a medusa or any intermediate stage.

The name is derived from the Greek words gone (that which produces seed) and phoreus (bearer).

Gonophores are borne on branching stalks that grow out as a ring from the hydranth (i.e. the hydroid polyp, bearing a mouth, digestive cavity and tentacles) wall. The germ cells are formed from the inner layer of the entocodon. The entocodon is the primordium (i.e. the first cells that give rise to the development of an organ) of the subumbrella ( i.e. the concave oral surface of a medusa) in the development of medusae from the gonophore.