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 and -φόρος. Gonophores are borne on branching stalks that grow out as a ring from the hydranth wall.

What is a Hydranth?

: one of the feeding zooids of a hydroid colony.

What is meant by Hypostome?

: any of several structures associated with the mouth: such as. a : the manubrium of a hydrozoan. b : a rodlike organ that arises at the base of the beak in various mites and ticks.