Hybocodon cryptus

Hybocodon cryptus is a species of tubularian hydrozoan in the family Tubulariidae. It is known around southern Port Phillip Bay and Bass Strait, growing and reproducing at temperatures of at least 10 °C on sponges, often on sandy sufaces of rocks between late autumn and winter.

Description

Hydrocauli up to 3 cm, total height of up to 8 cm. Solitary and unbranched greenish-yellow stems. 12-18 transparent aboral tentacles, 2.5 mm long, white oral tentacles. As a medusa, it has a diameter of 0.5 mm, with a single tentacle from a yellowish marginal bulb. Margin of the bell is slightly oblique, and a scattering of nematocysts on the exumbrella.