Vallentinia gabriellae, the hitch-hiking jellyfish, is a species of small, inconspicuous hydrozoan in the family Olindiidae.

It is elusive in the wild but sometimes makes its appearance unexpectedly in seawater cultures of other organisms in the laboratory.

Between the tentacles are statocysts, sensory organs which can detect gravitational pull and which help the animal to orient itself correctly.

It is known from isolated sites in Brazil, the Yucatan Peninsula, Louisiana, Florida and Bimini in the Bahamas.

In the Indian River Lagoon in Florida it was first detected in 1990, in a barrier ditch adjoining mangrove swamps.

[2] On several occasions, specimens of Vallentinia gabriellae have unexpectedly appeared in cultures of other marine organisms in the laboratory.

[2] The ease with which they can be cultured (fed on brine shrimps (Artemia salina)) has led to the possibility of their being used for teaching purposes and in medical research.

These were entangled and immobilised by the marginal tentacles, eventually being wrapped round and enclosed by the mobile manubrium.