Geryonia

Geryonia is a monotypic genus of hydrozoans in the family Geryoniidae. It is represented by the species Geryonia proboscidalis which occurs in the Mediterranean and subtropical seas. In the Mediterranean the species is more numerous and the polyps are larger than in other parts of the world. The diameter of a polyp can be up to 80 mm, while in Florida and the Bahamas it is rare to find specimens of more than 50 mm in diameter.

Geryonia
Geryonia
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Cnidaria
Class:	Hydrozoa
Order:	Trachymedusae
Family:	Geryoniidae
Genus:	Geryonia Péron & Lesueur, 1810
Species:	G. proboscidalis
Binomial name
Geryonia proboscidalis (Forsskål, 1775)
Synonyms
(Genus) Carmarina Haeckel, 1864 Carmaris Haeckel, 1879 Geryones Haeckel, 1879 (Species) Medusa proboscidalis Forsskål, 1775 Carmarina hastata Haeckel, 1864 Carmaris Glitschii Haeckel, 1879 Dianaea endrachtensis Quoy & Gaimard, 1824 Geryones elephas Haeckel, 1879 Geryonia conoides Haeckel, 1864 Geryonia dianaea Haeckel, 1879 Geryonia fungiformis Haeckel, 1864 Geryonia hexaphylla Péron & Lesueur, 1810 Geryonia umbella Haeckel, 1864

Description

The adult polyp has six long, hollow primary tentacles interspersed with six short, stiffer tentacles that break easily. The transparent bubble of the polyp is almost a hemisphere, with a diameter of 35 to 80 mm. The dense, gelatinous pedunculus ("stalk") is cone-to-trumpet-shaped and about the same length as the diameter of the bell. Muscles form six bands along the pedunculus and allow them to move back and forth or to pull together.