Physophora hydrostatica

Taxon-Order: 
Siphonophorae

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Distribution: 
Cosmopolitan in the world ocean, in more temperate waters.
Habitat: 
Surface to about 1000 m.
Size: 
Pneumatophore up to 5 mm; nectophores up to 20 mm.
Diet: 
Carnivorous.
Predators: 
Turtles, ocean sunfish and whales.
Useful Facts or Characters: 

This species has a pneumatophore (gas-filled float) with a deep red-pigmented cap.  Nectophores (swimming bells) are up 20 mm in height, flimsy, with no apparent ridges, and arranged in two rows, approximately 30cm each, down the nectosome. 

Natural History: 

Commonly called the hula skirt siphonophore.

References: 

video source: http://www.youtube.com/watch?v=_p48fMemu3E

Kirkpatrick, P.A., and Pugh, P.R. (1984) Siphonophores and velellids : keys and notes for the identification of the species. Synopses of the British Fauna (new series), No. 29.  D. M. Kermack and R.S.K. Barnes (eds), Linnean Society of London and the Estuarine and Brackish-Water Sciences Association, E. J. Brill/Dr. W. Backhuys, London., p.42.