David Shale / Siphonophore (Nanomia sp) close up of nectophores, and palpons. Gulf of Maine, Atlanic Ocean. Epipelagic species found up to 300m depth.

Doug Perrine / Pelagic nudibranch / Blue sea slug (Glaucus atlanticus) along with a much smaller relative, (Glaucilla sp) feeding on a Portuguese man o' war, (Physalia utriculus) Kona, Hawaii, Hawaiian Islands,...

Doug Perrine / Blue dragon / Blue seaslug (Glaucus atlanticus) feeding on a Portuguese man o' war (Physalia utriculus) along with a much smaller relative, Glaucilla sp. (upside down); Glaucus and Glaucilla store th...

Doug Perrine / Hula skirt siphonophore, (Physophora hydrostatica) with eggs, in surface waters of deep open ocean, Kona, Hawaii, USA.

Tony Wu / Blue sea slug (Glaucus atlanticus) approaching the venom-filled tentacles of a Indo-Pacific Portuguese man-of-war (Physalia utriculus). Both were washed ashore as part of a mass, multi-day stranding o...

Tony Wu / Blue sea slug (Glaucus atlanticus) that was washed ashore with a mass, multi-day stranding of thousands of Indo-Pacific Portuguese man-of-war (Physalia utriculus). This species predates Portuguese man...

Tony Wu / Top-down view of an Indo-Pacific Portuguese Man-of-War (Physalia utriculus). This is one of many thousands that were part of a mass stranding in South Africa. Atlantic ocean.

David Shale / Siphonophore (Nanomia) portion of siphosome with at least 15 cormidia, Gulf of Maine, Atlantic Ocean. Epipelagic species found up to 300m depth.

David Shale / Siphonophore (Nanomia cara) close up of coiled tentacles, Gulf of Maine, Atlantic ocean. Epipelagic species found up to 300m depth.

Pascal Kobeh / A siphonophore (Siphonophorae or Siphonophora) in open water at night, Palau, Philippine Sea

Doug Gimesy / Portuguese man-of-war (Physalia physalis) washed up on a beach among fallen leaves, Thompson Sound, Fiordland, New Zealand, January.

Franco Banfi / Man-of-war fish (Nomeus gronovi) living within deadly tentacles of Portuguese man o' war (Physalia physalis), to whose toxin it is ten times more resistant than other fish, at sea surface. Domi...