(Quoy & Gaimard, 1827)
Praya dubia, or the Giant Siphonophore, is a deep sea organism (700 m to 1000 m below sea level), a member of the Hydrozoa. With a body length of 40–50 m, Praya dubia is one of the largest invertebrates. It is actually a colony made up of numerous small connected individuals, each with a specific function, such as feeding, attack and defense.
Praya dubia has a dome-like section (the nectosome), sometimes referred to as the swimming bell, as well as long, thin sensory and stinging organs (siphosomes). Its body is whitish and transparent. Praya dubia attracts its prey with blue bioluminescent light. The sting may cause paralysis or death.[clarification needed]
When raised to the surface these animals burst, as they have a hydrostatic skeleton that normally experiences an average pressure of above 0.47 ton/cm2 (460 bars). Praya dubia has been known since the nineteenth century, but its length was discovered only after the Monterey Bay Aquarium Research Institute undertook a systematic study of the water column in 1987.