Velella velella

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Oceanic worldwide in temperate and tropical seas.
Floats at the sea surface.
40-80 mm long, as adults.
Zooplankton and fish eggs, supplemented by symbiotic zooxanthellae.
Pelagic snails and nudibranchs.
Useful Facts or Characters: 

A clear, chitinous semicircular to triangular sail sticks up above the water with a blue float beneath made of concentric circles of gas-filled chambers. Small tentacles extend below the circular chambers.  The sail is angled left or right.

Natural History: 

Called  the "by-the-wind sailor."  Generally floats offshore but can be blown onshore in large numbers.


Schuchert, P. (2010) The European athecate hydroids and their medusae (Hydrozoa, Cnidaria): Capitata Part 2. Revue Suisse de Zoologie 117: 337-555.

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