We just learned about the Octopus Gills.
Another part of a cephalopod's body is the Funnel, also sometimes called a siphon.
When a cephalopod like a squid or octopus breathes in, they suck water into their mantle and then push it through their gills.
When they breathe out, they shoot the water out of a tube called a funnel.
They can even use that water shooting out like a little water jet and push their body along under water.
(from: wikipedia - octopus)
Octopus jet siphon system - clarkq
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