This is a very good question. Squids move through the water at high speeds using a jet propulsion-like organ called a "siphon". What the siphon does is take in water and thrust it out, much like a jet engine. The end result is the jet-like streamline of a squid.
Squid move by jet propulsion, using its lips to suck water in then squirts it out its bottom.
The water jet is a means of propulsion.
they jet through the water at really high speed
Octopuses and squids can also move by using a form of jet propulsion. Water is drawn into the mantle cavity and then forced out through a tube, propelling the cephalopods backwards from danger. In addition, squids and octopuses produce a dark-colored ink when the are frightened. As this ink is released into the water, it helps to hide the mollusks/squids/octopuses and confuse its predators
The giant squid (Architeuthis dux) is motile; they move themselves by a mechanism similar to jet propulsion. Sessile animals do not have brains, but the squid does.
JPL, Jet Propulsion Laboratory JPL, Jet Propulsion Laboratory JPL, Jet Propulsion Laboratory
Bivalves move by using a blade shaped muscular foot.
The squid sucks up water a tube called the siphon, then shoots it out to provide locomotion by jet propulsion.
They use jet propulsion, expelling water from inside their bodies out through an orifice in between their tentacles. It may be the beak, I don't know. They also make some motion by swinging their tentacles, but very little. It is the same way Nautiluses and Octopi move.
Jet Propulsion Laboratory was created in 1930.
A siphon enables the animal to squirt water, and move quickly by jet propulsion. Squids do this if they need a quick burst of speed, to grab prey or escape, and scallops use it to swim up and around, for example (look it up on YouTube, it looks really nonsensical!).
Impeller jet propulsion.