Click on the image above to see an mpeg video (128 Kbytes) which
shows a squid jet propelling itself by forcing water through its body.
Squid also swim by flapping their fins.
Video credits
A series of split-second reactions
make jet propulsion possible.
1- Suck in water - Mantle opening
2- Shut mantle - Locking mechanism
3- Tell mantle muscles: Contract! (uses the Brain and Giant axon)
4- Jet out water - Funnel