The cuttlefish is part of the phylum Mollusca; it has ten arms, eight shorter ones and two long ones broadened at the end, which serve to catch prey and pull it towards the shorter arms, and then, bring the prey near the mouth with the shorter arms. The cuttlefish use their lateral fins to swim. Like the octopus, the cuttlefish also use jet propulsion to move. Their muscular system permits them to move more effectively using the jet propulsion because they have tendon layers, instead of the longitudinal muscles, surrounding the circular and radial muscles.
The cuttlefish’s layers of tendons are called the tunic. The tunic is made up of two layers that cover the inside and outside of the body just like the longitudinal muscles of the octopus. In between the layers are the circular muscles, and the radial muscles are between these in a perpendicular orientation.