The Giant Squid has a very complex nervous system. The squid brain consists of two fused nerve centers that are linked down the length of the body by two giant nerve axons. Axons are vital to the Giant Squid. They control jet propulsion. Squid eyes have eyelids and a pupil that can expand and contract. Squids can focus each eye separately, providing them with vision that may be twice of that as a humans. The nerve impulses from each eye travel through huge optic nerves that feed into the brain for processing information. It is the second largest mollusk, only the colossal squid is larger, but not much is known about it.