Loligo shows a typical squid body form. The body is formed by a long tapering tube-shaped mantle. The fins vary in size and placement amongst different species. The mantle forms a casing that protects the internal organs and from which the head protrudes.
Strong muscles expand the mantle, drawing water into the mantle and over the gills.
The muscles contract and send the water through a narrow muscular funnel. This funnel can be aimed forward or backward by the squid and gives it extraordinary manueverability. The adaptations required for this quick escape system are one of the reasons squid have been so valuable to science and is further explored in our section on neurobiology . The eyes are large and complex, giving the squid very sharp vision. Squids have ten limbs, only two of which are appropriately called tentacles.