European squid propulsion. The posterior border is slightly concave. The head is relatively small and has large eyes which are covered with a transparent membrane. Like almost all squid, this species has ten limbs surrounding the mouth and beak: eight are relatively short arms, and two, which form the tentacles, are long, as they are used to catch prey. The fourth left arm of males is a hectocotylus. The European squid can grow up to 30–40 cm in the mantle length, but more usually they are 15–25 cm long. The males are generally bigger than the females and exhibit more rapid rates
Giant squid produces sperm that move into a complex system of glands that manufacture the spermatophores. These are stored in the elongate sac, or Needham's sac, that terminates in the penis from which they are expelled during mating. The penis is prehensile, over long, and extends from inside the mantle. How the sperm is transferred to the egg mass is much debated, as giant squid lack the hectocotylus used for reproduction in many other cephalopods. It may be transferred in sacs of spermatophores, called spermatangia, which the male injects into the female's arms. This is suggested by a female specimen recently found