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
Vampire squid its dark colour, cloak-like webbing, and red eyes, rather than habit—it feeds on detritus, not blood. Mature adults have a pair of small fins projecting from the lateral sides of the mantle. These fins serve as the adult's primary means of propulsion: vampire squid move through the water by flapping their fins. Their beak-like jaws are white. Within the webbing are two pouches wherein the tactile velar filaments are concealed. The filaments are analogous to a true squid's tentacles, extending well past the arms; but differ in origin, and represent the pair that was lost by the ancestral octopus. The