Argonauta

Argonauta (lat),
genus pelagic. octopuses. Length. torso from 1.1 cm (in males) to 10 cm (in females). Argonauta are the only two-gill cephalopods with an external single-chamber shell (up to 25-30 cm long), which is present only in females, which form it with special lobes at the ends of the dorsal arms. Unlike other cephalopods, they multiply many times throughout their lives. During the breeding season, a specially modified arm of the male (hectocotyl) filled with spermatozoa breaks away from the body and independently penetrates into the mantle cavity of the female (previously it was mistaken for a parasitic worm). Argonauta females live in the upper layers of the water, rise to the surface at night and passively drift, clinging to floating objects and to each other and forming chains. They feed mainly on pelagic molluscs.

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