The male octopus inserts its hectocotylus (a specialized and extended arm) into the female's mantle cavity, there he deposits packets of sperm. Soon after, the hectocotylus falls off and before too long the male will die.
The female then carries the eggs in strings while continuing to feed, a feature unusual for octopus. The larvae hatch and shortly thereafter the female dies. The larvae drift as plankton until they mature.
