The brain is connected to the mantle cavity's muscles by giant neurons, with the furthest muscles serviced by the largest neurons, permitting simultaneous impulse reception and muscle contraction throughout the cavity's wall. Active brains and muscles require more oxygen and nutrients. All this produces higher pressure and more efficient circulation of the blood and its contents. After courtship displays, he inserts his hectocotylus into the female's mantle cavity and deposits the sperm near the opening of her oviduct. Males die soon afterwards.
Females attach fertilized egg masses to the substrate for several days, then also perish.
The new generation of squid hatch out a month later.