While photographing mating behavior in Hapalochlaena lunulata, I got some decent shots of the male's insertion of his hectocotylus into the female's mantle cavity including a clear view of the spermatophoral groove. This was followed by the movement of the male's spermatophore down the groove and into the female's mantle cavity. I'm posting four pictures. The first shows hectocotylus insertion with the second showing a close-up of the spermatophoral groove; the third is another view of insertion with the fourth showing a close-up of the spermatophore,
