I just stumbled over my notes from my "Comparative Nervous Systems" course, which had a section on cephalopods. I just skimmed my notes, and found something interesting: "When cephs breed, they stop eating, senesce, and die. removing the optic gland prevents this." I'm not sure what the source is (the prof was John Allman, I can probably ask him) but I wonder if removing the optic gland in a pet octopus would prolong its lifespan without reducing its quality of life, if it's a simple surgery like spaying and neutering is for cats and dogs... Anyone know details about this? Nixon and Young report that the optic gland is involved in sexual maturity, but not this particular detail. Hanlon and Messenger describe it a bit, but again, rather non-sepecifically.