1. Octopuses after removal of the lip kill and eat crabs apparently normally. They learn to attack a strange figure moving in the visual field.
2. The pair of nerves that originates from cells at the back of the superior buccal lobe is shown to be responsible for the discharge of secretion from the posterior salivary glands. If this pair of nerves is interrupted the octopus does not poison a crab after catching it. It still eats, however, and learns to attack a strange figure.
3. If both interbuccal connectives have been severed the octopus does not remove the flesh properly from crabs. It does not learn to attack a strange figure.
4. Any operation on the central nervous system that interrupts the pathway from the interbuccal connectives to the lateral superior frontal and optic lobes prevents learning to attack a figure that has been seen.
5. If such cuts pass through the middle of the superior buccal lobe the animal does not poison crabs or completely remove the flesh from their exoskeletons.
6. If the cut is through the back of the superior buccal lobe the octopus does not poison crabs but may tear them open and then clean and eat them.
7. With cuts still farther back the animal poisons, cleans and eats crabs, but still does not learn to attack.