Figure 1. Octopus chemical senses from whole animal to organ to cells in the organ. A—whole animal in which are visible the olfactory organ and suckers; B—adult Octopus vulgaris CNS diagram showing a dorsal view of the lobes involved in chemoreception (msf: median superior frontal; mif: median inferior frontal; ol: olfactory lobe; og: optic gland; ped: peduncle lobe; optl: optic lobe; ps: posterior suboesophageal mass; es: esophagus); C—3D reconstruction of the octopus olfactory organ and the different types of OSNs; D—diagram of segment of the arm of Octopus with a sucker and its chemical sensory cell.