Dolphins are very agil, clever, play, "speak", and help swimmers in distress of the sea. Dolphins, and also harbour porpoises have a highly developed echolocation System, and orientated themself by the echo of her sounds. Dolphins have a highly sensible tough sense, and also all the senses like other mammals. The limbic layer of the dolphin brain has much more folds and windings than human brains. In his architecture the dolphin brain is the highest developed brain of all mammals. But up to date the level of efficience of the doplphin brains is unknow. I present a description of the architecture and the cytoarchitecture of the cortical limbic formation of the harbour porpoise brain. Analyses include the number of the cortical laminae, their thickness and the form, and the densities of the neurons and glia cells. Comparisons have been made between dolphins and human cortices. All results were finaly used to produce the first map of cortical fields of the harbour porpoise brain. Last thisis a trial to find out the level of efficience of the harbour porpoise brain in comparison to human and other dolphin brains.