There was an article just yesterday on HN about such a creature, with a decentralized nervous system: > Ctenophores have no brain or central nervous system, bu

There was an article just yesterday on HN about such a creature, with a decentralized nervous system: > Ctenophores have no brain or central nervous system, but instead have a nerve net (rather like a cobweb) that forms a ring round the mouth and is densest near structures such as the comb rows, pharynx, tentacles (if present) and the sensory complex furthest from the mouth ... Ctenophore nerve cells and nervous system evolved separately from other animals and have a different biochemistry.