Freshwater hydra are probably closer to a topology that was never truly centralized. https://en.wikipedia.org/wiki/Hydra_(genus)#Nervous_system https://en.wiki

Freshwater hydra are probably closer to a topology that was never truly centralized. https://en.wikipedia.org/wiki/Hydra_(genus)#Nervous_system https://en.wikipedia.org/wiki/Hydra_(genus)#Nervous_system