Myelin-like sheaths in copepod axons

It appears that nerve fibres of many copepods are designed for rapid signalling. They have well-developed myelin-like sheaths, which reduce a copepod's reaction time to predatory attack and may therefore be vital for the survival of the large copepod populations found in dangerous oceanic ecosystems. In copepods with the myelin-like sheaths, almost all axons of both sensory and motor nerves of the first antenna are ensheathed. Copepod myelin has concentrically arranged layers of membrane around the axon.