what nervous system?
Unlike any other species we have seen so far, Porifera, better known as sponges, do not contain much of anything. That includes any sort of nervous system all together. They rely mostly on water and oxygen intake, waste removal, and digestion as their only needs. They react to nothing around them and that may also include where they are actually placed too. Although some species do move across the ocean, it is vary rare to find a sponge like that. The only reason for them not to have a nervous system is because they are just too simple, having only 4 main parts in their body.