What type of nervous system do coelenterates have?

Intestinal animals are the first invertebrates to develop a nervous system. Special nerve cells appear in hydras, as well as other representatives of this type. These cells are connected to each other and do not form a full-fledged nervous system, but only represent isolated highly branched cells, or form a neural network, which includes cells connected to each other by processes. Consequently, the nervous system of coelenterates is a diffuse nervous system.