The notochordal process (or, otherwise, the cephalic process) is a unique brain structure that can only be found in certain species of cephalopods and some crustaceans. Although the notochordal process can vary significantly depending on the species of animal, its main property is that it is a very thin structure of nerves that animals use to obtain information about the space around them.
The peculiarity of the notochordal process lies in its unique structure, which allows it to have the properties of a seismometer and radar. It consists of neurons that are located under a thin layer of cuticle, a tissue membrane,