Try your best to answer 60 describe the degree of cephilization shown by cnidarians, flatworms, octopi, and vertebrates. here is some information to you: animals that have bilateral symmetry often show cephalization. cephalization (sef-uh-lih-zay-shun) is the concentration of sensory neurons and interneurons into a "head." certain flatworms and roundworms have some cephalization. cephalopod mollusks, such as optopi and squid have more developed cephalization. so do many arthropods. in these animals, interneurons form ganglia throughout the body. the largest ganglia, called cerebral ganglia, are found in the head. : )