A list of phyla that show cephalization would be chordata, arthropoda, platyhelminthes and nematoda. Chordates are animals that have a skeletal rod called a notochord at some point in their development. Most chordates go on to develop vertebrae, but others, such as tunicates, hagfish and lancelets, don't.Continue Reading
Vertebrates include such animals as placental mammals, marsupials, birds, reptiles, amphibians and most fish.
Most animals are arthropoda. These include insects, spiders, millipedes and centipedes, and crustaceans such as shrimp and lobster. All of them have a segmented exoskeleton and jointed legs. Many live out of water, while some are aquatic. In others the larval stage is aquatic, while the adult is terrestrial. This life cycle can be seen in dragonflies and damselflies.
Platyhelminthes include flatworms. They're the simplest type of animal that show bilateral symmetry, which means one side mirrors the other if the animal is cut in half. Some flatworms are free living, though many, such as flukes and tapeworms, are parasitic on other animals.
Nematodes are also known as roundworms. Like flatworms, they can be parasitic or free-living. Parasitic nematodes include hookworms and pinworms, and they live in both plants and animals. Free living nematodes are often found in water.Learn more about Zoology