Amphioxus!!!

Amphioxus is important to the evolutionary view of the developing vertebrates. It's also known as Lancelet. They have translucent fish like bodies. Amphioxus is believed to be the most simple animal that has the basic characteristics of vertebrae, possessing a nerve chord along their back. Amphioxus is very strange because it has gills, but uses them for eating. It has no sensory organs, brain nor skeleton. Unlike other vertebrates, Amphioxus has a notochord which is basically compacted cells toughened up in the shape of a rod. The notochord protects the nerve chord unlike other vertebrates that use bone.