What makes a jaw less fish unique?

Jawless fish, such as lampreys and hagfish, are unique because they lack jaws and paired fins, which distinguishes them from other vertebrates. Instead of jaws, they have a round, sucker-like mouth that allows them to feed by attaching to their prey or scavenging. They also possess a notochord, a primitive backbone structure, and their bodies are often covered in slime rather than scales. Their evolutionary adaptations provide insights into the early stages of vertebrate development.