Agnatha is a class of jawless fishes, meaning they lack jaws and have a more primitive skeletal structure than other fish groups.
Here's a breakdown:
* Lampreys are parasitic, meaning they attach to other fish and suck their blood.
* Hagfishes are scavengers, feeding on dead or dying fish and other marine animals.
Both groups have elongated, eel-like bodies and lack paired fins. They are considered the most primitive of living vertebrates.