Agnatha

Image: http://upload.wikimedia.org/wikipedia/commons/3/3f/Lampetra_fluviatilis.jpg

Information: http://en.m.wikipedia.org/wiki/Agnatha 

Distinguishing features:

No jaws, no paired fins, have seven or more gill pouches, no identifiable stomach or appendages. 

Examples:

Hagfish, lampreys

Molly and Julia