| In traditional classifications, the hagfish, lampreys, and extinct armored jawless fish are grouped together in the paraphyletic Class Agnatha. |
| In addition, there is little known about how the hagfish feed, grow, or sexually mature. |
| One form is lamprey like, whereas the other is closer to the more primitive hagfish. |
| These data from our studies suggest a seasonal reproductive cycle in the Atlantic hagfish. |
| Apparently living at great depths with the hagfish, the prehistoric ratfish was recently discovered off Brazil by scientists. |
| Single forms were cloned from dogfish shark, greenland shark, both lamprey species, hagfish, and amphioxus. |
