Hagfish and Lampreys

Hagfish

Pacific hagfish Myxine

Figure 2. Pacific hagfish
"Pacific hagfish Myxine" by U.S. National Oceanic and Atmospheric Administration, Wikimedia Commons is in the Public Domain 

 

Hagfish are marine craniates of the class Agnatha or Myxini, also known as Hyperotreti. Some researchers regard Myxini as not belonging to the subphylum Vertebrata. That is, they are the only living animals that have a skull but not a vertebral column.

Lampreys

Lampreys

Figure 3. Lampreys
"Diversas lampreas.1 - Aquarium Finisterrae" by Drow_male, Wikimedia Commons is licensed under CC BY-SA 3.0

 

The lamprey ingests the blood of fish by boring holes through tissues with its mouth and tongue.