Family Petromyzontidae - Lamprey Family
Class: Cephalaspidomorphi - These fishes do not have jaws. They do not have paired fins. The body is cylindrical and has a cartilage skeleton.
Order: Petromyzontiformes - The lampreys have teeth on both the tongue and the oral disc. They have seven gills. They have one or two dorsal fins.
Family: Petromyzontidae - Lampreys have a skeleton made of cartilage and a long, tube-shaped body. They have seven gill openings on each side of the head. These animals lack pectoral and pelvic fins, have only one nostril and no jaws. Some lampreys do not feed as adults while others act as a parasite on fishes, attaching with their mouth and scraping flesh and fluids with the teeth on their tongue and oral disc. There are no scales on the body. A larval lamprey is known as an ammocoete.