Fishes Class Cephalaspidomorphi Moy-Thomas & Mile, 1971 Order Petromyzontiformes Berg, 1940 - lampreys Family Petromyzontidae Bonaparte, 1832 - lampreys 1 Genus Chilopterus Philippi, 1858, incertae sedis 2 Subfamily Petromyzontinae 3 Subfamily Geotriinae see Family Geotriidae Gill, 1893 4 Subfamily Mordaciinae see Family Mordaciidae Gill, 1893