Halosauriformes
Halosauriformes are eellike fishes. The abdominal pelvic fins are connected. Tha anal fin is long. The tail is tapering with a weak or no skeleton, and is easily regenerated. The gape includes the maxilla and premaxilla. The maxilla bears a posteroirly directed spine on the posterodorsal edge. The Halosauriformes have a leptocephalous ("glass eel") larval stage.