A. Praecaudal vertebrae without parapophyses.
1. Margin of the upper jaw formed by the praemaxillaries and the maxillaries.
Body without or with minute scales, usually with rows of scutes; adipose dorsal fin usually present .......... 3. Enchodontidae.†
Body scaly; post-temporal forked; no adipose dorsal fin; ventrals with 6 to 11 rays .......... 4. Esocidae.
Body scaly; post-temporal incompletely ossified; pectoral fin without pterygials; no adipose dorsal fin; ventrals with 3 rays only .......... 5. Dalliidae.
2. Maxillaries excluded from the oral border.
a. Adipose dorsal fin usually present; ventral fin with 7 to 10 rays.
Post-temporal forked; dorsal fin formed of articulated rays .......... 6. Scopelidae.
Post-temporal simple; dorsal fin very long, formed of slender, non-articulated, simple or bifid rays .......... 7. Alepidosauridae.
b. No adipose dorsal fin; head and mouth enormous, dentition feeble; body naked; ventral fins, if present, with 5 rays .......... 8. Cetomimidae.