Vertebral centra nearly complete, but with perforation; no fulcra; scales cycloid .......... 4. Leptolepididae.†
II. Fins without fulcra; scales without ganoin; vertebral centra complete.
A. Supraoccipital separated from the frontals by the parietals or upper surface of skull; no adipose fin.
1. Ventral fins with 10 to 16 rays.
An intergular bone; parasphenoid narrow .......... 5. Elopidae.
No intergular bone; parasphenoid very broad .......... 6. Albulidae.
2. Ventrals with not more than 7 rays.
a. Supratemporal very large, plate-like.
Praemaxillary single, its posterior extremity free from the maxillary; symplectic absent; basis cranii simple .......... 7. Mormyridae.
Praemaxillary paired, its posterior extremity firmly attached to the maxillary; symplectic present; basis cranii double .......... 8. Hyodontidae.