Compare to Snapping Turtle Skull
 
 

Dorsal View of Sea Turtle Skull 1. Premaxilla  2. Prefrontal  3. Frontal  4. Postorbital  5. Parietal  6. Squamosal  7. Supraoccipital 3 & 5 are part of the Medial Series

Ventral View of Sea Turtle Skull 1. Premaxilla  2. Vomer  3. Zygomatic (jugal)  4. Parietal  5. Quadratojugal  6. Postorbital  7.Quadrate  8. Opistotic  9. Squamosal 10. Supraoccipital  11. Basioccipital  12. Basispheniod  13. Pterygoid  14. Palatine  15. Maxilla 1 & 15 are marginal bones.  2, 12, 13, & 14 are bones of the palate and under side of chondrocranium. 5 & 9 are cheek bones. 8, 10, & 11 are bones of the chondrocranium.

Side View of Sea Turtle Skull     1. Premaxilla  2. Maxilla  3. Vomer  4. Palatine  5. Zygomatic (jugal)  6. Postorbital  7. Quadratojugal  8. Quadrate  9. Squamosal  10. Supraoccipital  11.Parietal

Chondrocranium of Sea Turtle   1. Postorbital  2. Parietal  3. Supraoccipital  4. Squamosal  5. Quadrate  6. Exoccipital  7. Basioccipital  8. Opistotic  9. Prootic The postorbital (1), parietal (2), and squamosal (4) are not bones of the chondrocranium, but they are easily seen from this view.

Lower Jaw of Sea Turtle   1.Dentary  2. Angular  3. Surangular  4. Articular The dentary, angular, and surangular are dermal bones. The articular is endochondral bone.