- 7. squamosal.
- 8. quadrate.
- 10. pterygoid.
- 11. transpalatine.
- 12. quadratojugal.
- 13. exoccipital.
- 14. basioccipital.
- 15. foramen for carotid artery.
- 23. parietal.
- 26. supraoccipital.
- VII. foramen for 7th nerve and certain blood-vessels. bs, position of basisphenoid.
Fig. 23. Longitudinal Section through the Skull of an Alligator (Caiman latirostris).
×¹⁄₃. (Brit. Mus.) (After Reynolds.)
- 1. premaxilla.
- 2. nasal.
- 3. frontal.
- 4. parietal.
- 5. supra-occipital.
- 6. epiotic.
- 7. prootic.
- Immediately in front of the figure 7 is the prominent foramen for the trigeminal nerve.
- 8. opisthotic.
- 9. basioccipital.
- 10. quadrate.
- 11. pterygoid.
- 12. basisphenoid.
- 13. alisphenoid.
- 14. prefrontal.
- 15. vomer.
- 16. maxilla.
- 17. palatine.
- 18. dentary.
- 19. splenial.
- 20. angular.
- 21. supra-angular.
- 22. articular.
- 23. coronoid.
- 24. exoccipital.
- 25. squamosal.
- 26. jugal.
- 27. external mandibular foramen.
- 28. internal mandibular foramen.
- VIII. internal auditory meatus.
- XII. hypoglossal foramen.
Fig. 24. Dorsal View of Lower Jaw of Alligator (A. Mississippiensis).
- 18. dentary.
- 19. splenial.
- 21. supra-angular.
- 22. articular.
- 23. coronoid.
The basioccipital (14) which, as has been said, forms a small part of the ventral wall of the foramen magnum, consists of a heavy dorsal portion, the ventrally curved condyle, and of a broader, irregular ventral portion, between which and the basisphenoid is the single opening of the Eustachian canals (eu). Dorsally and laterally the basioccipital articulates with the exoccipitals; ventrally, laterally, and anteriorly with the basisphenoid which was described in the lateral view.
The Sagittal Section
([Fig. 23]). The only bones shown in this figure (besides those of the mandible, to be described later) that have not already been described are the vomers and those of the auditory capsules.