In the skull[78] the orbits are separated from one another, only by an imperfectly developed interorbital septum, the cranial cavity not extending forwards between them, while the alisphenoidal region is unossified. The premaxillae may be paired or united (Amphisbaenidae), and there is usually an interparietal foramen. There may be a complete supratemporal[79] arcade bounding the lower margin of the supratemporal fossa, or the supratemporal fossa may be open below. The quadratojugal is not ossified, and the quadrate articulates with the exoccipital. There is no infratemporal arcade. There is commonly a rod-like epipterygoid[80] (fig. 33, 14) connecting the pterygoid and parietal.

Teeth are always present, and may be confined to the jaws or may be developed also on the pterygoids and rarely on the palatines; they are either acrodont or pleurodont. The rami of the mandible are suturally united.

A pectoral girdle is always present, and generally also a sternum. Clavicles and a T-shaped interclavicle are commonly present, but are absent in the Chamaeleons.

Fig. 33. A, Lateral view, and B, longitudinal section of the skull of a Lizard (Varanus varius). × 3/5. (Brit. Mus.)

1. premaxillae.16. transpalatine.
2. maxillae.17. parasphenoid.
3. nasal.18. quadrate.
4. lateral ethmoid.19. parietal.
5. supra-orbital.20. squamosal.
6. lachrymal.21. supratemporal.
7. frontal.22. exoccipital.
8. postfrontal.23. dentary.
9. prefrontal.24. splenial.
10. basisphenoid.25. supra-angular.
11. pro-otic.26. angular.
12. epi-otic.27. coronoid.
13. pterygoid.28. articular.
14. epipterygoid (columella29. vomer.
cranii).30. basi-occipital.
15. jugal.31. orbitosphenoid.

There is no separate precoracoid but a precoracoidal process (fig. 34, 7) of the coracoid is generally prominent.

Fig. 34. Lateral view of the shoulder-girdle of Varanus. × 3/5. (Brit. Mus.).