XXIII] 



RHYNCHOCEPHALA 



583 



male genital organs, however, Sphenodon is widely different from 

 the Lizard. The quadrate in the skull is quite immovable, being 

 firmly clamped by the squamosal and quadratojugal. The latero- 

 temporal fossa is thus completely bounded below and the supra- 

 temporal fossa is uncovered. The postorbital and tabulare bones 

 are distinct. Between the parietals is a gap called, the inter- 

 parietal foramen: in this is situated the tip of the pineal body 

 which has here all the characters of a simple eye. 



A 



.-10 



.10 



FIG. 288. Skull of SpTienodon punctatus x 1. 



A. Lateral view. B. Dorsal view. C. Ventral view. D. Posterior view. 

 After von Zittel. 



1. Premaxilla. 2. Nasal. 3. Prefrontal. 4. Frontal. 6. Post- 

 frontal. 6. Parietal. 7. Squamosal. 8. Quadratojugal. 9. Quad- 

 rate. 10. Postorbital. 11. Jugal. 12. Maxilla. 13. Vomer. 

 14. Palatine. 15. Pterygoid. 16. Ectopterygoid or transverse bone. 

 17. Exoccipital. 18. Epipterygoid. 19. Basisphenoid. 20. Supra- 

 temporal fossa. 21. Lateral temporal fossa. 22. Orbit. 23. Post- 

 temporal fossa. 24. Foramen magnum. 25. Anterior nares. 

 26. Interparietal foramen. 27. Dentary. 28. Supra-angular. 

 29. Articular. 



The animal has teeth when young, but they become worn away, 

 while the edges of the maxilla and premaxilla become converted 

 into cutting edges. 



The vertehrae are amphicoelous, i.e. in the dried state, since 

 distinct joints are not formed and the intervertebral cartilage 



