SKULL 



111 



basioccipital are a pair of exoccipitals, and above these again a 

 supraoccipital, which arises in the cartilage of this region (tectum 

 synotiemn, cf. p. 97). In contradistinction to the Amphibia, 

 only a single condyle connects the skull with the vertebral column 

 in the Sauropsida : this, on close examination, is usually seen to be 



Denlary 



Pi'esplenial 



Meckel's cart 



'Entoglossiit 



Supra-angular^ 

 Angular 



Postsplemal 

 Articular 



Hy. cornu 



Branch 

 1-0,-nu 11 ? 



FIG. 80, C. 



formed of three parts, derived from the basioccipital and soccipitals 

 respectively. 



The auditory capsules are ossified from three centres, the 

 most important of which, as in Amphibians, is the prootic, which 

 usually remains free, the epiotic uniting with the supraoccipital 

 and the opisthotic with the exoccipital. A fenestra rotunda is 

 present in the walls of the capsule in addition to a fenestra ovalis, 

 into which latter the stapedial plate of the bony columella is 

 inserted (cf. p. 98), and the tympanic cavity in most Reptiles 



