110 



COMPARATIVE AN ATOM Y 



The cranial bones (Figs. 80-86) are much more numerous and 

 varied in form than in recent Amphibia. The solid base of the 

 skull is formed by bones developed on a cartilaginous foundation, 

 viz., of a basioccipital and a basisphenoid, on which latter there 

 may be a liasiptcrygold process on either side for articulation with 

 the pterygoid bone. An alisphenoid ossification may be present ; 

 presphenoids and orbitosphenoids are usually wanting. The 



Pr, ma - 



.In rial ' 

 Transpal. 



/</,;. tal 

 Pti, <o d 



Postfroiti. -2 - 



. proc.r" 



cart. 



I'll ,'<!.<' ptl't ffti't. 



Optic " n ~tru 

 A-.prot. ofpal.quad. 



Quad, (artic. 



jiroc.) 



1 PI i-il/mpli. jo,'. 



Post. basicran.foiitnne!/( u<-. cond. 

 Fin. SO, B. 



parasphenoid, which plays so important a part in the Anamnia 

 as an investing bone on the roof of the mouth, undergoes a 

 gradual reduction, but can still be recognised, although more or 

 less included within the basisphenoid : it may be represented by 

 lasitemporal ossifications which unite with the latter bone, and 

 its anterior part may form a lasisphenoidal rostrum. Above the 



