Fig. 54. — Diagrams of skulls, showing especially the composition of the bony arches of 

 the orbito-temporal region. 



A, C, D, E, Theeomoepha. A, Elginia, p. 305 ; C, Cynognathus, p. 306 ; D, 

 Gordonia, p. 310 ; E, JJicynodon, p. 310. 



B, G, Peosaueia. B, Sphenodon, p. 294; G, Palaeohatteria, p. 291. 

 F, Crocodilia, p. 434. / 



H, I, K, Chelokia, p. 316. H, Ghelydra, p. 338 ; I, Chrysem,ys/-p. 346 ; K, 

 CistudOf p. 361. 



E, Epiotic ; F, frontal ; IT, infratemporal fossa ; J, jugal, shaded vertically ; 

 L, lacrymal ; Af, maxillary ; JV, nasal groove ; Ifa, nasal bone ; 0, orbit ; 

 P, parietal ; Po, postorbital, dotted ; Pf, post-frontal ; Pm, premaxillary ; 

 Pr, prefrontal ; Ptg, pterygoid ; Q, quadrate ; Qj, quadrato-jugal ; So, supra- 

 occipital ; (Sg, squamosal, shaded obliquely ; St (in B-E), suprateinporal fossa ; 

 St (in A), Supratemporal bone. 



