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

 the orbito-temporal region. 



A, C, D, E, THKKOMORrHA. A, Ehjinia, j). 305 ; C, Cynognafhus, p. 306 ; D, 

 (■urdoniu, p. 310 ; E, JHctpiodon, p. 310. 



B. G, Prosauria. B, Splwnodun, p. 294 ; G, Palaeolmtteria, p. 291. 

 F, ('HdconiUA, p. 434. 



H, I, K, Chei.onia, p. 316. H, Chehjdra, p. 338 ; I, Chrysemys, p. 346 ; K, 

 Cistudo, p. 361. 



E, Epiotic ; ]'\ frontal ; IT, inl'ratemjioial fossa ; ./, jngal, shaded vertically ; 

 L, lacrynial ; ^[, maxillary ; X, nasal groove ; Xa, nasal Iwne ; 0, orbit : 

 P, parietal ; Po, postorbital, dotted ; J\f, post-frontal ; Pm, preniaxillary ; 

 Pr, prefrontal ; /V^, pterygoid ; Q, quadrate ; ijj, qnadrato-jugal ; So, supra- 

 occipital ; Sq, squamosal, shaded obliijuelj' ; St (in B-E), supr.atemporal fossa ; 

 St (in A), Supratemporal bone. 



