Uj J 



Qj ■' 



R 



Fig. 55. — Diagrams of skulls, showing especially the composition of the bony arches of 

 the orbito-temporal I'egion. 



L, Pythoxomorpha. Clidastes, p. 490. 



M, N, 0, Lacertilia, p. 496. M, Varanus, p. 543 ; N, Uromastvr, p. 524 ; 0, 



Lacerta, p. 550. 

 P, IcHTHYOSADRiA, p. 479. IclitliyosauTus, p. 483. 

 Q, PterosaURIA, p. 484. Dimorjihodon, p. 486. 

 R, Ayes, generalised, for comparison. 

 S, ^Ia.mmalia, generalised, for comparison. 

 T, Ophidia, p. 581. 



C, Condyle of mandible ; Col, columella cranii ; F, frontal : /, interparietal or 

 pineal foramen ; l.A, Inner angle of mandible : J, jugal, shaded vertically ; 

 L, lacrynial ; M, maxillary ; N, nasal groove : Xa, nasal bone ; C, orbit ; 

 0,, preorbital fossa ; P, parietal ; Pf, postfrontal ; I'm', premaxillary ; Pr, pre- 

 frontal : Ft'i, pterygoid ; Q, quadrate ; (Jj, quadrato - jugal ; %, squamosal, 

 shaded obliquely ; St, supratemporal bone. 



