I'ROSAUKI RHYNCHOCEPHALI 



!95 



only recent reptile which is devoid of them ; a most primitive 

 condition, sutficient hy itself to separate tliis creature from all the 

 other living reptiles. 



The supratemporal bridge is formed hj the squamosal and 



Pmx 



Fig. 59. — A, Dorsal; B, ventral; C, left-sided view of the skull of Sphenodon. x ^. 

 Ool, columella auris ; Oond, occipital condyle ; H. P, ectopterygoid ; F, frontal ; Jug, 

 jugal ; Alax, maxillary ; Juc, nasal ; JVb, anterior nasal opening ; Pal, palatine ; 

 Par, parietal ; Pmx, premaxillary ; Prf, prefrontal ; Pt.f, postfrontal and post- 

 orbital ; Ptg, pterygoid or endoi:iterygoid ; Q, quadrate and quadrato-jugal ; /S'g. 

 squamosal ; Vo, vomer. See also Fig. .54, B, p. 280. 



postorbital (Fig. 59, C, I^f-f), the latter being continued forwards 

 and fused with the postfrontal (A, Ptf). Tlie postorbital joins 

 the ascending branch of the jugal, both together forming the 

 hinder border of the orbit ; this is bordered below chiefly by 



