350 



ZOOLOGY 



SECT. XIII 



In the Chelonia (Figs. 991, 992) all the bones, including the 

 quadrate, are solidly connected together. Transverse bones 

 (ectopterygoids), lacrymals, orbitosphenoids and alispbenoids are 

 absent. The place of alisphenoids is taken to a certain extent 

 by vertical downward plate-like extensions of the parietals, the 



Pmx 



Pmx 



Prf 



Fin. 990. Skull of Sphenodon. A, Dorsal ; B, ventral ; C, left-sided view of skull of 

 Sphenodon, xf. Col. Columella auris ; Con<L occipital condyle ; E. P. ectopterygoid ; 

 F. frontal; Juy. jugal ; Max. maxilla; Na. nasal; Nc. anterior nasal opening; Pal. 

 palatine; Par. parietal ; Pmx. premaxilla ; Prf. prefrontal ; Pt.f. post-frontal and post- 

 orbital ; Ptg. pterygoid or endopVrygoid ; Q. quadrate and quadrate- jugal ; Sq. squamosal ; 

 Vo. vomer. (From the Cambridge Natural History.) 



lower part of the plates representing the epipterygoids of 

 Lizards. There may be open temporal fossae, the inferior boundary 

 of which (inferior temporal arch) may be incomplete owing 

 to the absence of the quadrato-jugal, or the entire temporal 

 region may be covered over (Turtles, Fig. 992) by a sort of false 



