xni 



PHYLUM CHORDATA 



339 



separated below by a bar of bone (superior temporal arch), formed 

 of processes of the two last-mentioned bones and of the post- 

 frontal, from a still larger space the lateral temporal fossa. The 

 latter is bounded below by a slender bony bar (the inferior temporal 

 arch), formed of the long narrow jugal (Jug), with a small quad- 



PTUX 



Pmx 



Prf 



E.P 



FIG. 1001. Skull of Sphenodon. A, dorsal ; B, ventral ; C, left-sided view of skull of 

 Sphenodon, x 3. Col. Columella auris ; Cond. occipital condyle ; E. P. ectopterygoid ; 

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

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

 orbital ; Pig. pterygoid or endopterygoid ; Q. quadrate and quadrato-jugal (paraquadrate) ; 

 Sq. squamosal ; Vo. vomer. (From the Cambridge Natural History.) 



rato- jugal or paraquadrate, by which the jugal is connected with 

 the quadrate (Q). The lateral temporal fossa is separated from 

 the orbit in front by a bar of bone formed of the jugal and post- 

 orbital, and is bounded behind by a posterior temporal arch formed 

 of the parietal and squamosal. The quadrate (Qu) is immovably 

 fixed, wedged in by the quadrato-jugal, squamosal and pterygoid. 

 The premaxillse (Pmx) are not fused together, but separated by 



