188 



REPTILIA. 



The orbits are large, and the temporal arcades remarkably stout. The 

 mandibular rami are apparently fused in the long symphysis, which is 

 slightly forked at its toothless anterior end. The teeth are depressed 

 cones, apparently in single series in the mandible, but in several longi- 

 tudinal series on the maxilla and palatine. The vertebral centra are 

 well-ossified, and there are about 24 in front of the sacrum, which com- 

 prises two vertebrae ; those of the cervical region seem to be opisthocoelous, 



u / 



Fio. 116. 



Hyperoilapedon gordoni; skull from the superior aspect (A), right lateral aspect 

 (B), and inferior aspect of mandibular symphysis (C), one-quarter nat. 

 size. Triassic (?) ; Elgin, d, dentary ; /.frontal; j, jugal ; l.t.f., lateral 

 temporal vacuity; na., nasal; nar., external narial opening; orb., orbit; 

 pa., parietal; pmx., premaxilla; prf., prefrontal; ptf., postfrontal ; pto., 

 postorbital; s.t.f., superior temporal vacuity. (British Museum, no. E. 699.) 



and no intercentra (hypocentra) have been observed. The anterior 

 cervical ribs are longer and stouter than those of Sphenodon, those beyond 

 much resemble the ribs of the existing genus; it is uncertain, however, 

 whether there were uncinate processes. The limbs are very imperfectly 

 known, but the fore foot is proved to have been remarkably short and 



