212 



REPTILIA. 



FIG. 131. 



Stegosaurus stenops ; skull from the superior (A) and left lateral (B) aspects, 

 one-quarter nat. size. U. Jurassic; Colorado, a, external narial opening; 

 aw., angular; a?\, articular; b, orbit; c, lateral temporal vacuity ; d, dentary; 

 e , supratemporal vacuity; /, frontal ; fp., postfrontal; j, jugal ; I, lachrymal ; 

 TO, maxilla; n, nasal; oc., occipital condyle; os., supraoccipital ; p, parietal ; 

 pd., predentary ; pf., prefrontal; pm., premaxilla ; po., postorbital ; 

 q, quadrate; s, splenial; sa., surangular ; so., supraorbital ; sq., squamosal. 

 (After Marsh.) 



