DINOSAURIA. 



203 



FIG. 123. 



Diplodocus longus; skull from the left lateral (A) anti palatal (B) aspects, 

 one-sixth nat. size. Jurassic; Colorado, b, basioccipital ; eo., exoccipital; 

 m. maxilla; mp., extension of maxilla; o, occipital condyle; p, palatine; 

 /'///.. premaxilla; /-.--.. parasphenoid ; pt., pterygoid; q, quadrate; /. ecto- 

 pterygoid; v, vomer. In the upper figure (A) the external narial opening is 

 seen at the vertex of the skull, while the antorbital and small maxillary 

 vacuities are shown on the face. In the lower figure (B), the posterior (in- 

 ternal) nares are the pair of vacuities adjoining the vomers. (After Marsh.) 



