PLATE XX. 



Jurassic Dinosaurs. — Satjropoda. 



Atlantosauridjs. 



Page. 



Fig. 1. Tooth of Brontosaurus excelsus Marsh ; natural size 168 



a, outer view ; b, posterior view ; c. inner view ; d, front view. 

 Fig. 2. Left dentary hone of Brontosaurus excelsus ; outer view ; one-third 

 natural size 168 



a, edentulous margin; 8, symphysis; sr, face for surangular. 



Fig. 3. Sixth cervical vertebra of Brontosaurus excelsus; side view; one-twelfth 



natural size 169 



Fig. 4. The same vertebra; back view; one-twelfth natural size 169 



b, ball ; c, cup ; d, diapophysis ; /, lateral foramen ; n, neural canal ; p, 

 parapophysis ; r, cervical rib; z, anterior zygapophysis ; z' ', posterior 

 zygapophysis. 



284 



