Am. Jour. Sci., Vol. XXXIV, 1887. 



Plate VIII. 



Figure 1. — Dorsal spine of Stegosaurus ungulatus, Marsh; a, side view; b, posterior 



view ; c section ; d, inferior view of base. 

 Figure 2. — Large caudal spine of same individual; a, side view; b, front view : other 



letters as above. 

 Figure 3.— Smaller caudal spine of same individual; b, posterior view; other letters as 



above. 

 Figure 4.— Caudal spine of Stegosaurus sukatus, Marsh ; side view. 

 Figure 5. — The same spine ; posterior view. 

 Figure 6. — The same spine ; inner view. 



All the figures are one-twelfth natural size. 



