GEOL. Mac. 1888. DECADE III. Vou. V. Pt. II. 
Fic. 1.—Dorsal spine of Stegosaurus ungulatus, Marsh; a, side view ; 4, posterior 
view ; ¢, section ; d, inferior view of base. 
Fie. 2.—Large caudal spine of same individual; a, side view; 0, front view ; 
other letters as above. 
Fie. 3.--Smaller caudal spine of same individual; 0, posterior view; other 
letters as above. 
Fie. 4.—Caudal spine of Stegosaurus sulcatus, Marsh ; side view. 
Fre. 5.—The same spine ; posterior view. 
Fie. 6.—The same spine; inner view. 
All the figures are one-twelfth natural size. 
From the Atlantosaurus Beds of the Upper Jurassic, Southern Colorado. 
