258 O. G. Marsh—American Jurassic Dinosaurs. 
DerRMAL SPINES AND PLATES. 
_ Figure 8 represents a different kind of spine. This also 
is obliquely truncated at the base, and thus is unsymmetrical, 
but its fellow has not been discovered. Its sides are flat and 
covered with vascular markings. There is a distinct ridge 
spines were especially adapted to support them. 
* Palzeontographical Society, 1875, 
