1892.] 1»>1 [Cope. 



plate. This tuberosity is in some of the plates developed into a promi- 

 nent spine or horn, which has an anteroposteriorly oval section. The 

 surfaces of the tuberosities are punctate. These horns are placed on the 

 sides, and probably not far from the median line, since they form with 

 the adjacent tuber-bearing plates a strong angle, such as would be neces- 

 sary to enclose the neural spines of the vertebral column. It is also not 

 certain whether these spines were on the dor,sal, cervical or caudal regions, 

 or whether they were on all of them. The plates adjacent to those bear- 

 ing spines are the most robust. The spines are gently curved, probaI)ly 

 backwards. 



Measurements of Dermal Plates. 



MM. 



{anteroposterior 90 

 transverse 78 

 vertical at suture 18 



{anteroposterior 100 

 transverse 70 

 vertical at suture 37 



i anteroposterior 115 

 transverse (chord) 65 

 vertical at suture 35 



Elevation of spine of plate last, measured from base (apex 



restored) 190 



f anteroposterior 95 



Diameters of spine at base | transverse 65 



f anteroposterior 30 



Diameters of spine 45 mm. below apex | tl.a^sverse 20 



Diameter of pits on flat bone 5 



Diameter of pits on knobbed bone 9 



In comparison with the only species of the genus known thus far, the 

 E. horridiis, from the Triassic bed of New Mexico, the present species has 

 the tuberosities and horns of a different shape. In that species the former 

 are compressed and keel-like, and the horns are also compressed, having 

 an edge in front and a triangular section. The individual which served 

 as the basis of the description of the £J. horridus is also of rather smaller 

 size than the present one. 



