COPE ON GEOLOGY AND VERTEBRATE FOSSILS. 579 



tinus is nearly double that in the E. plaiyurus, while the vertical 

 diameter is subequal in the two. In the E. serpentimis, the centra of 

 the cervicals are somewhat less elongate. In the four anterior iDre- 

 served, the transverse diameter exceeds the longitudinal ; in the seven 

 following, the transverse and longitudinal diameters are equal 5 in the 

 twenty-one which succeed, the longitudinal exceeds the transverse diam- 

 eter. In the ten following, the two diameters are equal, while the 

 transverse exceeds the longitudinal in the remainder of the cervical 

 column. There is a longitudinal lateral angle of the centrum on all 

 the cervicals excepting some of the posterior. It is weak on some of 

 the smaller ones. On the thirty-seventh, this angle is more than an inch 

 above the base of the parapophysis, and is very obtuse on the posterior 

 half of the centrum. On the thirty-eighth, it is obscure on the anterior 

 part of the centrum, and on the thirty-ninth is obsolete. The poste- 

 rior eighteen cervical vertebrae are then in this species without the lat- 

 eral angle, a character which distinguishes it well from both the others. 

 In them, this angle is distinct up to the point of origin of the ribs. The 

 articular faces of the centra of the median and anterior cervicals of the 

 E. serpentimis are slightly concave. In all except the last cervicals, the 

 sides are more or less concave. The two large inferior foramina are con- 

 tinued in two longitudinal grooves of the inferior face. 



The first dorsal differs from the last cervical in the greater truncation 

 of the protuberance, which takes the place of a diapophysis. It is sit- 

 uated on the plane of the inferior surface of the centrum. On the suc- 

 ceeding vertebra?, its position gradually rises until, on the seventh dor- 

 sal, its base stands on the neural arch, half of it being above the neural 

 canal. On the twelfth, the base of the diapophysis is entirely above the 

 neural canal, but, on the sixteenth, its position is a little lower. Oa the 

 twenty-fifth, it is altogether situated- on the centrum. These processes 

 increase in length to the eighth, and maintain their greatest promi- 

 nence to the sixteenth inclusive ; they then shorten until, on the twenty- 

 sixth, they are nearly sessile. Where longest, the diapophyses are stout, 

 and overhang the centrum by three inches. Their articular extremities 

 are subround. The last dorsal only differs from the first caudal in the 

 absence of facets for the chevron-bones. The sides of the dorsal centra 

 are without angles, and are concave antero-posteriorly ; an obtuse angle 

 separating the lateral from the inferior face appears on the twenty-ninth. 



The caudal vertebrae are wider than long, and the transverse and 

 vertical diameters of the articular faces are about equal. The facets 

 for the free pleurapophyses are large and nearly sessile ; the anterior are 

 horizontally oval, the posterior round. An obtuse angle extends from 

 the chevron-facet anteriorly, but it does not reach the anterior articular 

 border before the ninth vertebra ; they separate a flat plane as far as 

 the sixth, where the surface begins to be concave. This concavity in- 

 creases somewhat to the eighteenth, but is nowhere strongly marked. 

 In this respect, it diflftrs from the E. platyirus, where the inferior ridges 

 4 B n 



