AN!) AVES OF NORTH AMERICA. 



19 





This species Is larger than the 0. poc- Fig. 2. 



fcinatus, and about equal to the Urooor- 

 dylus wandesfordii Huxl. The oaudal 

 spines differ in the greater attenuation of 

 the neural series, and the presence of a 

 basal lamina, on the haemal. The caudal 

 region is represented by a portion of the 

 vertebral column three inches in length. 

 In this space may be counted twenty-four 

 vertebrae. Such of the latter whose out- 

 lines are visiblt;, display centra character- 

 istic of the genus ; their terminal concavi- 

 ties conic, with apices meeting in the 

 centrum, medially; zygapophyses rudi- 

 mental if present. 



Characteristic of the species are the 

 remarkable length and slenderness of the 



fan-shaped neural and haemal spines, and caudal vebtebe2e, nat. size. 



the absence of an acute serration on their margins. In this species the spines have a laminiform expansion at the 

 base in their plane. In the other speoies here described these spines are not only relatively broader and more fan- 

 shaped, but they are acutely serrate on the margin and constricted at the base. 



In ('. remex the dilate haemal spines arc a little more than three times as broad distally, as they are long, 

 while the neural spines are a little narrower. The haemal spines stand about the middle of the centrum. The 

 basal half is furnished with an anterior ala, which leaves the anterior margin rather abruptly and extends to the 

 next spine in advance. It returns gradually to the centrum and is separated from the articular face of the latter 

 by a notch. A similar ala exists on the posterior margin of the haemal spine, which extends for a shorter distance 

 above the base, and is narrower than the anterior. Each spine presents a median groove on its surface, which 

 extends half way to the base or further; on each side of this are some three other grooves which extend but a 

 short distance ; surface otherwise smooth. The ends of the grooves slightly notch the truncated end of the spine. 



The neural spines are on the posterior portions of the centra, and not in contact with the bases of those adjacent,. 

 They are without the dilatations of the haemal spines, and are directed rather more obliquely backwards. They 

 are similarly grooved, 1, hough without that SO distinctly median, seen in the haemal series. 



Both neural and haemal spines become stronger towards the anterior part of the vertebral column. There 

 appear to be no zygapophyses nor diapophyses, nor rudiments of ribs. The centra are rather stout and somewhat 

 constricted medially. There arc no traces of dermal armature of any kind. 



Measurements, 

 Length of a posterior centrum, 

 Depth do. do. do. 



Length haemal spine of adjoining vert., 



Basal width, 



Median width, 



Distal width, 



Length of a, more anterior haemal spine, 



Distal width do. do. do., 



Length anterior neural spine, 



Width do. do. 



Lines. 

 1.3 

 1 



4.4 

 1.4 



.9 

 1.1 

 4,:s 

 1.5 

 4 

 1.4 



From the Coal Measures, the Bituminous basin at Linton, Columbiana County, Ohio, near the Ohio River 

 Prof. J. S. Newberry. 



