Page:Synopsis of the Exinct Batrachia and Reptilia of North America. Part 1..pdf/23

 AND AYES OF NORTH AMERICA. This species is larger than the O. pee-tinatus, and about equal to the Urocor-dylus wandesfordii Huxl. The caudal 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 vertebra:. Such of the latter whose out-lines are visible, 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 spine; and CAUDAL 'VERTEBRAE, 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 species 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 C. remex the dilate haemal spines are 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, though 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 diapophyscs, nor rudiments of ribs. The centra are rather stout and somewhat constricted medially. There are no traces of dermal armature of any kind. Fig. 2. 19 Measurements. Lines. Length of a posterior centrum, 1•62 Depth do. do. do. 1 Length llamal spine of adjoining mt., 4.4 Basal width, 1.4 Median width, .9 Distal width, 1.1 Length of a more anterior haemal spine, 4.3 Distal width do. do. do.. 1.5 Length anterior neural spine, 4 Width do. do. 1.4 From the Coal Measures, the Bituminous basin at Linton, Columbiana Comity, Ohio, near the Ohio River. Prof. J. S. Newberry.