Page:Synopsis of the Exinct Batrachia and Reptilia of North America. Part 1..pdf/54

50 {| align=center width="80%"
 * ||In.||Lin.
 * Antero-posterior diam. ?11th dorsal,||3||4.5
 * Transverse posterior of articular face.||5||3.
 * Vertical do. do. do.,||3||10.
 * Transverse posterior of neural canal,|| ||10.2
 * Transverse posterior of articular face, 3d dorsal,||5||2.5
 * Elevation centrum, arch and spine, 2c1 dorsal,||11||9.
 * Elevation upper edge zygantrum 2d dorsal,||6||
 * Length zygantrum, upper edge, do.,||1||10.2
 * Length centrum, last cervical,||4||
 * Width centrum articular face cervical,||5||3.
 * Elevation neural arch and spine cervical,||7||9.
 * Antero-posterior width neural spine of cervical at zygapophysis,||3||7.
 * }
 * Elevation upper edge zygantrum 2d dorsal,||6||
 * Length zygantrum, upper edge, do.,||1||10.2
 * Length centrum, last cervical,||4||
 * Width centrum articular face cervical,||5||3.
 * Elevation neural arch and spine cervical,||7||9.
 * Antero-posterior width neural spine of cervical at zygapophysis,||3||7.
 * }
 * Elevation neural arch and spine cervical,||7||9.
 * Antero-posterior width neural spine of cervical at zygapophysis,||3||7.
 * }
 * Antero-posterior width neural spine of cervical at zygapophysis,||3||7.
 * }
 * }

The cervical vertebræ are assumed to commence where the rib pits cease, and the continuous lateral processes commence. This point is ascertained with difficulty on the specimen. It is, however, perhaps the same point where the longitudinal lateral ridge leaves the upper margin of the rib pit ; and it was to the series of vertebræ which pass this point, the scapular bones,—the clavicle and coracoid were found attached. On the anterior dorsals the inferior margin of the rib pit is most prominent, and is finally produced in a flat thin process which is directed obliquely downwards. Both these and the posterior ribs are crushed on the centra and project obliquely below them; their mode of attachment is thus rendered rather obscure. A similar structure exists in the posterior cervicals of Cimoliasaurus, while on the anterior dorsals or where the rib-origins are on the lower plane, short thick diapophyses support the ribs. The proximal cervicals are remarkable for their compressed and elongate form. They are for a considerable distance longer than any dorsals. The lateral longitudinal ridge rises successively nearer to the neural arch and disappears. The articular surfaces are vertically oval, flattened above and below. The inferior faces are slightly grooved in line with the venous foramina. These vertebræ diminish in length, and after the posterior third of the series, materially in depth. They diminish to terminal ones of very small size. In most the declined ?pleurapophyses are broken near the base, but the basal portion of various lengths generally adheres. They are as wide as a rib; and scarcely half as thick. On some of the most anterior vertebra, they are quite short and broad antero-posteriorly. They have much greater antero-posterior extent on the terminal than the proximal cervical centra, having a base five-sixths the length of the latter. The zygapophyses have relatively a larger size on these than any other vertebræ. In such the centrum is less compressed, though with concave sides, and with a section rather quadrate.

The caudal vertebræ have slightly concave articular surfaces, which are not bounded by groove or ridge. The neural arches have flat sides, and there is no longitudinal ridge above the diapophyses. The neural spines are elevated, the margins of those of the adjacent vertebræ close together. The diapophysis is very short and wide, terminating in a large oval concavity for the pleurapophyses. Each limb of the chevron bone is attached to an articular surface on the lower posterior face of the vertebra, at the extremity of a strong inferior ridge. These inferior ridges are rather close together, and distinguish the vertebræ from those of Cimoliasamms magnus, where they are wanting. They are absent on the anterior seven of the caudal series. The diapophysis is nearer the anterior than the posterior face of the vertebra. The venous foramen is single and media; on all but the last six cervicals.

Heads of fourteen ribs are preserved, and a great number of shafts. The heads are simple, with elongate oval articular face. They are oblique in the narrow direction, and frequently in their length also ; the margins are somewhat everted. The extremities of the diapophyses of the larger dorsal vertebræ are transverse, some flattened,