Page:Synopsis of the Exinct Batrachia and Reptilia of North America. Part 1..pdf/53

Rh {| align="center" ! ! Cranium,
 * colspan="2" align="center"| Present.
 * colspan="2"| Lost.
 * Total
 * No.
 * Length In.
 * No.
 * Length In.
 * lengths.





24 24 Cervicals, 68½ 237.5 3½ 22.3 279.8 Dorso-lumbars, 14 55.10 10 37.6 93.4 Caudals, 21 60.4 30 60. 120.4 Total, 103½

43½

517.6
 * }
 * }

This gives the total length to the animal of forty-three feet, two inches, which, increased by the amount taken up by intervertebral cartilages, will give roundly about forty-five feet. Of this, twenty-two feet must be reckoned to the neck.

The cervical vertebrae from the sixty-sixth to the thirty-ninth are all longer than the dorsals; they commence four inches in length, increase to five, and diminish to four again.

Many of the ribs preserved have been pressed upon the vertebræ and crushed.

The first dorsal is that vertebra which first presents a distinct articulation for a rib. The diapophyses are never much elevated above the centrum and are longest on the thirteenth (inserting seven supposed to be lost). Their form is stout and much depressed, and distally expanded. They diminish gradually, and on the third are represented by a longitudinal, slightly concave articular surface, somewhat similar to those of the caudals. This surface is bounded above and below by a longitudinal, angulation; the superior is first distinct on the first, and bounds the articular surface last on the third. They give the transverse section of the posterior cervicals a pentagonal form; that of the anterior dorsals is nearly circular. The latter are strongly constricted medially, and the articular faces are slightly con-cave. The external surface near the included angle is coarsely ridged, in conformity with coarse cellular texture of the spongy bone. The venous foramina gradually become more widely separated, approaching each other again on the posterior cervicals. On the dorsals they occupy the bottom of a more or less pronounced concavity. These concavities, on the posterior dorsals, arc bounded externally by a strong obtuse longitudinal angulation, giving a quadrate outline to the section of the centrum in this part of the series.

The posterior cervicals are not readily distinguished from the anterior dorsals. In the latter the ribs appear to be present, of reduced length, judging from the smaller size of the remaining heads. The articular pits continue to descend till their lower marginal ridge is the inferior lateral angle of the vertebra. On such vertebræ the inferior surface is flat. The neural spines on dorsals and posterior cervicals are of great height as well as antero-posterior width, and they allow a very narrow interval between them.

AMERI. PHILOSO. SOC.-VOL. XIV. 13