Page:Quarterly Journal of the Geological Society of London, vol. 26.djvu/463

 The transverse processes (tr) are simple, stout and short. They project horizontally outwards from the outer border of the praezygapophyses. The left one, which appears to be unmutilated, measures nearly 3.5 inches along its upper surface. It bears a terminal, oval, slightly hollow costal surface (cs), the long axis of which, nearly vertical, measures 2.5 inches, while the horizontal shorter axis is 1.1 inch. The under surface of the transverse process rests on a strong buttress-like plate, which ascends towards its outer end from the anterior margin and adjacent outer aspect of the neurapophysis. This plate forms the outer wall of a large and deep triangular hollow beneath the anterior margin of the transverse process.

One of the most remarkable characters in the vertebra is a thin horizontal platform (plt) which extends along the side of the vertebra, from the back of the transverse process anteriorly to the postzygapophyses behind, in the level of the crown of the arch. Its original breadth is not now ascertainable, for its outer border is broken ; but in its present mutilated state, it extends outwards to the distance of 5 inches from the neural spine. It is strengthened in front by a stout ridge produced outwards from the outer half of the posterior border of the praezygapophysis and the adjacent anterior pillar of the neural spine. A curved notch, 2 inches long, the only remaining natural edge of the platform, separates the outer end of this ridge from that of the transverse process. At about 2.5 inches behind the first ridge the platform is strengthened by a second ; and, corresponding to this, a strong bracket-like plate (btt) descends from the under surface (of the platform) towards the centrum, filling the angle included by the horizontal under surface of the platform and the nearly vertical outer surface of the neurapophysis. The lower end of this bracket forks just before it reaches the centrum. Between the bracket and the buttress which springs from the anterior border of the neurapophysis to the outer end of the transverse process, is a very large deep hollow under the platform. Its sides are formed by the bracket and buttress just mentioned ; and its bottom corresponds to the thinnest part of the neurapophysis, which at this part is only about .1 inch thick, and is strengthened by small buttresses and arches in high relief. A similar but smaller hollow is present behind the great vertical bracket, between it and the postzygapophysis. A third, and still smaller pit occurs at each side of the vertical median plate descending from the postzygapophyses to the arch, which allows the entrance of the plate into the notch between the praezygapophyses when the vertebrae are articulated. From the upper surface of the platform several thin strut-like plates ascend on the sides of the neural spine.

The neural canal (nc) has a singular construction, which I do not remember to have seen in any other vertebra. The anterior margins of the neurapophyses form a wide, simple, low-spanned opening ; and within this there is a very beautiful interior arch (g) with groins projecting from the spring of the arch and from the roof, and converging to a central point lying just under the front of the neural