408 PROCEEDINGS OF THE ACADEMY OF 



and a small capitular articulation is seen sessile on the border of 

 the cup of two of the dorsals. 



The axis has a singular form, owing to the tubular perforation 

 which continues the posterior excavation to the anterior face of 

 the centrum. There are three articular faces, a larger subround 

 inferior and two smaller superior, which border the neural canal 

 in front and below, and are separated from each other and the 

 inferior face by the perforation in question. The anterior face 

 slopes obliquely backwards and downwards, and is convex in 

 transverse section. There is no facet for the free hypapoph} r sis 

 of the odontoid, but it appears that the inferior articular face was 

 applied exclusively to the centrum of the atlas, as in Sphenodon. 

 But the axis differs from that of the latter genus in the absence of 

 a coossified odontoid process. Either that element is altogether 

 wanting, or it consists of two pieces, interrupted in the middle by 

 the notochordal foramen, and in correspondence with the superior 

 articular facets. There is no true lrypapophysis of the axis, and 

 the only indication of lateral processes is a small articular facet 

 on each side on the lower part of the rim of the posterior funnel. 

 These may have been related to rudimental cervical ribs. The 

 neural arch is broken off. 



The dorsal vertebrae have their sides somewhat contracted; in 

 one specimen the inferior face is rounded, in another, which I 

 suppose to belong to a different part of the column, it is longitu- 

 dinally acute. In this and another dorsal, where the parts are 

 exposed, the floor of the neural canal is interrupted by a deep 

 fissure, which has a triangular shape with the apex downward, 

 when seen in profile. This is due to the fact that the opposite 

 halves of the centrum are united by the circumferences of the 

 articular cups, which have in profile an \A shape. The diapo- 

 physis' does not project far beyond the base of the neural arch, 

 and is compressed. 



The caudals are elongate, and resemble, in the forms of the 

 centrum and neural arch, those of Laelaps. The neural spines 

 are not preserved, but if present were directed well backwards, 

 bearing the posterior zygapophyses, since the arch stands only on 

 the anterior three-fifths of the centrum. Chevron facets are not 

 distinct, but two emarginations on the rim of the posterior face of 

 one of the vertebrae indicates their existence. In other centra, 

 even these notches are wanting. The tail was evidently tapering. 



