9 



of the genera Otodus and Lamna, and a species of Enchodvs. 

 Above them I fouod lying loose a fragment of a Baculites. 



CHAMPSOSATJRUS, Cope. 



Genus novum. Vertebrae of more than a hundred individuals 

 referable to several species, which I obtained from the Judith River 

 beds of the Upper Missouri region, present characters which de- 

 mand the establishment of a new genus for their reception. 



The characters presented by the vertebral column are the fol- 

 lowing: The ribs have a single head, which articulates with a 

 prominent tuberculum, excepting those of the cervical vertebrae. 

 On these there is a small capitular tubercle below the diapophysis. 

 It commences very small, and inferior in position, being removed, 

 in fact, but a short distance from the inferior middle line in the 

 first vertebra in which it appears. It rises rapidly in the suc- 

 ceeding centra until it is merged in the tuberculum of the diapo- 

 physis. The latter projects from the neural arch, which is free 

 from the centrum, but in none does the base of the diapophysis 

 rise from a point above the floor of the neural canal. On the dor- 

 sals it is vertically compressed. One of the anterior cervicals, 

 probably the axis, is obliquely truncated below its anterior articu- 

 lar face, for a free hypopophysis or os oclontoideum. This vertebra 

 has no parapophysis, and the articular faces for the neuropophysis 

 are superior. The few vertebrae in each of several series, probably 

 from the sacral region, are more depressed than the others, and 

 the facets for the diapophyses present a greater antero-posterior 

 extent, but none are coossified. The caudal vertebrae are distally 

 quite compressed. In all, except the anterior ones, the neural 

 arch is coossified with the centrum, and in such there are no dia- 

 popl^ses. In those with free neural arch, the facets for the 

 neuropophyses turn down on the sides of the centrum. 



The articular extremities of the centra are plane, those of the 

 caudal series slightly concave. There are no hypapophyses be- 

 hind the axis, excepting a longitudinal carina, which ceases to 

 exist on the dorsal vertebrae. The zygapophyses are simple. The 

 chevron bones are free. 



The relations of the atlas and axis, though not fully elucidated 

 by my specimens, are peculiar. The former has separate neura- 

 pophyses, which have nearly the shape of those of the Strepto- 

 stylicate Rejrtilia, resembling much those of the Pythonomorpha. 



