104 THE WASATCH AND BRIDGEB FAUNiB. 



1LACERTILIA. 

 CHORISTODERA. 



Cope, Proceedings Academy Phila. 1376, p. 350. 



Vertebral centra amphiplatyan. Processus dentatus free from axis. 

 Neural arches separate from centrum during maturity. 



CHAMPSOSAURUS Cope. 



Loo. oit. p. 348, pnblisbed Jan. 30, 1677. Paleoatological Balletin Xo. 23, p. 9, Jan. 10, 1877, Simado- 

 taurua Gervais, Journal de Zoologie, 1877, No. 1, p. 76, f February. 



This genus was established on species found in the Laramie Cretaceous 

 formation. It has been found to be abundant in the Puerco of the Tertiary 

 series, and is hence introduced here. 



The characters presented by the vertebral column are the following: 

 The ribs have a single head, which articulates with a prominent tuberculum, 

 excepting those of the cervical vertebrae. On these there is a small capit- 

 ular 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 

 succeeding centra until it is merged in the tuberculum of the diapophysis. 

 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 dorsals it is vertically compressed. One 

 of the anterior cervicals, probably the axis, is obliquely truncated below 

 its anterior articulate face, for a free hypopophysis or os odontoideum. This 

 vetebra has no parapophysis, and the articular faces for the neurapophysis 

 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 coossi- 

 fied. 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 diapophyses. 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 behind the axis, ex- 



