OPHIDIA. 781 



smaller. Axis with an elevated neural arch, with obtuse, inferior carina. 

 Odontoid a crescentic element, with a transvei'se groove on its anterior face. 

 All the centra with an obtuse but prominent hypapophysial keel. 



Cremastosaurus carinicollis Cope. 



Locis citatis. 

 Plate LX ; fig. 16. 



Ball of sixth cervical vertebra round. Neural arches broad, each with 

 a low, acute keel for spine, which is elevated on the third, and produced 

 roof-shaped backward and forward on the axis. The costal articulations 

 are not produced below the centrum. 



Measurements. 



M. 



Length of cervical vcrtebrie II to VI 0. 0140 



Length of axis 0038 



Elevation of axis behind 0047 



Diameter of odontoid (in front) 0034 



Length of c. VI 0029 



Diameter of ball of same 001 1 



Total elevation of same 0030 



Size of the "horned-toad", Phrynosoma cornutum. 



OPIIIDIA. 



Several species of snakes have been found in the beds of the White 

 River and John Day epochs. The characters presented by the yertebrfe, the 

 only parts as yet discovered, do not differ much from those of existing 

 types. None of them represent species of more than the average size of 

 the colubrine snakes now existing in the f-ame region. 



APHELOPHIS Cope. 



Synopsis of New Species of Vertebrata obt.iiued in Colorado in 1873 (Miscell. Pnb. U. S. Geol. Sarv. 

 Terrs.), p. 16. Annual Report U. S. Geol. Surv. Terrs., 1873 (1874), p. 518. 



The vertebrse of this genus have various well-marked characters which 

 distinguish them. The neural spine is short and robust, and does not ex- 

 tend along the entire length of the neural arch as exposed in the articulated 

 column. There is no diapophysial process below the prezygapophysis. 

 The zvgosphene exceeds the articular cup in width, and the posterior bor- 

 der of the neural arch is not interrupted. There is no hypapophysis, iior 



