102 THE WASATCH AND BRIDGER FATIiTiE. 



lows: Thinosaunis Mai>h, five species; Glifptosattrus Marsh, eight species; 

 Xest02)S Cope (1873, Oreosaunis Marsh, not Peters), five species; Tinosaurus 

 Marsli, two species; and Iguanavus Marsh, one species. As Profesor Marsh 

 does not give us any clue to the aflinities of these forms, they cannot be 

 furtlier considered here. In Lieutenant Wheeler's Survey Report* I have 

 pointed out that the dermal scuta and a few other fragments Avhich I 

 obtained in the Wasatch beds of New Mexico, were probably referable to 

 the Flacosaurida, a family created by Gervais to receive certain Lacerdlia 

 of the Eocene of France. To this family no doubt some of the species 

 described by Marsh from the Bridgor horizon are to be referred. 



The snakes of the Eocene are not very numerous as to species. The 

 first known j^merican species {Palcrojihis Uttoralis and P. halidanus) were 

 determined by myself from Kew Jersey specimens. None have been pro- 

 cured from beds lower than the Bridger, and in that formation I found a 

 single foi-m. Professor Marsh has described five species.* 



The whole number of species of reptiles thus far discovered in the 

 Eocene of the central region of North America is as follows: 



Crocodilia 12 



Tcstudiiiat.i 42 



Lacertilia 22 



Opbiilia 6 



82 



OPHIDIA. 



PROTAGRAS Cope. 



Paleontological Bulletin No. 3, p. 3, August 7, 1872. Aunual Report U. S. Gcol. Surv. Terrs., 1672 (1873) 

 p. 632. Proceed. Amer. Philos. Soc., l!?72, p. 471. 



Transverse processes large, the extremity entirely occupied by the costal 

 articular surfiice. This consists of a superior and an inferior convex por- 

 tions, which are separated by a constriction, which is most profound on the 

 posterior border. Zygosphene wider than articular cups, and giving rise to a 

 low ridge which extends along the side of the neurapophysis. Articular ball 

 and cuj) wider than deep, the former looking very obliqely upwards, its surface 

 extending to the bases of the neurapophyses. A prominent ridge connects 

 the pre- and postzygajjophyses. A strong hypapophysial keel, and a latero- 

 inferior ridge extending posteriorly from the base of tlie transverse process. 



• Vol. iv, pt. ii, p. 42, pi. xxxii, figs. 26-36. 



