53 



Cope, in Proceedings of the American Philosophical Society (separata 

 August 12). Genus Agathaumas described. 



1873. Cope, Proceedings of the Academy of Natural Sciences, Philadelphia, 



p. 10. Toxochelys latiremis described. 

 Leidy, Report of the United States Geological Survey of the Territo- 

 ries, by F. V. Hayden. Clidastes affinis and Plesiosaurus occiduus 

 described and other known species figured. 



1874. Cope, in Hayden's Bulletin of the United States Geological Survey of the 



Territories, No. 2 (issued April). Species of Cionodon, Polyonax, 

 Bottosaurus, Trionyx, Plastomenus, Adocus, Clidastes, and Liodon 

 described ; structure of Dinosauria of the Fort Union epoch eluci- 

 dated. 



DINOSAUBIA. 



AGATHAUMAS, Cope. 



Proceedings of tbe American Philosophical Society, 1872, p. 482. 



The characters of this genus are derived from the typical species A. syl- 

 vestris, which is represented by dorsal and lumbar vertebrae and an entire 

 sacrum, with the ilia, one nearly entire, ribs, and a number of other bones the 

 character of which have not yet been positively ascertained. One of these 

 resembles the proximal part of the pubis; others, portions of the sternum, &c. 



On eight (and, perhaps, nine) vertebrae, anterior to the sacrum, there is 

 no indication of the capitular articular facet for the rib. This facet is found, 

 as in Crocodilia, at or near the base of the elongate diapophyses. The centra 

 are slightly concave posteriorly, and still less so on the anterior face, with 

 gently convex margins. The neural canal is very small, and the neural arch 

 short, and quite distinct from the centrum, having scarcely any suture. The 

 neural arch has a subcubical form, partly truncated above by the anterior 

 zygapophyses. In like manner, the base of the combined neural spine and dia- 

 pophyses are truncated below by the square-cut posterior zygapophyses. The 

 diapophyses are long, and directed upward ; they are triangular in section. 



There are eight (and, perhaps, nine) sacral vertebra, which exhibit a con- 

 siderable diminution in the diameters of the centra. The diapophyses and 

 neural arches are shared by two centra, the anterior part of a centrum bear- 

 ing the larger portion of both. The diapophyses are united distally in pairs; 

 each pair inclosing a large foramen. The anterior is the most massive 



