1873.] ^03 [Cope. 



There are no cingula on the teeth, and the enamel is perfectly smooth. 

 The appearance of the crowns as well as the bones indicates an adult 

 animal. 



The bones of this animal were found together on the bluffs of Cotton- 

 wood Creek, Wyoming, by myself while attached to Hayden's Geological 

 Survey of the Territories for 1872. 



SYNOPLOTHERIUM. Cope. 



Proceedings American Philosophical Society, 1872, page 483, read Sep- 

 tember 20th, 1872. 



Represented as yet by a single species, which is known from frag- 

 mentary remains of a single individual. The portions preserved are : 

 a large part of the skull with nearly complete dentition, the superior 

 molars loose ; lumbar and caudal vertebrae ; large portions of both fore 

 limbs, including the bones of the feet; smaller portions of the hind 

 limbs and feet. 



The bones of the fore limbs are stout in their proportions. The 

 humerus* has a well marked rugose line for muscular insertion on its 

 posterior face, but no prominent angle. Distally the inner and outer 

 condylar tuberosities are almost wanting, and there is neither external 

 aliform ridge, nor internal arterial foramen. The olecranar and coronoid 

 foss;e are confluent, forming a very large supracondylar foramen. The 

 condyles are moderately constricted medially, and there is a well marked 

 submedian rib separated from the outer condyle by a constriction. The 

 latter is continued as an acute ridge on the outer side of the olecranar 

 fossa. The inner condyle is the more prominent and its outer margin is 

 a sharp elevated crest. The ulna has a very prominent superior process, 

 continuing the cotylus upwards. The coronoid process, on the other 

 hand, is rather low. The radial cotylus is flat and broad. The distal 

 end is not preserved. The radius has a more transverse head than Canis 

 or Felis, and has three articular planes, the inner being a wide oblique 

 truncation of the edge. The shaft is angulate below, and becomes a 

 little deeper than wide near the distal end. The extremity is lost. The 

 carpal bones are probably all present. The fore foot was found in place 

 so that the relations of the bones are known with certainty. The 

 scaphoid and lunar appear to be distinct. The former exhibits proximal- 

 ly the inner tuberosity, then a slight concavity, and then the convexity, 

 where it is obliquely truncated so as to give a general rhomboid outline. 

 Beneath there are but two facets, the inner the deepest, and divided 

 lengthwise by the truncation of the bone. The larger facet fits correctly 

 the 0.0. trapezium and trapezoides. The lunar was not found in its 

 place, but two fragments taken from the matrix just behind it, adhering 

 to the pisiforme, probably belong to it. The upper face is convex. 

 The cuneiform is large and concave lengthwise above for the narrow 

 extremity of the ulna. Below it has a large concave facet for the 

 unciform. The pisiforme is of unusual size, and is as stout as the largest 



