EPOREODON 



95 



the other distinctly concave. The navicular is deeply concave dorsally to receive the astragalus and 

 is not flattened, as it is in the perissodactyles. Its distal surface is flat for articulation with the ecto- 

 cuneiform and mesocuneiform bones. The posterior hook of the navicular overhangs the ectocu- 

 neiform and mesocuneiform bones and is apparently a distinct character of the artiodactyles, while 

 absent in the perissodactyles. 



The fourth and fifth metatarsals articulate with the cuboid, and the facets are fairly broad and 

 flat. The two median metatarsals, as well as the second and fifth, are about equal in length and 

 size. Again the carnivore character appears in the large rounded distal ends of the metatarsals. It 

 would seem from the characters of these bones of the manus and pes that the members of this genus 



Fig. 62. — Eforeodon socialis 

 Marsh. Femur. CT. Cat. No. 

 13119 Y.P.M. 1/2 nat. size. 

 (After Thorpe, 1931.) 



Fig. 63. — Eforeodon socialis 

 Marsh. Tibia and fibula. CT. 

 Cat. No. 13119 Y.P.M. 1/2 nat. 

 size. (After Thorpe, 1931.) 



Fig. 64. — Eforeodon socialis 

 Marsh. Left pes. CT. Cat. No. 

 13119 Y.P.M. 1/3 nat. size. 

 (After Marsh, 1885.) 



were digitigrade, although perhaps unguligrade approaching digitigradism. It is probable that the 

 main flexure of the foot took place at the distal ends of the metatarsals, as in C Italic otherium, an 

 undoubtedly digitigrade type. Distal keels are present on the ventral surface. 



The phalanges apparently formed a gentle curve when seen from the side, as in A griochcerus . 

 The proximal articular facets of the proximal phalanges looked forward and upward, which would 

 indicate that the metatarsals were raised from the ground. The median phalanges are shorter but 

 only slightly narrower than the proximal ones. The ungues are much like those of the manus and 

 seem to be intermediate between those of Agriochaerus and of Merycoidodon. The hallux has been 

 lost through evolution. 



Discussion: The skeletons of the cotypes were very close to each other in the matrix, in fact, 

 the skull of one was only three inches from that of the other and their vertebral columns were 

 parallel. Cat. No. 13118 is slightly smaller and somewhat more slenderly constructed than the 

 other skeleton. Both animals are fully adult, and it is possible that the larger specimen, Cat. No. 

 13119, may have been a male and the other a female. 



