El'OREODON 



91 



first caudal. The transverse processes are separate, broad, and plate-like. The total length of the 

 ankylosed sacral and first caudal vertebra; is 1 13 mm. 



The number of caudal vertebra; in Eporeodon (Figs. 54 and 55) is twenty-one, but there 

 should be at least two more if the tail tapered as in the pig. Those in the anterior part of the series 

 are short and broad, possessing complete neural arches, well-defined metapophyses, and anterior and 

 posterior zygapophyses. The first ten have well-developed single transverse processes and a neural 

 arch, and the latter gradually diminish in size until the twelfth vertebra has no arch. The trans- 



Fig. 56. — Eforeodo?i socialis 

 Marsh. Scapula. CT. Cat. No. 

 13118 Y.P.M. 1/2 nat. size. 

 (After Thorpe, 1931.) 



Fig. 5 7. — Eforeodon socialis 

 Marsh. Humerus. CT. Cat. No. 

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

 (After Thorpe, 1931.) 



Fig. 58. — Eforeodon socialis 

 Marsh. Head of humerus. CT. 

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

 size. (After Thorpe, 1931.) 



verse processes of the first two caudals bend slightly backward; the third and fourth bend forward; 

 and the remainder, up to and including the tenth, again bend backward. Beyond the tenth the trans- 

 verse process is very much reduced and is limited to the posterior extremity of the centrum, while an 

 anterior one appears on that extremity. Including and beyond the twelfth, a pair of processes at each 

 end of the centrum represents the neural arch. Beginning at the anterior end the centra are short, 

 gradually increasing in length to the thirteenth and again diminishing in length to the tip. The 

 posterior vertebra; are cylindrical in shape. It is possible, although there is no evidence upon which 

 to base conclusions, that Eforeodon had chevrons, since its possible European Eocene ally, Anoplo- 

 therium, appears to have had these bones beneath the vertebra; of its long tail. 



The scapula (Fig. 56) is represented by the distal fourth of three scapula;, the best preserved 

 of which belongs to Cat. No. 13118 and is used for description. This specimen includes the cora- 

 coid, glenoid cavity, acromion, metacromion, and part of the spine. The spine divides the external 

 surface into two subequal fossx. The acromion projects over the neck and is directed toward the 

 coracoid process. It is transversely distended near the end and terminates in a point. The meta- 

 cromion is small but distinct, its tip being 22 mm. above the acromion and at the same time being 

 more extended along the crest of the spine. The neck is very narrow transversely. The coracoid 

 is well developed. The axillary border is thick, with its surface roughened for the attachment of 

 the triceps muscle. The crest of the spine curls over posteriorly at right angles to the main body, 

 while the vertical part of the spine is extremely thin, except at its distal termination. The scapula of 

 Eporeodon corresponds closely to that of Agriochcerus, except that the greatest diameter of the 



