298 THE OSTEOLOGY OF ELOTHERITJM. 



The scapula is remarkably high, narrow and slender, at least in the White River 

 species, while in the John Day forms there is reason to believe that its proportions are 

 quite different. The glenoid cavity forms a narrow, elongate oval, with its long axis 

 directed antero-posteriorly, and is not very deeply concave. The coracoid is a large, but 

 not very conspicuous rugosity, which sends off from its inner side a compressed, hook-like 

 process ; when the shoulder-blade is seen from the external side, this process is concealed 

 from view. The neck of the scapvda is broad and rather thick, and there is no distinct 

 coraco-scajralar notch. The coracoid border in its upward course inclines forward but 

 little, and for the upper one-third of its height curves gently backward, to join the 

 suprascapular border, which is exceedingly short. The glenoid border is more oblique, 

 and inclines backward and upward at a moderate angle. The spine is shifted far forward, 

 dividing the blade very unequally, so that the prescapular fossa is very much smaller 

 than the postscapular. Indeed, the distal one-third of the shoulder-blade can hardly be 

 said to have any prescapular fossa at all. The spine itself is rather low, and for much of 

 its course its free border is curved backward and thickened to form a massive meta- 

 cromion. The acromion is very short and inconspicuous, ending considerably above the 

 level of the glenoid cavity. 



The scapula associated with the large species of Ehtherium from the John Day 

 beds, which Cope has described under the name of Boochcerus ('79, j). 59), is very 

 different in shape from that of K. ingens from the White River, to which the description 

 in the preceding paragraph more particularly applies. The blade is very much broader, 

 both fossa' widening rapidly toward the dorsal end : these fossae are of nearly equal width 

 and the spine is placed almost in the middle of the blade. There can be little doubt that 

 this scapula is properly referred to the incomplete skeleton with which it was found 

 associated. Aside from its similarity in color and texture to the rest of the skeleton, 

 there is no other animal known from the John Day horizon to which so large a scapula 

 could belong. 



The shoulder-blade of Hippopotamus is much broader, in proportion to its height, 

 than that of E. ingens; the coracoid is more prominent and the coraco-scapular notch is 

 distinctly marked : the postscapular fossa is somewhat larger than the prescapular, but 

 the difference is much less extreme than in the White River species, the spine occupying 

 a more median position ; the acromion is much the same in the two forms, but the meta- 

 cromion is larger in the fossil. In Sus also the scapula is relatively broader than in 

 E. ingens, ami, in particular, it has a wider prescapular fossa, but is without any distinct 

 coraco-scapular notch. The spine rises from the suprascapular border very steeply to 

 the high (but much smaller) metaeromion, and then descends gradually to the neck, 

 without forming an acromion. In spite of these differences, the resemblance in the 

 character of the scapula between Stis and Ehtherium is unmistakable. 



