88 DINOCERATA. 



The external surface of the scapula is divided into two unequal fossse. 

 The anterior of these, or pre-scapular fossa, extends the entire length of the 

 bone, bnt is less than half as wide as the post-scapular fossa, from which it 

 is divided by a thick and stout spine. The latter is less elevated than in 

 the elephant and mastodon, and less expanded, but extends farther 

 downward, nearly to the level of the glenoid cavity. It is destitute of the 

 curved posterior })i-ocess seen in the elejdiant and mastodon. 



The ])Ost-scapular fossa is strongly roughened near the jjosterior angle, 

 which is I'ounded. 



The glenoid cavity is only moderately concave transversely, and 

 somewhat broader behind than before. 



The inner surface of the scapula is for the most part smooth, except 

 over a large quadrilateral area in the region of tlie apex. The supra- 

 scajjular border is ossified separately from the bodv of the bone. 



The coracoid is firmly miited to the scapula in Dhinceras mirabile 

 (number 1215), and forms a rounded salient ju'oeess, projecting freely in 

 front of the glenoid cavit}^ Seen from the front, it appears to be tri-lobed 

 in outline. 



The main dimensions of the scapula in one specimen of Binoceras 

 mirabile are as follows : 



Measurements af Left Scajmhi. {Binoceras mirabile. No. 1215.) 



m. 



Aiitero-posterior diameter of glenoid cavity, 115 



Transverse diameter of glenoid cavity, .. .090 



Greatest vertical diameter of scapula, 575 



Greatest horizontal diameter, .480 



Length of coracoid border, _ _ . .570 



Tjength of supra-scapular border, . _ . _ _ ^ .390 



Length of glenoid border, .__. ... ... _.., .350 



Height of acromion above glenoid cavitv, .120 



Greatest diameter of pre-scapular fossa, _ .140. 



Greatest diameter of post-scapular fossa, .310 



