42 



Annals of the Carnegie Museum. 



The sacrum is not represented. The caudals appear to be short 

 and heavy and in other respects like those of the Oligocene forms. 



The ribs are represented only by a few fragments and there are no 

 sternebrae. 



Fore Limb. 



The greater portion of the scapula is represented with No. 2859. 

 The upper and lower ends were found separately imbedded in the 

 sandstone ledge, but in working out the two portions it is seen that 

 they pertain to the same side of two individuals. The bone as a 

 whole, so far as comparison may be made, presents characters not 

 unlike those in the Princeton specimen referred to Diplacodon. How- 

 ever, in the specimen under description 

 (possibly a female) the coracoid is seen to 

 be relatively smaller than in the latter. 

 The groove between the base of the cora- 

 coid and the border of the glenoid cavity 

 is larger in proportion than in Titanothe- 

 rium, and the excavation on the coracoid 

 border, immediately above the coracoid, 

 has a less abrupt curvature. This is due 

 to the smaller development of this angle in 

 Diploceras. The coracoid border is other- 

 wise quite straight, as in Titanotherium. 

 The superior portion of the glenoid border 

 is broken off, but in the region of the break 

 there is a similar broad extent of the supe- 

 rior portion of the blade. The spine is 

 damaged, but it was apparently overhang- 

 ing like that in Diplacodon described by 

 Osborn, and thus less extended over the postscapular fossa than in 

 Titanotherium. 



In comparing the humerus of the present form with that of Titano- 

 therium validum, the difference most noticeable is the relative robust- 

 ness and the length. In the Oligocene form the bone is short and 

 very heavy, while in the present genus the bone is longer in propor- 

 tion and also lighter. Superiorly the greater tuberosity extends 

 higher above the head than in Titanotherium, but is not so robust, 

 the proximal end as a whole being more delicately proportioned. The 



Fig. 7. Scapula of Diplo- 

 ceras osborni Peterson. (Type. 

 No. 2859.) X i 



