Diameters distally \ anteropost. 

 { transverse 



BATHMODOK 553 



u. 



-erior 0i>8 



040 



Uroximally^'^"*"°P°«*<'"<"" 037 



Diameters of a phalange < < transverse 0'24 



( longitudinally (lateral) 022 



A second individual, apparently, of this species is represented by an 

 entire humerus and radius. The articular extremities of the humerus and 

 radius agree closely with those of the specimen first described, differing only 

 in being a little larger. 



The humerus differs from that of Coryphodon anax much as the calca- 

 neum of the first described specimen does from the corresponding bone of 

 the latter species. It is nearly identical in length, but considerably more 

 robust in every part. In the size of its articulations it equals some of the 

 large species of Uintatherium, but the shaft is relatively longer in the latter. 

 The radius is also remarkable for its very robust form and the large size 

 of its articular extremities. The head resembles that of the specimen first 

 described ii^ wanting the prominent tuberosity of the superior border found 

 in C. anax. There is, however, a convexity in the corresponding position 

 in the B. pachyjms. The inferior surface next to the ulnar band is rough, 

 with longitudinal ridges and grooves, but there is no defined fossa. The 

 long axis of the distal extremity is oblique to that of the head, the external 

 face looking outwards and upwards. The carpal face presents several 

 peculiarities in which it differs much from the corresponding part of a 

 Corypliodon figured on Plate LXIV, fig. 6, of my final Report to Captain 

 Wheeler. The carpal facets only occupy a part of the extremity of the 

 bone, which is much expanded outwards. On this obliquely truncate club- 

 shaped extremity the long axis of the facets extends backwards and out- 

 wards, their margin only coinciding with that of the former at the point of 

 contact with the ulna. The facets for the scaphoid and lunar are distinct, 

 the former being plane, the latter concave. The scaphoid, moreover, has 

 only about one-fifth the area of the lunar, a relation quite different from 

 that which prevails among mammals generally. The extremity has a liga- 

 mentous fossa between the scaphoid facet and the internal border of the 

 dimensions of the lattei'. The ulnar face is not distinct. There is an 

 angular ridge just above the external border of the head, and another on 

 the inner side, defining it from the inferior side just above the head. There 

 are no distinct grooves of the supero-external surface. 



