No. i.] OSTEOLOGY OF PCEBROTHERIUM. 63 



the groove for the intercondylar ridge of the humerus is very- 

 shallow, and to the inner side of the median line there is an ele- 

 vation of the anterior margin, which is more prominent than 

 in Leptotragulus. The distal end is but moderately expanded, 

 and the three carpal facets are of nearly the same transverse 

 breadth. The olecranon is very high and in the line of the 

 shaft, projecting backwards but slightly, and has a deep tendinal 

 sulcus on its extremity. The shaft of the ulna is decidedly less 

 reduced than in the modern species. 



The proximal row of carpals is of considerably greater height 

 than the distal : in width the three bones of this row are nearly 

 equal. The radial facet of the scaphoid is considerably broader 

 in front than behind and is not emarginated on the internal side. 

 The proximal articular surface of the lunar is nearly quadrate in 

 outline ; distally there is a long median beak formed by the 

 junction of the facets for the magnum and unciform, which meet 

 at an acute angle ; the former is the longer and so obliquely 

 placed as to be rather lateral than distal. The cuneiform has 

 considerable antero-posterior depth, but is relatively narrow. 

 The pisiform is short and very much compressed, with a very 

 contracted neck, and expanded, rugose, and incurved free end ; 

 its articulation with the ulno-radius is much less extensive than in 

 the recent genera. The trapezium is present and forms a small 

 nodule, which is applied to the scaphoid and the rudimentary 

 second metacarpal. The trapezoid is free ; it is a very small 

 bone, little larger than the trapezium ; distally it is divided into 

 two facets of unequal size — a small one for mc. II, and a some- 

 what larger for mc. III. The magnum is broad and very low ; it 

 is broadest in front, and narrows almost to a point behind ; its 

 proximal surface is chiefly occupied by the scaphoid, the lunar 

 facet being much narrower and more obliquely placed ; distally it 

 is in contact only with mc. Ill, the extension of which upon the 

 trapezoid excludes mc. II from the magnum. The unciform is a 

 large bone, chiefly remarkable for its vertical height, which is 

 nearly double that of the magnum, thus extending much below 

 the level of that bone ; the lunar facet is relatively larger than in 

 the recent species. The unciform is connected with three meta- 

 carpals ; the whole distal surface proper is occupied by mc. IV, 

 but on the radial border there is a small facet for the projection 

 of mc. II, and on the ulnar border a still smaller one for mc. V. 



