-> 



36 SCOTT. [Vol. XI. 



which extends across the whole anterior face of the bone, is 

 elevated much above the level of the head, and rises toward the 

 inner side, where it forms a blunt, recurved hook, overhanging 

 the bicipital groove. The internal tuberosity is small and 

 laterally compressed, while the bicipital groove is deep and 

 rather narrow. The tuberosities are much more conspicuous 

 than in Moschus and (apparently) than in Gelociis. The deltoid 

 ridge is but little better developed than in the former genus. 

 The shaft is short and heavy ; its promixal portion is laterally 

 compressed, but very thick antero-posteriorly ; the middle part 

 is thicker and more rounded in section, and the distal portion is 

 but moderately widened and has a short but quite prominent 

 and rugose supinator ridge. The anconeal fossa is small and 

 of triangular shape ; it is considerably lower and broader than 

 in Gelociis. The supratrochlear fossa is quite deep, but there 

 is no perforation of the bone at this point. 



The trochlea is placed obliquely to the long axis of the shaft, 

 descending somewhat toward the outer side. The intercondy- 

 lar ridge is a rounded tuberosity, which is much broader and 

 more median in position than in Gelocns, though less so than 

 in OreodoUy to the humeral trochlea of which that of Protocet'as 

 bears but little resemblance. The internal epicondyle is much 

 less prominent than in the latter genus, though decidedly more 

 so than in Gelocns or the recent ruminants. 



The Ulna and Radius (PL XXI, Figs, ii and 12) are in old 

 individuals coossified at the distal end, but separate for most 

 of their length. The two bones are, however, closely applied 

 together throughout and the radio-cubital arcade is both short 

 and narrow. The ulna is less reduced than in the necent 

 Pecora and the olecranon is higher, straighter, and projects 

 less backward ; its free end is thickened and rounded, almost 

 club-shaped, instead of being squarely truncate, and the sulcus 

 along the summit is shallow and obscurely marked. The 

 sigmoid notch has a salient beak and shows a fully differenti- 

 ated humeral articulation ; on the proximal side of the notch 

 the humeral facet extends across the whole width, but distally 

 the facet abruptly contracts and is confined to a narrow strip 

 along the internal border. The shaft of the ulna is much 



